Positive electrode active material composition, positive electrode sheet, battery and electrical device

Abstract

This application provides a positive electrode active material composition, a positive electrode sheet, a battery, and an electrical device. The positive electrode active material composition includes a first positive electrode active material and a second positive electrode active material with a crystal form different from that of the first positive electrode active material. The first positive electrode active material includes phosphate. The particle size distribution curve of the positive electrode active material composition has at least two volume distribution peaks. The volume distribution peak with the maximum peak intensity is denoted as the first peak, and the volume distribution particle size corresponding to the maximum peak intensity of the first peak is denoted as Dv1. The volume distribution peak with the second maximum peak intensity is denoted as the second peak, and the volume distribution particle size corresponding to the maximum peak intensity of the second peak is denoted as Dv2. Then, 0 < |Dv1-Dv2| / Dv1≤50.

Description

Technical Field

[0001] This application relates to positive electrode active material compositions, positive electrode sheets, batteries, and electrical devices. Background Technology

[0002] In recent years, batteries have been widely used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, as well as in power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace, and many other fields. With the continuous expansion of battery applications, the demand for battery energy density and lifespan is increasing. Summary of the Invention

[0003] This application provides a positive electrode active material composition, a positive electrode sheet, a battery, and an electrical device, which enables the battery to achieve high energy density, low cost, and good service life.

[0004] The first aspect of this application provides a positive electrode active material composition, comprising a first positive electrode active material and a second positive electrode active material with a crystal form different from the first positive electrode active material. The first positive electrode active material comprises phosphate. The particle size distribution curve of the positive electrode active material composition has at least two volume distribution peaks. The volume distribution peak with the maximum peak intensity is denoted as the first peak, and the volume distribution particle size corresponding to the maximum peak intensity of the first peak is denoted as Dv1. The volume distribution peak with the second maximum peak intensity is denoted as the second peak, and the volume distribution particle size corresponding to the maximum peak intensity of the second peak is denoted as Dv2. Then, 0 < |Dv1-Dv2| / Dv1 ≤ 50.

[0005] By including a first positive electrode active material and a second positive electrode active material with different crystal forms in the positive electrode active material composition, and by making the particle size distribution curve of the positive electrode active material composition satisfy 0 < |Dv1-Dv2| / Dv1≤50, the first positive electrode active material and the second positive electrode active material can be tightly packed, thereby increasing the actual packing density of the positive electrode active material composition, increasing the compaction density and compaction efficiency of the positive electrode sheet, and further enabling the battery using the positive electrode active material composition to have higher energy density and longer service life.

[0006] In any embodiment, the volume distribution particle size Dv50 of the first positive electrode active material is from 0.25 μm to 12.5 μm.

[0007] In any embodiment, the volume distribution particle size Dv50 of the second positive electrode active material is from 2.5 μm to 16.5 μm.

[0008] In any embodiment, the volume distribution particle size Dv50 of the first positive electrode active material is from 0.25 μm to 3.5 μm, and the particle size distribution curve of the positive electrode active material composition satisfies:

[0009] 0.1 ≤ |Dv1-Dv2| / Dv1 ≤ 50, optionally, 0.46 ≤ |Dv1-Dv2| / Dv1 ≤ 39.6; and / or,

[0010] 0.3μm≤Dv1≤17.8μm, optionally, 0.35μm≤Dv1≤12.1μm; and / or,

[0011] 0.3μm≤Dv2≤17.8μm, optionally, 0.46μm≤Dv2≤14.2μm.

[0012] This allows the first and second positive electrode active materials to be stacked more tightly, further increasing the actual packing density of the positive electrode active material composition, the compaction density of the positive electrode sheet, and the compaction efficiency, thereby enabling batteries using positive electrode active material compositions to have higher energy density and / or longer service life.

[0013] In any embodiment, the volume distribution particle size Dv50 of the first positive electrode active material is 3.5 μm to 12.5 μm, and the particle size distribution curve of the positive electrode active material composition satisfies:

[0014] 0.1 ≤ |Dv1-Dv2| / Dv1 ≤ 6.0, optionally, 0.34 ≤ |Dv1-Dv2| / Dv1 ≤ 3.8; and / or,

[0015] 2.0μm≤Dv1≤12.5μm, optionally, 3.0μm≤Dv1≤12.3μm; and / or,

[0016] 2.0μm≤Dv2≤15.0μm, optionally, 3.4μm≤Dv2≤14.3μm.

[0017] This allows the first and second positive electrode active materials to be stacked more tightly, further increasing the actual packing density of the positive electrode active material composition, the compaction density of the positive electrode sheet, and the compaction efficiency, thereby enabling batteries using positive electrode active material compositions to have higher energy density and / or longer service life.

[0018] A second aspect of this application provides a positive electrode active material composition, the positive electrode active material composition comprising a first positive electrode active material and a second positive electrode active material with a crystal form different from the first positive electrode active material, the first positive electrode active material comprising a phosphate, and the particle size distribution curve of the positive electrode active material composition having at least two volume distribution peaks, the volume distribution peak with the maximum peak intensity being denoted as the first peak, and the volume distribution particle size corresponding to the maximum peak intensity of the first peak being denoted as Dv1, the volume distribution peak with the second maximum peak intensity being denoted as the second peak. The first positive electrode active material has two peaks, and the volume distribution particle size corresponding to the maximum peak intensity of the second peak is denoted as Dv2. The volume distribution particle size Dv50 of the first positive electrode active material is 0.25μm to 3.5μm, and 0.3μm≤Dv1≤17.8μm, 0.3μm≤Dv2≤17.8μm; or the volume distribution particle size Dv50 of the first positive electrode active material is 3.5μm to 12.5μm, and 2.0μm≤Dv1≤12.5μm, 2.0μm≤Dv2≤15.0μm.

[0019] This allows the first and second positive electrode active materials to be stacked more tightly, further increasing the actual packing density of the positive electrode active material composition, the compaction density of the positive electrode sheet, and the compaction efficiency, thereby enabling batteries using positive electrode active material compositions to have higher energy density and / or longer service life.

[0020] In any embodiment, the volume distribution particle size Dv50 of the first positive electrode active material is from 0.25 μm to 3.5 μm, and 0.35 μm ≤ Dv1 ≤ 12.1 μm, 0.46 μm ≤ Dv2 ≤ 14.2 μm. This allows the battery employing the positive electrode active material composition to further achieve higher energy density and / or longer lifespan.

[0021] In any embodiment, the volume distribution particle size Dv50 of the first positive electrode active material is 3.5 μm to 12.5 μm, and 3.0 μm ≤ Dv1 ≤ 12.3 μm, 3.4 μm ≤ Dv2 ≤ 14.3 μm. This allows the battery employing the positive electrode active material composition to further achieve higher energy density and / or longer lifespan.

[0022] In any embodiment, the morphology of the first positive electrode active material includes one or more of single crystal and polycrystalline, and the morphology of the second positive electrode active material includes one or more of single crystal and polycrystalline.

[0023] In any embodiment, the volume distribution particle size Dv50 of the first positive electrode active material with a single crystal morphology is from 0.25 μm to 3.5 μm, and optionally from 0.35 μm to 2.5 μm.

[0024] In any embodiment, the volume distribution particle size Dv10 of the first positive electrode active material with a single crystal morphology is from 0.05 μm to 1.5 μm, and can be selected from 0.1 μm to 1.0 μm.

[0025] In any embodiment, the volume distribution particle size Dv50 of the polycrystalline first cathode active material is from 3.5 μm to 12.5 μm, and optionally from 3.8 μm to 10.5 μm.

[0026] In any embodiment, the volume distribution particle size Dv10 of the polycrystalline first cathode active material is from 0.1 μm to 5.0 μm, and optionally from 0.5 μm to 4.5 μm.

[0027] In any embodiment, the volume distribution particle size Dv50 of the second positive electrode active material with a single crystal morphology is from 2.5 μm to 16.5 μm, and optionally from 3.0 μm to 8.5 μm.

[0028] In any embodiment, the volume distribution particle size Dv10 of the second positive electrode active material with a single crystal morphology is from 0.3 μm to 8 μm, and can be selected from 1.0 μm to 3.5 μm.

[0029] In any embodiment, the volume distribution particle size Dv50 of the polycrystalline second cathode active material is from 2.5 μm to 16.5 μm, and optionally from 3.0 μm to 15.5 μm.

[0030] In any embodiment, the volume distribution particle size Dv10 of the polycrystalline second cathode active material is from 0.5 μm to 12 μm, and can be selected from 1.0 μm to 8.5 μm.

[0031] When the volume distribution particle size of the first positive electrode active material and / or the second positive electrode active material is within the above range, the battery can have a higher energy density, and can also reduce side reactions, lower interface impedance, and give the battery a longer service life.

[0032] In any embodiment, the weight content of the first positive electrode active material is denoted as w based on the total weight of the positive electrode active material composition. a The weight content of the second positive electrode active material is denoted as w. b Then w a Selected from the range of 0.5% to 99.5%, optionally selected from the range of 2% to 95%; and / or, w b Selected from the range of 0.5% to 99.5%, or optionally from the range of 5% to 98%.

[0033] When the content of the first positive electrode active material and / or the second positive electrode active material is within the above range, the battery can have a higher energy density and / or a longer service life.

[0034] In any embodiment, the powder compaction density P1 of the first positive electrode active material at 30000N is 1.89 g / cm³. 3 The above can be selected as 1.95g / cm. 3 The above can also be selected as 1.98g / cm. 3 The above can be further selected as 2.0 g / cm³. 3 The above can be further optimized to 2.2 g / cm³. 3 The above, and optionally 2.2 g / cm³, are further options. 3 Above and 2.8g / cm 3 Below or 2.2g / cm 3 Above and 2.65g / cm 3 the following.

[0035] In any embodiment, the powder compaction density P2 of the second positive electrode active material at 30000N is greater than or equal to 2.90 g / cm³. 3 The value can be greater than or equal to 3.1 g / cm³. 3 Alternatively, a value greater than or equal to 3.3 g / cm³ can be selected. 3 .

[0036] When the powder compaction density of the first positive electrode active material and / or the second positive electrode active material is within the above range, the battery can have a higher energy density.

[0037] In any embodiment, the BET specific surface area of ​​the second positive electrode active material is less than or equal to 1.73 m². 2 / g, which can be less than or equal to 1.5m 2 / g, or 0.28m 2 / g to 1.5m 2 / g. This can reduce side reactions and improve battery cycle performance.

[0038] In any embodiment, the first positive electrode active material comprises a compound represented by formula (I).

[0039] Li a A x Mn 1-y M 1 y P 1-z M 2 z O 4-n D n (I)

[0040] A includes one or more elements selected from families IA, IIA, IIIA, IIB, VB, and VIB; M 1Includes one or more elements selected from families IA, IIA, IIIA, IVA, VA, IIB, IVB, VB, VIB, and VIII; C includes one or more elements selected from families IIIA, IVA, VA, and VIA; D includes one or more elements selected from families VIA and VIIA; a is selected from the range of 0.85 to 1.15; x is selected from the range of 0 to 0.1; y is selected from the range of 0.001 to 0.999; z is selected from the range of 0 to 0.5; n is selected from the range of 0 to 0.5.

[0041] By doping specific elements at the Mn site of the compound LiMnPO4 and optionally at the Li, P and / or O sites in specific amounts, it is possible to obtain improved rate performance, while reducing the dissolution of Mn and Mn-site dopants, improving cycle performance and / or high-temperature stability, and also increasing the specific capacity and compaction density of the material.

[0042] In any embodiment, A includes one or more elements selected from Rb, Cs, Be, Ca, Sr, Ba, Ga, In, Cd, V, Ta, Cr, Zn, Al, Na, K, Mg, Nb, Mo, and W, and optionally includes one or more elements selected from Zn, Al, Na, K, Mg, Nb, Mo, and W.

[0043] In any embodiment, M 1 Includes one or more elements selected from Rb, Cs, Be, Ca, Sr, Ba, In, Pb, Bi, Cd, Hf, Ta, Cr, Ru, Rh, Pd, Os, Ir, Pt, Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb, and Ge, and optionally includes one or more elements selected from Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb, and Ge.

[0044] In any embodiment, M 2 It includes one or more elements selected from B (boron), S, Si, and N.

[0045] In any embodiment, D includes one or more elements selected from S, F, Cl, and Br.

[0046] In any embodiment, A includes any element selected from Zn, Al, Na, K, Mg, Nb, Mo, and W, and may optionally include any element selected from Mg and Nb.

[0047] In any embodiment, M 1It includes one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb and Ge, and may optionally include at least two elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb and Ge, more preferably including at least two elements selected from Fe, Ti, V, Ni, Co and Mg, further preferably including at least two elements selected from Fe, Ti, V, Co and Mg, and even more preferably including Fe and one or more elements selected from Ti, V, Co and Mg.

[0048] In any embodiment, M 2 It includes any element selected from B (boron), S, Si and N, with S being an option.

[0049] In any embodiment, D includes any element selected from S, F, Cl and Br, and may be F.

[0050] By selecting doping elements at the Li sites within the aforementioned range, the lattice change rate during the lithium removal process can be further reduced, thereby further improving the rate performance of the battery. By selecting doping elements at the Mn sites within the aforementioned range, electronic conductivity can be further increased and the lattice change rate further reduced, thereby improving the rate performance and specific capacity of the battery. By selecting doping elements at the P sites within the aforementioned range, the rate performance of the battery can be further improved. By selecting doping elements at the O sites within the aforementioned range, interfacial side reactions can be further mitigated, improving the high-temperature performance of the battery.

[0051] In any embodiment, a is selected from the range of 0.9 to 1.1, and optionally from the range of 0.97 to 1.01.

[0052] In any embodiment, x is selected from the range of 0.001 to 0.005.

[0053] In any embodiment, y is selected from the range of 0.001 to 0.5, optionally from the range of 0.01 to 0.5, and optionally from the range of 0.25 to 0.5.

[0054] In any embodiment, z is selected from the range of 0.001 to 0.5, optionally from the range of 0.001 to 0.1, and more preferably from the range of 0.001 to 0.005.

[0055] In any embodiment, n is selected from the range of 0 to 0.1, and optionally from the range of 0.001 to 0.005.

[0056] By selecting the y value within the aforementioned range, the specific capacity and rate performance of the first positive electrode active material can be further improved. By selecting the x value within the aforementioned range, the kinetic performance of the first positive electrode active material can be further improved. By selecting the z value within the aforementioned range, the rate performance of the battery can be further improved. By selecting the n value within the aforementioned range, the high-temperature performance of the battery can be further improved.

[0057] In any embodiment, x is 0, z is selected from the range of 0.001 to 0.5, and n is selected from the range of 0.001 to 0.1; or, x is selected from the range of 0.001 to 0.1, z is 0, and n is selected from the range of 0.001 to 0.1; or, x is selected from the range of 0.001 to 0.1, z is selected from the range of 0.001 to 0.5, and n is 0; or, x is 0, z is 0, and n is selected from the range of 0.001 to 0.1; or, x is 0, z is selected from the range of 0.001 to 0.5, and n is 0; or, x is selected from the range of 0.001 to 0.1, z is selected from the range of 0.001 to 0.5, and n is selected from the range of 0.001 to 0.1.

[0058] By doping specific elements at the Mn site of the compound LiMnPO4 and optionally at the Li, P and / or O sites in specific amounts, especially at the Mn and P sites of LiMnPO4 or at the Li, Mn, P and O sites of LiMnPO4 in specific amounts, it is possible to improve rate performance, reduce the dissolution of Mn and Mn site dopants, improve cycle performance and / or high temperature stability, and increase the specific capacity and compaction density of the first positive electrode active material.

[0059] In any embodiment, y:z is selected from the range of 0.002 to 999, and can be selected from the range of 0.025 to 999 or the range of 0.002 to 500, more preferably from the range of 0.2 to 600. This reduces defects in the first positive electrode active material, improves the integrity of the framework structure of the first positive electrode active material, thereby effectively enhancing the structural stability of the first positive electrode active material, and consequently improving the cycle stability of the battery.

[0060] In any embodiment, z:n is selected from the range of 0.002 to 500, optionally from the range of 0.2 to 100, and more preferably from the range of 0.2 to 50. This further reduces defects in the first positive electrode active material, further improves the integrity of the framework structure of the first positive electrode active material, effectively enhances the structural stability of the first positive electrode active material, and improves the cycle stability of the battery.

[0061] In any embodiment, A includes one or more elements selected from Zn, Al, Na, K, Mg, Nb, Mo, and W; M 1Includes one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge; M 2 It includes one or more elements selected from B (boron), S, Si and N; D includes one or more elements selected from S, F, Cl and Br; a is selected from the range of 0.9 to 1.1, x is selected from the range of 0.001 to 0.1, y is selected from the range of 0.001 to 0.5, z is selected from the range of 0.001 to 0.1, and n is selected from the range of 0.001 to 0.1.

[0062] By simultaneously doping specific elements at specific amounts at the Li, Mn, P, and O sites of the compound LiMnPO4, improved rate performance can be obtained, while reducing the dissolution of Mn and Mn-site dopants, resulting in improved cycle performance and / or high-temperature stability. Furthermore, the specific capacity and compaction density of the first positive electrode active material can also be improved.

[0063] In any embodiment, M 1 Includes one or more elements selected from Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb, and Ge, and optionally includes one or more elements selected from Zn, Fe, Ti, V, Ni, Co, and Mg; M 2 It includes one or more elements selected from B (boron), Si, N and S; a is selected from the range of 0.9 to 1.1, x is 0, y is selected from the range of 0.001 to 0.5, z is selected from the range of 0.001 to 0.1, and n is 0.

[0064] By simultaneously doping specific elements at both the Mn and P sites of the compound LiMnPO4 with specific amounts, rate performance can be improved, dissolution of Mn and Mn-site dopants can be reduced, cycle performance and / or high-temperature stability can be improved, and the specific capacity and compaction density of the first positive electrode active material can be increased.

[0065] In any embodiment, (1-y):y is in the range of 0.1-999, preferably in the range of 0.1-10 or 0.67-999, more preferably in the range of 1 to 10, further preferably in the range of 1 to 4, and even more preferably in the range of 1.5 to 3. When the above conditions are met, the energy density and cycle performance of the first positive electrode active material can be further improved.

[0066] In any embodiment, a:x is in the range of 1 to 1200, preferably in the range of 9 to 1100, and more preferably in the range of 190 to 998. When the above conditions are met, the energy density and cycle performance of the first positive electrode active material can be further improved.

[0067] In any embodiment, z:(1-z) is 1:9 to 1:999, and can be selected as 1:499 to 1:249. When the above conditions are met, the energy density and cycle performance of the first positive electrode active material can be further improved.

[0068] In any embodiment, the first positive electrode active material includes a core and a shell covering the core, the core including the compound represented by formula (I); the shell including one or more coating layers; each coating layer having ionic conductivity and / or electronic conductivity.

[0069] By providing a coating layer with ionic and / or electronic conductivity on the core surface, a first positive electrode active material with a core-shell structure is provided. Applying the first positive electrode active material to a battery can improve the battery's high-temperature cycle performance, cycle stability, and high-temperature storage performance.

[0070] In any embodiment, each of the one or more coating layers independently comprises one or more selected from pyrophosphates, phosphates, carbon, doped carbon, oxides, borides, and polymers.

[0071] In any embodiment, the shell includes a coating layer; optionally, the coating layer includes one or more selected from pyrophosphates, phosphates, carbon, doped carbon, oxides, borides, and polymers.

[0072] Using the above materials, a coating layer with ionic conductivity and / or electronic conductivity can be obtained, thereby improving the high-temperature cycle performance, cycle stability and high-temperature storage performance of the battery.

[0073] In any embodiment, the shell includes a first coating layer covering the core and a second coating layer covering the first coating layer; optionally, the first coating layer and the second coating layer each independently comprise one or more selected from pyrophosphate, phosphate, carbon, doped carbon, oxide, boride, and polymer; more preferably, the first coating layer comprises one or more selected from pyrophosphate, phosphate, oxide, and boride, and the second coating layer comprises one or more selected from carbon and doped carbon. Using a first coating layer and a second coating layer made of specific materials can further improve rate performance and further reduce the dissolution of Mn and Mn-site dopants, thereby improving the battery's cycle performance and / or high-temperature stability.

[0074] In any embodiment, the shell includes a first coating layer covering the core, a second coating layer covering the first coating layer, and a third coating layer covering the second coating layer. Optionally, the first, second, and third coating layers each independently comprise one or more selected from pyrophosphate, phosphate, carbon, doped carbon, oxide, boride, and polymer. More preferably, the first coating layer comprises pyrophosphate, the second coating layer comprises one or more selected from phosphate, oxide, and boride, and the third coating layer comprises one or more selected from carbon and doped carbon. Using a first coating layer, a second coating layer, and a third coating layer made of specific materials further improves rate performance, further reduces the dissolution of Mn and Mn-site dopants, thereby improving the battery's cycle performance and / or high-temperature stability, and further increases the specific capacity and compaction density of the first positive electrode active material.

[0075] In any embodiment, the pyrophosphate is M b (P2O7) c ; and / or, the phosphate is X m (PO4) q ; and / or, the doping element in the doped carbon includes one or more selected from Group IIIA, Group VA, Group VIA, and Group VIIA; and / or, the oxide is M′ d O e ; and / or, the boride is Z v B w ; and / or, the polymer comprises one or more selected from polysaccharides and their derivatives, polysiloxanes; M, X and Z each independently comprise one or more elements selected from Group IA, Group IIA, Group IIIA, Group IB, Group IIB, Group IVB, Group VB, Group VIIB and Group VIII; b is selected from the range of 1 to 4; c is selected from the range of 1 to 6; m is selected from the range of 1 to 2; q is selected from the range of 1 to 4; M′ comprises one or more elements selected from alkali metals, alkaline earth metals, transition metals, Group IIIA elements, Group IVA elements, lanthanides and Sb; d is greater than 0 and less than or equal to 2; e is greater than 0 and less than or equal to 5; v is selected from the range of 1 to 7; w is selected from the range of 1 to 2.

[0076] By using the above-mentioned materials as a coating layer, the dissolution of Mn and Mn site dopants can be further reduced, the specific capacity and compaction density of the first positive electrode active material can be further improved, and the rate performance, high-temperature cycle performance and high-temperature storage performance of the battery can be further improved.

[0077] In any embodiment, M, X and Z each independently include one or more elements selected from Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb, Mn and Al.

[0078] In any embodiment, the doping element in the doped carbon includes one or more selected from nitrogen, phosphorus, sulfur, boron and fluorine.

[0079] In any embodiment, M′ includes one or more elements selected from Li, Be, B, Na, Mg, Al, Si, P, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, W, La, and Ce, and may optionally include one or more elements selected from Mg, Al, Si, Zn, Zr, and Sn.

[0080] In any embodiment, the polysiloxane is selected from one or more of linear polysiloxanes and cyclic polysiloxanes.

[0081] In any embodiment, the polysaccharide is selected from one or more plant polysaccharides and marine polysaccharides.

[0082] By using the aforementioned specific materials as a coating layer, the dissolution of Mn and Mn-site dopants can be further reduced, thereby further improving the high-temperature cycle performance and high-temperature storage performance of the battery.

[0083] In any embodiment, the first positive electrode active material includes a core and a shell covering the core, wherein the core includes Li a Mn 1-y M 1 y P 1-z M 2 z O4, a is selected from the range of 0.9 to 1.1, y is selected from the range of 0.001 to 0.5, z is selected from the range of 0.001 to 0.1, M 1 Includes one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge, M 2 The shell comprises one or more elements selected from B (boron), S, Si, and N; the shell comprises a first coating layer covering the core and a second coating layer covering the first coating layer, the first coating layer comprising pyrophosphate MP2O7 and phosphate XPO4, M and X each independently comprising one or more elements selected from Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb, and Al; the second coating layer comprises carbon.

[0084] In any embodiment, the first positive electrode active material includes a core and a shell covering the core, wherein the core includes Li a Mn 1-y M 1 y P 1-z M 2 z O4, a is selected from the range of 0.9 to 1.1, y is selected from the range of 0.001 to 0.5, z is selected from the range of 0.001 to 0.1, M 1 Includes one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge, M 2 The shell includes one or more elements selected from B (boron), S, Si, and N; the shell includes a first coating layer covering the core, a second coating layer covering the first coating layer, and a third coating layer covering the second coating layer, wherein the first coating layer includes Li pyrophosphate. f QP2O7 and / or Q g (P2O7) h , 0≤f≤2, 1≤g≤4, 1≤h≤6, the pyrophosphate Li f QP2O7 and / or Q g (P2O7) h Each of the elements Q in the first layer independently includes one or more elements selected from Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb, and Al; the second coating layer includes crystalline phosphate XPO4, where X includes one or more elements selected from Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb, and Al; and the third coating layer contains carbon.

[0085] By performing specific element doping and surface coating on lithium manganese phosphate, the dissolution of Mn during the lithium insertion / extraction process can be effectively reduced, while promoting the migration of lithium ions, thereby improving the rate performance, cycle performance and high-temperature performance of the battery.

[0086] In any embodiment, one or more coating layers in the shell that are furthest from the core independently comprise one or more selected from polysiloxanes, polysaccharides, and polysaccharide derivatives. This improves the uniformity of the coating, effectively blocks interfacial side reactions caused by high voltage, thereby enhancing the high-temperature cycling performance and high-temperature storage performance of the first positive electrode active material; furthermore, the coating layers have good ionic conductivity, which helps to increase the specific capacity of the first positive electrode active material while reducing heat generation in the battery.

[0087] In any embodiment, the polysiloxane comprises the structural unit shown in formula (i).

[0088]

[0089] R1 and R2 are independently selected from H, -COOH, -OH, -SH, -CN, -SCN, amino, phosphate ester, carboxylic ester, amide, aldehyde, sulfonyl, polyether segment, C1-C20 aliphatic hydrocarbon, C1-C20 halogenated aliphatic hydrocarbon, C1-C20 heteroaliphatic hydrocarbon, C1-C20 halogenated heteroaliphatic hydrocarbon, C6-C20 aromatic hydrocarbon, C6-C20 halogenated aromatic hydrocarbon, C2-C20 heteroaromatic hydrocarbon and C2-C20 halogenated heteroaromatic hydrocarbon; optionally, R1 and R2 are independently selected from H, amino, phosphate ester, polyether segment, C1-C8 alkyl, C1-C8 halogenated alkyl, C1-C8 heteroalkyl, C1-C8 halogenated heteroalkyl, C2-C8 alkenyl and C2-C8 halogenated alkenyl.

