Positive electrode active material composition, positive electrode sheet, battery, and power using device

Abstract

The present application provides a positive electrode active material composition, a positive electrode sheet, a battery, and an electric device, the positive electrode active material composition including 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 second positive electrode active material including a phosphate material, and the positive electrode active material composition satisfying Dv10 (1) / Dv50 (2) ≥ 1.4 and -2.0 ≤ 1 - [(p2 x W2) / (p1 x W1)] ≤ 0.98. Each of the above parameters is defined herein. (1) / Dv50 (2) ≥ 1.4 and -2.0 ≤ 1 - [(p2 x W2) / (p1 x W1)] ≤ 0.98. Each of the above parameters is defined herein.

Description

Technical Field

[0001] This application relates to a positive electrode active material composition, a positive electrode sheet, a battery, and an electrical device. 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] A first 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 having a crystal form different from the first positive electrode active material, the second positive electrode active material comprising a phosphate material, and the first positive electrode active material having a volume distribution particle size Dv10. (1) The volume distribution particle size Dv50 of the second positive electrode active material (2) Meets Dv10 (1) / Dv50 (2) >1, the volume distribution particle size Dv50 of the first positive electrode active material (1) The volume distribution particle size Dv50 of the second positive electrode active material (2) Meets Dv50 (1) / Dv50 (2) ≥1.4, the true density of the first positive electrode active material is denoted as ρ1, and the true density of the second positive electrode active material is denoted as ρ2, both in g / cm³. 3 Based on the total mass of the positive electrode active material composition, the mass ratio of the first positive electrode active material is denoted as W1, and the mass ratio of the second positive electrode active material is denoted as W2. Then the positive electrode active material composition satisfies -2.0≤1-[(ρ2×W2) / (ρ1×W1)]≤0.98.

[0005] By adjusting the volume distribution, particle size, true density, and mass ratio of the first and second positive electrode active materials in the positive electrode active material composition, batteries using the positive electrode active material composition of this application can achieve high energy density, low cost, and good service life.

[0006] In any embodiment, 1 < Dv10 (1) / Dv50 (2)≤16.5, optionally, 1.07≤Dv10 (1) / Dv50 (2) ≤11.3. 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 the positive electrode active material composition of this application to have higher energy density and / or longer service life.

[0007] In any embodiment, 1.4 < Dv50 (1) / Dv50 (2) ≤30.0, optionally, 2.0≤Dv50 (1) / Dv50 (2) ≤23.8. 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 the positive electrode active material composition of this application to have higher energy density and / or longer service life.

[0008] In any embodiment, -0.78 ≤ 1 - [(ρ2×W2) / (ρ1×W1)] ≤ 0.96, optionally, -0.14 ≤ 1 - [(ρ2×W2) / (ρ1×W1)] ≤ 0.92, and more preferably, 0.67 ≤ 1 - [(ρ2×W2) / (ρ1×W1)] ≤ 0.92. This allows for a more compact packing of the first and second positive electrode active materials, further increasing the actual packing density of the positive electrode active material composition, improving the compaction density and compaction efficiency of the positive electrode sheet, thereby enabling batteries using the positive electrode active material composition of this application to have higher energy density and longer service life.

[0009] In any embodiment, W2 = ρ2 / [(β×ρ1)+ρ2], 0.3≤β≤30, optionally, 0.5≤β≤6.9, and more preferably, 1.8≤β≤6.9. By keeping β within the above range, the positive electrode active material composition can have a higher actual packing density, thereby further improving the compaction density and compaction efficiency of the positive electrode sheet, thus enabling the battery using the positive electrode active material composition of this application to have a higher energy density and / or a longer service life.

[0010] In any embodiment, the particle size distribution curve of the positive electrode active material composition has at least two volume distribution peaks. The peak with the smallest volume distribution particle size is denoted as peak I, and the other peaks are denoted as peak II. The volume distribution particle size corresponding to the maximum peak intensity of peak I is between 0.3 μm and 2.1 μm, and the volume distribution particle size corresponding to the maximum peak intensity of peak II is between 3 μm and 15 μm. The ratio of the integral area of ​​peak I to the total integral area of ​​peak II is (0.010-2.5):1, which can be optionally (0.011-1.3):1. By ensuring that the ratio of the integral area of ​​peak I to the total integral area of ​​peak II in the particle size distribution curve of the positive electrode active material composition is within the aforementioned range, the contribution of the first positive electrode active material to the compaction density of the positive electrode sheet can be increased. Furthermore, the second positive electrode active material can better fill the gaps between the particles of the first positive electrode active material. This allows the first and second positive electrode active materials to be packed more tightly, thereby increasing the actual packing density of the positive electrode active material composition, improving the compaction density and compaction efficiency of the positive electrode sheet, and consequently enabling batteries using the positive electrode active material composition of this application to have higher energy density and / or longer service life.

[0011] In any embodiment, the particle size distribution curve of the second positive electrode active material has at least two volume distribution peaks. The peak with the smallest volume distribution particle size is denoted as peak III, and the other peaks are denoted as peak IV. The volume distribution particle size corresponding to the maximum peak intensity of peak III is between 0.3 μm and 2.1 μm, and the volume distribution particle size corresponding to the maximum peak intensity of peak IV is between 2.1 μm and 10 μm. The ratio of the integral area of ​​peak III to the total integral area of ​​peak IV is (0.5-20):1. By ensuring that the ratio of the integral area of ​​peak III to the total integral area of ​​peak IV in the particle size distribution curve of the second positive electrode active material is within the above range, the second positive electrode active material can better fill the gaps between the particles of the first positive electrode active material. This allows the first and second positive electrode active materials to be packed more tightly, 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 of this application to have higher energy density and / or longer service life.

[0012] In any embodiment, the ratio of the major axis length to the minor axis length of the first positive electrode active material is 1-2, and can be selected as 1-1.4.

[0013] In any embodiment, the ratio of the major axis length to the minor axis length of the second positive electrode active material is 1-2, and can be selected as 1-1.4.

[0014] In any embodiment, the volume distribution particle size Dv10 of the first positive electrode active material is... (1)The range is 0.3-8μm, with an optional range of 1.6-6.6μm.

[0015] In any embodiment, the volume distribution particle size Dv50 of the first positive electrode active material is... (1) The range is 1.5-15μm, with an optional range of 3-12μm.

[0016] In any embodiment, the volume distribution particle size Dv50 of the second positive electrode active material is... (2) The thickness ranges from 0.25 to 3 μm, and can be selected from 0.4 to 2 μm.

[0017] 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 side reactions can be reduced, resulting in a longer battery life.

[0018] In any embodiment, the true density ρ1 of the first positive electrode active material is 4.40-5.15 g / cm³. 3 The selectable value is 4.60-5.10 g / cm³. 3 .

[0019] In any embodiment, the true density ρ2 of the second positive electrode active material is 3.20-3.65 g / cm³. 3 The selectable value is 3.30-3.60 g / cm³. 3 .

[0020] In any embodiment, based on the total mass of the positive electrode active material composition, the mass percentage W1 of the first positive electrode active material is 30%-98%, and optionally 70%-90%. This allows the battery to better balance high energy density and long service life.

[0021] In any embodiment, based on the total mass of the positive electrode active material composition, the mass percentage W2 of the second positive electrode active material is 2%-70%, optionally 10%-30%. This allows the battery to better balance high energy density and long service life.

[0022] In any embodiment, the second positive electrode active material comprises a compound represented by formula (I).

[0023] Li a A x Mn 1-y B y P 1-z C z O 4-n D n (I)

[0024] A includes one or more elements selected from families IA, IIA, IIIA, IIB, VB, and VIB; B includes 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 1; z is selected from the range of 0 to 0.5; n is selected from the range of 0 to 0.5.

[0025] In any embodiment, y is selected from the range of 0.001 to 0.999. 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 the dopant elements at the Mn site, improving cycle performance and / or high-temperature stability, and also increasing the specific capacity and compaction density of the material.

[0026] 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 may optionally include one or more elements selected from Zn, Al, Na, K, Mg, Nb, Mo, and W; and / or, B includes elements selected from Rb, Cs, Be, Ca, Sr, Ba, In, Pb, Bi, Cd, Hf, Ta, Cr, Ru, Rh, Pd, Os, Ir, Pt, and Zn. The elements selected from n, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb, and Ge may include 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, C may include one or more elements selected from B (boron), S, Si, and N; and / or, D may include one or more elements selected from S, F, Cl, and Br.

[0027] In any embodiment, A includes any one element selected from Zn, Al, Na, K, Mg, Nb, Mo, and W, and optionally includes any one element selected from Mg and Nb; and / or, B includes one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge, optionally including 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; and / or, C includes any one element selected from B (boron), S, Si, and N, optionally S; and / or, D includes any one element selected from S, F, Cl, and Br, optionally F.

[0028] 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.

[0029] In any embodiment, a is selected from the range of 0.9 to 1.1, optionally from the range of 0.97 to 1.01; 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, optionally from the range of 0.01 to 0.5, optionally from the range of 0.25 to 0.5; and / or, z is selected from the range of 0.001 to 0.5, optionally from the range of 0.001 to 0.1, more preferably from the range of 0.001 to 0.005; and / or, n is selected from the range of 0 to 0.1, optionally from the range of 0.001 to 0.005.

[0030] By selecting the y value within the above range, the specific capacity and rate performance of the second cathode active material can be further improved. By selecting the x value within the above range, the kinetic performance of the second cathode active material can be further improved. By selecting the z value within the above range, the rate performance of the battery can be further improved. By selecting the n value within the above range, the high-temperature performance of the battery can be further improved.

[0031] 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.

[0032] 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 second cathode active material.

[0033] 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 second positive electrode active material, improves the integrity of the framework structure of the second positive electrode active material, thereby effectively enhancing the structural stability of the second positive electrode active material, and consequently improving the cycle stability of the battery.

[0034] 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 second positive electrode active material, further improves the integrity of the framework structure of the second positive electrode active material, effectively enhances the structural stability of the second positive electrode active material, and improves the cycle stability of the battery.

[0035] In any embodiment, A includes one or more elements selected from Zn, Al, Na, K, Mg, Nb, Mo, and W; B includes one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge; C 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.

[0036] 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 second cathode active material can also be improved.

[0037] In any embodiment, B 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; C 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.

[0038] 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 second cathode active material can be increased.

[0039] In any embodiment, (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. Thus, the energy density and cycle performance of the second positive electrode active material can be further improved.

[0040] In any embodiment, z:(1-z) is 1:9 to 1:999, and can be selected as 1:499 to 1:249. Therefore, the energy density and cycle performance of the second positive electrode active material can be further improved.

[0041] 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 (I); the shell including one or more coating layers; each coating layer having ionic conductivity and / or electronic conductivity.

[0042] By providing a coating layer with ionic and / or electronic conductivity on the core surface, a second positive electrode active material with a core-shell structure is provided. Applying the second positive electrode active material to a battery can improve the battery's high-temperature cycle performance, cycle stability, and high-temperature storage performance.

[0043] 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.

[0044] Using the above materials, a coating layer with ionic and / or electronic conductivity can be obtained, thereby improving the high-temperature cycle performance, cycle stability and high-temperature storage performance of the battery.

[0045] 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.

[0046] 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 include one or more selected from pyrophosphate, phosphate, carbon, doped carbon, oxide, boride and polymer; more preferably, the first coating layer includes one or more selected from pyrophosphate, phosphate, oxide and boride, and the second coating layer includes one or more selected from carbon and doped carbon.

[0047] 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.

[0048] 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 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; more preferably, the first coating layer includes pyrophosphate, the second coating layer includes one or more selected from phosphate, oxide, and boride, and the third coating layer includes one or more selected from carbon and doped carbon.

[0049] By employing a first coating layer, a second coating layer, and a third coating layer made of specific materials, the rate performance is further improved, the dissolution of Mn and Mn-site dopants is further reduced, thereby improving the cycle performance and / or high-temperature stability of the battery, and further increasing the specific capacity and compaction density of the second positive electrode active material.

[0050] 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.

[0051] By using the above 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 second 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.

[0052] 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; and / or, the doping element in the doped carbon includes one or more elements selected from nitrogen, phosphorus, sulfur, boron, and fluorine; and / or, M′ includes elements selected from Li, Be, B, Na, Mg, Al, Si, P, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, One or more elements selected from Ga, Ge, As, Se, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, W, La, and Ce, optionally including one or more elements selected from Mg, Al, Si, Zn, Zr, and Sn; and / or, the polysiloxane is selected from one or more linear polysiloxanes and cyclic polysiloxanes; and / or, the polysaccharide is selected from one or more plant polysaccharides and marine polysaccharides.

[0053] 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.

[0054] In any embodiment, the second positive electrode active material includes a core and a shell covering the core, wherein the core includes Li a Mn 1-y B y P 1-z C z O4, where 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, B includes one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb and Ge, and C includes one or more elements selected from B (boron), S, Si and N; the shell includes a first coating layer covering the core and a second coating layer covering the first coating layer, the first coating layer including pyrophosphate MP2O7 and phosphate XPO4, M and X each independently including 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.

[0055] 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.

[0056] In any embodiment, the second positive electrode active material includes a core and a shell covering the core, wherein the core includes Lia Mn 1-y B y P 1-z C z O4, where 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, B includes one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge, and C 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.

[0057] Therefore, the second positive electrode active material can improve the specific capacity and cycle performance of the battery.

[0058] 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 second positive electrode active material. Furthermore, the coating layers have good ionic conductivity, which helps to increase the specific capacity of the second positive electrode active material while reducing heat generation in the battery.

[0059] In any embodiment, the polysiloxane comprises the structural unit shown in formula (i).

[0060]

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] In any embodiment, the mass percentage of polar functional groups in the polysiloxane is α, where 0 ≤ α < 50%, and optionally, 5% ≤ α ≤ 30%.

[0066] 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.

[0067] 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.

[0068] 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%.

[0069] 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.

[0070] In any embodiment, based on the total weight of the second 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.

[0071] Limiting the manganese content within the aforementioned range can further improve the stability and density of the second 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.

[0072] Limiting the phosphorus content within the aforementioned range can effectively reduce the impact of small polaron conductivity on the conductivity of the second positive electrode active material, further improve the stability of the crystal structure, and thus enhance the overall stability of the second positive electrode active material.

[0073] 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 second positive electrode active material, and improve the cycle performance and storage performance of the battery; it can also reduce impurities, allowing the second positive electrode active material to maintain a high discharge voltage platform, thus enabling the battery to have high energy density.

[0074] In any embodiment, the surface of the second positive electrode active material is coated with one or more of carbon and carbon doping; optionally, the surface of the second positive electrode active material is coated with carbon. This improves the conductivity of the second positive electrode active material.

[0075] In any embodiment, 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.

[0076] In any embodiment, the coating amount of the shell 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 second positive electrode active material.

[0077] 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.

[0078] 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.

[0079] 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 second positive electrode active material.

[0080] In any embodiment, the shell covers 40% to 90% of the surface of the core, optionally 60% to 80% of the surface.

[0081] This allows for full coating of the core, thereby improving the battery's dynamic performance.

[0082] In any embodiment, the thickness of the shell is 1-15 nm.

[0083] 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.

[0084] 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%.

[0085] 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.

[0086] In any embodiment, the weight ratio of pyrophosphate to phosphate and the weight ratio of pyrophosphate to oxide in the shell are each independently 1:3 to 3:1, optionally 1:3 to 1:1.

[0087] Therefore, by using pyrophosphate and phosphate in a suitable weight ratio range or pyrophosphate and oxide in a suitable weight ratio range, manganese leaching can be effectively reduced, surface lithium content can be effectively reduced, and interfacial side reactions can be reduced, thereby improving the high-temperature storage performance and high-temperature cycling performance of the battery.

[0088] 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 is improved.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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°, further preferably 29.00°-30.00°; and / or, 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, preferably 0.345-0.358 nm, and the included angle of the crystal orientation (111) is in the range of 20.00°-37.00°, preferably 24.25°-26.45°.

[0094] Both the first and second coating layers in the second 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.

[0095] In any embodiment, the first or second coating layer comprises phosphate.

[0096] In any embodiment, the lattice change rate of the second 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 second positive electrode active material is stronger, which is beneficial to improving the rate performance of the battery.

[0097] In any embodiment, the Li / Mn anti-site defect concentration of the second 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 second positive electrode active material.

[0098] In any embodiment, the surface oxygen valence state of the second 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 second positive electrode active material and the electrolyte can be reduced, thereby improving the cycle performance and high-temperature stability of the battery.

[0099] In any embodiment, the powder compaction density P1 of the first positive electrode active material at 30000N is 3.0 g / cm³. 3 The above can be selected as 3.2g / cm. 3 The above can also be selected as 3.3g / cm. 3 The above can be further selected as 3.4 g / cm³. 3 The above can be further optimized to 3.5g / cm³. 3 above.

[0100] In any embodiment, the powder compaction density P2 of the second 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.

[0101] The higher the compaction density of the powder, the greater the weight of the material per unit volume, which is beneficial for improving the compaction density of the positive electrode sheet and the volumetric energy density of the battery.

[0102] In any embodiment, the first positive electrode active material includes one or more of layered oxide materials, lithium-rich oxide materials, spinel-type lithium manganese oxide materials, and their respective modified compounds, wherein the modification method includes doping and / or surface coating modification. By reasonably combining the above-mentioned second positive electrode active material with the first 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, and the battery can also achieve high energy density, low cost and good service life.

[0103] In any embodiment, the first positive electrode active material comprises a compound represented by formula (II).

[0104] Li a1 A 1 b1 Ni c1 Co d1 B 1 e1 C 1 f1 O 2-g1 D 1 g1 (II)

[0105] 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.

[0106] In any embodiment, A 1 Includes one or more elements selected from Na, K, Mg, Rb, Zn, and Zr; and / or, 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, D 1Includes one or more elements selected from N, S, F, Cl, and Br, optionally including S and / or F; 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, optionally selected from the range of 0.500 to 0.990; and / or, d1 is selected from the range of 0 to 0.320, optionally selected from the range of 0 to 0.150; and / or, e1 is selected from the range of 0.001 to 0.450, optionally selected from the range of 0.005 to 0.4; and / or, f1 is selected from the range of 0.001 to 0.1, optionally selected from the range of 0.001 to 0.05; and / or, g1 is selected from the range of 0 to 0.01, optionally selected from the range of 0.01 to 0.05.

[0107] 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 (II); the shell including one or more coating layers; each coating layer having ionic conductivity and / or electronic conductivity.

[0108] In any embodiment, one or more coating layers in the shell covering the compound represented by formula (II) each independently comprise 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.

[0109] In any embodiment, the shell covering the compound represented by formula (II) comprises a coating layer; optionally, the coating layer comprises one or more selected from phosphates, pyrophosphates, and oxides.

[0110] In any embodiment, the shell covering the compound represented by formula (II) 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.

[0111] In any embodiment, the coating amount of the shell covering the compound represented by formula (II) is from 0.005% by weight to 1% by weight, optionally from 0.01% by weight to 0.5% by weight, based on the weight of the core; and / or, the thickness of the shell covering the compound represented by formula (II) is from 2 nm to 200 nm, optionally from 5 nm to 50 nm.

[0112] In any embodiment, the first positive electrode active material comprises the compound shown in formula (III).

[0113] Li 1+p1 A 2 q1 B 2 r1 O s1 (III)

[0114] 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.

[0115] In any embodiment, the first positive electrode active material includes a core and a shell coating the core, the core includes the compound represented by the formula (III); the shell includes one or more coating layers; each coating layer has ionic conductivity and / or electronic conductivity.

[0116] In any embodiment, one or more of the coating layers in the shell coating the compound represented by the formula (III) independently includes one or more selected from phosphates, pyrophosphates, solid electrolytes, conductive polymers, and materials capable of reversibly intercalating and deintercalating lithium ions.

[0117] In any embodiment, the coating amount of the shell coating the compound represented by the 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 the formula (III) is 2 nm to 200 nm, optionally 5 nm to 50 nm.

[0118] In any embodiment, the first positive electrode active material includes a compound represented by the formula (IV),

[0119] LiMn t1 A 3 2-t1 O4 (IV)

[0120] t1 is selected from the range of 0 to 2, A 3 comprises one or more elements selected from Ni, Cr, Al, Zr, V, Ti, Mo, Ru, Mg, Nb, Ba, Si, P, W, Co, Cu, and Zn.

[0121] 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 comprising one or more coating layers; each coating layer having ionic conductivity and / or electronic conductivity.

[0122] In any embodiment, one or more coating layers in the shell covering the compound represented by formula (IV) each independently comprise one or more selected from phosphates, pyrophosphates, solid electrolytes, conductive polymers, and materials capable of reversibly inserting and deinserting lithium ions.

[0123] In any embodiment, the coating amount of the shell covering the compound represented by formula (IV) is from 0.1% by weight to 3% by weight, optionally from 0.2% by weight to 1.5% by weight, based on the weight of the core; and / or, the thickness of the shell covering the compound represented by formula (IV) is from 2 nm to 200 nm, optionally from 5 nm to 50 nm.