[0090] In any embodiment, the polysiloxane further comprises a capping group, the capping group comprising one or more of the following functional groups: polyether, C1-C8 alkyl, C1-C8 haloalkyl, C1-C8 heteroalkyl, C1-C8 haloheteroalkyl, C2-C8 alkenyl, C2-C8 haloalkenyl, C6-C20 aromatic hydrocarbon, C1-C8 alkoxy, C2-C8 epoxy, hydroxyl, C1-C8 hydroxyalkyl, amino, C1-C8 aminoalkyl, carboxyl, C1-C8 carboxylalkyl.

[0091] In any embodiment, the polysiloxane includes those selected from polydimethylsiloxane, polydiethylsiloxane, polymethylethylsiloxane, polymethylvinylsiloxane, polyphenylmethylsiloxane, polymethylhydrosiloxane, carboxyl-functionalized polysiloxane, epoxy-terminated polysiloxane, methoxy-terminated polydimethylsiloxane, hydroxypropyl-terminated polydimethylsiloxane, polymethylchloropropylsiloxane, hydroxyl-terminated polydimethylsiloxane, polymethyltrifluoropropylsiloxane, perfluorooctylmethylpolysiloxane, aminoethylaminopropylpolydimethylsiloxane, terminal polyether polydimethylsiloxane, and side-chain aminopropylpolysiloxane. One or more of the following: aminopropyl-terminated polydimethylsiloxane, side-chain phosphate-grafted polydimethylsiloxane, side-chain polyether-grafted polydimethylsiloxane, 1,3,5,7-octamethylcyclotetrasiloxane, 1,3,5,7-tetrahydro-1,3,5,7-tetramethylcyclotetrasiloxane, cyclopentapolydimethylsiloxane, 2,4,6,8-tetramethylcyclotetrasiloxane, 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane, cyclic polymethylvinylsiloxane, hexadecylcyclooctasiloxane, tetradecylcycloheptasiloxane, and cyclic polydimethylsiloxane.

[0092] In any embodiment, the number average molecular weight of the polysiloxane, the polysaccharide, and the polysaccharide derivative is independently below 300,000, optionally from 10,000 to 200,000, more preferably from 20,000 to 120,000, and even more preferably from 400 to 80,000.

[0093] In any embodiment, the mass percentage of polar functional groups in the polysiloxane is α, where 0 ≤ α < 50%, and optionally, 5% ≤ α ≤ 30%.

[0094] In any embodiment, the substituents attached to the sugar units in the polysaccharide and the polysaccharide derivative each independently include one or more of the following functional groups: -OH, -COOH and their salts, -R-OH, -SO3H and their salts, -R-OH, -R-SO3H and their salts, sulfate ester group, alkoxy group, where R represents an alkylene group, optionally representing a C1 to C5 alkylene group; optionally, the substituents attached to the sugar units in the polysaccharide and the polysaccharide derivative each independently include one or more of the following functional groups: -OH, -COOH, -COOLi, -COONa, -COOK, -SO3H, -SO3Li, -SO3Na, -SO3K, -CH2-SO3H, -CH2-SO3Li, -CH2-SO3Na, -CH2-SO3K, methoxy group, ethoxy group.

[0095] In any embodiment, the polysaccharide comprises one or more selected from pectin, carboxymethyl starch, hydroxypropyl starch, dextrin, cellulose ether, carboxymethyl chitosan, hydroxyethyl cellulose, carboxymethyl cellulose, carboxypropyl methyl cellulose, guar gum, guar gum, gum arabic, lithium alginate, sodium alginate, potassium alginate, fucoidan, agar, carrageenan, carrageenan, xanthan gum, and fenugreek gum.

[0096] In any embodiment, the mass percentage of substituents attached to the sugar units in the polysaccharide and the polysaccharide derivative is independently 20% to 85%, and optionally 30% to 78%.

[0097] In any embodiment, the lattice mismatch between the core material and the shell material is less than 10%. This ensures good contact between the core and the shell (or covering layer), preventing the shell (or covering layer) from detaching.

[0098] In any embodiment, based on the total weight of the first positive electrode active material, the manganese content is in the range of 10 wt%-35 wt%, preferably in the range of 13.3 wt%-33.2 wt%, more preferably in the range of 15 wt%-30 wt%, and even more preferably in the range of 17 wt%-20 wt%; and / or, the phosphorus content is in the range of 12 wt%-25 wt%, preferably in the range of 15 wt%-20 wt%, and more preferably in the range of 16.8 wt%-19.5 wt%; and / or, the weight ratio of manganese to phosphorus is in the range of 0.71-1.85, preferably in the range of 0.90-1.25, and more preferably in the range of 0.95-1.20.

[0099] Limiting the manganese content within the aforementioned range can further improve the stability and density of the first positive electrode active material, thereby enhancing the battery's cycle, storage, and compaction performance; and it can also maintain a high voltage platform, thereby increasing the battery's energy density.

[0100] Limiting the phosphorus content within the aforementioned range can effectively reduce the impact of small polaron conductivity on the conductivity of the first positive electrode active material, further improve the stability of the crystal structure, and thus enhance the overall stability of the first positive electrode active material.

[0101] Limiting the weight ratio of manganese and phosphorus within the above range can further reduce manganese leaching, improve the stability and specific capacity of the first positive electrode active material, and improve the cycle performance and storage performance of the battery; it can also reduce impurities, allowing the first positive electrode active material to maintain a high discharge voltage platform, thus enabling the battery to have high energy density.

[0102] In any embodiment, the surface of the first positive electrode active material is coated with one or more of carbon and carbon doping; optionally, the surface of the first positive electrode active material is coated with carbon. This improves the conductivity of the first positive electrode active material.

[0103] In any embodiment, the doping element in the doped carbon includes one or more selected from nitrogen, phosphorus, sulfur, boron and fluorine.

[0104] In any embodiment, the shell covers an area of ​​0.1% to 6% by weight, based on the weight of the core.

[0105] In any embodiment, the coating amount of the first coating layer is greater than 0 and less than or equal to 7% by weight, optionally greater than 0 and less than or equal to 6% by weight, more preferably greater than 0 and less than or equal to 5.5% by weight or 4-5.6% by weight, further optionally greater than 0 and less than or equal to 2% by weight, based on the weight of the core; and / or, the coating amount of the second coating layer is greater than 0 and less than or equal to 6% by weight, optionally greater than 0 and less than or equal to 5.5% by weight, more preferably 2-4% by weight or 3-5% by weight, based on the weight of the core; and / or, the coating amount of the third coating layer is greater than 0 and less than or equal to 6% by weight, optionally greater than 0 and less than or equal to 5.5% by weight, more preferably greater than 0 and less than or equal to 2% by weight, based on the weight of the core.

[0106] In any embodiment, the shell further includes a fourth covering layer covering the third covering layer and a fifth covering layer covering the fourth covering layer; the covering amount of the fourth covering layer and the fifth covering layer is independently 0.01% to 10% by weight, optionally 0.05% to 10% by weight, more preferably 0.1% to 5% by weight, and further preferably 0.1% to 2% by weight, based on the weight of the core.

[0107] The coating amount of each coating layer is preferably within the above range, thereby enabling sufficient coating of the core and further improving the dynamic performance of the battery without sacrificing the specific capacity of the first positive electrode active material.

[0108] In any embodiment, the shell covers 40% to 90% of the surface of the core, optionally 60% to 80%. This allows for sufficient encapsulation of the core, thereby improving the battery's kinetic performance.

[0109] In any embodiment, the thickness of the shell is 1-15 nm.

[0110] In any embodiment, the thickness of the first coating layer is 1-10 nm, optionally 2-10 nm; and / or, the thickness of the second coating layer is 2-25 nm, optionally 2-15 nm, more preferably 3-15 nm; and / or, the thickness of the third coating layer is 2-25 nm, optionally 5-25 nm.

[0111] In any embodiment, each of the one or more coating layers independently comprises one or more selected from pyrophosphate, phosphate, and oxide, and the one or more selected from the pyrophosphate, phosphate, and oxide are crystalline; optionally, the crystallinity of the pyrophosphate, the phosphate, and the oxide is independently 10% to 100%, more preferably 50% to 100%.

[0112] Pyrophosphate and phosphate with a certain degree of crystallinity not only help to fully utilize the pyrophosphate coating to reduce manganese leaching and the phosphate coating to effectively conduct lithium ions and reduce interfacial side reactions, but also enable the pyrophosphate coating and phosphate coating to better match their crystal lattices, thereby achieving a tight bond between the coatings.

[0113] In any embodiment, the weight ratio of pyrophosphate to phosphate and the weight ratio of pyrophosphate to oxide in the casing are each independently from 1:3 to 3:1, optionally from 1:3 to 1:1. Thus, by maintaining a suitable weight ratio of pyrophosphate to phosphate or a suitable weight ratio of pyrophosphate to oxide, manganese leaching can be effectively reduced, as can the surface lithium content and interfacial side reactions, thereby improving the battery's high-temperature storage performance and high-temperature cycling performance.

[0114] In any embodiment, each of the one or more coating layers independently comprises carbon, and the carbon is a mixture of SP2 and SP3 carbon. Optionally, the molar ratio of SP2 to SP3 carbon in the carbon is any value within the range of 0.07-13, more preferably any value within the range of 0.1-10, and even more preferably any value within the range of 2.0-3.0. By selecting the form of carbon in the carbon coating layer, the overall electrical performance of the battery can be improved.

[0115] In any embodiment, each of the one or more coating layers independently comprises doped carbon, and the mass content of the dopant element in the doped carbon is less than 30%; optionally, the mass content of the dopant element in the doped carbon is less than 20%. Dopant elements within the above-mentioned content range can sufficiently improve the conductivity of the pure carbon layer while effectively avoiding excessive surface activity due to excessive doping, thereby effectively controlling interfacial side reactions caused by excessive doping of the coating layer.

[0116] In any embodiment, each of the one or more coating layers independently comprises doped carbon, wherein the doping element is nitrogen and / or sulfur, and the mass content of the doping element in the doped carbon is 1% to 15%; or, the doping element is phosphorus, boron and / or fluorine, and the mass content of the doping element in the doped carbon is 0.5% to 5%; optionally, the doping element is nitrogen, phosphorus, sulfur, boron or fluorine.

[0117] Since nitrogen and sulfur atoms have a similar atomic radius to carbon atoms and are less likely to damage the carbon skeleton, when the doping amount of nitrogen and sulfur atoms is within the relatively wide range mentioned above, it can fully utilize the conductivity of the doped carbon layer and promote lithium-ion transport and lithium-ion desolvation capabilities.

[0118] Since phosphorus, boron and / or fluorine atoms have different atomic radii from carbon atoms, excessive doping can easily damage the carbon framework. Therefore, when the doping amount of phosphorus, boron and / or fluorine atoms is within the relatively small range mentioned above, it can fully utilize the conductivity of the doped carbon layer and promote lithium-ion transport and lithium-ion desolvation capabilities.

[0119] In any embodiment, each of the one or more coating layers independently comprises pyrophosphate, wherein the interplanar spacing of the pyrophosphate is in the range of 0.293-0.470 nm, optionally 0.297-0.462 nm or 0.293-0.326 nm, more preferably 0.300-0.310 nm, and the included angle of the crystal orientation (111) is in the range of 18.00°-32.57°, optionally 18.00°-32.00° or 26.41°-32.57°, more preferably 19.211°-30.846°, and further preferably 29.00°-30.00°.

[0120] In any embodiment, each of the one or more coating layers independently comprises a phosphate, wherein the interplanar spacing of the phosphate is in the range of 0.244-0.425 nm, optionally 0.345-0.358 nm, and the included angle of the crystal orientation (111) is in the range of 20.00°-37.00°, optionally 24.25°-26.45°.

[0121] This effectively reduces impurity phases in the coating layer, thereby improving the material's specific capacity, cycle performance, and rate performance.

[0122] In any embodiment, the first or second coating layer comprises phosphate.

[0123] In any embodiment, the lattice change rate of the first positive electrode active material before and after complete lithium insertion / extraction is less than 50%, preferably less than 9.8%, more preferably less than 8.1%, further preferably less than 7.5%, even more preferably less than 6%, even more preferably less than 4%, even more preferably less than 3.8%, and even more preferably 2.0-3.8%. By reducing the lattice change rate, Li ion transport becomes easier, that is, the migration ability of Li ions in the first positive electrode active material is stronger, which is beneficial to improving the rate performance of the battery.

[0124] In any embodiment, the Li / Mn anti-site defect concentration of the first positive electrode active material is 5.3% or less, optionally 5.1% or less, more preferably 4% or less, further preferably 2.2% or less, even more preferably 2% or less, and even more preferably 1.5%-2.2% or 0.5% or less. Reducing the Li / Mn anti-site defect concentration is beneficial for improving the specific capacity and rate performance of the first positive electrode active material.

[0125] In any embodiment, the surface oxygen valence state of the first positive electrode active material is below -1.55, preferably below -1.82, more preferably below -1.88, further preferably below -1.90, or between -1.98 and -1.88, even more preferably between -1.98 and -1.89, and even more preferably between -1.98 and -1.90. By reducing the surface oxygen valence state, interfacial side reactions between the first positive electrode active material and the electrolyte can be reduced, thereby improving the cycle performance and high-temperature stability of the battery.

[0126] In any embodiment, the positive electrode active material composition satisfies 0.0004 ≤ w a ×y×(3.4-V B 0.0015≤w ≤ 0.063, optionally, 0.0015≤w a ×y×(3.4-V B )≤0.045, w a The weight content of the first positive electrode active material is expressed as y, based on the total weight of the positive electrode active material composition, and y is the amount of M in 1 molar of the compound represented by formula (I). 1 molar quantity of an element, V B M in the compound shown in formula (I) 1 The voltage plateau of an element is measured in volts (V). When the positive electrode active material composition further meets the above conditions, it is beneficial for the positive electrode sheet to achieve both high solid density and high solid density efficiency, and for the battery to achieve both high energy density and long service life.

[0127] In any embodiment, the second positive electrode active material comprises a layered oxide. By reasonably combining the first positive electrode active material and the second positive electrode active material, the actual packing density of the positive electrode active material composition, the compaction density and compaction efficiency of the positive electrode sheet can be improved, thereby enabling the battery using the positive electrode active material composition to have higher energy density and longer service life.

[0128] In any embodiment, the second positive electrode active material comprises a compound represented by formula (II).

[0129] Li a1 A 1 b1 Ni c1 Co d1 B 1 e1 C 1 f1 O 2-g1 D 1 g1 (II)

[0130] A1 Includes one or more elements selected from Groups IA, IIA, VIII, VIB, and IIB; B 1 Including those selected from Mn and / or Al; C 1 Includes one or more elements selected from families IA, IIA, IIIA, IVA, VA, VIA, IIB, IIIB, IVB, VB, VIB, and VIII; D 1 Includes one or more elements selected from families VIA and VIIA; a1 is selected from the range of 0.8 to 1.2; b1 is selected from the range of 0 to 0.2; c1 is selected from the range of 0 to 1; d1 is selected from the range of 0 to 1; e1 is selected from the range of 0 to 1; f1 is selected from the range of 0 to 0.1; g1 is selected from the range of 0 to 0.1; and c1+d1+e1+f1=1.

[0131] In any embodiment, A 1 It includes one or more elements selected from Na, K, Mg, Rb, Zn, and Zr.

[0132] In any embodiment, C 1 It includes one or more elements selected from Al, Mg, Ca, Na, Ti, W, Zr, Sr, Cr, Fe, Zn, Ba, Mo, V, Ce, Nb, Sb, Ta, Ge, Nb, Sc, Ba, B, S, and Y, and may optionally include one or more elements selected from Al, Ti, Zr, Nb, Sr, Sc, Sb, Y, Ba, and B.

[0133] In any embodiment, D 1 It includes one or more elements selected from N, S, F, Cl and Br, and optionally includes S and / or F.

[0134] In any embodiment, a1 is selected from the range of 0.9 to 1.1.

[0135] In any embodiment, b1 is selected from the range of 0 to 0.1.

[0136] In any embodiment, c1 is selected from the range of 0.314 to 0.990, and may be selected from the range of 0.500 to 0.990.

[0137] In any embodiment, d1 is selected from the range of 0 to 0.320, and may be selected from the range of 0 to 0.150.

[0138] In any embodiment, e1 is selected from the range of 0.001 to 0.450, and may be selected from the range of 0.005 to 0.4.

[0139] In any embodiment, f1 is selected from the range of 0.001 to 0.1, and may be selected from the range of 0.001 to 0.05.

[0140] In any embodiment, g1 is selected from the range of 0 to 0.01, and may be selected from the range of 0.01 to 0.05.

[0141] In any embodiment, the second positive electrode active material includes a core and a shell covering the core, the core including the compound represented by formula (II); the shell including one or more coating layers; each coating layer having ionic conductivity and / or electronic conductivity.

[0142] In any embodiment, the shell of the second positive electrode active material contains one or more coating layers that independently include one or more selected from phosphates, pyrophosphates, carbon, doped carbon, oxides, and fast ion conductors, and may optionally include one or more selected from phosphates, pyrophosphates, and oxides.

[0143] In any embodiment, the shell of the second positive electrode active material includes a coating layer; optionally, the coating layer includes one or more selected from phosphates, pyrophosphates, and oxides.

[0144] In any embodiment, the shell of the second positive electrode active material includes a first coating layer covering the core and a second coating layer covering the first coating layer; optionally, the first coating layer and the second coating layer each independently include one or more selected from phosphates, pyrophosphates, and oxides; more preferably, the first coating layer includes one or more selected from phosphates and oxides, and the second coating layer includes one or more selected from pyrophosphates and oxides.

[0145] In any embodiment, the coating amount of the shell of the second positive electrode active material is 0.005% to 1% by weight, optionally 0.01% to 0.5% by weight, based on the weight of the core; and / or, the thickness of the shell is 2nm to 200nm, optionally 5nm to 50nm.

[0146] A third aspect of this application provides a positive electrode sheet, including a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector, the positive electrode film layer including a positive electrode active material, the positive electrode active material including the positive electrode active material composition of the first aspect of this application or the positive electrode active material composition of the second aspect of this application.

[0147] In any embodiment, the content of the positive electrode active material composition in the positive electrode film layer is 90% to 99.5% by weight, more preferably 95% to 99.5% by weight, based on the total weight of the positive electrode film layer.

[0148] In any embodiment, the positive electrode film layer further includes a third positive electrode active material, and the third positive electrode active material includes one or more of a lithium-rich oxide material, a lithium iron phosphate material, a spinel-type lithium manganate material, and their respective modified compounds. The modification methods include doping and / or surface coating modification.

[0149] In any embodiment, the third positive electrode active material includes a compound represented by formula (III).

[0150] Li 1+p1 A 2 q1 B 2 r1 O s1 , (III)

[0151] 0.05 ≤ p1 < 0.2, 0.10 < q1 ≤ 0.95, 0 ≤ r1 ≤ 0.2, and 2 ≤ s1 < 3, where A 2 includes one or more elements selected from Co, Ni, Mn, and Al; and B 2 includes one or more elements selected from Mg, Ti, Cr, Zr, Nb, Fe, Mo, Cu, Sb, V, P, and F.

[0152] In any embodiment, the third positive electrode active material includes a core and a shell coating the core. The core includes the compound represented by formula (III); the shell includes one or more coating layers; and each coating layer has ionic conductivity and / or electronic conductivity.

[0153] In any embodiment, one or more of the coating layers in the shell coating the compound represented by formula (III) independently include one or more selected from phosphates, pyrophosphates, solid electrolytes, conductive polymers, and materials capable of reversibly intercalating and deintercalating lithium ions.

[0154] In any embodiment, the coating amount of the shell coating the compound represented by formula (III) is 0.1 wt% to 5 wt%, optionally 0.5 wt% to 2 wt%, based on the weight of the core; and / or, the thickness of the shell coating the compound represented by formula (III) is 2 nm to 2 hundred nm, optionally 5 nm to 50 nm.

[0155] In any embodiment, the third positive electrode active material includes a compound represented by formula (IV).

[0156] Li a2 A 3 x2 B 3 y2 P 1-z2 C 3z2 O 4-n2 D 3 n2 (IV)

[0157] A 3 Includes one or more elements selected from families IA, IIA, IIIA, IIB, VB, and VIB; B 3 Includes one or more elements selected from families IA, IIA, IIIA, IVA, VA, IIB, IVB, VB, VIB, and VIII; C 3 Includes one or more elements selected from families IIIA, IVA, VA, and VIA; D 3 Includes one or more elements selected from groups VIA and VIIA; a2 is selected from the range of 0.85 to 1.15; x2 is selected from the range of 0 to 0.1; y2 is selected from the range of 0.001 to 0.999; z2 is selected from the range of 0 to 0.5; n2 is selected from the range of 0 to 0.5.

[0158] In any embodiment, A 3 It includes one or more elements selected from Rb, Cs, Be, Ca, Sr, Ba, Ga, In, Cd, V, Ta, Cr, Zn, Al, Na, K, Mg, Nb, Mo, and W, and may optionally include one or more elements selected from Zn, Al, Na, K, Mg, Nb, Mo, and W.

[0159] In any embodiment, B 3 Includes one or more elements selected from Rb, Cs, Be, Ca, Sr, Ba, In, Pb, Bi, Cd, Hf, Ta, Cr, Ru, Rh, Pd, Os, Ir, Pt, Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb, and Ge, and optionally includes one or more elements selected from Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb, and Ge.

[0160] In any embodiment, C 3 It includes one or more elements selected from B (boron), S, Si, and N.

[0161] In any embodiment, D 3 It includes one or more elements selected from S, F, Cl, and Br.

[0162] In any embodiment, a2 is selected from the range of 0.9 to 1.1, and optionally from the range of 0.97 to 1.01.

[0163] In any embodiment, x2 is selected from the range of 0.001 to 0.005.

[0164] In any embodiment, y2 is selected from the range of 0.001 to 0.5, optionally from the range of 0.01 to 0.5, and optionally from the range of 0.25 to 0.5.

[0165] In any embodiment, z2 is selected from the range of 0.001 to 0.5, optionally from the range of 0.001 to 0.1, and more preferably from the range of 0.001 to 0.005.

[0166] In any embodiment, n2 is selected from the range of 0 to 0.1, and optionally from the range of 0.001 to 0.005.

[0167] In any embodiment, the third positive electrode active material includes a core and a shell covering the core, the core comprising the compound represented by formula (IV); the shell is the same as the shell covering the compound represented by formula (I).

[0168] In any embodiment, the third positive electrode active material comprises a compound of formula (V).

[0169] LiMn t1 A 4 2-t1 O4, (V)

[0170] t1 is selected from the range 0 to 2, A 4 It includes one or more elements selected from Ni, Cr, Al, Zr, V, Ti, Mo, Ru, Mg, Nb, Ba, Si, P, W, Co, Cu, and Zn.

[0171] In any embodiment, the third positive electrode active material includes a core and a shell covering the core, the core comprising a compound represented by formula (V); the shell comprising one or more coating layers; each coating layer having ionic conductivity and / or electronic conductivity.

[0172] In any embodiment, one or more coating layers in the shell covering the compound represented by formula (V) each independently comprise one or more selected from phosphates, pyrophosphates, solid electrolytes, conductive polymers, and materials capable of reversibly inserting and deinserting lithium ions.

[0173] In any embodiment, the coating amount of the shell covering the compound represented by formula (V) is from 0.1% by weight to 5% by weight, optionally from 0.5% by weight to 2% by weight, based on the weight of the core; and / or, the thickness of the shell covering the compound represented by formula (V) is from 2 nm to 200 nm, optionally from 5 nm to 50 nm.

[0174] In any embodiment, the positive electrode film layer includes a positive electrode binder and / or a positive electrode conductive agent.

[0175] In any embodiment, the positive electrode binder comprises vinylidene fluoride homopolymer and / or copolymer, and more preferably, the comonomer comprises one or more of tetrafluoroethylene, hexafluoropropylene, and propylene.

[0176] In any embodiment, the weight-average molecular weight of the positive electrode binder is between 300,000 and 2,000,000.

[0177] In any embodiment, the positive electrode film layer further includes functional additives, which include one or more of dispersants, plasticizers, pore-forming agents, dehydrating additives, deacidifying additives, and lithium replenishing agents.

[0178] In any embodiment, the positive electrode sheet further includes a functional coating, which is located between the positive current collector and the positive electrode film layer and / or on the surface of the positive electrode film layer away from the positive current collector. The functional coating includes one or more of conductive carbon, dehydrating additives, deacidifying additives, and lithium replenishing agents.

[0179] The fourth aspect of this application provides a battery, including the positive electrode active material composition of the first aspect of this application, the positive electrode active material composition of the second aspect of this application, or the positive electrode sheet of the third aspect of this application.

[0180] In any embodiment, the battery includes an electrolyte, which includes one or more of a liquid electrolyte, an all-solid electrolyte, and a gel electrolyte.

[0181] In any embodiment, the liquid electrolyte includes a lithium salt, a non-aqueous solvent for dissolving the lithium salt, and optional additives; optionally, the lithium salt includes one or more selected from LiPF6, LiBF4, LiN(SO2F)2, LiN(CF3SO2)2, LiClO4, LiAsF6, LiB(C2O4)2, LiBF2C2O4, and LiPO2F2.

[0182] In any embodiment, the concentration of the lithium salt is 0.5-1.5 mol / L.

[0183] In any embodiment, the non-aqueous solvent includes one or more selected from propylene carbonate, ethylene carbonate, butene carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl formate, ethyl acetate, methyl butyrate, ethyl butyrate, methyl propionate, ethyl propionate, propyl propionate, methyl acrylate, ethylene sulfite, propylene sulfite, dimethyl sulfite, diethyl sulfite, acid anhydride, N-methylpyrrolidone, acetonitrile, sulfolane, dimethyl sulfoxide, dimethyl sulfide, γ-butyrolactone, and tetrahydrofuran.