[0124] A second 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 comprising the positive electrode active material composition of the first aspect of this application.

[0125] In any embodiment, the content of the positive electrode active material composition in the positive electrode film layer is 90-99.5% by weight, more preferably 95-99.5% by weight, based on the total weight of the positive electrode film layer.

[0126] In any embodiment, the positive electrode sheet satisfies 0.23≤(h1×N1) / (CW / PD / 10000)<1, optionally, 0.63≤(h1×N1) / (CW / PD / 10000)≤0.87, where h1 represents the average size of the first positive electrode active material particles along the thickness direction of the positive electrode film, in μm; N1 represents the number of first positive electrode active material particles contained in the positive electrode film along the thickness direction of the positive electrode film; and CW represents the areal density of the positive electrode film, in g / cm³. 2 ; PD represents the compaction density of the positive electrode film, in g / cm³. 3 This allows the battery to have a long cycle life.

[0127] In any embodiment, along the thickness direction of the positive electrode film, the average size h1 of the first positive electrode active material particles is 0.5-20 μm, and can be selected as 2.8-9.2 μm.

[0128] In any embodiment, along the thickness direction of the positive electrode film, the number N1 of the first positive electrode active material particles contained in the positive electrode film is 5-25, and can be selected as 6-20.

[0129] In any embodiment, the areal density CW of the positive electrode film is 0.01-0.05 g / cm³. 2 The selectable value is 0.015-0.035 g / cm³. 2 .

[0130] In any embodiment, the compaction density ρ of the positive electrode film is 1.8-3.6 g / cm³. 3 The selectable value is 2.0-3.4 g / cm³. 3 .

[0131] In any embodiment, the positive electrode sheet also satisfies 0.5 ≤ α1 + (PD / ρ1) ≤ 1.5, where α1 represents the porosity of the positive electrode film. This allows the battery to have a long cycle life and / or high energy density.

[0132] In any embodiment, the porosity α1 of the positive electrode film is 0.28-0.50, and can be selected as 0.30-0.39.

[0133] In any embodiment, based on the total mass of the positive electrode active material composition, the mass percentage of the first positive electrode active material is denoted as W1, the mass percentage of the second positive electrode active material is denoted as W2, the powder compaction density of the first positive electrode active material at 30000N is denoted as P1, and the powder compaction density of the second positive electrode active material at 30000N is denoted as P2, all in g / cm³. 3 If , then ΡD / [(P1×W1)+(P2×W2)] is 89% or higher, and can be selected as 92% or higher.

[0134] A third aspect of this application provides a battery comprising a positive electrode active material composition of the first aspect of this application, or a positive electrode sheet of the second aspect of this application.

[0135] The fourth aspect of this application provides an electrical device, including the battery of the third aspect of this application.

[0136] 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

[0137] 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.

[0138] Figure 1 This is a schematic diagram of one embodiment of the battery cell of this application.

[0139] Figure 2 This is an exploded view of one embodiment of the battery cell of this application.

[0140] Figure 3 This is a schematic diagram of one embodiment of the battery module of this application.

[0141] Figure 4 This is a schematic diagram of one embodiment of the battery pack of this application.

[0142] Figure 5 yes Figure 4 An exploded view of an embodiment of the battery pack shown.

[0143] 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.

[0144] 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

[0145] 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.

[0146] 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.

[0147] 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.

[0148] 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.

[0149] 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.

[0150] 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.

[0151] 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).

[0152] 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.

[0153] In this application, the terms "multiple" or "various" refer to two or more kinds.

[0154] 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.

[0155] Unless otherwise stated, the terms used in this application have the common meanings as commonly understood by those skilled in the art.

[0156] 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.

[0157] 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.

[0158] 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.

[0159] 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).

[0160] 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.

[0161] 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.

[0162] 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.

[0163] In some embodiments, the battery can be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0164] 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.

[0165] 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.

[0166] 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).

[0167] 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.

[0168] 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.

[0169] Optionally, the battery module 4 may also include a housing with a receiving space in which multiple battery cells 5 are received.

[0170] 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.

[0171] 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.

[0172] 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.

[0173] 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.

[0174] [Positive Electrode Active Material Composition]

[0175] 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 crystal form different from that of the first positive electrode active material. The second positive electrode active material includes a phosphate material.

[0176] The volume distribution particle size of the first positive electrode active material is Dv10. (1) The volume distribution particle size Dv50 of the second positive electrode active material (2) Meets Dv10 (1) / Dv50 (2) >1, the volume distribution particle size Dv50 of the first positive electrode active material (1) The volume distribution particle size Dv50 of the second positive electrode active material (2) Meets Dv50 (1) / Dv50 (2) ≥1.4.

[0177] The true density of the first positive electrode active material is denoted as ρ1, and the true density of the second positive electrode active material is denoted as ρ2, both in g / cm³. 3 Based on the total mass of the positive electrode active material composition, the mass ratio of the first positive electrode active material is denoted as W1, and the mass ratio of the second positive electrode active material is denoted as W2. Then the positive electrode active material composition satisfies -2.0≤1-[(ρ2×W2) / (ρ1×W1)]≤0.98.

[0178] The second positive electrode active material includes phosphate, which typically has an olivine structure and is generally inexpensive to produce. However, the compaction density of the second positive electrode active material is relatively low, making it difficult to meet the requirements of high-energy-density batteries. Combining it with another positive electrode active material with a higher compaction density can improve the compaction density of the positive electrode sheet, but simply mixing the two positive electrode active materials usually does not significantly improve the compaction density and compaction efficiency of the positive electrode sheet, making it difficult to fully utilize the battery's capacity and also affecting the battery's lifespan.

[0179] The inventors have discovered that by adjusting the volume distribution, particle size, true density, and mass ratio of the first and second positive electrode active materials in the positive electrode active material composition, batteries using the positive electrode active material composition of this application can achieve a balance of high energy density, low cost, and good service life.

[0180] By adjusting the volume distribution particle size Dv10 of the first positive electrode active material (1) The volume distribution particle size Dv50 of the second positive electrode active material (2) Meets Dv10 (1) / Dv50 (2) A value greater than 1 allows the second positive electrode active material to fill the gaps between the particles of the first positive electrode active material, thereby facilitating a more compact stacking of the first and second positive electrode active materials.

[0181] By adjusting the volume distribution particle size Dv50 of the first positive electrode active material (1) The volume distribution particle size Dv50 of the second positive electrode active material (2) Meets Dv50 (1) / Dv50 (2) ≥1.4 is beneficial for the more compact stacking of the first and second positive electrode active materials.

[0182] The inventors also discovered that simply adjusting the volume distribution particle size of the first and second positive electrode active materials is insufficient to achieve a high compaction density in the positive electrode sheet. However, by further adjusting the true density ρ1 and mass ratio W1 of the first positive electrode active material, and the true density ρ2 and mass ratio W2 of the second positive electrode active material, to satisfy -2.0 ≤ 1 - [(ρ2×W2) / (ρ1×W1)] ≤ 0.98, the first and second positive electrode active materials can be more tightly packed, increasing the actual packing density of the positive electrode active material composition, improving the compaction density and compaction efficiency of the positive electrode sheet. This results in batteries using the positive electrode active material composition of this application exhibiting high energy density and long service life.

[0183] The true density ρ1 of the first positive electrode active material is related to parameters such as the type, elemental composition, crystal form, particle morphology, and structure (e.g., porosity, optional coating layer type, optional coating layer thickness, etc.) of the first positive electrode active material. By adjusting one or more of the above parameters, the first positive electrode active material can have a suitable true density ρ1.

[0184] The true density ρ2 of the second positive electrode active material is related to parameters such as the type, elemental composition, crystal form, particle morphology, and structure (e.g., porosity, optional coating layer type, optional coating layer thickness, etc.) of the second positive electrode active material. By adjusting one or more of the above parameters, the second positive electrode active material can have a suitable true density ρ2.

[0185] The true density ρ1 of the first positive electrode active material and the true density ρ2 of the second positive electrode active material have meanings known in the art and can be determined using methods known in the art. For example, they can be determined by referring to GB / T1033.1, GB / T6155, GB / T23561, YB / T5300, JB / T7984.3, GB / T 1713, GB / T8929, GB / T1713, GB / T208, GB / T5071, QB / T1010, GB / T9966, GB / T18856, GB / T24203, GB / T8330, or SL-237.

[0186] The volumetric distribution particle sizes Dv10 and Dv50 of materials (e.g., the first positive electrode active material and the second positive electrode active material) 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.

[0187] The difference in crystal form between the first positive electrode active material and the second positive electrode active material refers to the difference in crystal system between the first positive electrode active material and the second positive electrode active material.

[0188] In some embodiments, 1 < Dv10 (1) / Dv50 (2) ≤16.5, optionally, 1.07≤Dv10 (1) / Dv50 (2) ≤11.3, 1.07≤Dv10 (1) / Dv50 (2) ≤9.0, 1.07≤Dv10 (1) / Dv50 (2) ≤8.0, 1.07≤Dv10 (1) / Dv50 (2) ≤7.0. 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 the positive electrode active material composition of this application to have higher energy density and / or longer service life.

[0189] As an example, Dv10 (1) / Dv50 (2) It can be 1.02, 1.05, 1.07, 1.1, 1.2, 1.4, 1.8, 2.0, 2.5, 2.7, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.3, 14.0, 16.5, or any range of the above values.

[0190] In some embodiments, 1.4 < Dv50 (1) / Dv50 (2) ≤30.0, optionally, 2.0≤Dv50 (1) / Dv50 (2) ≤23.8, 2.0≤Dv50 (1) / Dv50 (2)≤9.8. 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 the positive electrode active material composition of this application to have higher energy density and / or longer service life.

[0191] As an example, the Dv50 (1) / Dv50 (2) The value can be 1.5, 1.8, 2.0, 2.3, 2.5, 3.0, 4.0, 5.7, 7.0, 8.5, 9.0, 9.8, 11.0, 12.0, 14.0, 16.0, 18.0, 20.0, 22.0, 23.8, 26.0, 28.0, 30.0, or any range of the above values.

[0192] In some embodiments, -0.78 ≤ 1 - [(ρ2×W2) / (ρ1×W1)] ≤ 0.96, and optionally, -0.14 ≤ 1 - [(ρ2×W2) / (ρ1×W1)] ≤ 0.92, 0.24 ≤ 1 - [(ρ2×W2) / (ρ1×W1)] ≤ 0.92, 0.49 ≤ 1 - [(ρ2×W2) / (ρ1×W1)] ≤ 0.92, and 0.67 ≤ 1 - [(ρ2×W2) / (ρ1×W1)] ≤ 0.92. This allows for a more compact packing of the first and second positive electrode active materials, further increasing the actual packing density of the positive electrode active material composition, improving the compaction density and compaction efficiency of the positive electrode sheet, thereby enabling batteries using the positive electrode active material composition of this application to have higher energy density and longer service life.