[0184] In any embodiment, the additive comprises one or more selected from cyclic carbonate compounds containing carbon-carbon double bonds, halogen-substituted cyclic carbonate compounds, nitriles and polynitriles, phosphazene compounds, aromatic hydrocarbons and halogenated aromatic hydrocarbons, isocyanate compounds, acid anhydride compounds, sulfate compounds, sulfite compounds, sulfonate compounds, disulfonate compounds, borate compounds, phosphate compounds, amide compounds, carbodiimide compounds, crown ethers and azacrown ethers, and their respective derivatives, optionally including vinylene carbonate, 1,2,3-tris(2-cyanethoxy)propane, 1-aza-12-crown 4-ether, N,N'-dicyclohexylcarbodiimide, N,N'-diisopropylcarbodiimide, N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, tris(hexafluoroisopropyl)borate, tris(2,2,3,3-tetrafluoropropyl)borate, and tris(pentafluorophenyl)borate. .

[0185] In any embodiment, the battery includes a negative electrode sheet, the negative electrode sheet includes a negative current collector and a negative electrode film layer disposed on at least one surface of the negative current collector, the negative electrode film layer includes a negative electrode active material, the negative electrode active material includes one or more of carbon-based materials, silicon-based materials, tin-based materials and lithium titanate; optionally, the negative electrode active material includes a carbon-based material or a combination of carbon-based materials and silicon-based materials.

[0186] In any embodiment, the porosity of the negative electrode film is 20% to 50%.

[0187] In any embodiment, the negative electrode active material includes a carbon-based material, and the carbon-based material includes graphite, or a combination of graphite and hard carbon.

[0188] In any embodiment, the negative electrode active material comprises a combination of carbon-based materials and silicon-based materials, wherein the carbon-based materials include graphite or a combination of graphite and hard carbon, and the silicon content in the negative electrode active material is greater than 0 and less than or equal to 30% by weight, based on the total weight of the negative electrode active material.

[0189] In any embodiment, the negative electrode sheet further includes a functional coating located between the negative current collector and the negative electrode film layer and / or on the surface of the negative electrode film layer opposite to the negative current collector; optionally, the functional coating includes carbon.

[0190] In any embodiment, the negative electrode film layer further includes a lithium replenishing material. Optionally, the lithium replenishing material includes one or more of lithium foil, lithium strip, lithium powder, and pre-lithiation reagent. Optionally, the pre-lithiation reagent includes one or more of Li-aromatic hydrocarbons, complexes of Li-aromatic hydrocarbons and ether solvents, and more preferably includes one or more of lithium naphthalene and lithium biphenyl dimethyl ether.

[0191] In any embodiment, the negative electrode sheet includes a negative current collector and a first negative electrode film layer and a second negative electrode film layer respectively disposed on two surfaces of the negative current collector. Optionally, the thickness ratio of the first negative electrode film layer and the second negative electrode film layer is 5:95 to 95:5.

[0192] In any embodiment, the battery includes a negative electrode sheet, and the negative electrode sheet does not include a negative electrode active material capable of lithium ion intercalation / deintercalation.

[0193] In any embodiment, the negative electrode sheet comprises a lithium sheet or a lithium alloy sheet.

[0194] In any embodiment, the negative electrode sheet includes a mesh or foam-like three-dimensional skeleton layer.

[0195] In any embodiment, the battery includes a separator membrane, the separator membrane comprising a porous substrate.

[0196] In any embodiment, the isolation membrane further includes a coating on at least one surface of the porous substrate, optionally including one or more of inorganic heat-resistant particles and organic heat-resistant particles.

[0197] In any embodiment, the porosity of the isolation membrane is 10%-40%.

[0198] The fifth aspect of this application provides an electrical device, including the battery of the fourth aspect of this application.

[0199] The electrical device of this application includes the battery provided in this application, and therefore has at least the same advantages as the battery. Attached Figure Description

[0200] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly described below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0201] Figure 1 This is a schematic diagram of one embodiment of the battery cell of this application.

[0202] Figure 2 This is an exploded view of one embodiment of the battery cell of this application.

[0203] Figure 3 This is a schematic diagram of one embodiment of the battery module of this application.

[0204] Figure 4 This is a schematic diagram of one embodiment of the battery pack of this application.

[0205] Figure 5 yes Figure 4 An exploded view of an embodiment of the battery pack shown.

[0206] Figure 6 This is a schematic diagram of one embodiment of an electrical device that uses the battery of this application as a power source.

[0207] Figure 7 This is the particle size distribution curve of the positive electrode active material composition of Example 11.

[0208] The accompanying drawings are not necessarily drawn to scale. The reference numerals are explained as follows: 1 Battery pack, 2 Upper casing, 3 Lower casing, 4 Battery module, 5 Individual battery cell, 51 Housing, 52 Electrode assembly, 53 Cover plate. Detailed Implementation

[0209] The following detailed description, with appropriate reference to the accompanying drawings, discloses embodiments of the positive electrode active material composition, positive electrode sheet, battery, and power device of this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for the purpose of enabling those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0210] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0211] Unless otherwise specified, all embodiments and optional embodiments of this application may be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of this application.

[0212] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions, and such technical solutions shall be deemed to be included in the disclosure of this application.

[0213] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0214] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0215] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0216] Unless otherwise specified, in this application, the terms "first," "second," "third," "fourth," "fifth," etc., are used to distinguish different objects, rather than to describe a specific order or primary / secondary relationship.

[0217] In this application, the terms "multiple" or "various" refer to two or more kinds.

[0218] Throughout this specification, substituents of compounds are disclosed by groups or ranges. It is expressly intended that such description include each individual sub-combination of members of these groups and ranges. For example, it is expressly intended that the term "C1-C6 alkyl" individually discloses C1, C2, C3, C4, C5, C6, C1-C6, C1-C5, C1-C4, C1-C3, C1-C2, C2-C6, C2-C5, C2-C4, C2-C3, C3-C6, C3-C5, C3-C4, C4-C6, C4-C5, and C5-C6 alkyl.

[0219] Unless otherwise stated, the terms used in this application have the common meanings as commonly understood by those skilled in the art.

[0220] Unless otherwise stated, the values ​​of the parameters mentioned in this application can be determined using various testing methods commonly used in the art, for example, according to the testing methods given in the embodiments of this application. Unless otherwise stated, the test temperature for each parameter is 25°C.

[0221] Unless otherwise stated, all ratio parameters involved in this application are compared under the condition that the units are the same. For example, if the ratio of the volumetric particle size distribution of A to B is 1:1, then the units of the volumetric particle size distribution of A and B are the same.

[0222] In this application, the term "compacted density efficiency" refers to the ratio of the compacted density of the film to the theoretical compacted density of the active material powder.

[0223] In this application, the elemental content of the first positive electrode active material, the second positive electrode active material, and the third positive electrode active material can be detected by inductively coupled plasma atomic emission spectroscopy (ICP).

[0224] In the embodiments of this application, the battery refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in this application may include battery cells, battery modules, or battery packs.

[0225] A battery cell is the smallest unit that makes up a battery, and it can independently perform the functions of charging and discharging. A battery cell can be cylindrical, flat, cuboid, or other shapes, etc., and the embodiments of this application are not limited in this respect. Figure 1 The example shown is a rectangular battery cell 5.

[0226] When there are multiple battery cells, they are connected in series, parallel, or mixed via a busbar. In some embodiments, the battery can be a battery module; when there are multiple battery cells, they are arranged and fixed to form a battery module. In some embodiments, the battery can be a battery pack, which includes a housing and battery cells, with the battery cells or battery modules housed within the housing. In some embodiments, the housing can be part of the vehicle's chassis structure. For example, a portion of the housing can be at least part of the vehicle's floor, or a portion of the housing can be at least part of the vehicle's crossbeams and longitudinal beams.

[0227] In some embodiments, the battery can be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0228] The battery cells mentioned in the embodiments of this application include lithium-ion primary battery cells, lithium-ion secondary battery cells, lithium metal battery cells, and negative electrode-free lithium metal battery cells, etc., but the embodiments of this application are not limited to these.

[0229] A single battery cell generally includes an electrode assembly. The electrode assembly typically includes a positive electrode, a negative electrode, and a separator between the positive and negative electrode. The electrode assembly can be a wound structure or a stacked structure, and the embodiments of this application are not limited to this.

[0230] The battery cell may also include an outer packaging, which can be used to encapsulate the aforementioned electrode components and electrolyte. The outer packaging can be a rigid shell, such as a hard plastic shell, aluminum shell, or steel shell. The outer packaging can also be a flexible package, such as a pouch-type flexible package. The material of the flexible package can be plastic, such as one or more of polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0231] In some embodiments, such as Figure 2As shown, the outer packaging may include a housing 51 and a cover 53. The housing 51 may include a base plate and side plates connected to the base plate, the base plate and side plates enclosing a receiving cavity. The housing 51 has an opening communicating with the receiving cavity, and the cover 53 is used to cover the opening to close the receiving cavity. Electrode assemblies 52 are encapsulated in the receiving cavity. The number of electrode assemblies 52 contained in the battery cell 5 may be one or more, and can be adjusted as needed.

[0232] In some embodiments, individual battery cells can be assembled into a battery module, and the number of individual battery cells contained in the battery module can be multiple, the specific number of which can be adjusted according to the application and capacity of the battery module. Figure 3 This is a schematic diagram of battery module 4 as an example. Figure 3 As shown, in battery module 4, multiple battery cells 5 can be arranged sequentially along the length of battery module 4. Of course, they can also be arranged in any other manner. Furthermore, these multiple battery cells 5 can be fixed in place using fasteners.

[0233] Optionally, the battery module 4 may also include a housing with a receiving space in which multiple battery cells 5 are received.

[0234] In some embodiments, the battery modules described above can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be adjusted according to the application and capacity of the battery pack.

[0235] Figure 4 and Figure 5 This is a schematic diagram of battery pack 1 as an example. Figure 4 and Figure 5 As shown, the battery pack 1 may include a housing and multiple battery modules 4 disposed within the housing. The housing includes an upper housing 2 and a lower housing 3. The upper housing 2 covers the lower housing 3, forming a closed space for accommodating the battery modules 4. The multiple battery modules 4 can be arranged in any manner within the housing.

[0236] The positive electrode sheet includes the positive electrode active material. As a crucial component of the battery, the performance of the positive electrode active material is a significant factor limiting the battery's energy density and lifespan. Currently, a positive electrode active material that can simultaneously meet the requirements of low cost, high capacity, and minimal side reactions has not yet been developed.

[0237] In view of this, the inventors have proposed a positive electrode active material composition that enables the battery to achieve high energy density, low cost and good service life.

[0238] The positive electrode active material composition provided in this application includes a first positive electrode active material and a second positive electrode active material with a different crystal form than the first positive electrode active material. The first positive electrode active material includes a phosphate. The difference in crystal form between the first positive electrode active material and the second positive electrode active material means that the first positive electrode active material and the second positive electrode active material have different crystal systems.

[0239] The particle size distribution curve of the positive electrode active material composition has at least two volume distribution peaks. The volume distribution peak with the maximum peak intensity is denoted as the first peak, and the volume distribution particle size corresponding to the maximum peak intensity of the first peak is denoted as Dv1. The volume distribution peak with the second maximum peak intensity is denoted as the second peak, and the volume distribution particle size corresponding to the maximum peak intensity of the second peak is denoted as Dv2. Then, 0 < |Dv1-Dv2| / Dv1 ≤ 50. "||" represents an absolute value.

[0240] The primary cathode active material typically includes phosphate, which usually has an olivine structure and is generally inexpensive to produce. However, the compaction density of this primary cathode active material is relatively low, making it difficult to meet the requirements of high-energy-density batteries. Combining it with another cathode active material with a higher compaction density can improve the compaction density of the cathode sheet, but simply mixing the two materials usually does not significantly improve the compaction density and compaction efficiency of the cathode sheet, making it difficult to fully utilize the battery's capacity and also affecting its lifespan.

[0241] The inventors discovered that by including a first positive electrode active material and a second positive electrode active material with different crystal forms in the positive electrode active material composition, and by making the particle size distribution curve of the positive electrode active material composition satisfy 0 < |Dv1-Dv2| / Dv1≤50, the first positive electrode active material and the second positive electrode active material can be tightly packed, thereby increasing the actual packing density of the positive electrode active material composition, increasing the compaction density and compaction efficiency of the positive electrode sheet, and further enabling the battery using the positive electrode active material composition to have higher energy density and longer service life.

[0242] The particle size distribution curve of the positive electrode active material composition can be adjusted by regulating one or more parameters such as the volume distribution particle size, volume particle size distribution width, and mass content of the first and second positive electrode active materials.

[0243] In some embodiments, the volume distribution particle size Dv50 of the first positive electrode active material is from 0.25 μm to 12.5 μm.

[0244] In some embodiments, the volume distribution particle size Dv50 of the second positive electrode active material is 2.5 μm to 16.5 μm.

[0245] In some embodiments, the volume distribution particle size Dv50 of the first positive electrode active material is from 0.25 μm to 3.5 μm, and the particle size distribution curve of the positive electrode active material composition satisfies:

[0246] 0.1 ≤ |Dv1-Dv2| / Dv1 ≤ 50, optionally, 0.46 ≤ |Dv1-Dv2| / Dv1 ≤ 39.6; and / or,

[0247] 0.3μm≤Dv1≤17.8μm, optionally, 0.35μm≤Dv1≤12.1μm; and / or,

[0248] 0.3μm≤Dv2≤17.8μm, optionally, 0.46μm≤Dv2≤14.2μm.

[0249] This allows the first and second positive electrode active materials to be stacked more tightly, further increasing the actual packing density of the positive electrode active material composition, the compaction density of the positive electrode sheet, and the compaction efficiency, thereby enabling batteries using positive electrode active material compositions to have higher energy density and / or longer service life.

[0250] In some embodiments, the volume distribution particle size Dv50 of the first positive electrode active material is 3.5 μm to 12.5 μm, and the particle size distribution curve of the positive electrode active material composition satisfies:

[0251] 0.1 ≤ |Dv1-Dv2| / Dv1 ≤ 6.0, optionally, 0.34 ≤ |Dv1-Dv2| / Dv1 ≤ 3.8; and / or,

[0252] 2.0μm≤Dv1≤12.5μm, optionally, 3.0μm≤Dv1≤12.3μm; and / or,

[0253] 2.0μm≤Dv2≤15.0μm, optionally, 3.4μm≤Dv2≤14.3μm.

[0254] This allows the first and second positive electrode active materials to be stacked more tightly, further increasing the actual packing density of the positive electrode active material composition, the compaction density of the positive electrode sheet, and the compaction efficiency, thereby enabling batteries using positive electrode active material compositions to have higher energy density and / or longer service life.

[0255] This application also provides a positive electrode active material composition, the positive electrode active material composition comprising a first positive electrode active material and a second positive electrode active material with a crystal form different from the first positive electrode active material, the first positive electrode active material comprising a phosphate, and the particle size distribution curve of the positive electrode active material composition having at least two volume distribution peaks, the volume distribution peak with the maximum peak intensity being denoted as the first peak, and the volume distribution particle size corresponding to the maximum peak intensity of the first peak being denoted as Dv1, the volume distribution peak with the second maximum peak intensity being denoted as the second peak. The volume distribution particle size corresponding to the maximum peak intensity of the second peak is denoted as Dv2. The volume distribution particle size Dv50 of the first positive electrode active material is 0.25μm to 3.5μm, and 0.3μm≤Dv1≤17.8μm, 0.3μm≤Dv2≤17.8μm; or the volume distribution particle size Dv50 of the first positive electrode active material is 3.5μm to 12.5μm, and 2.0μm≤Dv1≤12.5μm, 2.0μm≤Dv2≤15.0μm.

[0256] This allows the first and second positive electrode active materials to be stacked more tightly, further increasing the actual packing density of the positive electrode active material composition, the compaction density of the positive electrode sheet, and the compaction efficiency, thereby enabling batteries using positive electrode active material compositions to have higher energy density and / or longer service life.

[0257] In any embodiment, the volume distribution particle size Dv50 of the first positive electrode active material is from 0.25 μm to 3.5 μm, and 0.35 μm ≤ Dv1 ≤ 12.1 μm, 0.46 μm ≤ Dv2 ≤ 14.2 μm. This allows the battery employing the positive electrode active material composition to further achieve higher energy density and / or longer lifespan.

[0258] In any embodiment, the volume distribution particle size Dv50 of the first positive electrode active material is 3.5 μm to 12.5 μm, and 3.0 μm ≤ Dv1 ≤ 12.3 μm, 3.4 μm ≤ Dv2 ≤ 14.3 μm. This allows the battery employing the positive electrode active material composition to further achieve higher energy density and / or longer lifespan.

[0259] The additional technical features described below apply to both the positive electrode active material composition of the first aspect and the positive electrode active material composition of the second aspect herein.

[0260] In some embodiments, the morphology of the first positive electrode active material includes one or more of single crystal and polycrystalline, and the morphology of the second positive electrode active material includes one or more of single crystal and polycrystalline.

[0261] The term "monocrystalline" also includes quasi-monocrystalline (also known as near-monocrystalline), which typically refers to particles formed by the aggregation of a small number of primary particles. Polycrystalline refers to secondary particles formed by the aggregation of multiple primary particles.

[0262] In some embodiments, the volume distribution particle size Dv50 of the first positive electrode active material with a single crystal morphology is from 0.25 μm to 3.5 μm, and optionally from 0.35 μm to 2.5 μm.

[0263] In some embodiments, the volume distribution particle size Dv10 of the first positive electrode active material with a single crystal morphology is from 0.05 μm to 1.5 μm, and optionally from 0.1 μm to 1.0 μm.

[0264] In some embodiments, the volume distribution particle size Dv50 of the polycrystalline first cathode active material is from 3.5 μm to 12.5 μm, and optionally from 3.8 μm to 10.5 μm.

[0265] In some embodiments, the volume distribution particle size Dv10 of the polycrystalline first cathode active material is from 0.1 μm to 5.0 μm, and optionally from 0.5 μm to 4.5 μm.

[0266] In some embodiments, the volume distribution particle size Dv50 of the single-crystal morphology of the second positive electrode active material is from 2.5 μm to 16.5 μm, and optionally from 3.0 μm to 8.5 μm.

[0267] In some embodiments, the volume distribution particle size Dv10 of the single-crystal morphology of the second positive electrode active material is 0.3 μm to 8 μm, and optionally 1.0 μm to 3.5 μm.

[0268] In some embodiments, the volume distribution particle size Dv50 of the polycrystalline second cathode active material is from 2.5 μm to 16.5 μm, and optionally from 3.0 μm to 15.5 μm.

[0269] In some embodiments, the volume distribution particle size Dv10 of the polycrystalline second cathode active material is from 0.5 μm to 12 μm, and is optionally from 1.0 μm to 8.5 μm.

[0270] When the volume distribution particle size of the first positive electrode active material and / or the second positive electrode active material is within the above range, the battery can have a higher energy density, and can also reduce side reactions, lower interface impedance, and give the battery a longer service life.

[0271] In some embodiments, the morphology of the first positive electrode active material includes single crystals, for example, the proportion of single crystals may be more than 80% or 90%. A polycrystalline morphology of the first positive electrode active material results in a higher specific surface area, which leads to increased hygroscopicity and increased processing time costs during production, thereby increasing the production cost of the battery.

[0272] In some embodiments, the morphology of the second positive electrode active material includes polycrystalline material, for example, the proportion of polycrystalline material may be 80% or more, or 90% or more. The polycrystalline morphology of the second positive electrode active material can have a larger particle size and a higher powder compaction density, thereby helping to improve the energy density of the battery.

[0273] In some embodiments, the weight content of the first positive electrode active material is denoted as w based on the total weight of the positive electrode active material composition. a Then w a Selected from the range of 0.5% to 99.5%, or optionally from the range of 2% to 95%.

[0274] In some embodiments, the weight content of the second positive electrode active material is denoted as w based on the total weight of the positive electrode active material composition. b Then w b Selected from the range of 0.5% to 99.5%, or optionally from the range of 5% to 98%.

[0275] When the content of the first positive electrode active material and / or the second positive electrode active material is within the above range, the battery can have a higher energy density and / or a longer service life.

[0276] In some embodiments, the powder compaction density P1 of the first positive electrode active material at 30000N is 1.89 g / cm³. 3 The above can be selected as 1.95g / cm. 3 The above can also be selected as 1.98g / cm. 3 The above can be further selected as 2.0 g / cm³. 3 The above can be further optimized to 2.2 g / cm³. 3 The above, and optionally 2.2 g / cm³, are further options. 3 Above and 2.8g / cm 3 Below or 2.2g / cm 3 Above and 2.65g / cm 3 the following.

[0277] In some embodiments, the powder compaction density P2 of the second positive electrode active material at 30000N is greater than or equal to 2.90 g / cm³. 3 The value can be greater than or equal to 3.1 g / cm³. 3 Alternatively, a value greater than or equal to 3.3 g / cm³ can be selected. 3 .

[0278] When the powder compaction density of the first positive electrode active material and / or the second positive electrode active material is within the above range, the battery can have a higher energy density.

[0279] In some embodiments, the BET specific surface area of ​​the second positive electrode active material is less than or equal to 1.73 m². 2 / g, which can be less than or equal to 1.5m 2 / g, or 0.28m 2 / g to 1.5m 2 / g. This can reduce side reactions and improve battery cycle performance.

[0280] The specific surface area of ​​a material has a well-known meaning in the art and can be determined using instruments and methods known in the art. For example, it can be measured using the nitrogen adsorption specific surface area analysis method according to GB / T 19587-2017, and calculated using the BET (Brunauer Emmett Teller) method. The testing instrument can be the Tri-Star 3020 specific surface area and pore size analyzer from Micromeritics, USA.

[0281] The compaction density of the powder (such as the first positive electrode active material, the second positive electrode active material, etc.) can be measured according to GB / T24533-2009.

[0282] The volumetric distribution particle sizes Dv10 and Dv50 of materials (e.g., first positive electrode active material, second positive electrode active material, etc.) have meanings known in the art, representing the particle size corresponding to a cumulative volume distribution percentage of 10% and 50%, respectively, and can be determined using instruments and methods known in the art. For example, they can be determined using a laser particle size analyzer, referring to GB / T 19077-2016. The testing instrument can be a Mastersizer 3000 laser particle size analyzer from Malvern Instruments Ltd., UK. Deionized water can be used as the solvent during testing, and the material can be sonicated for 5 minutes before testing.

[0283] The particle size distribution curve of the positive electrode active material composition can be determined using a laser particle size analyzer, referring to GB / T 19077-2016. The testing instrument can be a Mastersizer 3000 laser particle size analyzer from Malvern Instruments Ltd., UK. Deionized water can be used as the solvent during testing, and the material can be sonicated for 5 minutes before testing.

[0284] In some embodiments, the first positive electrode active material comprises a compound represented by formula (I).

[0285] Li a A x Mn 1-y M 1 y P 1-z M 2 zO 4-n D n (I)

[0286] A includes one or more elements selected from families IA, IIA, IIIA, IIB, VB, and VIB; M 1 Includes one or more elements selected from families IA, IIA, IIIA, IVA, VA, IIB, IVB, VB, VIB, and VIII; M 2 Includes one or more elements selected from families IIIA, IVA, VA, and VIA; D includes one or more elements selected from families VIA and VIIA; a is selected from the range of 0.85 to 1.15; x is selected from the range of 0 to 0.1; y is selected from the range of 0.001 to 0.999; z is selected from the range of 0 to 0.5; n is selected from the range of 0 to 0.5.

[0287] Unless otherwise stated, in the above chemical formulas, when A consists of two or more elements, the limitation on the range of x values ​​described above applies not only to the stoichiometric coefficient of each element as A, but also to the sum of the stoichiometric coefficients of all elements as A. For example, when A consists of two or more elements A1, A2...An, the stoichiometric coefficients x1, x2...xn of each of A1, A2...An must each fall within the range of x values ​​defined in this application, and the sum of x1, x2...xn must also fall within this range.

[0288] Similarly, other symbols mentioned in the embodiments of this application (e.g., B, C, D, M, M′, X, Z, P, Q, A) 1 B 1 C 1 D 1 A 2 B 2 A 3 A 4 When there are two or more elements (e.g., stoichiometric coefficients), the limitation on the numerical range of their stoichiometric coefficients in this application also has the above meaning.

[0289] The first positive electrode active material is obtained by elemental doping of the compound LiMnPO4, wherein A and M 1 C and M 2 These are the elements doped at the Li, Mn, P, and O sites of the compound LiMnPO4, respectively. Not wanting to be confined to theory, it is now believed that the performance improvement of lithium manganese phosphate is related to reducing the lattice change rate and decreasing surface activity during the lithium insertion / extraction process. Reducing the lattice change rate can decrease the difference in lattice constants between the two phases at the grain boundary, reduce interfacial stress, and enhance Li... +The transport capacity at the interface improves the rate performance of the first cathode active material. However, high surface activity easily leads to severe interfacial side reactions, exacerbating gas generation, electrolyte consumption, and interface damage, thus affecting the battery's cycle performance. Doping at Li and / or Mn sites can reduce the lattice change rate. Mn site doping can also effectively reduce surface activity, thereby reducing Mn dissolution and interfacial side reactions between the first cathode active material and the electrolyte. P-site doping accelerates the change rate of Mn-O bond length, lowering the small polaron migration barrier and thus improving electronic conductivity. O-site doping has a good effect on reducing interfacial side reactions. P-site and / or O-site doping also affects the dissolution of Mn from antisite defects and the kinetic properties. Therefore, doping reduces the concentration of antisite defects in the material, improves the kinetic properties and specific capacity, and can also change the particle morphology, thereby increasing the compaction density. The inventors unexpectedly discovered that by doping specific elements in specific amounts at the Mn site of the compound LiMnPO4 and optionally at the Li, P and / or O sites, improved rate performance can be obtained, while reducing the dissolution of Mn and Mn-site dopants, improving cycle performance and / or high-temperature stability, and also increasing the specific capacity and compaction density of the material.

[0290] In some embodiments, A includes one or more elements selected from Rb, Cs, Be, Ca, Sr, Ba, Ga, In, Cd, V, Ta, Cr, Zn, Al, Na, K, Mg, Nb, Mo, and W, and optionally includes one or more elements selected from Zn, Al, Na, K, Mg, Nb, Mo, and W; and / or,

[0291] M 1 Includes one or more elements selected from Rb, Cs, Be, Ca, Sr, Ba, In, Pb, Bi, Cd, Hf, Ta, Cr, Ru, Rh, Pd, Os, Ir, Pt, Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb, and Ge, optionally including one or more elements selected from Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb, and Ge; and / or,

[0292] M 2 Includes one or more elements selected from B (boron), S, Si, and N; and / or,

[0293] D includes one or more elements selected from S, F, Cl, and Br.

[0294] In some embodiments, A includes any element selected from Zn, Al, Na, K, Mg, Nb, Mo, and W, and optionally includes any element selected from Mg and Nb; and / or,

[0295] M 1 Includes one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge; optionally includes at least two elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge; more preferably includes at least two elements selected from Fe, Ti, V, Ni, Co, and Mg; further preferably includes at least two elements selected from Fe, Ti, V, Co, and Mg; even more preferably includes Fe and one or more elements selected from Ti, V, Co, and Mg; and / or,

[0296] M 2 Includes any element selected from B (boron), S, Si, and N, with S as an option; and / or,

[0297] D includes any element selected from S, F, Cl, and Br, and can be F.

[0298] By selecting doping elements at the Li sites within the aforementioned range, the lattice change rate during the lithium removal process can be further reduced, thereby further improving the rate performance of the battery. By selecting doping elements at the Mn sites within the aforementioned range, electronic conductivity can be further increased and the lattice change rate further reduced, thereby improving the rate performance and specific capacity of the battery. By selecting doping elements at the P sites within the aforementioned range, the rate performance of the battery can be further improved. By selecting doping elements at the O sites within the aforementioned range, interfacial side reactions can be further mitigated, improving the high-temperature performance of the battery.

[0299] In some embodiments, a is selected from the range of 0.9 to 1.1, and optionally from the range of 0.97 to 1.01; and / or,

[0300] x is selected from the range of 0.001 to 0.005; and / or,

[0301] y is selected from the range of 0.001 to 0.5, optionally from the range of 0.01 to 0.5, optionally from the range of 0.25 to 0.5; and / or,

[0302] z is selected from the range of 0.001 to 0.5, optionally from the range of 0.001 to 0.1, and more preferably from the range of 0.001 to 0.005; and / or,

[0303] n is selected from the range of 0 to 0.1, and optionally from the range of 0.001 to 0.005.

[0304] By selecting the y value within the aforementioned range, the specific capacity and rate performance of the first positive electrode active material can be further improved. By selecting the x value within the aforementioned range, the kinetic performance of the first positive electrode active material can be further improved. By selecting the z value within the aforementioned range, the rate performance of the battery can be further improved. By selecting the n value within the aforementioned range, the high-temperature performance of the battery can be further improved.

[0305] In some embodiments, x is 0, z is selected from the range of 0.001 to 0.5, and n is selected from the range of 0.001 to 0.1; or, x is selected from the range of 0.001 to 0.1, z is 0, and n is selected from the range of 0.001 to 0.1; or, x is selected from the range of 0.001 to 0.1, z is selected from the range of 0.001 to 0.5, and n is 0; or, x is 0, z is 0, and n is selected from the range of 0.001 to 0.1; or, x is 0, z is selected from the range of 0.001 to 0.5, and n is 0; or, x is selected from the range of 0.001 to 0.1, z is selected from the range of 0.001 to 0.5, and n is selected from the range of 0.001 to 0.1.

[0306] Therefore, by doping specific elements in specific amounts at the Mn site of the compound LiMnPO4 and optionally at the Li, P and / or O sites, especially at the Mn and P sites of LiMnPO4 or at the Li, Mn, P and O sites of LiMnPO4, it is possible to improve rate performance, reduce the dissolution of Mn and Mn site dopants, improve cycle performance and / or high temperature stability, and increase the specific capacity and compaction density of the first positive electrode active material.

[0307] In some embodiments, y:z is selected from the range of 0.002 to 999, and can be selected from the range of 0.025 to 999 or the range of 0.002 to 500, more preferably from the range of 0.2 to 600, such as 0.2, 0.25, 1, 2, 3, 4, 5, 6, 8, 10, 12, 13, 15, 17, 20, 70, 80, 84, 67, 91, 100, 134, 150, 182, 200, 250, 300, 320, 350, 400, 420, 450, 500, 600, 999 or any two of the above values. This reduces defects in the first positive electrode active material, improves the integrity of the framework structure of the first positive electrode active material, thereby effectively improving the structural stability of the first positive electrode active material, and further improving the cycle stability of the battery.

[0308] In some embodiments, z:n is selected from the range of 0.002 to 500, optionally from the range of 0.2 to 100, and more preferably from the range of 0.2 to 50, such as 0.2, 0.8, 1, 1.25, 4, 5, 50, or any two of the above values. This further reduces defects in the first positive electrode active material, further improves the integrity of the framework structure of the first positive electrode active material, effectively enhances the structural stability of the first positive electrode active material, and improves the cycle stability of the battery.

[0309] In some embodiments, (1-y):y is in the range of 0.1-999, optionally in the range of 0.1-10 or in the range of 0.67-999, more preferably in the range of 1 to 10, further preferably in the range of 1 to 4, and even more preferably in the range of 1.5 to 3; and / or, a:x is in the range of 1 to 1200, optionally in the range of 9 to 1100, and more preferably in the range of 190-998.

[0310] Here, y represents the sum of the stoichiometric coefficients of the Mn-doped elements. Under the above conditions, the energy density and cycle performance of the first cathode active material can be further improved.

[0311] In some embodiments, z:(1-z) is 1:9 to 1:999, optionally 1:499 to 1:249. When the above conditions are met, the energy density and cycle performance of the first positive electrode active material can be further improved.

[0312] In some embodiments, A includes one or more elements selected from Zn, Al, Na, K, Mg, Nb, Mo, and W; M 1 Includes one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge; M 2 It includes one or more elements selected from B (boron), S, Si and N; D includes one or more elements selected from S, F, Cl and Br; a is selected from the range of 0.9 to 1.1, x is selected from the range of 0.001 to 0.1, y is selected from the range of 0.001 to 0.5, z is selected from the range of 0.001 to 0.1, and n is selected from the range of 0.001 to 0.1.

[0313] By simultaneously doping specific elements at specific amounts at the Li, Mn, P, and O sites of the compound LiMnPO4, improved rate performance can be obtained, while reducing the dissolution of Mn and Mn-site dopants, resulting in improved cycle performance and / or high-temperature stability. Furthermore, the specific capacity and compaction density of the first positive electrode active material can also be improved.

[0314] In some embodiments, M 1Includes one or more elements selected from Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb, and Ge, and optionally includes one or more elements selected from Zn, Fe, Ti, V, Ni, Co, and Mg; M 2 It includes one or more elements selected from B (boron), Si, N and S; a is selected from the range of 0.9 to 1.1, x is 0, y is selected from the range of 0.001 to 0.5, z is selected from the range of 0.001 to 0.1, and n is 0.

[0315] By simultaneously doping specific elements at both the Mn and P sites of the compound LiMnPO4 with specific amounts, rate performance can be improved, dissolution of Mn and Mn-site dopants can be reduced, cycle performance and / or high-temperature stability can be improved, and the specific capacity and compaction density of the first positive electrode active material can be increased.

[0316] In some embodiments, the first positive electrode active material includes a core and a shell covering the core, the core comprising a compound represented by formula (I) above. The shell comprises one or more coating layers. Each coating layer has ionic conductivity and / or electronic conductivity. In practice, each coating layer may be a complete or partial coating.

[0317] By providing a coating layer with ionic and / or electronic conductivity on the core surface, a first positive electrode active material with a core-shell structure is provided. Applying the first positive electrode active material to a battery can improve the battery's high-temperature cycle performance, cycle stability, and high-temperature storage performance.

[0318] In some embodiments, one or more coating layers each independently comprise one or more selected from pyrophosphates, phosphates, carbon, doped carbon, oxides, borides, and polymers.

[0319] In some embodiments, the shell includes a coating layer; optionally, the coating layer includes one or more selected from pyrophosphate, phosphate, carbon, doped carbon, oxide, boride and polymer.

[0320] Using the above materials, a coating layer with ionic conductivity and / or electronic conductivity can be obtained, thereby improving the high-temperature cycle performance, cycle stability and high-temperature storage performance of the battery.

[0321] In some embodiments, the shell includes a first coating layer covering the core and a second coating layer covering the first coating layer; optionally, the first coating layer and the second coating layer each independently include one or more selected from pyrophosphate, phosphate, carbon, doped carbon, oxide, boride and polymer.

[0322] Using the above-mentioned materials as the coating material and setting two coating layers can further improve the high-temperature cycle performance, cycle stability and high-temperature storage performance of the battery.

[0323] In some embodiments, the first coating layer comprises one or more selected from pyrophosphate, phosphate, oxide and boride, and the second coating layer comprises one or more selected from carbon and doped carbon.

[0324] By employing a first coating layer and a second coating layer made of specific materials, rate performance can be further improved, and the dissolution of Mn and Mn-site dopants can be further reduced, thereby improving the cycle performance and / or high-temperature stability of the battery.

[0325] In some embodiments, the shell includes a first coating layer covering the core, a second coating layer covering the first coating layer, and a third coating layer covering the second coating layer; optionally, the first coating layer, the second coating layer, and the third coating layer each independently include one or more selected from pyrophosphate, phosphate, carbon, doped carbon, oxide, boride, and polymer. "Polymer" can be either an oligomer or a high polymer, and this embodiment of the application is not limited in this respect.

[0326] Using the above-mentioned materials as the coating layer and setting three coating layers can further reduce the dissolution of Mn and Mn site dopants, and further improve the high-temperature cycle performance, cycle stability and high-temperature storage performance of the battery.

[0327] In some embodiments, the first coating layer comprises pyrophosphate, the second coating layer comprises one or more selected from phosphates, oxides and borides, and the third coating layer comprises one or more selected from carbon and doped carbon.

[0328] The use of a first coating layer, a second coating layer, and a third coating layer made of specific materials further improves rate performance, further reduces the dissolution of Mn and Mn-site dopants, thereby improving the cycle performance and / or high-temperature stability of the battery, and further increases the specific capacity and compaction density of the first positive electrode active material.

[0329] In some embodiments, pyrophosphate is M b (P2O7) c ; and / or,

[0330] Phosphate is X m (PO4) q ; and / or,

[0331] The doping elements in the carbon include one or more selected from Group IIIA, Group VA, Group VIA, and Group VIIA; and / or,

[0332] The oxide is M′d O e ; and / or,

[0333] The boride is Z v B w ; and / or,

[0334] Polymers include one or more selected from polysaccharides and their derivatives, and polysiloxanes;

[0335] M, X, and Z each independently include one or more elements selected from Groups IA, IIA, IIIA, IB, IIB, IVB, IVB, VB, VIIB, and VIII;

[0336] b is selected from the range 1 to 4, c is selected from the range 1 to 6; m is selected from the range 1 to 2, q is selected from the range 1 to 4;

[0337] M′ includes one or more elements selected from alkali metals, alkaline earth metals, transition metals, Group IIIA elements, Group IVA elements, lanthanides, and Sb;

[0338] d is greater than 0 and less than or equal to 2, e is greater than 0 and less than or equal to 5;

[0339] v is selected from the range 1 to 7, and w is selected from the range 1 to 2.

[0340] By using the above-mentioned materials as a coating layer, the dissolution of Mn and Mn site dopants can be further reduced, the specific capacity and compaction density of the first positive electrode active material can be further improved, and the rate performance, high-temperature cycle performance and high-temperature storage performance of the battery can be further improved.

[0341] In some embodiments, M, X, and Z each independently include one or more elements selected from Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb, Mn, and Al; and / or,

[0342] The doping elements in carbon include one or more selected from nitrogen, phosphorus, sulfur, boron, and fluorine; and / or,

[0343] M′ includes one or more elements selected from Li, Be, B, Na, Mg, Al, Si, P, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, W, La, and Ce, and may optionally include one or more elements selected from Mg, Al, Si, Zn, Zr, and Sn; and / or,

[0344] The polysiloxane is selected from one or more of linear polysiloxanes and cyclic polysiloxanes; and / or,

[0345] The polysaccharide is selected from one or more plant polysaccharides and marine polysaccharides.

[0346] By using the aforementioned specific materials as a coating layer, the dissolution of Mn and Mn-site dopants can be further reduced, thereby further improving the high-temperature cycle performance and high-temperature storage performance of the battery.

[0347] In some embodiments, the first positive electrode active material includes a core and a shell covering the core.

[0348] The kernel includes Li a Mn 1-y M 1 y P 1-z M 2 z O4, a is selected from the range of 0.9 to 1.1, y is selected from the range of 0.001 to 0.5, z is selected from the range of 0.001 to 0.1, M 1 Includes one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge, M 2 It includes one or more elements selected from B (boron), S, Si, and N.

[0349] The shell includes a first coating layer covering the core and a second coating layer covering the first coating layer. The first coating layer includes pyrophosphate MP2O7 and phosphate XPO4, where M and X each independently include one or more elements selected from Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb and Al. The second coating layer contains carbon.

[0350] The first positive electrode active material can be a core-shell structure with two coating layers, with element M doped at the manganese site of lithium manganese phosphate. 1 This helps reduce the lattice change rate of lithium manganese phosphate during lithium insertion / extraction, improves the structural stability of the first cathode active material, significantly reduces manganese dissolution, and lowers oxygen activity on the particle surface. The element M doped at the phosphorus site... 2This process helps to alter the ease of Mn-O bond length changes, thereby lowering the lithium-ion migration barrier, promoting lithium-ion migration, and improving the rate performance of the battery. The first coating layer of the first positive electrode active material includes pyrophosphate and phosphate. Since the migration barrier of transition metals in pyrophosphate is relatively high (>1 eV), it can effectively reduce the dissolution of transition metals. Phosphate has excellent lithium-ion conduction capabilities and can reduce surface impurity lithium content. Furthermore, since the second coating layer is a carbon-containing layer, it can effectively improve the conductivity and desolvation capability of LiMnPO4. In addition, the "barrier" effect of the second coating layer can further reduce the migration of manganese ions into the electrolyte and reduce the corrosion of the second active material by the electrolyte. Therefore, by specifically doping and surface coating lithium manganese phosphate, it is possible to effectively reduce Mn dissolution during the lithium insertion / extraction process while promoting lithium-ion migration, thereby improving the rate performance, cycle performance, and high-temperature performance of the battery.

[0351] In some embodiments, the first positive electrode active material includes a core and a shell covering the core.

[0352] The kernel includes Li a Mn 1-y M 1 y P 1-z M 2 z O4, a is selected from the range of 0.9 to 1.1, y is selected from the range of 0.001 to 0.5, z is selected from the range of 0.001 to 0.1, M 1 Includes one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge, M 2 It includes one or more elements selected from B (boron), S, Si, and N.

[0353] The shell includes a first covering layer that covers the core, a second covering layer that covers the first covering layer, and a third covering layer that covers the second covering layer.

[0354] The first coating layer includes pyrophosphate Li f QP2O7 and / or Q g (P2O7) h , 0≤f≤2, 1≤g≤4, 1≤h≤6, Li pyrophosphate f QP2O7 and / or Q g (P2O7) h Each of the elements Q in the equation independently includes one or more elements selected from Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb, and Al.

[0355] The second coating layer comprises crystalline phosphate XPO4, where X includes one or more elements selected from Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb, and Al.

[0356] The third coating layer contains carbon.

[0357] The first positive electrode active material has a core-shell structure, in which the manganese and phosphorus sites in the core are doped with element M. 1 and element M 2 This process not only effectively reduces manganese dissolution, thereby reducing the number of manganese ions migrating to the negative electrode and reducing electrolyte consumption due to SEI film decomposition, thus improving battery cycle performance, but also promotes Mn-O bond adjustment, lowers the lithium-ion migration barrier, promotes lithium-ion migration, and improves battery rate performance. By coating the core with a first coating layer including pyrophosphate, the migration resistance of manganese can be further increased, reducing its dissolution, and decreasing the surface lithium content and contact between the core and electrolyte, thereby reducing interfacial side reactions, reducing gas production, and improving the battery's high-temperature storage and cycle performance. Further coating with a phosphate coating layer with excellent lithium-ion conductivity can effectively reduce interfacial side reactions on the surface of the first positive electrode active material, thus improving the battery's high-temperature cycle and storage performance. Further coating with a carbon layer as a third coating layer can further enhance the battery's kinetic performance. In addition, in the core, the element M at the manganese site... 1 It also helps to reduce the lattice change rate of lithium manganese phosphate during lithium insertion / extraction, improves the structural stability of the first cathode active material, greatly reduces manganese dissolution, and lowers the oxygen activity on the particle surface; the element M doped at the phosphorus site 2 It also helps to change the ease with which the Mn-O bond length changes, thereby improving electronic conductivity and lowering the lithium-ion migration barrier, promoting lithium-ion migration, and improving the rate performance of the battery.

[0358] Furthermore, maintaining the overall electroneutrality of the core system minimizes defects and impurities in the first cathode active material. If an excess of transition metal (e.g., manganese) exists in the first cathode active material, due to the relatively stable structure of the material system itself, the excess transition metal is likely to precipitate as elemental or form impurities within the crystal lattice. Maintaining electroneutrality minimizes such impurities. Additionally, maintaining system electroneutrality can, in some cases, generate lithium vacancies in the material, thereby improving the kinetic performance of the first cathode active material.

[0359] In some embodiments, one or more covering layers in the shell that are furthest from the core each independently include one or more selected from polysiloxanes, polysaccharides, and polysaccharide derivatives.

[0360] This improves the uniformity of the coating, effectively blocks interfacial side reactions caused by high voltage, thereby enhancing the high-temperature cycling performance and high-temperature storage performance of the first positive electrode active material. Furthermore, the coating layer has good ionic conductivity, which helps to increase the specific capacity of the first positive electrode active material while reducing heat generation in the battery.

[0361] In some embodiments, the polysiloxane comprises the structural unit shown in formula (i) below.

[0362]

[0363] R1 and R2 are independently selected from H, -COOH, -OH, -SH, -CN, -SCN, amino, phosphate ester, carboxylic acid ester, amide, aldehyde, sulfonyl, polyether segment, C1-C20 aliphatic hydrocarbon, C1-C20 halogenated aliphatic hydrocarbon, C1-C20 heteroaliphatic hydrocarbon, C1-C20 halogenated heteroaliphatic hydrocarbon, C6-C20 aromatic hydrocarbon, C6-C20 halogenated aromatic hydrocarbon, C2-C20 heteroaromatic hydrocarbon and C2-C20 halogenated heteroaromatic hydrocarbon;

[0364] Optionally, R1 and R2 are independently selected from H, amino, phosphate ester group, polyether segment, C1-C8 alkyl, C1-C8 haloalkyl, C1-C8 heteroalkyl, C1-C8 haloheteroalkyl, C2-C8 alkenyl and C2-C8 haloalkenyl.

[0365] In some embodiments, the polysiloxane further comprises a capping group, which includes one or more of the following functional groups: polyether, C1-C8 alkyl, C1-C8 haloalkyl, C1-C8 heteroalkyl, C1-C8 haloheteroalkyl, C2-C8 alkenyl, C2-C8 haloalkenyl, C6-C20 aromatic hydrocarbon, C1-C8 alkoxy, C2-C8 epoxy, hydroxyl, C1-C8 hydroxyalkyl, amino, C1-C8 aminoalkyl, carboxyl, and C1-C8 carboxylalkyl.

[0366] In some embodiments, the polysiloxane includes those selected from polydimethylsiloxane, polydiethylsiloxane, polymethylethylsiloxane, polymethylvinylsiloxane, polyphenylmethylsiloxane, polymethylhydrosiloxane, carboxyl-functionalized polysiloxane, epoxy-terminated polysiloxane, methoxy-terminated polydimethylsiloxane, hydroxypropyl-terminated polydimethylsiloxane, polymethylchloropropylsiloxane, hydroxyl-terminated polydimethylsiloxane, polymethyltrifluoropropylsiloxane, perfluorooctylmethylpolysiloxane, aminoethylaminopropylpolydimethylsiloxane, terminal polyether polydimethylsiloxane, and side-chain aminopropylpolysiloxane. The following are some of the following: aminopropyl-terminated polydimethylsiloxane, side-chain phosphate-grafted polydimethylsiloxane, side-chain polyether-grafted polydimethylsiloxane, 1,3,5,7-octamethylcyclotetrasiloxane, 1,3,5,7-tetrahydro-1,3,5,7-tetramethylcyclotetrasiloxane, cyclopentapolydimethylsiloxane, 2,4,6,8-tetramethylcyclotetrasiloxane, 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane, cyclic polymethylvinylsiloxane, hexadecylcyclooctasiloxane, tetradecylcycloheptasiloxane, and cyclic polydimethylsiloxane.

[0367] In some embodiments, the number average molecular weight of the polysiloxane, polysaccharide, and polysaccharide derivative is independently below 300,000, optionally from 10,000 to 200,000, more preferably from 20,000 to 120,000, and even more preferably from 400 to 80,000.

[0368] The number-average molecular weights of polysiloxanes, polysaccharides, and polysaccharide derivatives can be determined by methods known in the art, such as gel permeation chromatography (GPC). A PL-GPC 220 high-temperature gel permeation chromatograph can be used as the instrument.

[0369] In some embodiments, the mass percentage of polar functional groups in the polysiloxane is α, where 0 ≤ α < 50%, and optionally, 5% ≤ α ≤ 30%.

[0370] "The mass percentage of polar functional groups in polysiloxanes" refers to the mass proportion of polar functional groups in R1, R2, and the end-capping groups in the polysiloxane. Polar functional groups include one or more of the following: -COOH, -OH, -SH, -CN, -SCN, amino (including -NH2, -NH-), phosphate ester group, carboxylic ester group (-COO-), amide group (-CONH-), aldehyde group (-CHO), sulfonyl group (-S(=O)2-), polyether segment, halogen, alkoxy, and epoxy. When the aforementioned polar functional groups are directly connected to silicon atoms, α represents the mass fraction of these polar functional groups in the polysiloxane. When the aforementioned polar functional groups are not directly connected to silicon atoms, α represents the sum of the mass fractions of the polar functional groups and the divalent to tetravalent methyl groups (e.g., -CH2, -CH-, -C-, etc.) directly connected to them in the polysiloxane. Here, "divalent to tetravalent methyl groups" refers to the carbon atom directly connected to the polar functional group and located between the polar functional group and the silicon atom, as well as other nonpolar functional groups connected to the carbon atom. Taking polymethyltrifluoropropylsiloxane as an example, α refers to the mass percentage of -CF3, excluding the ethylidene; taking polymethylchloropropylsiloxane as an example, α refers to the mass percentage of -CH2Cl, excluding the ethylidene; taking hydroxypropyl-terminated polydimethylsiloxane as an example, α refers to the mass percentage of -CH2OH. The mass percentage of polar functional groups in polysiloxanes can be determined by methods known in the art, such as titration (e.g., acid-base titration, redox titration, precipitation titration), infrared spectroscopy, and nuclear magnetic resonance spectroscopy.

[0371] In some embodiments, the substituents attached to the sugar units in the polysaccharide and the polysaccharide derivative each independently include one or more of the following functional groups: -OH, -COOH and their salts, -R-OH, -SO3H and their salts, -R-OH, -R-SO3H and their salts, sulfate ester group, alkoxy group, where R represents an alkylene group, optionally representing a C1 to C5 alkylene group.

[0372] Optionally, the substituents attached to the sugar units in the polysaccharide and the polysaccharide derivative each independently include one or more of the following functional groups: -OH, -COOH, -COOLi, -COONa, -COOK, -SO3H, -SO3Li, -SO3Na, -SO3K, -CH2-SO3H, -CH2-SO3Li, -CH2-SO3Na, -CH2-SO3K, methoxy, ethoxy.

[0373] The term "substituents attached to sugar units" includes all groups attached to the backbone of sugar units.

[0374] In some embodiments, the polysaccharide includes one or more selected from pectin, carboxymethyl starch, hydroxypropyl starch, dextrin, cellulose ether, carboxymethyl chitosan, hydroxyethyl cellulose, carboxymethyl cellulose, carboxypropyl methyl cellulose, guar gum, guar gum, gum arabic, lithium alginate, sodium alginate, potassium alginate, fucoidan, agar, carrageenan, carrageenan, xanthan gum, and fenugreek gum.

[0375] In some embodiments, the mass percentage of substituents attached to the sugar units in the polysaccharide and the polysaccharide derivative is independently 20% to 85%, optionally 30% to 78%. The mass percentage of substituents attached to the sugar units in the polysaccharide and the polysaccharide derivative can be determined by methods known in the art, such as titration (e.g., acid-base titration, redox titration, precipitation titration), infrared spectroscopy, and nuclear magnetic resonance spectroscopy.

[0376] In some embodiments, the lattice mismatch between the core material and the shell material is less than 10%. This enables good contact between the core and the shell (or covering layer) to prevent the shell (or covering layer) from detaching.

[0377] In some embodiments, a gravimetric method based on the positive electrode active material is used.

[0378] The manganese content is in the range of 10% to 35% by weight, preferably in the range of 13.3% to 33.2% by weight, more preferably in the range of 15% to 30% by weight, and even more preferably in the range of 17% to 20% by weight; and / or,

[0379] The phosphorus content is in the range of 12%-25% by weight, preferably in the range of 15%-20% by weight, and even more preferably in the range of 16.8%-19.5% by weight; and / or,

[0380] The weight ratio of manganese to phosphorus ranges from 0.71 to 1.85, with a possible range of 0.90 to 1.25, and even more preferably 0.95 to 1.20.