[0193] As an example, 1-[(ρ2×W2) / (ρ1×W1)] can be -1.5, -1.0, -0.78, -0.50, -0.25, -0.14, 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.67, 0.80, 0.87, 0.9, 0.92, 0.94, 0.96, 0.98, or any range of the above values.

[0194] In some embodiments, the ratio of the major axis length to the minor axis length of the first positive electrode active material is 1-2, and can be selected as 1-1.4.

[0195] In some embodiments, the ratio of the major axis length to the minor axis length of the second positive electrode active material is 1-2, and can be selected as 1-1.4.

[0196] The first and second positive electrode active materials can have regular morphologies, such as spherical or near-spherical, or they can have irregular morphologies.

[0197] In some embodiments, the volume distribution particle size Dv10 of the first positive electrode active material (1) The range is 0.3-8μm, with an optional range of 1.6-6.6μm.

[0198] In some embodiments, the volume distribution particle size Dv50 of the first positive electrode active material (1) The range is 1.5-15μm, with an optional range of 3-12μm.

[0199] In some embodiments, the volume distribution particle size Dv50 of the second positive electrode active material (2) The thickness ranges from 0.25 to 3 μm, and can be selected from 0.4 to 2 μm.

[0200] 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 side reactions can be reduced, resulting in a longer battery life.

[0201] In some embodiments, the true density ρ1 of the first positive electrode active material is 4.40-5.15 g / cm³. 3 The selectable value is 4.60-5.10 g / cm³. 3 .

[0202] In some embodiments, the true density ρ2 of the second positive electrode active material is 3.20-3.65 g / cm³. 3 The selectable value is 3.30-3.60 g / cm³. 3 .

[0203] In some embodiments, based on the total mass of the positive electrode active material composition, the mass percentage W1 of the first positive electrode active material is 30%-98%, optionally 50%-90% or 70%-90%. This allows the battery to better balance high energy density and long service life.

[0204] In some embodiments, based on the total mass of the positive electrode active material composition, the mass percentage W2 of the second positive electrode active material is 2%-70%, optionally 10%-50% or 10%-30%. This allows the battery to better balance high energy density and long service life.

[0205] In some embodiments, the powder compaction density P1 of the first positive electrode active material at 30000N is 3.0 g / cm³. 3 The above can be selected as 3.2g / cm. 3 The above can also be selected as 3.3g / cm. 3 The above can be further selected as 3.4 g / cm³. 3 The above can be further optimized to 3.5g / cm³. 3 above.

[0206] In some embodiments, the powder compaction density P2 of the second 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.

[0207] Higher powder compaction density results in a greater weight of material per unit volume, which is beneficial for increasing the compaction density of the positive electrode and improving the volumetric energy density of the battery. Powder compaction density can be measured according to GB / T 24533-2009.

[0208] In some embodiments, W2 = ρ2 / [(β×ρ1)+ρ2], 0.3≤β≤30, optionally, 0.5≤β≤6.9, 0.8≤β≤6.9, 1.1≤β≤6.9, 1.8≤β≤6.9. By keeping β within the above range, the positive electrode active material composition can have a higher actual packing density, thereby further improving the compaction density and compaction efficiency of the positive electrode sheet, thus enabling the battery using the positive electrode active material composition of this application to have a higher energy density and / or a longer service life.

[0209] In some embodiments, the particle size distribution curve of the positive electrode active material composition has at least two volume distribution peaks, the peak with the smallest volume distribution particle size is denoted as peak I, and the other peaks besides peak I are denoted as peak II, and peak II may have one or more peaks.

[0210] The volumetric particle size corresponding to the maximum peak intensity of peak I is between 0.3 μm and 2.1 μm, and the volumetric particle size corresponding to the maximum peak intensity of peak II is between 3 μm and 15 μm. The ratio of the integral area of ​​peak I to the total integral area of ​​peak II is (0.010-2.5):1, which can be selected as (0.011-1.3):1. The total integral area of ​​peak II refers to the sum of the integral areas of multiple peaks in peak II.

[0211] By ensuring that the ratio of the integral area of ​​peak I to the total integral area of ​​peak II in the particle size distribution curve of the positive electrode active material composition is within the aforementioned range, the contribution of the first positive electrode active material to the compaction density of the positive electrode sheet can be increased. Furthermore, the second positive electrode active material can better fill the gaps between the particles of the first positive electrode active material. This allows the first and second positive electrode active materials to be packed more tightly, thereby increasing the actual packing density of the positive electrode active material composition, improving the compaction density and compaction efficiency of the positive electrode sheet, and consequently enabling batteries using the positive electrode active material composition of this application to have higher energy density and / or longer service life.

[0212] 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.

[0213] In some embodiments, the particle size distribution curve of the second positive electrode active material has at least two volume distribution peaks, with the peak having the smallest volume distribution particle size denoted as peak III, and the other peaks besides peak III denoted as peak IV.

[0214] The volumetric particle size corresponding to the maximum peak intensity of peak III is between 0.3 μm and 2.1 μm, and the volumetric particle size corresponding to the maximum peak intensity of peak IV is between 2.1 μm and 10 μm. The ratio of the integral area of ​​peak III to the total integral area of ​​peak IV is (0.5-20):1.

[0215] By ensuring that the ratio of the integral area of ​​peak III to the total integral area of ​​peak IV in the particle size distribution curve of the second positive electrode active material is within the aforementioned range, the second positive electrode active material can better fill the gaps between the particles of the first positive electrode active material. This allows the first and second positive electrode active materials to be packed more tightly, thereby increasing the actual packing density of the positive electrode active material composition, improving the compaction density and compaction efficiency of the positive electrode sheet, and further enabling batteries using the positive electrode active material composition of this application to have higher energy density and / or longer service life.

[0216] The particle size distribution curve of the second positive electrode active material 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.

[0217] In some embodiments, the second positive electrode active material comprises a compound represented by formula (I).

[0218] Li a A x Mn 1-y B y P 1-z C z O 4-n D n (I)

[0219] A includes one or more elements selected from families IA, IIA, IIIA, IIB, VB, and VIB; B includes 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 1; z is selected from the range of 0 to 0.5; n is selected from the range of 0 to 0.5.

[0220] 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.

[0221] Similarly, for B, C, D, M, M′, X, Z, P, Q, A mentioned in the embodiments of this application... 1 B 1 C 1 D 1 A 2 B 2 A 3 When there are two or more elements, the limitation on the numerical range of their stoichiometric coefficients in this application also has the above meaning.

[0222] In some embodiments, y is selected from the range of 0.001 to 0.999.

[0223] The second positive electrode active material is obtained by elemental doping of the compound LiMnPO4, where A, B, C, and D are the elements doped at the Li, Mn, P, and O sites of 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 of lithium manganese phosphate during lithium insertion / extraction and reducing surface activity. Reducing the lattice change rate can reduce 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 enhances the rate performance of the second 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 also effectively reduces surface activity, thereby reducing Mn dissolution and interfacial side reactions between the second 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.

[0224] 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,

[0225] B 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 may optionally include 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,

[0226] C includes one or more elements selected from B (boron), S, Si, and N; and / or,

[0227] D includes one or more elements selected from S, F, Cl, and Br.

[0228] 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,

[0229] B comprises one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge, optionally comprising at least two elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge, more preferably comprising at least two elements selected from Fe, Ti, V, Ni, Co, and Mg, further preferably comprising at least two elements selected from Fe, Ti, V, Co, and Mg, and even more preferably comprising Fe and one or more elements selected from Ti, V, Co, and Mg; and / or,

[0230] C includes any element selected from B (boron), S, Si, and N, with S being a possible choice; and / or,

[0231] D includes any element selected from S, F, Cl, and Br, and can be F.

[0232] 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.

[0233] 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,

[0234] x is selected from the range of 0.001 to 0.005; and / or,

[0235] 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,

[0236] 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,

[0237] n is selected from the range of 0 to 0.1, and optionally from the range of 0.001 to 0.005.

[0238] By selecting the y value within the above range, the specific capacity and rate performance of the second cathode active material can be further improved. By selecting the x value within the above range, the kinetic performance of the second cathode active material can be further improved. By selecting the z value within the above range, the rate performance of the battery can be further improved. By selecting the n value within the above range, the high-temperature performance of the battery can be further improved.

[0239] In some embodiments, y is selected from the range of 0.001 to 0.999, and 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.

[0240] 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 second cathode active material.

[0241] 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 second positive electrode active material, improves the integrity of the framework structure of the second positive electrode active material, thereby effectively improving the structural stability of the second positive electrode active material, and consequently improving the cycle stability of the battery.

[0242] 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 combination of two of the above values. This further reduces defects in the second positive electrode active material, further improves the integrity of the framework structure of the second positive electrode active material, effectively enhances the structural stability of the second positive electrode active material, and improves the cycle stability of the battery.

[0243] 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,

[0244] a:x can be in the range of 1 to 1200, or in the range of 9 to 1100, or even in the range of 190 to 998.

[0245] 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 second cathode active material can be further improved.

[0246] In some embodiments, z:(1-z) is 1:9 to 1:999, and optionally 1:499 to 1:249. When the above conditions are met, the energy density and cycle performance of the second positive electrode active material can be further improved.

[0247] In some embodiments, A includes one or more elements selected from Zn, Al, Na, K, Mg, Nb, Mo, and W; B includes one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge; C 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.

[0248] 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 second cathode active material can also be improved.

[0249] In some embodiments, B 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; C 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.

[0250] 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 second cathode active material can be increased.

[0251] In some embodiments, the second 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. The coating layers have ionic conductivity and / or electronic conductivity. In practice, each coating layer may be a complete or partial coating.

[0252] By providing a coating layer with ionic and / or electronic conductivity on the core surface, a second positive electrode active material with a core-shell structure is provided. Applying the second positive electrode active material to a battery can improve the battery's high-temperature cycle performance, cycle stability, and high-temperature storage performance.

[0253] In some embodiments, 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.

[0254] Using the above materials, a coating layer with ionic and / or electronic conductivity can be obtained, thereby improving the high-temperature cycle performance, cycle stability and high-temperature storage performance of the battery.

[0255] 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.

[0256] 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.

[0257] 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.

[0258] 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.

[0259] 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.

[0260] 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.

[0261] 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.