[0381] When only the core of the first positive electrode active material contains manganese, the manganese content can correspond to the content of the core.

[0382] Limiting the manganese content within the aforementioned range can further improve the stability and density of the first positive electrode active material, thereby enhancing the battery's cycle, storage, and compaction performance; and it can also maintain a high voltage platform, thereby increasing the battery's energy density.

[0383] Limiting the phosphorus content within the aforementioned range can effectively reduce the impact of small polaron conductivity on the conductivity of the first positive electrode active material, further improve the stability of the crystal structure, and thus enhance the overall stability of the first positive electrode active material.

[0384] Limiting the weight ratio of manganese and phosphorus within the above range can further reduce manganese leaching, improve the stability and specific capacity of the first positive electrode active material, and improve the cycle performance and storage performance of the battery; it can also reduce impurities, allowing the first positive electrode active material to maintain a high discharge voltage platform, thus enabling the battery to have high energy density.

[0385] The measurement of manganese and phosphorus can be performed using conventional techniques in the field. In particular, the content of manganese and phosphorus is determined by the following method: the material is dissolved in dilute hydrochloric acid (concentration 10-30%), the content of each element in the solution is tested by ICP, and then the content of manganese is measured and converted to obtain its weight percentage.

[0386] In some embodiments, the surface of the first positive electrode active material is coated with one or more of carbon and carbon doping; optionally, the surface of the first positive electrode active material is coated with carbon. This improves the conductivity of the first positive electrode active material.

[0387] In some embodiments, the doping element in the doped carbon includes one or more selected from nitrogen, phosphorus, sulfur, boron, and fluorine. This facilitates control over the properties of the doped carbon layer.

[0388] In some embodiments, the coating amount of the shell (only one coating layer) is from 0.1% to 6% by weight, based on the weight of the core. The coating amount is preferably within the above range, which enables sufficient coating of the core and further improves the kinetic performance of the battery without sacrificing the specific capacity of the first positive electrode active material.

[0389] In some embodiments, the coating amount of the first coating layer is greater than 0 and less than or equal to 7% by weight, optionally greater than 0 and less than or equal to 6% by weight, more preferably greater than 0 and less than or equal to 5.5% by weight, or 4-5.6% by weight, and further optionally greater than 0 and less than or equal to 2% by weight, based on the weight of the core; and / or,

[0390] The coating amount of the second coating layer is greater than 0 and less than or equal to 6% by weight, optionally greater than 0 and less than or equal to 5.5% by weight, more preferably 2-4% by weight or 3-5% by weight, based on the weight of the core; and / or,

[0391] The coating amount of the third coating layer is greater than 0 and less than or equal to 6% by weight, optionally greater than 0 and less than or equal to 5.5% by weight, and even more optionally greater than 0 and less than or equal to 2% by weight, based on the kernel weight.

[0392] In some embodiments, the shell further includes a fourth covering layer covering the third covering layer and a fifth covering layer covering the fourth covering layer.

[0393] The coating amounts of the fourth and fifth coating layers are each independently from 0.01 wt% to 10 wt%, optionally from 0.05 wt% to 10 wt%, more preferably from 0.1 wt% to 5 wt%, and further from 0.1 wt% to 2 wt%, based on the weight of the core.

[0394] The coating amount of each coating layer is preferably within the above range, thereby enabling sufficient coating of the core and further improving the dynamic performance of the battery without sacrificing the specific capacity of the first positive electrode active material.

[0395] In some embodiments, the shell covers 40% to 90% of the surface of the core, optionally 60% to 80%. This allows for adequate coverage of the core, thereby improving the battery's kinetic performance.

[0396] In some embodiments, the shell (which is only a single covering layer) has a thickness of 1-15 nm.

[0397] In some embodiments, the thickness of the first coating layer is 1-10 nm, optionally 2-10 nm; and / or,

[0398] The thickness of the second coating layer is 2-25 nm, optionally 2-15 nm, and more preferably 3-15 nm; and / or,

[0399] The thickness of the third coating layer is 2-25nm, and can be selected as 5-25nm.

[0400] In some embodiments, the thickness of the first coating layer may be about 2 nm, about 3 nm, about 4 nm, about 5 nm, about 6 nm, about 7 nm, about 8 nm, about 9 nm, or about 10 nm, or within any range of any of the above values.

[0401] In some embodiments, the thickness of the second coating layer may be about 2 nm, about 3 nm, about 4 nm, about 5 nm, about 6 nm, about 7 nm, about 8 nm, about 9 nm, about 10 nm, about 11 nm, about 12 nm, about 13 nm, about 14 nm, about 15 nm, or any range of any of the above values.

[0402] In some embodiments, the thickness of the third coating layer may be about 2 nm, about 3 nm, about 4 nm, about 5 nm, about 6 nm, about 7 nm, about 8 nm, about 9 nm, about 10 nm, about 11 nm, about 12 nm, about 13 nm, about 14 nm, about 15 nm, about 16 nm, about 17 nm, about 18 nm, about 19 nm, about 20 nm, about 21 nm, about 22 nm, about 23 nm, about 24 nm, or about 25 nm, or any range of any of the above values.

[0403] The first coating layer has the aforementioned thickness range, which can further reduce the adverse effects on the kinetic performance of the first positive electrode active material.

[0404] The second coating layer has the aforementioned thickness range, which makes the surface structure of the second coating layer stable and reduces the side reactions with the electrolyte. Therefore, it can effectively reduce interfacial side reactions and thus improve the high-temperature performance of the battery.

[0405] The third coating layer has the aforementioned thickness range, which can improve the electrical conductivity of the first positive electrode active material and improve the compaction density of the positive electrode sheet prepared using the first positive electrode active material.

[0406] The thickness of the coating layer is mainly tested by FIB. The specific method may include the following steps: randomly select a single particle from the powder of the first positive electrode active material to be tested, cut a thin slice with a thickness of about 100 nm from the middle position or near the middle position of the selected particle, and then perform TEM test on the thin slice to measure the thickness of the coating layer. Measure 3-5 positions and take the average value.

[0407] In some embodiments, one or more coating layers each independently comprise one or more selected from pyrophosphate, phosphate, and oxide, and the one or more selected from pyrophosphate, phosphate, and oxide are crystalline.

[0408] Optionally, the crystallinity of the pyrophosphate, phosphate, and oxide is independently 10% to 100%, and more preferably 50% to 100%.

[0409] In this document, "crystalline" means a crystallinity of 50% or higher, i.e., 50%-100%. That is, when the crystalline pyrophosphate and crystalline phosphate of this application appear, it indicates a crystallinity of 50% to 100%.

[0410] Pyrophosphate and phosphate with a certain degree of crystallinity not only help to fully utilize the pyrophosphate coating to reduce manganese leaching and the phosphate coating to effectively conduct lithium ions and reduce interfacial side reactions, but also enable the pyrophosphate coating and phosphate coating to better match their crystal lattices, thereby achieving a tight bond between the coatings.

[0411] It should be noted that crystallinity can be adjusted, for example, by adjusting the process conditions of the sintering process, such as sintering temperature and sintering time. Crystallinity can be measured by methods known in the art, such as X-ray diffraction, density method, infrared spectroscopy, differential scanning calorimetry, and nuclear magnetic resonance absorption method. Specifically, a method for testing the crystallinity of the first positive electrode active material using X-ray diffraction may include the following steps:

[0412] A certain amount of the first positive electrode active material powder is taken, and the total scattering intensity is measured by X-rays. It is the sum of the scattering intensities of all matter in space. It is only related to the intensity of the primary rays, the chemical structure of the first positive electrode active material powder, and the total number of electrons participating in diffraction, i.e., the mass, and is independent of the order state of the sample. Then, crystalline scattering and non-crystalline scattering are separated from the diffraction pattern. The crystallinity is the ratio of the scattering of the crystalline part to the total scattering intensity.

[0413] In some embodiments, the weight ratio of pyrophosphate to phosphate and the weight ratio of pyrophosphate to oxide in the casing are each independently from 1:3 to 3:1, optionally from 1:3 to 1:1. Thus, by maintaining a suitable weight ratio of pyrophosphate to phosphate or a suitable weight ratio of pyrophosphate to oxide, manganese leaching can be effectively reduced, as can the surface lithium content and interfacial side reactions, thereby improving the battery's high-temperature storage performance and high-temperature cycling performance.

[0414] In some embodiments, one or more coating layers each independently comprise carbon, and the carbon is a mixture of SP2 carbon and SP3 carbon. Optionally, the molar ratio of SP2 carbon to SP3 carbon in the carbon is any value in the range of 0.07-13, more preferably any value in the range of 0.1-10, and even more preferably any value in the range of 2.0-3.0.

[0415] In some embodiments, the molar ratio of SP2 carbon to SP3 carbon may be about 0.1, about 0.2, about 0.3, about 0.4, about 0.5, about 0.6, about 0.7, about 0.8, about 0.9, about 1, about 2, about 3, about 4, about 5, about 6, about 7, about 8, about 9 or about 10, or any range of any of the above values.

[0416] In this application, "about" for a certain value represents a range, specifically a range of ±10% of that value.

[0417] By selecting the form of carbon in the carbon coating layer, the overall electrical performance of the battery can be improved. Specifically, by using a mixture of SP2 and SP3 carbon forms and limiting the ratio of SP2 to SP3 carbon within a certain range, the following situations can be avoided: if the carbon in the coating layer is all amorphous SP3, the conductivity is poor; if it is all graphitized SP2, although the conductivity is good, there are few lithium-ion pathways, which is not conducive to lithium insertion / extraction. In addition, limiting the molar ratio of SP2 to SP3 carbon within the above-mentioned range can achieve both good conductivity and promote lithium-ion transport, thus benefiting the realization of battery function and its cycle performance.

[0418] The mixing ratio of SP2 and SP3 carbon can be controlled by sintering conditions such as sintering temperature and sintering time. The molar ratio of SP2 to SP3 carbon can be determined by Raman spectroscopy. The specific test method is as follows: by dividing the Raman spectrum into peaks, the Id / Ig ratio is obtained (where Id is the peak intensity of SP3 carbon and Ig is the peak intensity of SP2 carbon), thus confirming the molar ratio.

[0419] In some embodiments, one or more coating layers independently include doped carbon, and the mass content of the dopant element in the doped carbon is less than 30%; alternatively, the mass content of the dopant element in the doped carbon is less than 20%. Dopant elements within the above-mentioned content range can sufficiently improve the conductivity of the pure carbon layer while effectively avoiding excessive surface activity due to excessive doping, thereby effectively controlling interfacial side reactions caused by excessive doping of the coating layer.

[0420] In some embodiments, one or more coating layers each independently comprise doped carbon, in which,

[0421] The doping element is nitrogen and / or sulfur, and the mass content of the doping element in the doped carbon is 1% to 15%; or,

[0422] The doping elements are phosphorus, boron and / or fluorine, and the mass content of the doping elements in the doped carbon is 0.5% to 5%.

[0423] Optionally, the doping element is nitrogen, phosphorus, sulfur, boron or fluorine.

[0424] Since nitrogen and sulfur atoms have a similar atomic radius to carbon atoms and are less likely to damage the carbon skeleton, when the doping amount of nitrogen and sulfur atoms is within the relatively wide range mentioned above, it can fully utilize the conductivity of the doped carbon layer and promote lithium-ion transport and lithium-ion desolvation capabilities.

[0425] Since phosphorus, boron and / or fluorine atoms have different atomic radii from carbon atoms, excessive doping can easily damage the carbon framework. Therefore, when the doping amount of phosphorus, boron and / or fluorine atoms is within the relatively small range mentioned above, it can fully utilize the conductivity of the doped carbon layer and promote lithium-ion transport and lithium-ion desolvation capabilities.

[0426] In some embodiments, one or more coating layers each independently comprise pyrophosphate, wherein the interplanar spacing of the pyrophosphate is in the range of 0.293-0.470 nm, optionally 0.297-0.462 nm or 0.293-0.326 nm, more preferably 0.300-0.310 nm, and the included angle of the crystal orientation (111) is in the range of 18.00°-32.57°, optionally 18.00°-32.00° or 26.41°-32.57°, more preferably 19.211°-30.846°, and further preferably 29.00°-30.00°; and / or,

[0427] One or more coating layers each independently comprise a phosphate, wherein the interplanar spacing of the phosphate is in the range of 0.244-0.425 nm, optionally 0.345-0.358 nm, and the included angle of the crystal orientation (111) is in the range of 20.00°-37.00°, optionally 24.25°-26.45°;

[0428] Optionally, the first or second coating layer contains phosphate.

[0429] Both the first and second coating layers in the first positive electrode active material are made of crystalline materials, and their interplanar spacing and angles are within the aforementioned range. This effectively reduces impurity phases in the coating layers, thereby improving the material's specific capacity, cycle performance, and rate performance.

[0430] In some embodiments, the lattice change rate of the first positive electrode active material before and after complete lithium insertion / extraction is less than 50%, optionally less than 9.8%, more preferably less than 8.1%, further preferably less than 7.5%, even more preferably less than 6%, even more preferably less than 4%, even more preferably less than 3.8%, and even more preferably 2.0-3.8%.

[0431] By reducing the lattice change rate, Li ion transport becomes easier, meaning Li ions have a stronger migration ability in the first cathode active material, which is beneficial for improving the rate performance of the battery. The lattice change rate can be measured by methods known in the art, such as X-ray diffraction (XRD).

[0432] In some embodiments, the Li / Mn antisite defect concentration of the first positive electrode active material is 5.3% or less, optionally 5.1% or less, more preferably 4% or less, further preferably 2.2% or less, even more preferably 2% or less, and even more preferably 1.5%-2.2% or less.

[0433] The so-called Li / Mn antisite defect refers to the presence of Li in the LiMnPO4 lattice. + With Mn 2+ The positions of Li and Mn are interchanged. The Li / Mn antisite defect concentration refers to the concentration of Li / Mn antisite defects in the first positive electrode active material. 2+ Interchangeable Li + Zhan Li + Percentage of the total. Mn of the inversion defect. 2+ It will hinder Li + The transport of Li / Mn antisite defects, by reducing the concentration of Li / Mn antisite defects, is beneficial to improving the specific capacity and rate performance of the first positive electrode active material. The concentration of Li / Mn antisite defects can be measured by methods known in the art, such as XRD.

[0434] In some embodiments, the surface oxygen valence state of the first positive electrode active material is below -1.55, optionally below -1.82, more preferably below -1.88, further preferably below -1.90 or from -1.98 to -1.88, even more preferably from -1.98 to -1.89, and even more preferably from -1.98 to -1.90.

[0435] By reducing the surface oxygen valence state, interfacial side reactions between the first cathode active material and the electrolyte can be reduced, thereby improving the battery's cycle performance and high-temperature stability. The surface oxygen valence state can be measured using methods known in the art, such as electron energy loss spectroscopy (EELS).

[0436] In some embodiments, the positive electrode active material composition satisfies 0.0004 ≤ w a ×y×(3.4-V B 0.0015≤w ≤ 0.063, optionally, 0.0015≤w a ×y×(3.4-V B )≤0.045.

[0437] w a The weight content of the first positive electrode active material is indicated based on the total weight of the positive electrode active material composition.

[0438] y is the amount of M in the compound represented by formula (I) in 1 mole. 1 The molar amount of an element, y, can be detected using inductively coupled plasma atomic emission spectrometry (ICP).

[0439] VB M in the compound shown in formula (I) 1 The voltage plateau of an element, measured in volts (V). B The following method can be used for testing: At 25℃, let the battery stand for 10 minutes, then discharge it at 0.33C to the lower cutoff voltage; after standing for 10 minutes, charge the battery at a constant current of 0.33C to the upper cutoff voltage, and continue constant voltage charging until the current ≤ 0.05C; after standing for 10 minutes, discharge the battery at 0.33C to the lower cutoff voltage, and obtain the battery's discharge capacity, denoted as C0; after standing for 10 minutes, charge the battery at a constant current of 0.04C0 to the upper cutoff voltage, and continue constant voltage charging until the current ≤ 0.05C0; after standing for 10 minutes, discharge the battery at 0.04C0 to the lower cutoff voltage, and obtain the battery's discharge capacity, denoted as C1. Plot the discharge differential capacity dQ / dV curve based on the discharge curve, and take the peak less than 3.4V on the dQ / dV curve as M. 1 The peak of an element, and the voltage corresponding to that peak is V. B .

[0440] The battery is a battery that includes a positive electrode active material composition.

[0441] When the positive electrode active material composition further meets the above conditions, it is beneficial for the positive electrode sheet to achieve both high solid density and high solid density efficiency, and for the battery to achieve both high energy density and long service life.

[0442] In some embodiments, the second positive electrode active material comprises a layered oxide.

[0443] The second positive electrode active material has a high compaction density, but it is expensive and often exhibits numerous side reactions and relatively poor crystal structure stability during battery use. By rationally combining the first and second positive electrode active materials, the actual packing density of the positive electrode active material composition, the compaction density and compaction efficiency of the positive electrode sheet can be improved. Consequently, batteries using the positive electrode active material composition can achieve higher energy density and longer lifespan.

[0444] In some embodiments, the second positive electrode active material comprises a compound represented by formula (II).

[0445] Li a1 A 1 b1 Ni c1 Co d1 B 1 e1 C 1 f1 O 2-g1 D 1 g1 (II)

[0446] A 1 Includes one or more elements selected from Groups IA, IIA, VIII, VIB, and IIB; B 1 Including those selected from Mn and / or Al; C 1 Includes one or more elements selected from families IA, IIA, IIIA, IVA, VA, VIA, IIB, IIIB, IVB, VB, VIB, and VIII; D 1 Includes one or more elements selected from families VIA and VIIA; a1 is selected from the range of 0.8 to 1.2; b1 is selected from the range of 0 to 0.2; c1 is selected from the range of 0 to 1; d1 is selected from the range of 0 to 1; e1 is selected from the range of 0 to 1; f1 is selected from the range of 0 to 0.1; g1 is selected from the range of 0 to 0.1; and c1+d1+e1+f1=1.

[0447] In some embodiments, A 1 Includes one or more elements selected from Na, K, Mg, Rb, Zn, and Zr; and / or,

[0448] C 1 Includes one or more elements selected from Al, Mg, Ca, Na, Ti, W, Zr, Sr, Cr, Fe, Zn, Ba, Mo, V, Ce, Nb, Sb, Ta, Ge, Nb, Sc, Ba, B, S, and Y, optionally including one or more elements selected from Al, Ti, Zr, Nb, Sr, Sc, Sb, Y, Ba, and B; and / or,

[0449] D 1 Includes one or more elements selected from N, S, F, Cl, and Br, optionally including S and / or F; and / or,

[0450] a1 is selected from the range of 0.9 to 1.1; and / or,

[0451] b1 is selected from the range 0 to 0.1; and / or,

[0452] c1 is selected from the range of 0.314 to 0.990, and may be selected from the range of 0.500 to 0.990; and / or,

[0453] d1 is selected from the range of 0 to 0.320, and may optionally be selected from the range of 0 to 0.150; and / or,

[0454] e1 is selected from the range of 0.001 to 0.450, and may be selected from the range of 0.005 to 0.4; and / or,

[0455] f1 is selected from the range of 0.001 to 0.1, and may optionally be selected from the range of 0.001 to 0.05; and / or,

[0456] g1 selects a range from 0 to 0.01, or a range from 0.01 to 0.05.

[0457] In some embodiments, the second positive electrode active material includes a core and a shell covering the core, the core including a compound represented by formula (II); the shell including one or more coating layers; each coating layer having ionic conductivity and / or electronic conductivity.

[0458] In some embodiments, one or more coating layers each independently include one or more selected from phosphates, pyrophosphates, carbon, doped carbon, oxides, and fast ion conductors, and optionally include one or more selected from phosphates, pyrophosphates, and oxides.

[0459] In some embodiments, one or more coating layers each independently include one or more elements selected from Al, Zr, Mg, Ba, Cd, Zn, Ti, Co, W, Y, Si, Sn, B, P, S, and C.

[0460] In some embodiments, fast ion conductors include Li 3x3 La 2 / 3-x3 M 2 a3 TiN 2 z3 O3, Li 2+2x4 Zn 1-x4 GeO4, LiM 3 One or more of 2(PO4)3, M 2 Includes one or more elements selected from Ba and Sr, N 2 Includes one or more elements selected from Al and Zr, M 3 It is one or more elements among Zr, Ti, Ge, and Hf, where 0.04≤x3≤0.167, 0≤a3≤1, 0≤z3≤1, and -0.3≤x4≤0.8.

[0461] In some embodiments, the shell of the second positive electrode active material includes a coating layer; optionally, the coating layer includes one or more selected from phosphates, pyrophosphates, and oxides.

[0462] In some embodiments, the shell of the second positive electrode active material includes a first coating layer covering the core and a second coating layer covering the first coating layer; optionally, the first coating layer and the second coating layer each independently include one or more selected from phosphates, pyrophosphates, and oxides.

[0463] Optionally, the first coating layer comprises one or more selected from phosphates and oxides, and the second coating layer comprises one or more selected from pyrophosphates and oxides. Optionally, the oxide in the first coating layer is an oxide of one or more elements selected from Al, Zr, Mg, Ti, Co, Y, Ba, and Cd. Optionally, the oxide in the second coating layer is an oxide of one or more elements selected from B, Sn, S, and P.

[0464] In some embodiments, the shell of the second positive electrode active material has a coating weight of 0.005% to 1% by weight, optionally 0.01% to 0.5% by weight, based on the weight of the core.

[0465] In some embodiments, the thickness of the shell of the second positive electrode active material is 2 nm to 200 nm, and optionally 5 nm to 50 nm.

[0466] The first and second positive electrode active materials can be prepared by sintering. The shells of the first and second positive electrode active materials can be prepared by liquid-phase coating.

[0467] [Positive electrode plate]

[0468] The positive electrode provided in this application includes a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector. The positive electrode film layer includes a positive electrode active material, which includes the aforementioned positive electrode active material composition. The positive current collector has two surfaces opposite each other in its own thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0469] In some embodiments, the content of the positive electrode active material composition in the positive electrode film layer is 50-99.5% by weight, optionally 90-99.5% by weight, or 95-99.5% by weight, based on the total weight of the positive electrode film layer.

[0470] In some embodiments, the positive electrode film layer further includes a third positive electrode active material, which includes one or more of lithium-rich oxide materials, lithium iron phosphate materials, spinel-type lithium manganese oxide materials, and their respective modified compounds, and the modification methods include doping and / or surface coating modification.

[0471] In some embodiments, the third positive electrode active material comprises the compound shown in formula (III).

[0472] Li 1+p1 A 2 q1 B 2 r1 O s1 (III)

[0473] 0.05 ≤ p1 < 0.2, 0.10 < q1 ≤ 0.95, 0 ≤ r1 ≤ 0.2, and 2 ≤ s1 < 3, A 2 comprises one or more elements selected from Co, Ni, Mn, and Al; B 2 comprises one or more elements selected from Mg, Ti, Cr, Zr, Nb, Fe, Mo, Cu, Sb, V, P, and F.

[0474] In some embodiments, the third positive electrode active material comprises one or more selected from 1.11 Li 0.22 Ni 0.58 Mn 0.02 Ti 1.2 O2, Li 0.6 Mn 0.2 Ni 1.16 O2, Li 0.22 Ni 0.6 Mn 1.16 O2, Li 0.13 Ni 0.06 Co 0.59 Mn 1.1 O2 and Li 0.2 Ni 0.2 Co 0.48 Mn

[0475] O2.

[0476] In some embodiments, the third positive electrode active material comprises a core and a shell coating the core, the core comprises a compound represented by formula (III); the shell comprises one or more coating layers; each coating layer has ionic conductivity and / or electronic conductivity.

[0477] Phosphate, pyrophosphate, and solid electrolyte can improve the ionic transport performance of the third positive electrode active material.

[0478] The conductive polymer can form a uniform thin film with high electronic conductivity and improve the charge transfer at the interface between the positive electrode and the electrolyte. At the same time, the conductive polymer can adapt to the volume change of the material, thereby reducing crack formation.

[0479] The material capable of reversibly inserting and extracting lithium ions can include some different types of positive electrode active materials.

[0480] In some embodiments, the coating amount of the shell coating the compound represented by formula (III) is 0.1 wt% to 5 wt%, optionally 0.5 wt% to 2 wt%, based on the weight of the core.

[0481] In some embodiments, the shell thickness of the compound of formula (III) is from 2 nm to 200 nm, optionally from 5 nm to 50 nm.

[0482] In some embodiments, the third positive electrode active material comprises the compound shown in formula (IV).

[0483] Li a2 A 3 x2 B 3 y2 P 1-z2 C 3 z2 O 4-n2 D 3 n2 (IV)

[0484] A 3 Includes one or more elements selected from families IA, IIA, IIIA, IIB, VB, and VIB; B 3 Includes one or more elements selected from families IA, IIA, IIIA, IVA, VA, IIB, IVB, VB, VIB, and VIII; C 3 Includes one or more elements selected from families IIIA, IVA, VA, and VIA; D 3 Includes one or more elements selected from groups VIA and VIIA; a2 is selected from the range of 0.85 to 1.15; x2 is selected from the range of 0 to 0.1; y2 is selected from the range of 0.001 to 0.999; z2 is selected from the range of 0 to 0.5; n2 is selected from the range of 0 to 0.5.

[0485] In some embodiments, A 3 Includes one or more elements selected from Rb, Cs, Be, Ca, Sr, Ba, Ga, In, Cd, V, Ta, Cr, Zn, Al, Na, K, Mg, Nb, Mo, and W, optionally including one or more elements selected from Zn, Al, Na, K, Mg, Nb, Mo, and W; and / or,

[0486] B 3 Includes one or more elements selected from Rb, Cs, Be, Ca, Sr, Ba, In, Pb, Bi, Cd, Hf, Ta, Cr, Ru, Rh, Pd, Os, Ir, Pt, Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb, and Ge, optionally including one or more elements selected from Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb, and Ge; and / or,

[0487] C 3 Includes one or more elements selected from B (boron), S, Si, and N; and / or,

[0488] D 3 Includes one or more elements selected from S, F, Cl, and Br; and / or,

[0489] a2 is selected from the range of 0.9 to 1.1, and optionally from the range of 0.97 to 1.01; and / or,

[0490] x2 is selected from the range of 0.001 to 0.005; and / or,

[0491] y2 is selected from the range of 0.001 to 0.5, optionally from the range of 0.01 to 0.5, optionally from the range of 0.25 to 0.5; and / or,

[0492] z2 is selected from the range of 0.001 to 0.5, optionally from the range of 0.001 to 0.1, and more preferably from the range of 0.001 to 0.005; and / or,

[0493] n2 is selected from the range of 0 to 0.1, and optionally from the range of 0.001 to 0.005.

[0494] In some embodiments, the third positive electrode active material includes a core and a shell covering the core, the core including the compound shown in formula (IV); the shell is the same as the shell covering the compound shown in formula (I), and will not be described again here.

[0495] In some embodiments, the third positive electrode active material comprises a compound of formula (V).

[0496] LiMn t1 A 4 2-t1 O4, (V)

[0497] t1 is selected from the range 0 to 2, A 4 It includes one or more elements selected from Ni, Cr, Al, Zr, V, Ti, Mo, Ru, Mg, Nb, Ba, Si, P, W, Co, Cu, and Zn.

[0498] In some embodiments, the third positive electrode active material includes a core and a shell covering the core, the core including a compound represented by formula (V); the shell including one or more coating layers; each coating layer having ionic conductivity and / or electronic conductivity.

[0499] In some embodiments, one or more coating layers each independently comprise one or more selected from phosphates, pyrophosphates, solid electrolytes, conductive polymers, and materials capable of reversibly inserting and deinserting lithium ions.

[0500] Phosphates, pyrophosphates, and solid electrolytes can improve the ion transport performance of the third cathode active material.

[0501] Conductive polymers can form uniform thin films with high electronic conductivity, improving charge transfer at the cathode-electrolyte interface. Simultaneously, conductive polymers can adapt to changes in material volume, thereby reducing crack formation.

[0502] Materials capable of reversibly inserting and deinserting lithium ions can include a variety of different types of positive electrode active materials.

[0503] In some embodiments, the shell of the compound shown in the encapsulation form (V) has an encapsulation amount of 0.1% to 5% by weight, optionally 0.5% to 2% by weight, based on the weight of the core.

[0504] In some embodiments, the shell thickness of the compound shown in encapsulation formula (V) is from 2 nm to 200 nm, optionally from 5 nm to 50 nm.

[0505] The third positive electrode active material can be prepared by sintering. The shell can be prepared by liquid-phase coating.

[0506] In some embodiments, the positive electrode film layer may include a positive electrode binder.

[0507] In some embodiments, the positive electrode binder may include a polyvinylidene fluoride homopolymer and / or copolymer. Optionally, the comonomer may include one or more of tetrafluoroethylene, hexafluoropropylene, and propylene. Optionally, the weight percentage of the comonomer is ≤1%. As an example, the positive electrode binder may include one or more of polyvinylidene fluoride (PVDF), polyvinylidene fluoride-tetrafluoroethylene-propylene terpolymer, and polyvinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer.

[0508] In some embodiments, the positive electrode binder may include one or more of polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resins.

[0509] In some embodiments, the weight-average molecular weight of the positive electrode binder may be from 300,000 to 2,000,000.

[0510] In some embodiments, the positive electrode film layer may include a positive electrode conductive agent. As an example, the positive electrode conductive agent may include one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers, and the embodiments of this application are not limited thereto.

[0511] In some embodiments, the positive electrode film layer may further include functional additives, which may include one or more of dispersants, plasticizers, pore-forming agents, dehydrating additives, deacidifying additives, and lithium replenishing agents.

[0512] The dispersant may include an abc type block copolymer, where the a-block includes polyvinylpyrrolidone, the b-block includes polyacrylic acid, and the c-block includes one or more of the following: polytetrahydrofuran chain, polyethylene oxide chain, polyethylene glycol chain, polypropylene glycol chain, and polypropylene triol chain. Optionally, the ratio of the average degree of polymerization of the a-block to the b-block is greater than 10:1. Optionally, the ratio of the average degree of polymerization of the a-block to the c-block is (0.1-10):1. Optionally, the weight-average molecular weight of the dispersant is from 2,000 to 100,000.

[0513] Plasticizers may include one or more of the following: strong solvent type (PP-SS) plasticizer, low temperature resistant type (PP-LT) plasticizer, low volatility type (PP-LV) plasticizer, low diffusion type (SP-LD) plasticizer, heat stable type (SP-Stab) plasticizer, and flame retardant type (SP-FR) plasticizer.

[0514] Strong solvent-based (PP-SS) plasticizers can provide strong plasticizing properties, and may include phthalates and non-phthalates (such as benzoates, tricresyl phosphate, etc.).

[0515] Low-temperature resistant (PP-LT) plasticizers can also provide good low-temperature resistance, for example, they may include aliphatic diesters.

[0516] Low-volatility (PP-LV) plasticizers also have lower volatility and may include, for example, trimellitates and polyesters.

[0517] Low-diffusion (SP-LD) plasticizers also have lower diffusion properties, and may include, for example, polyesters.

[0518] Heat-stabilized (SP-Stab) plasticizers also have heat-stabilizing properties, and may include, for example, epoxy compounds.

[0519] Flame-retardant (SP-FR) plasticizers also have flame-retardant properties, and may include, for example, phosphate esters and halogenated hydrocarbons.

[0520] Lithium supplements may include one or more of lithium-rich oxides (such as Li2NiO2, Li5FeO4, etc.), nanocomposites and binary lithium compounds. Optionally, the number of Li atoms in the molecular formula of the lithium supplement may be ≥1.5.

[0521] In some embodiments, the positive current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0522] The positive electrode sheet does not exclude additional functional layers besides the positive electrode film layer. For example, in some embodiments, the positive electrode sheet may also include a functional coating, which may be located between the positive current collector and the positive electrode film layer and / or on the surface of the positive electrode film layer facing away from the positive current collector. As an example, the functional coating may include one or more of conductive carbon, dehydrating additives, deacidifying additives, and lithium replenishing agents, and the embodiments of this application are not limited thereto. In some embodiments, the thickness of the functional coating may be 0.1 μm-10 μm.

[0523] The positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as the positive active material composition, conductive agent, binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and then obtaining the positive electrode sheet after drying, cold pressing and other processes.

[0524] [Negative electrode plate]

[0525] In some embodiments, the negative electrode sheet includes a negative current collector and a negative electrode film layer disposed on at least one surface of the negative current collector, the negative electrode film layer comprising a negative electrode active material. As an example, the negative current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode film layer is disposed on either or both of the opposite surfaces of the negative current collector.

[0526] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. The composite current collector may include a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector may be formed by forming a metal material (such as copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) on a polymer substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0527] In some embodiments, the thickness of the negative electrode current collector can be 3μm-20μm.

[0528] In some embodiments, the negative electrode active material may include one or more of carbon-based materials, silicon-based materials, tin-based materials, and lithium titanate. Carbon-based materials may include one or more of graphite (e.g., artificial graphite, natural graphite, etc.), soft carbon, and hard carbon. Silicon-based materials may include one or more of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may include one or more of elemental tin, tin oxide compounds, and tin alloys.

[0529] In some embodiments, the negative electrode active material may include a carbon-based material or a combination of a carbon-based material and a silicon-based material.

[0530] In some embodiments, the negative electrode active material may include a carbon-based material, and the carbon-based material includes graphite, or a combination of graphite and hard carbon. Optionally, the graphite may have a porous structure. Optionally, the specific capacity of the graphite may be greater than or equal to 340 mAh / g.

[0531] In some embodiments, the negative electrode active material may include a combination of carbon-based materials and silicon-based materials, wherein the carbon-based materials include graphite or a combination of graphite and hard carbon, and the silicon content in the negative electrode active material is greater than 0 and less than or equal to 30% by weight, based on the total weight of the negative electrode active material.

[0532] In some embodiments, the negative electrode film layer may include a negative electrode binder. As an example, the negative electrode binder may include one or more of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS), and the embodiments of this application are not limited thereto.

[0533] In some embodiments, the negative electrode film layer may further include a negative electrode conductive agent. As an example, the negative electrode conductive agent may include one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers, and the embodiments of this application are not limited thereto.

[0534] In some embodiments, the negative electrode film layer may also include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC)).

[0535] In some embodiments, the porosity of the negative electrode film is 20% to 50%.

[0536] The negative electrode sheet does not exclude additional functional layers besides the negative electrode film layer. In some embodiments, the negative electrode sheet may also include a functional coating, which may be located between the negative electrode current collector and the negative electrode film layer and / or on the surface of the negative electrode film layer facing away from the negative electrode current collector. Optionally, the functional coating may include carbon.

[0537] In some embodiments, the negative electrode film may further include a lithium replenishing material. Optionally, the lithium replenishing material includes one or more of lithium foil, lithium strip, lithium powder, and pre-lithiation reagent. Optionally, the pre-lithiation reagent may include one or more of Li-aromatic hydrocarbons, complexes of Li-aromatic hydrocarbons and ether solvents, and may be selected as one or more of lithium naphthalene and lithium biphenyl dimethyl ether (DME).

[0538] In some embodiments, the negative electrode sheet may include a negative current collector and a first negative electrode film layer and a second negative electrode film layer respectively disposed on two surfaces of the negative current collector. The composition of the first negative electrode film layer and the second negative electrode film layer may be the same or different; the thickness of the first negative electrode film layer and the second negative electrode film layer may be the same or different.

[0539] In some embodiments, the thickness ratio of the first negative electrode film layer and the second negative electrode film layer is 5:95 to 95:5.

[0540] The negative electrode sheet can be prepared by dispersing the above-mentioned components for preparing the negative electrode sheet, such as negative electrode active material, negative electrode conductive agent, negative electrode binder and any other components, in a solvent (e.g., deionized water) to form a negative electrode slurry; coating the negative electrode slurry onto the negative electrode current collector, and then obtaining the negative electrode sheet after drying, cold pressing and other processes.

[0541] In some embodiments, the negative electrode sheet may not include a negative electrode active material capable of lithium ion intercalation / deintercalation. For example, the negative electrode sheet may include a lithium sheet or a lithium alloy sheet; or, the negative electrode sheet may include a mesh or foam-like three-dimensional framework layer; or, the negative electrode sheet may include a negative current collector and a lithium-containing layer disposed on at least one surface of the negative current collector.

[0542] [Electrolytes]

[0543] The electrolyte acts as a conductor of ions between the positive and negative electrodes. This application does not specifically limit the type of electrolyte; it can be selected according to requirements. For example, the electrolyte may include one or more of the following: liquid electrolyte (also known as electrolyte solution), all-solid electrolyte, and gel electrolyte.

[0544] In some embodiments, the electrolyte is liquid and includes a lithium salt, a non-aqueous solvent for dissolving the lithium salt, and optional additives.

[0545] In some embodiments, the lithium salt may include one or more selected from LiPF6, LiBF4, LiN(SO2F)2, LiN(CF3SO2)2, LiClO4, LiAsF6, LiB(C2O4)2, LiBF2C2O4, and LiPO2F2.

[0546] In some embodiments, the concentration of lithium salt may be 0.5-1.5 mol / L.

[0547] In some embodiments, the non-aqueous solvent may include one or more selected from propylene carbonate, ethylene carbonate, butene carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl formate, ethyl acetate, methyl butyrate, ethyl butyrate, methyl propionate, ethyl propionate, propyl propionate, methyl acrylate, ethylene sulfite, propylene sulfite, dimethyl sulfite, diethyl sulfite, acid anhydride, N-methylpyrrolidone, acetonitrile, sulfolane, dimethyl sulfoxide, dimethyl sulfide, γ-butyrolactone, and tetrahydrofuran.

[0548] In some embodiments, the additive may include one or more of the following: negative electrode film-forming additive, positive electrode film-forming additive, additive to improve battery overcharge performance, additive to improve battery high-temperature performance, additive to improve battery low-temperature power performance, dehydration additive, deacidification additive, and additive capable of complexing transition metal ions. As an example, the additive may include...

[0549] The compounds are selected from one or more of the following: cyclic carbonate compounds containing carbon-carbon double bonds, halogen-substituted cyclic carbonate compounds, nitriles and polynitriles, phosphazene compounds, aromatic hydrocarbons and halogenated aromatic hydrocarbons, isocyanate compounds, acid anhydride compounds, sulfate ester compounds, sulfite ester compounds, sulfonate compounds, disulfonate ester compounds, borate ester compounds, phosphate ester compounds, amide compounds, carbodiimide compounds, crown ethers and azacrown ethers, and their respective derivatives; optionally... Including one or more of the following: vinylene carbonate (VC), 1,2,3-tris(2-cyanethoxy)propane (TCP), 1-aza-12-crown 4-ether (A12C4), N,N'-dicyclohexylcarbodiimide, N,N'-diisopropylcarbodiimide, N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, tris(hexafluoroisopropyl)boronic acid ester, tris(2,2,3,3-tetrafluoropropyl)boronic acid ester, and tris(pentafluorophenyl)boronic acid ester.

[0550] In some embodiments, the content of the additive may be less than or equal to 10%, based on the total weight of the electrolyte.

[0551] [Isolation membrane]

[0552] In some embodiments, the battery cell further includes a separator. This application does not impose any particular limitation on the type of separator; any known porous separator with good chemical and mechanical stability can be selected.

[0553] In some embodiments, the separator includes a porous substrate. The porous substrate may be made of at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, polyvinylidene fluoride, polytetrafluoroethylene, polyester, and polyimide. The porous substrate may be a single-layer film or a multi-layer composite film, without particular limitation. When the porous substrate is a multi-layer composite film, the materials of each layer may be the same or different, without particular limitation.

[0554] In some embodiments, the separator may further include a coating on at least one surface of the porous substrate. Optionally, the coating may include one or more of inorganic heat-resistant particles and organic heat-resistant particles.

[0555] In some embodiments, the porosity of the separator is 10%-40%.

[0556] In some embodiments, the thickness of the separator membrane may be 3μm-20μm.

[0557] This application also provides an electrical device, which includes at least one of the battery cell, battery module, or battery pack provided in this application. The battery cell, battery module, or battery pack can be used as the power source of the electrical device or as the energy storage unit of the electrical device. The electrical device may include, but is not limited to, mobile devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0558] As an electrical device, you can choose individual battery cells, battery modules, or battery packs according to your usage requirements.

[0559] Figure 6 This is an example of an electrical device. The device could be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the device's requirements for high power and high energy density, a battery pack or battery module can be used.

[0560] Another example of an electrical device could be a mobile phone, tablet, or laptop. These devices typically require a slim and lightweight design and can use a single battery cell as their power source.

[0561] Example

[0562] The following embodiments describe the disclosure of this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on mass, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0563] The batteries in Examples 1-26 and Comparative Example 3 were all prepared according to the following method.

[0564] Preparation of positive electrode sheet

[0565] The first and second positive electrode active materials, conductive agent acetylene black, and binder polyvinylidene fluoride (PVDF) shown in Tables 1 and 2 are thoroughly mixed in an appropriate amount of solvent NMP at a mass ratio of 96:2:2 to form a uniform positive electrode slurry. The positive electrode slurry is uniformly coated on both surfaces of the positive electrode current collector aluminum foil, and after drying and cold pressing, a positive electrode sheet is obtained.

[0566] Preparation of negative electrode sheet

[0567] The negative electrode active material graphite, the binder styrene-butadiene rubber (SBR), the thickener sodium carboxymethyl cellulose (CMC-Na), and the conductive agent carbon black (Super P) are mixed thoroughly in an appropriate amount of deionized water at a mass ratio of 96.2:1.8:1.2:0.8 to form a uniform negative electrode slurry. The negative electrode slurry is then uniformly coated onto the surface of the negative electrode current collector copper foil. After drying and cold pressing, the negative electrode sheet is obtained.

[0568] Preparation of electrolyte

[0569] Ethyl carbonate (EC), methyl ethyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a volume ratio of 1:1:1 to obtain an organic solvent. Then, fully dried LiPF6 was dissolved in the organic solvent to prepare an electrolyte with a concentration of 1 mol / L.

[0570] Preparation of the separating membrane

[0571] Porous polyethylene film is used as the separator.

[0572] Battery manufacturing

[0573] The positive electrode, separator, and negative electrode are stacked and wound in sequence to obtain the electrode assembly. The electrode assembly is placed in the outer packaging, dried, and then injected with electrolyte. After vacuum sealing, standing, formation, and shaping, the battery is obtained.

[0574] Comparative Example 1

[0575] The battery is prepared in the same way as in Example 1, except for the preparation of the positive electrode sheet.

[0576] The second positive electrode active material, conductive agent acetylene black, and binder polyvinylidene fluoride (PVDF) shown in Table 1 are thoroughly mixed in an appropriate amount of solvent NMP at a mass ratio of 96:2:2 to form a uniform positive electrode slurry. The positive electrode slurry is uniformly coated on both surfaces of the positive electrode current collector aluminum foil, and after drying and cold pressing, a positive electrode sheet is obtained.

[0577] Comparative Example 2

[0578] The battery is prepared in the same way as in Example 1, except for the preparation of the positive electrode sheet.

[0579] The first positive electrode active material, conductive agent acetylene black, and binder polyvinylidene fluoride (PVDF) shown in Table 1 are thoroughly mixed in an appropriate amount of solvent NMP at a mass ratio of 96:2:2 to form a uniform positive electrode slurry. The positive electrode slurry is uniformly coated on both surfaces of the positive electrode current collector aluminum foil, and after drying and cold pressing, a positive electrode sheet is obtained.

[0580] In Tables 1 and 2, NCM523 refers to LiNi 0.5 Co 0.2 Mn 0.3 O2, LMFP refers to carbon-coated LiMn 0.7 Fe 0.3 PO4.

[0581] The NCM523 and LMFP used in the various embodiments and comparative examples are commercially available. Multiple commercially available materials can be sieved using a suitable sieve and then mixed in a predetermined ratio to obtain the final product. Alternatively, the commercially available materials can be ball-milled to a suitable size, sieved using a suitable sieve, and then mixed in a predetermined ratio to obtain the final product. Alternatively, a sintering method can be used, and the sintering process parameters (e.g., sintering temperature, sintering time, sintering atmosphere, etc.) and grinding parameters (e.g., grinding speed, grinding time, etc.) can be adjusted, and a suitable sieve can be used for sintering. Alternatively, multiple materials of different sizes prepared by the sintering method can be mixed in a predetermined ratio to obtain the final product.

[0582] w a This indicates the weight content of the first positive electrode active material based on the total weight of the positive electrode active material composition. bThe weight content of the second positive electrode active material is indicated based on the total weight of the positive electrode active material composition.

[0583] P1 is the compacted powder density of the first positive electrode active material at 30000N. P2 is the compacted powder density of the second positive electrode active material at 30000N.

[0584] ρD represents the compaction density of the positive electrode film.

[0585] The compaction density efficiency of the positive electrode sheet = PD / [(P1×W)] a )+(P2×W b (P1×W) a )+(P2×W b ) represents the theoretical compaction density of the positive electrode active material composition.

[0586] y represents the molar amount of Fe in LMFP, which is 0.3.

[0587] V B This represents the voltage plateau for Fe in LMFP, measured in volts (V).

[0588] In the particle size distribution curve of the positive electrode active material composition, the volume distribution peak with the maximum peak intensity is denoted as the first peak, and the volume distribution particle size corresponding to the maximum peak intensity of the first peak is denoted as Dv1. The volume distribution peak with the second maximum peak intensity is denoted as the second peak, and the volume distribution particle size corresponding to the maximum peak intensity of the second peak is denoted as Dv2.

[0589] Figure 7 This is the particle size distribution curve of the positive electrode active material composition of Example 11, as shown below. Figure 7 As shown, in the particle size distribution curve of the positive electrode active material composition, the peak on the left is the second peak (i.e., the volume distribution peak with the second largest peak intensity), and the peak on the right is the first peak (i.e., the volume distribution peak with the largest peak intensity).

[0590] The above parameters can be measured according to the test methods given above.

[0591] In Table 1, the first positive electrode active material is mainly monocrystalline, accounting for over 90% of the total. The second positive electrode active material in Examples 1-11 is mainly polycrystalline, accounting for over 90% of the total. The second positive electrode active material in Examples 12-16 is mainly monocrystalline, accounting for over 90% of the total.

[0592] In Table 2, the first positive electrode active material is mainly polycrystalline, accounting for over 90% of the total. The second positive electrode active material in Examples 17-21 is mainly monocrystalline, accounting for over 90% of the total. The second positive electrode active material in Examples 22-26 is mainly polycrystalline, accounting for over 90% of the total.

[0593] Test section

[0594] At 25℃, the battery is charged at a constant current of 1C to 4.3V, and then charged at a constant voltage until the current reaches 0.05C. At this point, the battery is fully charged, and the charging capacity is recorded; this is the first charge capacity. After letting the battery rest for 5 minutes, it is discharged at a constant current of 1C to 2.8V. This completes one charge-discharge cycle, and the discharge capacity is recorded; this is the first discharge capacity. The battery is subjected to cyclic charge-discharge tests using the above method, and the discharge capacity after each cycle is recorded until the battery's discharge capacity decreases to 80% of the first cycle's discharge capacity. The number of cycles at this point characterizes the battery's cycle performance. The higher the number of cycles, the better the battery's lifespan.

[0595] As can be seen from the test results in Tables 1 and 2, when the particle size distribution curve of the positive electrode active material composition satisfies 0 < |Dv1-Dv2| / Dv1≤50, the positive electrode sheet using this positive electrode active material composition can have both high compaction density and high compaction efficiency. This can enable the secondary battery to have high energy density and long service life.

[0596] The preparation methods of the batteries in Examples 27-31 are similar to those in Example 4, except that the types of the first positive electrode active materials are different, as detailed in Table 3.

[0597] The first positive electrode active material in Examples 27-31 is obtained by sintering and by adjusting sintering process parameters (e.g., sintering temperature, sintering time, sintering atmosphere, etc.), grinding parameters (e.g., grinding speed, grinding time, etc.), and selecting a suitable sieve for sieving; or, by mixing materials of different particle sizes prepared by sintering in a predetermined ratio.

[0598] As shown in Table 3, by doping specific elements at the Mn site and at the Li, P and / or O sites of LiMnPO4, specifically at the Mn and P sites, or more specifically at the Li, Mn, P and O sites, the compaction density of the positive electrode sheet can be further improved, thereby increasing the energy density of the battery and improving its cycle performance.

[0599] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

[0600]

[0601]

Claims

1. A positive electrode active material composition, wherein, The positive electrode active material composition comprises a first positive electrode active material and a second positive electrode active material different in crystal form from the first positive electrode active material, the first positive electrode active material comprises a phosphate of olivine structure, the second positive electrode active material comprises a layered oxide, a particle size distribution curve of the positive electrode active material composition has at least two volume distribution peaks, a volume distribution peak with the maximum peak intensity is denoted as a first peak, and a volume distribution particle size corresponding to the maximum peak intensity of the first peak is denoted as Dv1, a volume distribution peak with the second maximum peak intensity is denoted as a second peak, and a volume distribution particle size corresponding to the maximum peak intensity of the second peak is denoted as Dv2, and 0 < |Dv1-Dv2| / Dv1 ≤ 50.

2. The positive electrode active material composition according to claim 1, wherein, the volume distribution particle size Dv50 of the first positive electrode active material is 0.25 μm to 12.5 μm; and / or, the volume distribution particle size Dv50 of the second positive electrode active material is 2.5 μm to 16.5 μm.

3. The positive electrode active material composition according to claim 1 or 2, wherein, the volume distribution particle size Dv50 of the first positive electrode active material is 0.25 μm to 3.5 μm, and the particle size distribution curve of the positive electrode active material composition satisfies: 0.1 ≤ |Dv1-Dv2| / Dv1 ≤ 50; and / or, 0.3 μm ≤ Dv1 ≤ 17.8 μm; and / or, 0.3 μm ≤ Dv2 ≤ 17.8 μm.

4. The positive electrode active material composition according to claim 3, wherein, the particle size distribution curve of the positive electrode active material composition satisfies: 0.46 ≤ |Dv1-Dv2| / Dv1 ≤ 39.6; and / or, 0.35 μm ≤ Dv1 ≤ 12.1 μm; and / or, 0.46 μm ≤ Dv2 ≤ 14.2 μm.

5. The positive electrode active material composition according to claim 1 or 2, wherein, the volume distribution particle size Dv50 of the first positive electrode active material is 3.5 μm to 12.5 μm, and the particle size distribution curve of the positive electrode active material composition satisfies: 0.1 ≤ |Dv1-Dv2| / Dv1 ≤ 6.0; and / or, 2.0 μm ≤ Dv1 ≤ 12.5 μm; and / or, 2.0 μm ≤ Dv2 ≤ 15.0 μm.

6. The positive electrode active material composition according to claim 5, wherein, the particle size distribution curve of the positive electrode active material composition satisfies: 0.34 ≤ |Dv1-Dv2| / Dv1 ≤ 3.8; and / or, 3.0 μm ≤ Dv1 ≤ 12.3 μm; and / or, 3.4 μm ≤ Dv2 ≤ 14.3 μm.

7. A positive electrode active material composition, wherein, The positive electrode active material composition comprises a first positive electrode active material and a second positive electrode active material different from the first positive electrode active material in crystal form, the first positive electrode active material comprises a phosphate with olivine structure, the second positive electrode active material comprises a layered oxide, a particle size distribution curve of the positive electrode active material composition has at least two volume distribution peaks, a volume distribution peak with the maximum peak intensity is recorded as a first peak, and a volume distribution particle size corresponding to the maximum peak intensity of the first peak is recorded as Dv1, a volume distribution peak with the second maximum peak intensity is recorded as a second peak, and a volume distribution particle size corresponding to the maximum peak intensity of the second peak is recorded as Dv2, wherein, the volume distribution particle size Dv50 of the first positive electrode active material is 0.25 μm to 3.5 μm, and 0.3 μm ≤ Dv1 ≤ 17.8 μm, 0.3 μm ≤ Dv2 ≤ 17.8 μm; or the volume distribution particle size Dv50 of the first positive electrode active material is 3.5 μm to 12.5 μm, and 2.0 μm ≤ Dv1 ≤ 12.5 μm, 2.0 μm ≤ Dv2 ≤ 15.0 μm.