[0262] By employing a first coating layer, a second coating layer, and a third coating layer made of specific materials, the rate performance is further improved, the dissolution of Mn and Mn-site dopants is further reduced, thereby improving the cycle performance and / or high-temperature stability of the battery, and further increasing the specific capacity and compaction density of the second positive electrode active material.

[0263] 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.

[0264] In some embodiments, pyrophosphate is M b (P2O7) c ; and / or,

[0265] Phosphate is X m (PO4) q ; and / or,

[0266] The doping elements in the carbon include one or more selected from Group IIIA, Group VA, Group VIA, and Group VIIA; and / or,

[0267] The oxide is M′ d O e ; and / or,

[0268] The boride is Z v B w ; and / or,

[0269] Polymers include one or more selected from polysaccharides and their derivatives, and polysiloxanes;

[0270] 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;

[0271] 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;

[0272] M′ includes one or more elements selected from alkali metals, alkaline earth metals, transition metals, Group IIIA elements, Group IVA elements, lanthanides, and Sb;

[0273] d is greater than 0 and less than or equal to 2, e is greater than 0 and less than or equal to 5;

[0274] v is selected from the range 1 to 7, and w is selected from the range 1 to 2.

[0275] By using the above 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 second 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.

[0276] 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,

[0277] The doping elements in carbon include one or more selected from nitrogen, phosphorus, sulfur, boron, and fluorine; and / or,

[0278] 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,

[0279] The polysiloxane is selected from one or more of linear polysiloxanes and cyclic polysiloxanes; and / or,

[0280] The polysaccharide is selected from one or more plant polysaccharides and marine polysaccharides.

[0281] 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.

[0282] In some embodiments, the second positive electrode active material includes a core and a shell covering the core.

[0283] The kernel includes Li a Mn 1-y B y P 1-z C z O4, where 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, B includes one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb and Ge, and C includes one or more elements selected from B (boron), S, Si and N.

[0284] 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.

[0285] The second positive electrode active material can be a core-shell structure with two coating layers. The element B doping at the manganese sites of lithium manganese phosphate helps reduce the lattice change rate of lithium manganese phosphate during lithium insertion / extraction, improving the structural stability of the second positive electrode active material, significantly reducing manganese dissolution, and lowering the oxygen activity on the particle surface. The element C doping at the phosphorus sites helps change the ease of Mn-O bond length changes, thereby lowering the lithium-ion migration barrier, promoting lithium-ion migration, and improving the battery's rate performance. The first coating layer of the second 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 ability and can reduce the surface impurity lithium content. Furthermore, since the second coating layer is a carbon-containing layer, it can effectively improve the conductivity and desolvation ability 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 performing specific element doping and surface coating on lithium manganese phosphate, the dissolution of Mn during the lithium intercalation 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.

[0286] In some embodiments, the second positive electrode active material includes a core and a shell covering the core.

[0287] The kernel includes Li a Mn 1-y B y P 1-z C z O4, where 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, B includes one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb and Ge, and C includes one or more elements selected from B (boron), S, Si and N.

[0288] 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.

[0289] 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.

[0290] 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.

[0291] The third coating layer contains carbon.

[0292] Therefore, the second positive electrode active material can improve the specific capacity and cycle performance of the battery.

[0293] The second positive electrode active material has a core-shell structure. By doping the manganese and phosphorus sites in the core with elements B and C, respectively, it can effectively reduce manganese dissolution, thereby reducing the number of manganese ions migrating to the negative electrode, reducing electrolyte consumption due to SEI film decomposition, and improving battery cycle performance. It can also promote Mn-O bond adjustment, lower the lithium-ion migration barrier, promote lithium-ion migration, and improve the 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, reducing the surface lithium content, and reducing the contact between the core and the electrolyte, thereby reducing interfacial side reactions, reducing gas production, and improving the battery's high-temperature storage performance and cycle performance. By further coating with a phosphate coating layer with excellent lithium-ion conductivity, the interfacial side reactions on the surface of the second positive electrode active material can be effectively reduced, thereby improving the battery's high-temperature cycle and storage performance. By further coating with a carbon layer as a third coating layer, the battery's kinetic performance can be further improved. Furthermore, in the core, the element B doping at the manganese site helps to reduce the lattice change rate of lithium manganese phosphate during the lithium insertion / extraction process, improves the structural stability of the second cathode active material, greatly reduces the dissolution of manganese and reduces the oxygen activity on the particle surface; the element C doping at the phosphorus site also helps to change the ease of Mn-O bond length change, thereby improving electronic conductivity and reducing the lithium ion migration barrier, promoting lithium ion migration and improving the rate performance of the battery.

[0294] Furthermore, maintaining the overall electroneutrality of the core system minimizes defects and impurities in the second cathode active material. If an excess of transition metal (e.g., manganese) exists in the second cathode active material, due to the relatively stable structure of the material system, 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 second cathode active material.

[0295] 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.

[0296] 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 second positive electrode active material. Furthermore, the coating layer has good ionic conductivity, which helps to increase the specific capacity of the second positive electrode active material while reducing heat generation in the battery.

[0297] In some embodiments, the polysiloxane comprises the structural unit shown in formula (i).

[0298]

[0299] 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;

[0300] 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.

[0301] 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.

[0302] 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.

[0303] 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.

[0304] 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.

[0305] In some embodiments, the mass percentage of polar functional groups in the polysiloxane is α, where 0 ≤ α < 50%, and optionally, 5% ≤ α ≤ 30%.

[0306] "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.

[0307] 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.

[0308] 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.

[0309] The term "substituents attached to sugar units" includes all groups attached to the backbone of sugar units.

[0310] 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.

[0311] 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.

[0312] 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.

[0313] In some embodiments, a gravimetric method based on the positive electrode active material is used.

[0314] 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,

[0315] 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,

[0316] 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.

[0317] When only the core of the second positive electrode active material contains manganese, the manganese content can correspond to the content of the core.

[0318] Limiting the manganese content within the aforementioned range can further improve the stability and density of the second 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.

[0319] Limiting the phosphorus content within the aforementioned range can effectively reduce the impact of small polaron conductivity on the conductivity of the second positive electrode active material, further improve the stability of the crystal structure, and thus enhance the overall stability of the second positive electrode active material.

[0320] 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 second positive electrode active material, and improve the cycle performance and storage performance of the battery; it can also reduce impurities, allowing the second positive electrode active material to maintain a high discharge voltage platform, thus enabling the battery to have high energy density.

[0321] 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.

[0322] In some embodiments, the surface of the second positive electrode active material is coated with one or more of carbon and doped carbon; optionally, the surface of the second positive electrode active material is coated with carbon. This improves the conductivity of the second positive electrode active material.

[0323] 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.

[0324] 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 second positive electrode active material.

[0325] 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,

[0326] 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,

[0327] 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.

[0328] 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.

[0329] 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.

[0330] In the second positive electrode active material with a core-shell structure of this application, the coating amount of each coating layer is preferably within the above-mentioned range, thereby enabling sufficient coating of the core and further improving the dynamic performance of the battery without sacrificing the specific capacity of the second positive electrode active material.

[0331] 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.

[0332] In some embodiments, the shell (which is only a single covering layer) has a thickness of 1-15 nm.

[0333] In some embodiments, the thickness of the first coating layer is 1-10 nm, optionally 2-10 nm; and / or,

[0334] The thickness of the second coating layer is 2-25 nm, optionally 2-15 nm, and more preferably 3-15 nm; and / or,

[0335] The thickness of the third coating layer is 2-25nm, and can be selected as 5-25nm.

[0336] 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.

[0337] 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.

[0338] 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.

[0339] The first coating layer has the aforementioned thickness range, which can further reduce the adverse effects on the kinetic performance of the second positive electrode active material.

[0340] 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.

[0341] The third coating layer has the aforementioned thickness range, which can improve the electrical conductivity of the second positive electrode active material and improve the compaction density of the positive electrode sheet prepared using the second positive electrode active material.

[0342] 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 second 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.

[0343] 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.

[0344] Optionally, the crystallinity of the pyrophosphate, phosphate, and oxide is independently 10% to 100%, and more preferably 50% to 100%.

[0345] In this document, "crystalline" means a crystallinity of 50% or higher, i.e., 50%-100%. That is, the presence of crystalline pyrophosphate and crystalline phosphate in this application indicates a crystallinity of 50% to 100%.

[0346] 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.

[0347] 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 second positive electrode active material using X-ray diffraction may include the following steps:

[0348] A certain amount of the second 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 second 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, the 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.

[0349] 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.

[0350] 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.

[0351] 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.

[0352] In this application, "about" for a certain value represents a range, specifically a range of ±10% of that value.

[0353] 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.

[0354] 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.

[0355] 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.

[0356] In some embodiments, one or more coating layers each independently comprise doped carbon, in which,

[0357] 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,

[0358] 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%.

[0359] Optionally, the doping element is nitrogen, phosphorus, sulfur, boron or fluorine.

[0360] 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.

[0361] 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.

[0362] 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,

[0363] 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°;

[0364] Optionally, the first or second coating layer contains phosphate.

[0365] Both the first and second coating layers in the second 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.

[0366] In some embodiments, the lattice change rate of the second 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%.

[0367] By reducing the lattice change rate, Li ion transport becomes easier, meaning that Li ions have a stronger migration ability in the second 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).

[0368] In some embodiments, the Li / Mn antisite defect concentration of the second 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.

[0369] 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 second cathode 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 second cathode active material. The concentration of Li / Mn antisite defects can be measured by methods known in the art, such as XRD.

[0370] In some embodiments, the surface oxygen valence state of the second 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.

[0371] By reducing the surface oxygen valence state, interfacial side reactions between the second 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).

[0372] In some embodiments, the first positive electrode active material may include one or more of layered oxide materials, lithium-rich oxide materials, spinel-type lithium manganese oxide materials, and their respective modified compounds, wherein the modification method includes doping and / or surface coating modification.

[0373] The first cathode active material has a high compaction density, but it is expensive and generates more side reactions during battery use, and its crystal structure stability is relatively poor compared to the first cathode material. By rationally combining the aforementioned second cathode active material with the first cathode active material, the actual packing density of the cathode active material composition, the compaction density and compaction efficiency of the cathode sheet can be improved, and the battery can achieve a balance of high energy density, low cost, and good service life.

[0374] In some embodiments, the first positive electrode active material comprises a compound represented by formula (II).

[0375] Li a1 A 1 b1 Ni c1 Co d1 B 1 e1 C 1 f1 O 2-g1 D 1 g1 (II)

[0376] 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.