8. The positive electrode active material composition according to claim 7, wherein, the volume distribution particle size Dv50 of the first positive electrode active material is 0.25 μm to 3.5 μm, and 0.35 μm ≤ Dv1 ≤ 12.1 μm, 0.46 μm ≤ Dv2 ≤ 14.2 μm.

9. The positive electrode active material composition according to claim 7, wherein, the volume distribution particle size Dv50 of the first positive electrode active material is 3.5 μm to 12.5 μm, and 3.0 μm ≤ Dv1 ≤ 12.3 μm, 3.4 μm ≤ Dv2 ≤ 14.3 μm.

10. The positive electrode active material composition according to any one of claims 1 to 9, wherein, the morphology of the first positive electrode active material comprises one or more of single crystal, polycrystal, the morphology of the second positive electrode active material comprises one or more of single crystal, polycrystal; and / or, the volume distribution particle size Dv50 of the first positive electrode active material with single crystal morphology is 0.25 μm to 3.5 μm; and / or, the volume distribution particle size Dv10 of the first positive electrode active material with single crystal morphology is 0.05 μm to 1.5 μm; and / or, the volume distribution particle size Dv50 of the first positive electrode active material with polycrystal morphology is 3.5 μm to 12.5 μm; and / or, the volume distribution particle size Dv10 of the first positive electrode active material with polycrystal morphology is 0.1 μm to 5.0 μm; and / or, the volume distribution particle size Dv50 of the second positive electrode active material with single crystal morphology is 2.5 μm to 16.5 μm; and / or, the volume distribution particle size Dv10 of the second positive electrode active material with single crystal morphology is 0.3 μm to 8 μm; and / or, the volume distribution particle size Dv50 of the second positive electrode active material with polycrystal morphology is 2.5 μm to 16.5 μm; the volume distribution particle size Dv10 of the second positive electrode active material with polycrystal morphology is 0.5 μm to 12 μm.

11. The positive electrode active material composition according to claim 10, wherein, the volume distribution particle size Dv50 of the first positive electrode active material of a single crystal morphology is 0.35 pm to 2.5 pm; and / or, the volume distribution particle size Dv10 of the first positive electrode active material of a single crystal morphology is 0.1 pm to 1.0 pm; and / or, the volume distribution particle size Dv50 of the first positive electrode active material of a polycrystal morphology is 3.8 pm to 10.5 pm; and / or, the volume distribution particle size Dv10 of the first positive electrode active material of a polycrystal morphology is 0.5 pm to 4.5 pm; and / or, the volume distribution particle size Dv50 of the second positive electrode active material of a single crystal morphology is 3.0 pm to 8.5 pm; and / or, the volume distribution particle size Dv10 of the second positive electrode active material of a single crystal morphology is 1.0 pm to 3.5 pm; and / or, the volume distribution particle size Dv50 of the second positive electrode active material of a polycrystal morphology is 3.0 pm to 15.5 pm; and / or, the volume distribution particle size Dv10 of the second positive electrode active material of a polycrystal morphology is 1.0 pm to 8.5 pm.

12. The positive electrode active material composition according to any one of claims 1 to 11, wherein The weight content of the first positive electrode active material is denoted as w a , the weight content of the second positive electrode active material is denoted as w b , and then w a selected from the range of 0.5% to 99.5%; and / or, w b is selected from the range of 0.5% to 99.5%.

13. The positive electrode active material composition according to claim 12, wherein w a selected from the range of 2% to 95%; and / or, w b is selected from the range of 5% to 98%.

14. The positive electrode active material composition according to any one of claims 1 to 13, wherein The powder compaction density P1 of the first positive electrode active material at 30000N is 1.89 g / cm 3 above; and / or, The powder compaction density P2 of the second positive electrode active material at 30000 N is greater than or equal to 2.90 g / cm3 3 ; and / or, The BET specific surface area of the second positive electrode active material is less than or equal to 1.73 m 2 / g.

15. The positive electrode active material composition according to claim 14, wherein The powder compaction density P1 of the first positive electrode active material at 30000N is 1.95 g / cm 3 above; and / or, The powder compaction density P2 of the second positive electrode active material at 30000 N is greater than or equal to 3.1 g / cm3 3 ; and / or, The BET specific surface area of the second positive electrode active material is less than or equal to 1.5 m 2 / g.

16. The positive electrode active material composition according to claim 15, wherein The powder compaction density P1 of the first positive electrode active material at 30000N is 1.98 g / cm 3 above; and / or, The powder compaction density P2 of the second positive electrode active material at 30000 N is greater than or equal to 3.3 g / cm3 3 ; and / or, The BET specific surface area of the second positive electrode active material is 0.28 m 2 / g to 1.5 m 2 / g.

17. The positive electrode active material composition according to claim 16, wherein The powder compaction density P1 of the first positive electrode active material at 30000 N is 2.0 g / cm3 3 The above.

18. The positive electrode active material composition according to claim 17, wherein The powder compaction density P1 of the first positive electrode active material at 30000 N is 2.2 g / cm 3 The above.

19. The positive electrode active material composition according to claim 18, wherein The powder compaction density P1 of the first positive electrode active material at 30000 N is 2.2 g / cm 3 above and 2.8 g / cm 3 below or 2.2 g / cm 3 above and 2.65 g / cm 3 below.

20. The positive electrode active material composition according to any one of claims 1 to 19, wherein, the first positive electrode active material comprises a compound represented by formula (I), Li a A x Mn 1-y M 1 y P 1-z M 2 z O 4-n D n (I) A comprises one or more elements selected from Group IA, Group IIA, Group IIIA, Group IIB, Group VB, and Group VIB; M 1 comprises one or more elements selected from Group IA, Group IIA, Group IIIA, Group IVA, Group VA, Group IIB, Group IVB, Group VB, Group VIB, and Group VIII; M 2 comprises one or more elements selected from Group IIIA, Group IVA, Group VA, and Group VIA; D comprises one or more elements selected from Group VIA and Group VIIA; a is selected from the range of 0.85 to 1.15; x is selected from the range of 0 to 0.1; y is selected from the range of 0.001 to 0.999; z is selected from the range of 0 to 0.5; n is selected from the range of 0 to 0.

5.

21. The positive electrode active material composition according to claim 20, wherein A comprises one or more elements selected from the group consisting of Rb, Cs, Be, Ca, Sr, Ba, Ga, In, Cd, V, Ta, Cr, Zn, Al, Na, K, Mg, Nb, Mo, and W; and / or, M 1 including one or more elements selected from Rb, Cs, Be, Ca, Sr, Ba, In, Pb, Bi, Cd, Hf, Ta, Cr, Ru, Rh, Pd, Os, Ir, Pt, Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb, and Ge; and / or, M 2 comprises one or more elements selected from B (boron), S, Si, and N; and / or, D comprises one or more elements selected from the group consisting of S, F, Cl, and Br.

22. The positive electrode active material composition according to claim 21, wherein A comprises one or more elements selected from the group consisting of Zn, Al, Na, K, Mg, Nb, Mo, and W; and / or, M 1 comprises one or more elements selected from the group consisting of Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb, and Ge.

23. The positive electrode active material composition according to claim 20, wherein A comprises any one element selected from the group consisting of Zn, Al, Na, K, Mg, Nb, Mo, and W; and / or, M 1 comprises one or more elements selected from the group consisting of Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge; and / or, M 2 comprises any one element selected from B (boron), S, Si, and N; and / or, D comprises any one element selected from the group consisting of S, F, Cl, and Br.

24. The positive electrode active material composition according to claim 23, wherein A comprises any one element selected from the group consisting of Mg and Nb; and / or, M 1 comprising at least two elements selected from the group consisting of Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge; and / or, M 2 S; and / or, D is F.

25. The positive electrode active material composition according to claim 24, wherein M 1 comprises at least two elements selected from the group consisting of Fe, Ti, V, Ni, Co and Mg.

26. The positive electrode active material composition according to claim 25, wherein M 1 comprises at least two elements selected from the group consisting of Fe, Ti, V, Co and Mg.

27. The positive electrode active material composition according to claim 26, wherein M 1 comprising one or more elements selected from the group consisting of Ti, V, Co, and Mg.

28. The positive electrode active material composition according to any one of claims 20 to 27, wherein, a is selected from the range of 0.9 to 1.1 ; and / or, x is selected from the range of 0.001 to 0.005; and / or, y is selected from the range of 0.001 to 0.5; and / or, z is selected from the range of 0.001 to 0.5; and / or, n is selected from the range of 0 to 0.

1.

29. The positive electrode active material composition according to claim 28, wherein, a is selected from the range of 0.97 to 1.01 ; and / or, y is selected from the range of 0.01 to 0.5; and / or, z is selected from the range of 0.001 to 0.1 ; and / or, n is selected from the range of 0.001 to 0.

005.

30. The positive electrode active material composition according to claim 29, wherein, y is selected from the range of 0.25 to 0.

5.

31. The positive electrode active material composition according to claim 30, wherein, z is selected from the range of 0.001 to 0.

005.

32. The positive electrode active material composition according to any one of claims 20 to 31, wherein, x is 0, z is selected from the range of 0.001 to 0.5, and n is selected from the range of 0.001 to 0.1 ; or, x is selected from the range of 0.001 to 0.1, z is 0, and n is selected from the range of 0.001 to 0.1 ; or, x is selected from the range of 0.001 to 0.1, z is selected from the range of 0.001 to 0.5, and n is 0; or, x is 0, z is 0, and n is selected from the range of 0.001 to 0.1 ; or, x is 0, z is selected from the range of 0.001 to 0.5, and n is 0; or, x is selected from the range of 0.001 to 0.1, z is selected from the range of 0.001 to 0.5, and n is selected from the range of 0.001 to 0.

1.

33. The positive electrode active material composition according to any one of claims 20 to 32, wherein, y : z is selected from the range of 0.002 to 999.

34. The positive electrode active material composition according to claim 33, wherein, y : z is selected from the range of 0.025 to 999 or 0.002 to 500.

35. The positive electrode active material composition according to claim 34, wherein, y : z is selected from the range of 0.2 to 600.

36. The positive electrode active material composition according to any one of claims 20 to 35, wherein, z : n is selected from the range of 0.002 to 500.

37. The positive electrode active material composition according to claim 36, wherein, z : n is selected from the range of 0.2 to 100.

38. The positive electrode active material composition according to claim 37, wherein, z : n is selected from the range of 0.2 to 50.

39. The positive electrode active material composition according to any one of claims 20 to 38, wherein, A comprises one or more elements selected from the group consisting of Zn, Al, Na, K, Mg, Nb, Mo and W; M 1 comprises one or more elements selected from the group consisting of Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb and Ge; M 2 comprises one or more elements selected from the group consisting of B (boron), S, Si and N; D comprises one or more elements selected from the group consisting of S, F, Cl and Br; a is selected from the range of 0.9 to 1.1, x is selected from the range of 0.001 to 0.1, y is selected from the range of 0.001 to 0.5, z is selected from the range of 0.001 to 0.1, n is selected from the range of 0.001 to 0.

1.

40. The positive electrode active material composition according to any one of claims 20 to 39, wherein, M 1 comprises one or more elements selected from the group consisting of Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb and Ge; M 2 comprises one or more elements selected from the group consisting of B (boron), Si, N and S; a is selected from the range of 0.9 to 1.1, x is 0, y is selected from the range of 0.001 to 0.5, z is selected from the range of 0.001 to 0.1, n is 0.

41. The positive electrode active material composition according to claim 40, wherein, M 1 comprises one or more elements selected from the group consisting of Zn, Fe, Ti, V, Ni, Co and Mg.

42. The positive electrode active material composition of any one of claims 20 to 41, wherein, (1 -y):y is in the range of 0.1 -999; and / or, a:x is in the range of 1 to 1200.

43. The positive electrode active material composition of claim 42, wherein, (1 -y):y is in the range of 0.1 -10 or in the range of 0.67-999; and / or, a:x is in the range of 9 to 1100.

44. The positive electrode active material composition of claim 43, wherein, (1 -y):y is in the range of 1 to 10; and / or, a:x is in the range of 190-998.

45. The cathode active material composition of claim 44, wherein, (1 -y):y is in the range of 1 to 4.

46. The cathode active material composition of claim 45, wherein, (1 -y):y is in the range of 1.5 to 3.

47. The positive electrode active material composition according to any one of claims 20 to 46, wherein, z : (1 -z) is 1 :9 to 1 :

999.

48. The positive electrode active material composition according to claim 47, wherein, z : (1 -z) is 1 :499 to 1 :

249.

49. The positive electrode active material composition of any one of claims 20 to 48, wherein, the first positive electrode active material comprises an inner core and a shell that coats the inner core, the inner core comprises the compound represented by the formula (I); the shell comprises one or more coating layers; each coating layer has ionic and / or electronic conductivity.

50. The cathode active material composition of claim 49, wherein, each of the one or more coating layers independently comprises one or more selected from the group consisting of pyrophosphate, phosphate, carbon, doped carbon, oxide, boride, and polymer.

51. The positive electrode active material composition of claim 49 or 50, wherein, the shell comprises one coating layer.

52. The positive electrode active material composition of claim 51, wherein, the coating layer comprises one or more selected from the group consisting of pyrophosphate, phosphate, carbon, doped carbon, oxide, boride, and polymer.

53. The positive electrode active material composition of claim 49, wherein, the shell comprises a first coating layer that coats the inner core and a second coating layer that coats the first coating layer.

54. The positive electrode active material composition of claim 53, wherein, each of the first and second coating layers independently comprises one or more selected from the group consisting of pyrophosphate, phosphate, carbon, doped carbon, oxide, boride, and polymer.

55. The positive electrode active material composition of claim 54, wherein, the first coating layer comprises one or more selected from the group consisting of pyrophosphate, phosphate, oxide, and boride, and the second coating layer comprises one or more selected from the group consisting of carbon and doped carbon.

56. The positive electrode active material composition of claim 49, wherein, the shell comprises a first coating layer that coats the inner core, a second coating layer that coats the first coating layer, and a third coating layer that coats the second coating layer.

57. The positive electrode active material composition of claim 56, wherein, each of the first, second, and third coating layers independently comprises one or more selected from the group consisting of pyrophosphate, phosphate, carbon, doped carbon, oxide, boride, and polymer.

58. The positive electrode active material composition of claim 57, wherein, the first coating layer comprises pyrophosphate, the second coating layer comprises one or more selected from the group consisting of phosphate, oxide, and boride, and the third coating layer comprises one or more selected from the group consisting of carbon and doped carbon.

59. The positive electrode active material composition of any one of claims 50, wherein, The pyrophosphate is M b (P2O7) c ; and / or, The phosphate is X m (PO4) q ; and / or, the doping element in the doped carbon comprises one or more selected from the group consisting of Group IIIA, Group VA, Group VIA, and Group VIIA; and / or, The oxide is M' d O e ; and / or, The boride is Z v B w ; and / or, the polymer comprises one or more selected from the group consisting of polysaccharide and derivatives thereof, and polysiloxane; M, X, and Z each independently comprise one or more elements selected from the group consisting of Group IA, Group IIA, Group IIIA, Group IB, Group IIB, Group IVB, Group VB, Group VIIB, and Group VIII; b is selected from the range of 1 to 4; c is selected from the range of 1 to 6; m is selected from the range of 1 to 2; q is selected from the range of 1 to 4; M' comprises one or more elements selected from alkali metals, alkaline earth metals, transition metals, Group IIIA elements, Group IVA elements, lanthanide series elements, and Sb; d is greater than 0 and less than or equal to 2; e is greater than 0 and less than or equal to 5; v is selected from the range of 1 to 7; w is selected from the range of 1 to 2.

60. The positive electrode active material composition of claim 59, wherein, M, X, and Z each independently comprise one or more elements selected from Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb, Mn, and Al; and / or, the doping element in the doped carbon comprises one or more elements selected from nitrogen, phosphorus, sulfur, boron, and fluorine; and / or, M' comprises one or more elements selected from Li, Be, B, Na, Mg, Al, Si, P, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, W, La, and Ce; and / or, the polysiloxane is selected from one or more of linear structured polysiloxanes and cyclic structured polysiloxanes; and / or, the polysaccharide is selected from one or more of plant polysaccharides and marine polysaccharides.

61. The positive electrode active material composition of claim 60, wherein, M' comprises one or more elements selected from Mg, Al, Si, Zn, Zr, and Sn.

62. The cathode active material composition of claim 49, wherein, the first positive electrode active material comprises a core and a shell coating the core, The core comprises Li a Mn 1-y M 1 y P 1-z M 2 z O4, a is selected from the range of 0.9 to 1.1, y is selected from the range of 0.001 to 0.5, z is selected from the range of 0.001 to 0.1, M 1 comprises one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb and Ge, M 2 comprises one or more elements selected from B (boron), S, Si and N; the shell comprises a first coating layer coating the core and a second coating layer coating the first coating layer, the first coating layer comprising pyrophosphate MP2O7 and phosphate XPO4, M and X each independently comprising one or more elements selected from Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb, and Al; the second coating layer comprising carbon.

63. The cathode active material composition of claim 49, wherein, the first positive electrode active material comprises a core and a shell coating the core, The core comprises Li a Mn 1-y M 1 y P 1-z M 2 z O4, a is selected from the range of 0.9 to 1.1, y is selected from the range of 0.001 to 0.5, z is selected from the range of 0.001 to 0.1, M 1 comprises one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb and Ge, M 2 comprises one or more elements selected from B (boron), S, Si and N; the shell comprises a first coating layer coating the core, a second coating layer coating the first coating layer, and a third coating layer coating the second coating layer, the first cladding layer comprises a pyrophosphate Li f QP2O7and / or Q g (P2O7) h , 0≤f≤2, 1≤g≤4, 1≤h≤6, the pyrophosphate Li f QP2O7and / or Q g (P2O7) h each Q in QP2O7and / or Q independently comprises one or more elements selected from Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb and Al; the second coating layer comprises crystalline phosphate XPO4, X comprising one or more elements selected from Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb, and Al; the third coating layer comprises carbon.

64. The cathode active material composition of claim 49, wherein, one or more coating layers in the shell that are farthest from the core each independently comprise one or more selected from polysiloxanes, polysaccharides, and polysaccharide derivatives.

65. The positive electrode active material composition of claim 64, wherein, the polysiloxane comprises structural units represented by formula (i), （i） R1and R2are independently selected from the group consisting of H, -COOH, -OH, -SH, -CN, -SCN, amino, phosphate, carboxylate, amide, aldehyde, sulfonyl, polyether segment, C1-C20 aliphatic, C1-C20 haloaliphatic, C1-C20 heteroaliphatic, C1-C20 haloheteroaliphatic, C6-C20 aromatic, C6-C20 haloaromatic, C2-C20 heteroaromatic, and C2-C20 haloheteroaromatic.

66. The cathode active material composition of claim 65, wherein, R1and R2are independently selected from the group consisting of H, amino, phosphate, polyether segment, C1-C8 alkyl, C1-C8 haloalkyl, C1-C8 heteroalkyl, C1-C8 haloheteroalkyl, C2-C8 alkenyl, and C2-C8 haloalkenyl.

67. The cathode active material composition of claim 64, wherein, The polysiloxane further comprises a capping group comprising one or more of the following functional groups selected from the group consisting of polyether, C1-C8 alkyl, C1-C8 haloalkyl, C1-C8 heteroalkyl, C1-C8 haloheteroalkyl, C2-C8 alkenyl, C2-C8 haloalkenyl, C6-C20 aromatic, C1-C8 alkoxy, C2-C8 epoxy, hydroxyl, C1-C8 hydroxyalkyl, amino, C1-C8 aminoalkyl, carboxyl, C1-C8 carboxyalkyl.

68. The cathode active material composition of claim 64, wherein, The polysiloxane comprises one or more selected from the group consisting of polydimethylsiloxane, polydiethylsiloxane, polymethylethylsiloxane, polymethylvinylsiloxane, polyphenylmethylsiloxane, polymethylhydrosiloxane, carboxyl functionalized polysiloxane, epoxy terminated polysiloxane, methoxy terminated polydimethylsiloxane, hydroxypropyl terminated polydimethylsiloxane, polymethylchloropropylsiloxane, hydroxyl terminated polydimethylsiloxane, polymethyltrifluoropropylsiloxane, perfluorooctylmethylpolysiloxane, aminoethyl aminopropyl polydimethylsiloxane, end group polyether polydimethylsiloxane, pendant aminopropyl polysiloxane, aminopropyl terminated polydimethylsiloxane, pendant phosphate grafted polydimethylsiloxane, pendant polyether grafted polydimethylsiloxane, 1,3,5,7-octamethylcyclotetrasiloxane, 1,3,5,7-tetrahydro-1,3,5,7-tetramethylcyclotetrasiloxane, cyclopentadimethylsiloxane, 2,4,6,8-tetramethylcyclotetrasiloxane, 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane, cyclic polymethylvinylsiloxane, hexadecamethylcyclooctasiloxane, tetradecamethylcyclotetrasiloxane, and cyclic polydimethylsiloxane.

69. The cathode active material composition of claim 64, wherein, The number average molecular weight of the polysiloxane, the polysaccharide, and the polysaccharide derivative are each independently 300,000 or less.

70. The cathode active material composition of claim 69, wherein, The number average molecular weight of the polysiloxane, the polysaccharide, and the polysaccharide derivative are each independently 10000 to 200,000.

71. The cathode active material composition of claim 70, wherein, The number average molecular weight of the polysiloxane, the polysaccharide, and the polysaccharide derivative are each independently 20000 to 120,000.

72. The cathode active material composition of claim 71, wherein, The number average molecular weight of the polysiloxane, the polysaccharide, and the polysaccharide derivative are each independently 400 to 80,000.

73. The cathode active material composition of claim 64, wherein, The mass percentage content of the polar functional group in the polysiloxane is a, 0 < a < 50%.

74. The positive electrode active material composition of claim 73, wherein, 5%≤α≤30%。 75. The cathode active material composition of claim 64, wherein, The substituents attached to the sugar units in the polysaccharide and the polysaccharide derivative each independently include one or more of the group consisting of -OH, -COOH and salts thereof, -R-OH, -SO3H and salts thereof, -R-OH, -R-SO3H and salts thereof, sulfate groups, alkoxy groups, R representing an alkylene group.

76. The cathode active material composition of claim 75, wherein, R represents a C1-C5 alkylene group.

77. The cathode active material composition of claim 75, wherein, The substituents attached to the sugar units in the polysaccharide and the polysaccharide derivative each independently include one or more of the group consisting of -OH, -COOH, -COOLi, -COONa, -COOK, -SO3H, -SO3Li, -SO3Na, -SO3K, -CH2-SO3H, -CH2-SO3Li, -CH2-SO3Na, -CH2-SO3K, methoxy, ethoxy.

78. The positive electrode active material composition of claim 64, the polysaccharide comprising one or more selected from the group consisting of pectin, carboxymethyl starch, hydroxypropyl starch, dextrin, cellulose ether, carboxymethyl chitosan, hydroxyethyl cellulose, carboxymethyl cellulose, carboxypropyl methyl cellulose, guar gum, sesbania gum, gum arabic, lithium alginate, sodium alginate, potassium alginate, fucoidan, agar, carrageenan, furcellaran, xanthan gum, and fenugreek gum.

79. The cathode active material composition of claim 64, wherein, The mass percentage content of the substituents attached to the sugar units in the polysaccharide and the polysaccharide derivative each independently is 20% to 85%.

80. The cathode active material composition of claim 79, wherein, The mass percentage content of the substituents attached to the sugar units in the polysaccharide and the polysaccharide derivative each independently is 30% to 78%.

81. The cathode active material composition of claim 49, wherein, The degree of lattice mismatch between the material of the inner core and the material of the shell is less than 10%.

82. The cathode active material composition of any one of claims 20 to 81, wherein, based on the total weight of the first positive electrode active material, the content of manganese element is in the range of 10% to 35% by weight; and / or, the content of phosphorus element is in the range of 12% to 25% by weight; and / or, the weight ratio of manganese element and phosphorus element ranges from 0.71 to 1.

85.

83. The cathode active material composition of claim 82, wherein, based on the total weight of the first positive electrode active material, the content of manganese element is in the range of 13.3% to 33.2% by weight; and / or, the content of phosphorus element is in the range of 15% to 20% by weight; and / or, the weight ratio of manganese element and phosphorus element ranges from 0.90 to 1.

25.

84. The cathode active material composition of claim 83, wherein, based on the total weight of the first positive electrode active material, the content of manganese element is in the range of 15% to 30% by weight; and / or, the content of phosphorus element is in the range of 16.8% to 19.5% by weight; and / or, the weight ratio of manganese element and phosphorus element ranges from 0.95 to 1.

20.

85. The cathode active material composition of claim 84, wherein, based on the total weight of the first positive electrode active material, 86. The cathode active material composition according to any one of claims 1 to 47, wherein, the content of manganese element is in the range of 17% to 20% by weight.

87. The cathode active material composition of claim 86, wherein, The first positive electrode active material is surface-coated with one or more of carbon and doped carbon.

88. The cathode active material composition of claim 86, wherein, The first positive electrode active material is surface-coated with carbon.

89. The cathode active material composition of claim 49, wherein, The doping element in the doped carbon includes one or more selected from the group consisting of nitrogen, phosphorus, sulfur, boron, and fluorine. The coating amount of the shell is 0.1% to 6% by weight based on the weight of the inner core.

90. The positive electrode active material composition of claim 56, wherein, the first coating layer has a coating amount of greater than 0 and less than or equal to 7 wt%, based on the weight of the core; and / or, the second coating layer has a coating amount of greater than 0 and less than or equal to 6 wt%, based on the weight of the core; and / or, the third coating layer has a coating amount of greater than 0 and less than or equal to 6 wt%, based on the weight of the core.