[0377] In some embodiments, A 1 Includes one or more elements selected from Na, K, Mg, Rb, Zn, and Zr; and / or,

[0378] 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,

[0379] D 1 Includes one or more elements selected from N, S, F, Cl, and Br, optionally including S and / or F; and / or,

[0380] a1 is selected from the range of 0.9 to 1.1; and / or,

[0381] b1 is selected from the range 0 to 0.1; and / or,

[0382] 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,

[0383] 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,

[0384] 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,

[0385] 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,

[0386] g1 selects a range from 0 to 0.01, or a range from 0.01 to 0.05.

[0387] In some embodiments, the first positive electrode active material includes a core and a shell covering the core, the core comprising the compound shown in formula (II) above; the shell comprising one or more coating layers. Each coating layer has ionic conductivity and / or electronic conductivity.

[0388] In some embodiments, one or more coating layers in the shell of the compound represented by formula (II) each independently comprise one or more selected from phosphates, pyrophosphates, carbon, doped carbon, oxides, and fast ion conductors, optionally including one or more selected from phosphates, pyrophosphates, and oxides.

[0389] In some embodiments, the shell of the compound represented by formula (II) includes a coating layer; optionally, the coating layer includes one or more selected from phosphates, pyrophosphates, and oxides.

[0390] In some embodiments, the shell of the compound represented by formula (II) 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.

[0391] In some embodiments, the coating amount of the shell of the compound represented by encapsulation formula (II) is from 0.005% by weight to 1% by weight, optionally from 0.01% by weight to 0.5% by weight, based on the weight of the core.

[0392] In some embodiments, the shell thickness of the compound represented by formula (II) is from 2 nm to 200 nm, optionally from 5 nm to 50 nm.

[0393] In some embodiments, the first positive electrode active material includes a compound represented by formula (III),

[0394] Li 1+p1 A 2 q1 B 2 r1 O s1 (III)

[0395] 0.05 ≤ p1 < 0.2, 0.10 < q1 ≤ 0.95, 0 ≤ r1 ≤ 0.2, and 2 ≤ s1 < 3, where A 2 comprises one or more elements selected from Co, Ni, Mn, and Al; and B 2 comprises one or more elements selected from Mg, Ti, Cr, Zr, Nb, Fe, Mo, Cu, Sb, V, P, and F.

[0396] In some embodiments, the first positive electrode active material includes a core and a shell coating the core, the core includes a compound represented by formula (III); the shell includes one or more coating layers; each coating layer has ionic conductivity and / or electronic conductivity.

[0397] In some embodiments, one or more of the coating layers of the shell coating the compound represented by formula (III) independently includes one or more selected from phosphates, pyrophosphates, solid electrolytes, conductive polymers, and materials capable of reversibly intercalating and deintercalating lithium ions.

[0398] 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.

[0399] In some embodiments, the thickness of the shell coating the compound represented by formula (III) is 2 nm to 200 nm, optionally 5 nm to 50 nm.

[0400] In some embodiments, the first positive electrode active material includes a compound represented by formula (IV),

[0401] LiMn t1 A 3 2-t1 O4 (IV)

[0402] t1 is selected from the range of 0 to 2, and A 3 comprises one or more elements selected from Ni, Cr, Al, Zr, V, Ti, Mo, Ru, Mg, Nb, Ba, Si, P, W, Co, Cu, and Zn.

[0403] 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 (IV); the shell including one or more coating layers; each coating layer having ionic conductivity and / or electronic conductivity.

[0404] In some embodiments, one or more coating layers of the shell of the compound of formula (IV) independently comprise one or more selected from phosphates, pyrophosphates, solid electrolytes, conductive polymers, and materials capable of reversibly inserting and deinserting lithium ions. Optionally, one or more coating layers of the shell of the compound of formula (IV) independently comprise one or more selected from lithium borosilicate glass, carbonates, carbon metal composites, metal oxides (such as MgO, Al2O3, LiAlO2), silicon oxide, KMnF3 and LiCoO2, acetylacetone, and conductive polymers.

[0405] In some embodiments, the shell of the compound represented by encapsulation (IV) has an encapsulation amount of 0.1% to 3% by weight, optionally 0.2% to 1.5% by weight, based on the weight of the core.

[0406] In some embodiments, the shell thickness of the compound shown in formulation (IV) is from 2 nm to 200 nm, optionally from 5 nm to 50 nm.

[0407] 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.

[0408] [Positive electrode plate]

[0409] The positive electrode sheet 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 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.

[0410] 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.

[0411] In some embodiments, the positive electrode sheet satisfies 0.23≤(h1×N1) / (CW / PD / 10000)<1, optionally, 0.63≤(h1×N1) / (CW / PD / 10000)≤0.87, where h1 represents the average size of the first positive electrode active material particles along the thickness direction of the positive electrode film, in μm; N1 represents the number of first positive electrode active material particles contained in the positive electrode film along the thickness direction of the positive electrode film; and CW represents the areal density of the positive electrode film, in g / cm³. 2 ; ρD represents the compaction density of the positive electrode film, in g / cm³. 3 This allows the battery to have a long cycle life.

[0412] The parameters mentioned above (e.g., h1, N1, CW, PD) all refer to the parameters of the positive electrode film layer on one side of the positive electrode current collector.

[0413] In some embodiments, the average size h1 of the first positive electrode active material particles along the thickness direction of the positive electrode film is 0.5-20 μm, and can be optionally 2.8-9.2 μm.

[0414] In some embodiments, along the thickness direction of the positive electrode film, the number N1 of the first positive electrode active material particles contained in the positive electrode film is 5-25, optionally 6-20, or optionally 6-18.

[0415] The number N1 and average size h1 of the first positive electrode active material particles along the thickness direction of the positive electrode film can be tested using the ion polishing cross-section method. For example, the test can be performed as follows: Using the ion polishing cross-section method, take a cross-section of the positive electrode sheet, and under a scanning electron microscope, take at least 5 reference lines perpendicular to the current collector. Count the number of first positive electrode active material particles on each reference line and take the average value, which is the number N1 of the first positive electrode active material particles along the thickness direction of the positive electrode film; count the particle size of the first positive electrode active material particles on each reference line and take the average value, which is the average size h1 of the first positive electrode active material particles along the thickness direction of the positive electrode film.

[0416] In some embodiments, the areal density CW of the positive electrode film is 0.01-0.05 g / cm³. 2 The selectable value is 0.015-0.035 g / cm³. 2 .

[0417] In some embodiments, the compaction density ρ of the positive electrode film is 1.8-3.6 g / cm³. 3 The selectable value is 2.0-3.4 g / cm³. 3 .

[0418] The areal density and compaction density of the positive electrode film are known in the art and can be tested using methods known in the art. The compaction density of the positive electrode film = areal density of the positive electrode film / thickness of the positive electrode film. The thickness of the positive electrode film is known in the art and can be tested using methods known in the art, such as a micrometer (e.g., Mitutoyo 293-100, with an accuracy of 0.1 μm). The areal density of the positive electrode film is known in the art and can be tested using methods known in the art. For example, a single-sided coated and cold-pressed positive electrode sheet (if it is a double-sided coated positive electrode sheet, the positive electrode film on one side can be wiped off first) can be punched into a small circular sheet with an area of ​​S1, weighed, and recorded as M1. Then, the positive electrode film on the weighed positive electrode sheet is wiped off, and the weight of the positive current collector is weighed and recorded as M0. The areal density of the positive electrode sheet = (M1 - M0) / S1.

[0419] In some embodiments, the positive electrode also satisfies 0.5 ≤ α1 + (PD / ρ1) ≤ 1.5, where α1 represents the porosity of the positive electrode film. This allows the battery to have a long cycle life and / or high energy density.

[0420] In some embodiments, the porosity α1 of the positive electrode film is 0.28-0.50, and optionally 0.30-0.39.

[0421] The porosity of the positive electrode film is a well-known concept in the art and can be determined using methods known in the art. An exemplary test method is as follows: Take a single-sided coated and cold-pressed positive electrode sheet (if it is a double-sided coated positive electrode sheet, the positive electrode film layer on one side can be wiped off first), and cut it into small circular samples of a certain area. Calculate the apparent volume V1 of the positive electrode sheet, V1 = S × H × A, where S represents the sample area, H represents the sample thickness, and A represents the number of samples. Referring to GB / T24586-2009, using an inert gas (such as helium) as the medium, employ the gas displacement method and measure the true volume V2 of the positive electrode sheet using a true density meter. The porosity of the positive electrode film layer = (V1 - V2) / V1 × 100%. The testing instrument can be a Micromeritics AccuPyc II1340 true density meter.

[0422] In some embodiments, based on the total mass of the positive electrode active material composition, the mass percentage of the first positive electrode active material is denoted as W1, the mass percentage of the second positive electrode active material is denoted as W2, the powder compaction density of the first positive electrode active material at 30000N is denoted as P1, and the powder compaction density of the second positive electrode active material at 30000N is denoted as P2, all in g / cm³. 3If ρD / [(P1×W1)+(P2×W2)] is 89% or higher, it can be selected as 92% or higher. (P1×W1)+(P2×W2) can represent the theoretical powder compaction density of the positive electrode active material composition, and ρD / [(P1×W1)+(P2×W2)] can represent the compaction density efficiency of the positive electrode sheet.

[0423] 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.).

[0424] In some embodiments, the positive electrode film layer may optionally include a binder. As an example, the binder may include at least one selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0425] In some embodiments, the positive electrode film may optionally include a conductive agent. As an example, the conductive agent may include at least one selected from superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0426] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, 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.

[0427] [Negative electrode plate]

[0428] 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 including a negative electrode active material.

[0429] As an example, the negative electrode 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 two opposite surfaces of the negative electrode current collector.

[0430] 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.).

[0431] In some embodiments, the negative electrode active material may be a material known in the art. As an example, the negative electrode active material may include at least one of the following: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may include at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may include at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0432] In some embodiments, the negative electrode film layer may optionally include an adhesive. As an example, the adhesive may include at least one 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).

[0433] In some embodiments, the negative electrode film may optionally include a conductive agent. As an example, the conductive agent may include at least one selected from superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0434] In some embodiments, the negative electrode film may optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC)).

[0435] In some embodiments, 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, conductive agent, 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.

[0436] 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.

[0437] [Electrolytes]

[0438] The electrolyte acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific restrictions on the type of electrolyte; it can be selected according to requirements. For example, the electrolyte can be liquid, gel, or entirely solid.

[0439] In some embodiments, the electrolyte is liquid (also known as an electrolyte solution) and includes an electrolyte salt and a solvent.

[0440] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0441] In some embodiments, the solvent may include at least one selected from ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0442] In some embodiments, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain battery performance, such as additives that improve battery overcharge performance, additives that improve battery high-temperature or low-temperature performance, etc.

[0443] [Isolation membrane]

[0444] 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.

[0445] 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.

[0446] 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.

[0447] 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.

[0448] As an electrical device, you can choose individual battery cells, battery modules, or battery packs according to your usage requirements.

[0449] 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.

[0450] 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.

[0451] Example

[0452] 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.

[0453] The batteries of Examples 1-14 and Comparative Examples 1-6 were all prepared according to the following method.

[0454] Preparation of positive electrode sheet

[0455] The first and second positive electrode active materials shown in Table 1, the conductive agent acetylene black, and the binder polyvinylidene fluoride (PVDF) were thoroughly mixed in an appropriate amount of NMP solvent at a mass ratio of 96:2:2 to form a uniform positive electrode slurry. The positive electrode slurry was then uniformly coated onto both surfaces of the positive electrode current collector aluminum foil. After drying and cold pressing, the positive electrode sheet was obtained. The areal density (CW) of the positive electrode film layer on one side of the positive electrode current collector was 0.0196 g / cm³. 2 .

[0456] Preparation of negative electrode sheet

[0457] 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.

[0458] Preparation of electrolyte

[0459] 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.

[0460] Preparation of the separating membrane

[0461] Porous polyethylene film is used as the separator.

[0462] Battery manufacturing

[0463] 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.

[0464] Test section

[0465] At 25℃, the battery is charged at a constant current of 0.5C to 4.2V, 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 0.5C 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.

[0466] In Tables 1 and 2, NCM811 refers to LiNi 0.8 Co 0.1 Mn 0.1 O2, LCO refers to LiCoO2, and LMFP refers to carbon-coated LiMn. 0.60 Fe 0.40 PO4.

[0467] The NCM811, LCO, and LMFP used in the various embodiments and comparative examples are commercially available. The materials are obtained by sieving multiple commercially available materials using a suitable sieve and then mixing them in a predetermined ratio. 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. Alternatively, the materials can be obtained by using a sintering method and adjusting sintering process parameters (e.g., sintering temperature, sintering time, sintering atmosphere, etc.) and grinding parameters (e.g., grinding speed, grinding time, etc.), and sieving using a suitable sieve. Alternatively, materials of different sizes prepared by the sintering method can be mixed in a predetermined ratio.

[0468] The ratio of the major axis length to the minor axis length of the first and second positive electrode active materials in Table 1 is between 1 and 1.4, which can be obtained by adjusting the grinding parameters (such as grinding speed, grinding time, etc.).

[0469] Dv10 (1) Dv50 (1) ρ1 is the volume distribution particle size of the first positive electrode active material, P1 is the true density of the first positive electrode active material, and P1 is the compacted density of the first positive electrode active material at 30000N.

[0470] Dv50 (2) ρ2 is the volume distribution particle size of the second positive electrode active material, ρ2 is the true density of the second positive electrode active material, and P2 is the powder compaction density of the second positive electrode active material at 30000N.

[0471] W1 represents the mass percentage of the first positive electrode active material based on the total mass of the positive electrode active material composition.

[0472] W2 is the mass percentage of the second positive electrode active material based on the total mass of the positive electrode active material composition, and W2=ρ2 / [(β×ρ1)+ρ2].

[0473] In the particle size distribution curve of the positive electrode active material composition, the integral area of ​​peak I represents the integral area of ​​the peak with the smallest volume distribution particle size, and the integral area of ​​peak II represents the total integral area of ​​all other peaks except peak I.

[0474] h1 represents the average size of the first positive electrode active material particles along the thickness direction of the positive electrode film.

[0475] N1 represents the number of first positive electrode active material particles contained in the positive electrode film along the thickness direction of the positive electrode film.

[0476] ρD represents the compaction density of the positive electrode film.

[0477] α1 represents the porosity of the positive electrode film.

[0478] The compaction density efficiency of the positive electrode sheet = PD / [(P1×W1)+(P2×W2)].

[0479] The above parameters can be measured according to the test methods given above.

[0480] From Tables 1 and 2, it can be seen that when both the first and second positive electrode active materials simultaneously satisfy Dv10... (1) / Dv50 (2) >1. Dv50 (1) / Dv50 (2) When ≥1.4 and -2.0≤1-[(ρ2×W2) / (ρ1×W1)]≤0.98, the positive electrode sheet using this positive electrode active material composition can have both high solid density and high solid density efficiency, and the battery using this positive electrode active material composition can have high energy density and long service life.

[0481] The preparation methods of the batteries in Examples 15-19 are similar to those in Example 5, except that the type of the second positive electrode active material is different, as detailed in Table 3. The test results are shown in Table 4.

[0482] The second positive electrode active material in Examples 15-19 can be 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. The ratio of the major axis length to the minor axis length of the second positive electrode active material used in Examples 15-19 is between 1 and 1.4.

[0483] As can be seen from Tables 3 and 4, by doping specific elements at the Mn site of LiMnPO4 and further at the Li, P and / or O sites, specifically at the Mn and P sites of LiMnPO4, or more specifically at the Li, Mn, P and O sites of LiMnPO4, the cycle performance of the battery can be further improved.

[0484] 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.

[0485]

[0486]

[0487]

Claims

1. A positive electrode active material composition, wherein, 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 one or more of layered oxide materials, lithium-rich oxide materials, spinel-type lithium manganese oxide materials, and their respective modified compounds, wherein the modification methods include doping and / or surface coating modification. The second positive electrode active material includes a phosphate material, and the second positive electrode active material includes a compound represented by formula (I). Li a A x Mr 1-y B y P 1-z C z Oh 4-n D n (I) A includes one or more elements selected from families IA, IIA, IIIA, IIB, VB, and VIB; B includes 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 1; z is selected from the range of 0 to 0.5; n is selected from the range of 0 to 0.

5. The first positive electrode active material has a volume distribution particle size Dv10 (1) The volume distribution particle size Dv50 of the second positive electrode active material (2) Meets Dv10 (1) / Dv50 (2) >1, The volume distribution particle size Dv50 of the first positive electrode active material (1) The volume distribution particle size Dv50 of the second positive electrode active material (2) Meets Dv50 (1) / Dv50 (2) ≥1.4, The true density of the first positive electrode active material is denoted as ρ1, and the true density of the second positive electrode active material is denoted as ρ2, both in g / cm³. 3 Based on the total mass of the positive electrode active material composition, let the mass percentage of the first positive electrode active material be W1 and the mass percentage of the second positive electrode active material be W2. Then, the positive electrode active material composition satisfies -2.0 ≤ 1 - [(ρ2×W2) / (ρ1×W1)] ≤ 0.

98. The particle size distribution curve of the positive electrode active material composition has at least two volume distribution peaks. The peak with the smallest volume distribution particle size is denoted as peak I, and the other peaks are denoted as peak II. The volume distribution particle size corresponding to the maximum peak intensity of peak I is between 0.3 μm and 2.1 μm, and the volume distribution particle size corresponding to the maximum peak intensity of peak II is between 3 μm and 15 μm. The ratio of the integral area of ​​peak I to the total integral area of ​​peak II is (0.010-2.5):

1.

2. The positive electrode active material composition according to claim 1, wherein, 1 < Dv10 (1) / Dv50 (2) ≤16.5; and / or, 1.4 < Dv50 (1) / Dv50 (2) ≤30.0; and / or, -0.78≤1 - [(ρ2×W2) / (ρ1×W1)]≤0.

96.

3. The positive electrode active material composition according to claim 2, wherein, 1.07≤Dv10 (1) / Dv50 (2) ≤11.3。 4. The positive electrode active material composition according to claim 2, wherein, 2.0≤Dv50 (1) / Dv50 (2) ≤23.8。 5. The positive electrode active material composition according to claim 2, wherein, -0.14≤1 - [(ρ2×W2) / (ρ1×W1)]≤0.

92.

6. The positive electrode active material composition according to claim 5, wherein, 0.67≤1 - [(ρ2×W2) / (ρ1×W1)]≤0.

92.

7. The positive electrode active material composition according to claim 1, wherein, W2=ρ2 / [(β×ρ1)+ρ2], 0.3≤β≤30.

8. The positive electrode active material composition according to claim 7, wherein, 0.5≤β≤6.9。 9. The positive electrode active material composition according to claim 8, wherein, 1.8≤β≤6.9。 10. The positive electrode active material composition according to claim 1, wherein, The ratio of the integral area of ​​peak I to the total integral area of ​​peak II is (0.011-1.3):

1.

11. The positive electrode active material composition according to claim 1, wherein, The particle size distribution curve of the second positive electrode active material has at least two volume distribution peaks. The peak with the smallest volume distribution particle size is denoted as peak III, and the other peaks are denoted as peak IV. The volume distribution particle size corresponding to the maximum peak intensity of peak III is between 0.3 μm and 2.1 μm, and the volume distribution particle size corresponding to the maximum peak intensity of peak IV is between 2.1 μm and 10 μm. The ratio of the integral area of ​​peak III to the total integral area of ​​peak IV is (0.5-20):

1.

12. The positive electrode active material composition according to claim 1, wherein, The ratio of the major axis length to the minor axis length of the first positive electrode active material is 1-2; and / or, The ratio of the major axis length to the minor axis length of the second positive electrode active material is 1-2; and / or, The first positive electrode active material has a volume distribution particle size Dv10 (1) 0.3-8 μm; and / or, The volume distribution particle size Dv50 of the first positive electrode active material (1) 1.5-15 μm; and / or, The volume distribution particle size Dv50 of the second positive electrode active material (2) 0.25-3 μm; and / or, The true density ρ1 of the first positive electrode active material is 4.40-5.15 g / cm³. 3 ; and / or, The true density ρ2 of the second positive electrode active material is 3.20-3.65 g / cm³. 3 ; and / or, Based on the total mass of the positive electrode active material composition, the mass percentage W1 of the first positive electrode active material is 30%-98%; and / or, Based on the total mass of the positive electrode active material composition, the mass percentage W2 of the second positive electrode active material is 2%-70%.

13. The positive electrode active material composition according to claim 12, wherein, The ratio of the major axis length to the minor axis length of the first positive electrode active material is 1-1.4; and / or, The ratio of the major axis length to the minor axis length of the second positive electrode active material is 1-1.4; and / or, The first positive electrode active material has a volume distribution particle size Dv10 (1) 1.6-6.6 μm; and / or, The volume distribution particle size Dv50 of the first positive electrode active material (1) 3-12 μm; and / or, The volume distribution particle size Dv50 of the second positive electrode active material (2) 0.4-2 μm; and / or, The true density ρ1 of the first positive electrode active material is 4.60-5.10 g / cm³. 3 ; and / or, The true density ρ2 of the second positive electrode active material is 3.30-3.60 g / cm³. 3 ; and / or, Based on the total mass of the positive electrode active material composition, the mass percentage W1 of the first positive electrode active material is 70%-90%; and / or, Based on the total mass of the positive electrode active material composition, the mass percentage W2 of the second positive electrode active material is 10%-30%.