91. The positive electrode active material composition of claim 90, wherein, the first coating layer has a coating amount of greater than 0 and less than or equal to 6 wt%, based on the weight of the core; and / or, the second coating layer has a coating amount of greater than 0 and less than or equal to 5.5 wt%, based on the weight of the core; and / or, the third coating layer has a coating amount of greater than 0 and less than or equal to 5.5 wt%, based on the weight of the core.

92. The positive electrode active material composition of claim 91, wherein, the first coating layer has a coating amount of greater than 0 and less than or equal to 5.5 wt% or 4-5.6 wt%, based on the weight of the core; and / or, the second coating layer has a coating amount of 2-4 wt% or 3-5 wt%, based on the weight of the core; and / or, the third coating layer has a coating amount of greater than 0 and less than or equal to 2 wt%, based on the weight of the core.

93. The positive electrode active material composition of claim 92, wherein, the first coating layer has a coating amount of greater than 0 and less than or equal to 2 wt%, based on the weight of the core.

94. The cathode active material composition of claim 56, wherein, the shell further comprises a fourth coating layer coating the third coating layer and a fifth coating layer coating the fourth coating layer; the fourth and fifth coating layers each independently have a coating amount of 0.01 wt% to 10 wt%, based on the weight of the core.

95. The positive electrode active material composition of claim 94, wherein, the fourth and fifth coating layers each independently have a coating amount of 0.05 wt% to 10 wt%, based on the weight of the core.

96. The positive electrode active material composition of claim 95, wherein, the fourth and fifth coating layers each independently have a coating amount of 0.1 wt% to 5 wt%, based on the weight of the core.

97. The positive electrode active material composition of claim 96, wherein, the fourth and fifth coating layers each independently have a coating amount of 0.1 wt% to 2 wt%, based on the weight of the core.

98. The cathode active material composition of claim 49, wherein, the shell is located on 40% to 90% of the surface of the core.

99. The cathode active material composition of claim 98, wherein, the shell is located on 60% to 80% of the surface of the core.

100. The cathode active material composition of claim 49, wherein, the shell has a thickness of 1-15 nm.

101. The positive electrode active material composition of claim 56, wherein, the first coating layer has a thickness of 1-10 nm; and / or, the second coating layer has a thickness of 2-25 nm; and / or, the third coating layer has a thickness of 2-25 nm.

102. The positive electrode active material composition of claim 101, wherein, the first coating layer has a thickness of 2 to 10 nm; and / or, the second coating layer has a thickness of 2 to 15 nm; and / or, the third coating layer has a thickness of 5 to 25 nm.

103. The positive electrode active material composition according to claim 102, wherein the second coating layer has a thickness of 3 to 15 nm.

104. The positive electrode active material composition according to any one of claims 49 to 103, wherein the one or more coating layers each independently comprise one or more selected from the group consisting of pyrophosphate, phosphate, and oxide, and one or more selected from the group consisting of pyrophosphate, phosphate, and oxide is in a crystalline state.

105. The positive electrode active material composition according to claim 104, wherein the crystallinity of the pyrophosphate, the phosphate, and the oxide each independently is 10% to 100%.

106. The positive electrode active material composition according to claim 104, wherein the crystallinity of the pyrophosphate, the phosphate, and the oxide each independently is 50% to 100%.

107. The cathode active material composition of any one of claims 49 to 106, wherein, the weight ratio of the pyrophosphate to the phosphate and the weight ratio of the pyrophosphate to the oxide in the shell each independently is 1:3 to 3:

1.

108. The cathode active material composition of claim 107, wherein, the weight ratio of the pyrophosphate to the phosphate and the weight ratio of the pyrophosphate to the oxide in the shell each independently is 1:3 to 1:

1.

109. The cathode active material composition of any one of claims 49 to 108, wherein, the one or more coating layers each independently comprise carbon, and the carbon is a mixture of SP2-form carbon and SP3-form carbon.

110. The cathode active material composition of claim 109, wherein, the molar ratio of the SP2-form carbon to the SP3-form carbon in the carbon is any value in the range of 0.07 to 13.

111. The cathode active material composition of claim 110, wherein, the molar ratio of the SP2-form carbon to the SP3-form carbon is any value in the range of 0.1 to 10.

112. The cathode active material composition of claim 111, wherein, the molar ratio of the SP2-form carbon to the SP3-form carbon is any value in the range of 2.0 to 3.

0.

113. The positive electrode active material composition according to any one of claims 49 to 112, wherein the one or more coating layers each independently comprise doped carbon, and the mass content of the doping element in the doped carbon is 30% or less.

114. The positive electrode active material composition according to claim 113, wherein the mass content of the doping element in the doped carbon is 20% or less.

115. The positive electrode active material composition according to any one of claims 49 to 114, wherein the one or more coating layers each independently comprise doped carbon, and in the doped carbon, the doping element is nitrogen element and / or sulfur element, and the mass content of the doping element in the doped carbon is 1% to 15%; or the doping element is phosphorus element, boron element, and / or fluorine element, and the mass content of the doping element in the doped carbon is 0.5% to 5%; the doping element is nitrogen, phosphorus, sulfur, boron, or fluorine.

116. The positive electrode active material composition according to any one of claims 49 to 115, wherein each of the one or more coating layers independently comprises a pyrophosphate having an interplanar spacing ranging from 0.293 nm to 0.470 nm and an angle of incidence (111) ranging from 18.00° to 32.57°; and / or, each of the one or more coating layers independently comprises a phosphate having an interplanar spacing ranging from 0.244 nm to 0.425 nm and an angle of incidence (111) ranging from 20.00° to 37.00°.

117. The positive electrode active material composition of claim 116, wherein, the pyrophosphate has an interplanar spacing ranging from 0.297 nm to 0.462 nm or 0.293 nm to 0.326 nm and an angle of incidence (111) ranging from 18.00° to 32.00° or 26.41° to 32.57°; and / or, the phosphate has an interplanar spacing ranging from 0.345 nm to 0.358 nm and an angle of incidence (111) ranging from 24.25° to 26.45°.

118. The positive electrode active material composition of claim 117, wherein, the pyrophosphate has an interplanar spacing ranging from 0.300 nm to 0.310 nm and an angle of incidence (111) ranging from 19.211° to 30.846°.

119. The positive electrode active material composition of claim 118, wherein, the pyrophosphate has an angle of incidence (111) ranging from 29.00° to 30.00°.

120. The cathode active material composition of claim 116, wherein, the first coating layer or the second coating layer comprises a phosphate.

121. The positive electrode active material composition of any one of claims 1 to 120, wherein, the first positive electrode active material has a lattice change rate before and after complete deintercalation of lithium of 50% or less; and / or, the first positive electrode active material has a Li / Mn antisite defect concentration of 5.3% or less; and / or, the first positive electrode active material has a surface oxygen valence state of -1.55 or less.

122. The positive electrode active material composition of claim 121, wherein, the first positive electrode active material has a lattice change rate before and after complete deintercalation of lithium of 9.8% or less; and / or, the first positive electrode active material has a Li / Mn antisite defect concentration of 5.1% or less; and / or, the first positive electrode active material has a surface oxygen valence state of -1.82 or less.

123. The positive electrode active material composition of claim 122, wherein, the first positive electrode active material has a lattice change rate before and after complete deintercalation of lithium of 8.1% or less; and / or, the first positive electrode active material has a Li / Mn antisite defect concentration of 4% or less; and / or, the first positive electrode active material has a surface oxygen valence state of -1.88 or less.

124. The positive electrode active material composition of claim 123, wherein, the first positive electrode active material has a lattice change rate before and after complete deintercalation of lithium of 7.5% or less; and / or, the first positive electrode active material has a Li / Mn antisite defect concentration of 2.2% or less; and / or, the surface oxygen valence state of the first positive electrode active material is -1.90 or less or -1.98 to -1.

88.

125. The positive electrode active material composition of claim 124, wherein, the lattice change rate of the first positive electrode active material before and after complete deintercalation of lithium is 6% or less; and / or, the Li / Mn antisite defect concentration of the first positive electrode active material is 2% or less; and / or, the surface oxygen valence state of the first positive electrode active material is -1.98 to -1.

89.

126. The positive electrode active material composition of claim 125, wherein, the lattice change rate of the first positive electrode active material before and after complete deintercalation of lithium is 4% or less; and / or, the Li / Mn antisite defect concentration of the first positive electrode active material is 1.5-2.2% or 0.5% or less; and / or, the surface oxygen valence state of the first positive electrode active material is -1.98 to -1.

90.

127. The positive electrode active material composition of claim 126, wherein, the lattice change rate of the first positive electrode active material before and after complete deintercalation of lithium is 3.8% or less.

128. The positive electrode active material composition of claim 127, wherein, the lattice change rate of the first positive electrode active material before and after complete deintercalation of lithium is 2.0-3.8%.

129. The positive electrode active material composition according to any one of claims 10, 20 to 128, wherein, The positive electrode active material composition satisfies 0.0004 ≤ w a x y x (3.4 - V B ) ≤ 0.063, w a represents the weight content of the first positive electrode active material based on the total weight of the positive electrode active material composition, y is the molar amount of M 1 of the element in the compound represented by formula (I), V B is the voltage plateau of the element, in V (volt). 1 of the element in the compound represented by formula (I), V 130. The cathode active material composition of claim 129, wherein, The positive electrode active material composition satisfies 0.0015 ≤ w a x y x (3.4 - V B ) ≤ 0.

045.

131. The cathode active material composition of claim 1, wherein, the second positive electrode active material comprises a compound represented by Formula (II), Li a1 A 1 b1 Ni c1 Co d1 B 1 e1 C 1 f1 O 2-g1 D 1 g1 , (II) A 1 comprises one or more elements selected from Group IA, Group IIA, Group VIII, Group VIB, Group IIB; B 1 comprises one or more elements selected from Mn and / or Al; C 1 comprises one or more elements selected from Group IA, Group IIA, Group IIIA, Group IVA, Group VA, Group VIA, Group IIB, Group IIIB, Group IVB, Group VB, Group VIB, and Group VIII; D 1 comprises one or more elements selected from Group VIA and Group VIIA; a1 is selected from the range of 0.8 to 1.2; b1 is selected from the range of 0 to 0.2; c1 is selected from the range of 0 to 1; d1 is selected from the range of 0 to 1; e1 is selected from the range of 0 to 1; f1 is selected from the range of 0 to 0.1; g1 is selected from the range of 0 to 0.1; and c1 + d1 + e1 + f1 = 1.

132. The positive electrode active material composition of claim 131, wherein, A 1 comprises one or more elements selected from the group consisting of Na, K, Mg, Rb, Zn, Zr; and / or, C 1 including one or more elements selected from the group consisting of Al, Mg, Ca, Na, Ti, W, Zr, Sr, Cr, Fe, Zn, Ba, Mo, V, Ce, Nb, Sb, Ta, Ge, Nb, Sc, Ba, B, S, and Y; and / or, D 1 comprises one or more elements selected from N, S, F, Cl and Br; and / or, a1 is selected from the range of 0.9 to 1.1; and / or, b1 is selected from the range of 0 to 0.1; and / or, c1 is selected from the range of 0.314 to 0.990; and / or, d1 is selected from the range of 0 to 0.320; and / or, e1 is selected from the range of 0.001 to 0.450; and / or, f1 is selected from the range of 0.001 to 0.1; and / or, g1 is selected from the range of 0 to 0.

01.

133. The positive electrode active material composition of claim 132, wherein, C 1 comprising one or more elements selected from the group consisting of Al, Ti, Zr, Nb, Sr, Sc, Sb, Y, Ba, B; and / or, D 1 comprising S and / or F; and / or, c1 is selected from the range of 0.500 to 0.990; and / or, d1 is selected from the range of 0 to 0.150; and / or, e1 is selected from the range of 0.005 to 0.4; and / or, f1 is selected from the range of 0.001 to 0.05; and / or, g1 is selected from the range of 0.01 to 0.

05.

134. The cathode active material composition of claim 131, wherein, the second positive electrode active material comprises a core and a shell that coats the core, the core comprises the compound represented by Formula (II); the shell comprises one or more coating layers; each coating layer has ionic and / or electronic conductivity.

135. The cathode active material composition of claim 134, wherein, each of the one or more coating layers independently comprises one or more selected from phosphate, pyrophosphate, carbon, doped carbon, oxide, fast ion conductor.

136. The positive electrode active material composition of claim 134, wherein, the shell comprises one coating layer.

137. The positive electrode active material composition of claim 136, wherein, the coating layer comprises one or more selected from phosphate, pyrophosphate, oxide.

138. The positive electrode active material composition of claim 134, wherein, The shell comprises a first coating layer coating the inner core and a second coating layer coating the first coating layer.

139. The positive electrode active material composition of claim 138, wherein, The first and second coating layers each independently comprise one or more selected from phosphate, pyrophosphate, oxide.

140. The positive electrode active material composition of claim 139, wherein, The first coating layer comprises one or more selected from phosphate, oxide, and the second coating layer comprises one or more selected from pyrophosphate, oxide.

141. The positive electrode active material composition of claim 134, wherein, The coating amount of the shell is 0.005 wt% to 1 wt% based on the weight of the inner core; and / or, The thickness of the shell is 2 nm to 200 nm.

142. The positive electrode active material composition of claim 141, wherein, The coating amount of the shell is 0.01 wt% to 0.5 wt% based on the weight of the inner core; and / or, The thickness of the shell is 5 nm to 50 nm.

143. A positive electrode sheet comprising a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector, the positive electrode film layer comprising a positive electrode active material, the positive electrode active material comprising the positive electrode active material composition of any one of claims 1 to 142.

144. The cathode sheet of claim 143, wherein, The content of the positive electrode active material composition in the positive electrode film layer is 90 wt% to 99.5 wt% based on the total weight of the positive electrode film layer.

145. The cathode sheet of Claim 144 wherein, The content of the positive electrode active material composition in the positive electrode film layer is 95 wt% to 99.5 wt% based on the total weight of the positive electrode film layer.

146. The cathode sheet of Claim 143 wherein, The positive electrode film layer further comprises a third positive electrode active material, the third positive electrode active material comprising one or more of a lithium-rich oxide material, a lithium iron phosphate material, a spinel lithium manganese oxide material, and respective modified compounds thereof, the modification comprising doping and / or surface coating modification.

147. The cathode sheet of Claim 146, wherein, The third positive electrode active material comprises a compound represented by formula (III), Li 1+p1 A 2 q1 B 2 r1 O s1 , (III) 0.05 < p1 < 0.2, 0.10 < q1 < 0.95, 0 < r1 < 0.2, and 2 < s1 < 3, A 2 comprising one or more elements selected from Co, Ni, Mn, and Al; B 2 comprising one or more elements selected from Mg, Ti, Cr, Zr, Nb, Fe, Mo, Cu, Sb, V, P, and F.

148. The cathode sheet of Claim 147, wherein, The third positive electrode active material comprises an inner core and a shell coating the inner core, The inner core comprises the compound represented by formula (III); The shell comprises one or more coating layers; each coating layer has ionic and / or electronic conductivity.

149. The cathode sheet of Claim 148, wherein, The one or more coating layers each independently comprise one or more selected from phosphate, pyrophosphate, solid-state electrolyte, electrically conductive polymer, material capable of reversible deintercalation of lithium ions.

150. The positive electrode sheet of claim 148, wherein, The coating amount of the shell is 0.1 wt% to 5 wt% based on the weight of the inner core; and / or, The thickness of the shell is 2 nm to 200 nm.

151. The positive electrode sheet of claim 150, wherein, The coating amount of the shell is 0.5 wt% to 2 wt% based on the weight of the inner core; and / or, The thickness of the shell is 5 nm to 50 nm.

152. The cathode sheet of Claim 146, wherein, The third positive electrode active material comprises a compound represented by formula (IV), Li a2 A 3 x2 B 3 y2 P 1-z2 C 3 z2 O 4-n2 D 3 n2 , (IV) A 3 comprises one or more elements selected from Group IA, Group IIA, Group IIIA, Group IIB, Group VB, and Group VIB; B 3 comprises one or more elements selected from Group IA, Group IIA, Group IIIA, Group IVA, Group VA, Group IIB, Group IVB, Group VB, Group VIB, and Group VIII; C 3 comprises one or more elements selected from Group IIIA, Group IVA, Group VA, and Group VIA; D 3 comprises one or more elements selected from Group VIA and Group VIIA; a2 is selected from the range of 0.85 to 1.15; x2 is selected from the range of 0 to 0.1; y2 is selected from the range of 0.001 to 0.999; z2 is selected from the range of 0 to 0.5; n2 is selected from the range of 0 to 0.

5.

153. The cathode electrode of claim 152, wherein, A 3 including one or more elements selected from Rb, Cs, Be, Ca, Sr, Ba, Ga, In, Cd, V, Ta, Cr, Zn, Al, Na, K, Mg, Nb, Mo, and W; and / or, B 3 including one or more elements selected from Rb, Cs, Be, Ca, Sr, Ba, In, Pb, Bi, Cd, Hf, Ta, Cr, Ru, Rh, Pd, Os, Ir, Pt, Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb, and Ge; and / or, C 3 comprises one or more elements selected from B (boron), S, Si, and N; and / or, D 3 comprises one or more elements selected from S, F, Cl, and Br; and / or, a2 is selected from the range of 0.9 to 1.1; and / or, x2 is selected from the range of 0.001 to 0.005; and / or, y2 is selected from the range of 0.001 to 0.5; and / or, z2 is selected from the range of 0.001 to 0.5; and / or, n2 is selected from the range of 0 to 0.

1.

154. The cathode electrode of claim 153, wherein, A 3 comprises one or more elements selected from the group consisting of Zn, Al, Na, K, Mg, Nb, Mo, and W; and / or, B 3 comprising one or more elements selected from the group consisting of Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb, and Ge; and / or, a2 is selected from the range of 0.97 to 1.01; and / or, y2 is selected from the range of 0.01 to 0.5; and / or, z2 is selected from the range of 0.001 to 0.1; and / or, n2 is selected from the range of 0.001 to 0.

005.

155. The cathode electrode of claim 154, wherein, y2 is selected from the range of 0.25 to 0.5; and / or, z2 is selected from the range of 0.001 to 0.

005.

156. The cathode sheet of claim 152 or 153, wherein, the third cathode active material comprises an inner core and a shell coating the inner core, the inner core comprises the compound of formula (IV); the shell is according to any one of claims 40 to 109.

157. The cathode sheet of Claim 146, wherein, the third cathode active material comprises a compound of formula (V), LiMn t1 A 4 2-t1 O4, (V) t1 is selected from the range of 0 to 2, A 4 comprising one or more elements selected from the group consisting of Ni, Cr, Al, Zr, V, Ti, Mo, Ru, Mg, Nb, Ba, Si, P, W, Co, Cu, and Zn.

158. The cathode electrode of claim 157, wherein, the third cathode active material comprises an inner core and a shell coating the inner core, the inner core comprises the compound of formula (V); the shell comprises one or more coating layers; each coating layer has ionic and / or electronic conductivity.

159. The cathode sheet of Claim 158, wherein, each of the one or more coating layers independently comprises one or more selected from phosphate, pyrophosphate, solid-state electrolyte, conductive polymer, material capable of reversible deintercalation of lithium ions.

160. The cathode electrode of claim 158 or 159, wherein, the shell has a coating amount of 0.1 wt% to 5 wt% based on the weight of the inner core; and / or, the shell has a thickness of 2 nm to 200 nm.

161. The cathode electrode of claim 160, wherein, the shell has a coating amount of 0.5 wt% to 2 wt% based on the weight of the inner core; and / or, the shell has a thickness of 5 nm to 50 nm.

162. The cathode sheet of Claim 160, wherein, the cathode film layer comprises a cathode binder and / or a cathode conductive agent.

163. The cathode sheet of Claim 162, wherein, the cathode binder comprises a vinylidene fluoride homopolymer and / or a copolymer.

164. The cathode sheet of claim 163, wherein, the comonomer of the copolymer comprises one or more of tetrafluoroethylene, hexafluoropropylene, propylene.

165. The cathode sheet of Claim 162, wherein, the cathode binder has a weight average molecular weight of 300,000 to 2,000,000.

166. The cathode electrode of claim 160 or 162, wherein, the cathode film layer further comprises a functional additive, the functional additive comprising one or more of dispersant, plasticizer, pore former, water-removing additive, acid-removing additive, lithium supplementing agent; and / or, the cathode electrode further comprises a functional coating, the functional coating being between the cathode current collector and the cathode film layer and / or on a surface of the cathode film layer facing away from the cathode current collector, the functional coating comprising one or more of conductive carbon, water-removing additive, acid-removing additive, lithium supplementing agent.

167. A battery comprising the positive electrode active material composition of any one of claims 1 to 142 or the positive electrode sheet of any one of claims 143 to 166.

168. The battery of claim 167, wherein, The battery comprises an electrolyte, the electrolyte comprising one or more of a liquid electrolyte, a solid-state electrolyte, a gel electrolyte.

169. The battery of claim 168, wherein, The liquid electrolyte comprises a lithium salt, a non-aqueous solvent dissolving the lithium salt, Alternatively, the liquid electrolyte comprises a lithium salt, a non-aqueous solvent dissolving the lithium salt, and an additive.

170. The battery of claim 169, wherein, The lithium salt comprises one or more selected from the group consisting of LiPF6, LiBF4, LiN(SO2F)2, LiN(CF3SO2)2, LiClO4, LiAsF6, LiB(C2O4)2, LiBF2C2O4, LiPO2F2.

171. The battery of claim 169, wherein, The concentration of the lithium salt is 0.5-1.5 mol / L.

172. The battery of claim 169, wherein, The non-aqueous solvent comprises one or more selected from the group consisting of propylene carbonate, vinylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl formate, ethyl acetate, methyl butyrate, ethyl butyrate, methyl propionate, ethyl propionate, propyl propionate, methyl acrylate, ethylene sulfite, propylene sulfite, dimethyl sulfite, diethyl sulfite, anhydride, N-methyl pyrrolidone, acetonitrile, sulfolane, dimethyl sulfoxide, methyl sulfide, γ-butyrolactone, tetrahydrofuran.

173. The battery of claim 169, wherein, The additive comprises one or more selected from the group consisting of cyclic carbonate compounds containing carbon-carbon double bonds, halogen-substituted cyclic carbonate compounds, nitrile and polynitrile compounds, phosphazene compounds, aromatic and halogenated aromatic compounds, isocyanate compounds, anhydride compounds, sulfate compounds, sulfite compounds, sulfonate compounds, disulfonate compounds, borate compounds, phosphate compounds, amide compounds, carbodiimide compounds, crown ether and azacrown ether compounds, and derivatives of each thereof.

174. The battery of claim 173, wherein, The additive comprises one or more of vinylene carbonate, 1,2,3-tris(2-cyanoethyloxy)propane, 1-aza-12-crown-4-ether, N,N'-dicyclohexyl carbodiimide, N,N'-diisopropyl carbodiimide, N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, tris(hexafluoroisopropyl)borate, tris(2,2,3,3-tetrafluoropropyl)borate, tris(pentafluorophenyl)borate.

175. The battery of any one of claims 167-174, wherein, The battery comprises a negative electrode sheet, the negative electrode sheet comprising a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector, the negative electrode film layer comprising a negative electrode active material, the negative electrode active material comprising one or more of a carbon-based material, a silicon-based material, a tin-based material, and lithium titanate.

176. The battery of claim 175, wherein, The negative electrode active material comprises a carbon-based material, or a combination of a carbon-based material and a silicon-based material.

177. The battery of claim 175, wherein, The negative electrode film layer has a porosity of 20% to 50%.

178. The battery of claim 175, wherein, The negative electrode active material comprises a carbon-based material, and the carbon-based material comprises graphite, or a combination of graphite and hard carbon; or The negative electrode active material comprises a carbon-based material, and the carbon-based material comprises graphite, or a combination of graphite and hard carbon; or The negative active material comprises a combination of a carbon-based material and a silicon-based material, the carbon-based material comprises graphite, or a combination of graphite and hard carbon, and the content of silicon element in the negative active material is greater than 0 and less than or equal to 30% by weight based on the total weight of the negative active material.

179. The battery of claim 175 or 178, wherein, the negative electrode sheet further comprises a functional coating layer between the negative current collector and the negative film layer and / or on the surface of the negative film layer away from the negative current collector; and / or, the negative film layer further comprises a lithium supplement material.

180. The battery of claim 179, wherein, the functional coating layer comprises carbon; and / or, the lithium supplement material comprises one or more of lithium foil, lithium ribbon, lithium powder, and pre-lithiation reagent.

181. The battery of claim 180, wherein, the pre-lithiation reagent comprises one or more of Li-arene, and complex of Li-arene and ether solvent.

182. The battery of claim 181, wherein, comprises one or more of naphthalene lithium, and diphenyl lithium-dimethyl ether.

183. The battery of any one of claims 175-182, wherein, the negative electrode sheet comprises a negative current collector, and a first negative film layer and a second negative film layer disposed on two surfaces of the negative current collector, respectively.

184. The battery of claim 183, wherein, the thickness ratio of the first negative film layer and the second negative film layer is 5:95 to 95:

5.

185. The battery of any one of claims 167-169, wherein, the battery comprises a negative electrode sheet, and the negative electrode sheet does not comprise a negative active material capable of deintercalating lithium ions.

186. The battery of claim 185, wherein, the negative electrode sheet comprises a lithium sheet or a lithium alloy sheet; or, the negative electrode sheet comprises a reticular or foamed three-dimensional skeleton layer.

187. The battery of any one of claims 167-186, wherein, the battery comprises a separator film, and the separator film comprises a porous substrate.

188. The battery of claim 187, wherein, the separator film further comprises a coating layer on at least one surface of the porous substrate.

189. The battery of claim 188, wherein, the coating layer comprises one or more of inorganic heat-resistant particles and organic heat-resistant particles.

190. The battery of claim 187 or 189, wherein, the porosity of the separator film is 10%-40%.

191. An electrical device comprising the battery of any one of claims 167-190.

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