14. The positive electrode active material composition according to claim 1, wherein, y is selected from the range of 0.001 to 0.

999.

15. The positive electrode active material composition according to claim 1, wherein, 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 / or, B 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 / or, C includes one or more elements selected from boron, S, Si, and N; and / or, D includes one or more elements selected from S, F, Cl, and Br.

16. The positive electrode active material composition according to claim 15, wherein, A includes one or more elements selected from Zn, Al, Na, K, Mg, Nb, Mo, and W; and / or, B 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.

17. The positive electrode active material composition according to claim 1, wherein, A includes any element selected from Zn, Al, Na, K, Mg, Nb, Mo, and W; and / or, B includes one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge; and / or, C includes any element selected from boron, S, Si, and N; and / or, D includes any element selected from S, F, Cl, and Br.

18. The positive electrode active material composition according to claim 17, wherein, A includes any element selected from Mg and Nb; and / or, B includes at least two elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge; and / or, C is S; and / or, D is F.

19. The positive electrode active material composition according to claim 17, wherein, B includes at least two elements selected from Fe, Ti, V, Ni, Co, and Mg.

20. The positive electrode active material composition according to claim 17, wherein, B includes at least two elements selected from Fe, Ti, V, Co, and Mg.

21. The positive electrode active material composition according to claim 17, wherein, B includes Fe and one or more elements selected from Ti, V, Co, and Mg.

22. The positive electrode active material composition according to claim 1, 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.

23. The positive electrode active material composition according to claim 22, 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.

24. The positive electrode active material composition according to claim 22, wherein, y is selected from the range of 0.25 to 0.5; and / or, z is selected from the range of 0.001 to 0.

005.

25. The positive electrode active material composition according to claim 1, 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 0.001 to 0.1, z is 0, and n is selected from the range 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.

26. The positive electrode active material composition according to claim 1, wherein, y : z is selected from the range of 0.002 to 999.

27. The positive electrode active material composition according to claim 1, wherein, y : z is selected from the range of 0.025 to 999.

28. The positive electrode active material composition according to claim 1, wherein, y : z is selected from the range of 0.002 to 500.

29. The positive electrode active material composition according to claim 1, wherein, y : z is selected from the range of 0.2 to 600.

30. The positive electrode active material composition according to claim 1, wherein, z : n is selected from the range of 0.002 to 500.

31. The positive electrode active material composition according to claim 1, wherein, z : n is selected from the range of 0.2 to 100.

32. The positive electrode active material composition according to claim 1, wherein, z: n is selected from the range of 0.2 to 50.

33. The positive electrode active material composition according to claim 1, wherein, A includes one or more elements selected from Zn, Al, Na, K, Mg, Nb, Mo, and W; B includes one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge; C includes one or more elements selected from 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.

34. The positive electrode active material composition according to claim 1, wherein, B 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; C includes one or more elements selected from 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.

35. The positive electrode active material composition according to claim 34, wherein, B includes one or more elements selected from Zn, Fe, Ti, V, Ni, Co, and Mg.

36. The positive electrode active material composition according to claim 1, wherein, (1-y): y is in the range of 0.1-999; and / or, a:x is in the range of 1 to 1200.

37. The positive electrode active material composition according to claim 1, wherein, (1-y): y is in the range of 0.1-10.

38. The positive electrode active material composition according to claim 1, wherein, (1-y): y is in the range of 0.67-999.

39. The positive electrode active material composition according to claim 1, wherein, (1-y): y is in the range of 1 to 10.

40. The positive electrode active material composition according to claim 1, wherein, (1-y): y is in the range of 1 to 4.

41. The positive electrode active material composition according to claim 1, wherein, (1-y): y is in the range of 1.5 to 3.

42. The positive electrode active material composition according to claim 1, wherein, a:x is in the range of 9 to 1100.

43. The positive electrode active material composition according to claim 1, wherein, a:x is in the range of 190-998.

44. The positive electrode active material composition according to claim 1, wherein, z : (1-z) is 1:9 to 1:

999.

45. The positive electrode active material composition according to claim 1, wherein, z : (1-z) ranges from 1:499 to 1:

249.

46. ​​The positive electrode active material composition according to claim 1, wherein, The second positive electrode active material includes a core and a shell covering the core. The core comprises the compound shown in formula (I); The shell includes one or more covering layers; each covering layer has ionic conductivity and / or electronic conductivity.

47. The positive electrode active material composition according to claim 46, wherein, Each of the one or more coating layers independently comprises one or more selected from pyrophosphates, phosphates, carbon, doped carbon, oxides, borides, and polymers. The pyrophosphate is M b (P2O7) c ; The phosphate is X m (PO4) q ; The doping elements in the doped carbon include one or more selected from Group IIIA, Group VA, Group VIA and Group VIIA; The oxide is M′ d O e ; The boride is Z v B w ; The polymer includes one or more selected from polysaccharides and polysiloxanes; 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; 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; M′ includes 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 1 to 7; w is selected from the range 1 to 2.

48. The positive electrode active material composition according to claim 46, wherein, The shell includes a covering layer.

49. The positive electrode active material composition according to claim 48, wherein, The coating layer comprises one or more selected from pyrophosphates, phosphates, carbon, doped carbon, oxides, borides, and polymers. The pyrophosphate is M b (P2O7) c ; The phosphate is X m (PO4) q ; The doping elements in the doped carbon include one or more selected from Group IIIA, Group VA, Group VIA and Group VIIA; The oxide is M′ d O e ; The boride is Z v B w ; The polymer includes one or more selected from polysaccharides and polysiloxanes; 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; 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; M′ includes 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 1 to 7; w is selected from the range 1 to 2.

50. The positive electrode active material composition according to claim 46, wherein, The shell includes a first covering layer covering the core and a second covering layer covering the first covering layer.

51. The positive electrode active material composition according to claim 50, wherein, 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. The pyrophosphate is M b (P2O7) c ; The phosphate is X m (PO4) q ; The doping elements in the doped carbon include one or more selected from Group IIIA, Group VA, Group VIA and Group VIIA; The oxide is M′ d O e ; The boride is Z v B w ; The polymer includes one or more selected from polysaccharides and polysiloxanes; 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; 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; M′ includes 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 1 to 7; w is selected from the range 1 to 2.

52. The positive electrode active material composition according to claim 51, wherein, 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.

53. The positive electrode active material composition according to claim 46, wherein, The shell includes a first covering layer covering the core, a second covering layer covering the first covering layer, and a third covering layer covering the second covering layer.

54. The positive electrode active material composition according to claim 53, wherein, The first coating layer, the second coating layer, and the third coating layer each independently comprise one or more selected from pyrophosphate, phosphate, carbon, doped carbon, oxide, boride, and polymer. The pyrophosphate is M b (P2O7) c ; The phosphate is X m (PO4) q ; The doping elements in the doped carbon include one or more selected from Group IIIA, Group VA, Group VIA and Group VIIA; The oxide is M′ d O e ; The boride is Z v B w ; The polymer includes one or more selected from polysaccharides and polysiloxanes; 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; 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; M′ includes 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 1 to 7; w is selected from the range 1 to 2.

55. The positive electrode active material composition according to claim 54, wherein, 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.

56. The positive electrode active material composition according to any one of claims 47, 49, 51, and 54, wherein, 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, The doping element in the doped carbon includes one or more selected from nitrogen, phosphorus, sulfur, boron, and fluorine; and / or, 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 / or, The polysiloxane is selected from one or more of linear polysiloxanes and cyclic polysiloxanes; and / or, The polysaccharide is selected from one or more plant polysaccharides and marine polysaccharides.

57. The positive electrode active material composition according to claim 56, wherein, M′ includes one or more elements selected from Mg, Al, Si, Zn, Zr, and Sn.

58. The positive electrode active material composition according to claim 46, wherein, The second positive electrode active material includes a core and a shell covering the core. The kernel includes Li a Mn 1-y B y P 1-z C z O4, where 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, B includes one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb and Ge, and C includes one or more elements selected from boron, S, Si and N; 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.

59. The positive electrode active material composition according to claim 46, wherein, The second positive electrode active material includes a core and a shell covering the core. The kernel includes Li a Mn 1-y B y P 1-z C z O4, where 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, B includes one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb and Ge, and C includes one or more elements selected from boron, S, Si and N; The shell includes a first covering layer covering the core, a second covering layer covering the first covering layer, and a third covering layer covering the second covering layer. 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 equation independently includes 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, wherein X comprises one or more elements selected from Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb and Al; The third coating layer contains carbon.

60. The positive electrode active material composition according to claim 47, wherein, The shell contains one or more covering layers that are furthest from the core, each of which independently includes one or more selected from polysiloxanes and polysaccharides.

61. The positive electrode active material composition according to any one of claims 47, 49, 51, and 54, wherein, The polysiloxane comprises the structural unit shown in formula (i). （i） 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.

62. The positive electrode active material composition according to claim 61, wherein, 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.

63. The positive electrode active material composition according to claim 61, wherein, The polysiloxane further comprises end-capping groups, which include 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.

64. The positive electrode active material composition according to claim 61, wherein, 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, side-chain aminopropylpolysiloxane, and aminopropyl... One or more of the following: end-capped 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.

65. The positive electrode active material composition according to any one of claims 47, 49, 51, and 54, wherein, The number average molecular weights of the polysiloxane and the polysaccharide are each independently below 300,000.

66. The positive electrode active material composition according to any one of claims 47, 49, 51, and 54, wherein, The number-average molecular weights of the polysiloxane and the polysaccharide are each independently between 10,000 and 200,000.

67. The positive electrode active material composition according to any one of claims 47, 49, 51, and 54, wherein, The number-average molecular weights of the polysiloxane and the polysaccharide are each independently between 20,000 and 120,000.

68. The positive electrode active material composition according to any one of claims 47, 49, 51, and 54, wherein, The number-average molecular weights of the polysiloxane and the polysaccharide are each independently between 400 and 80,000.

69. The positive electrode active material composition according to any one of claims 47, 49, 51, and 54, wherein, The mass percentage of polar functional groups in the polysiloxane is α, where 0 ≤ α < 50%.

70. The positive electrode active material composition according to claim 69, wherein, 5%≤α≤30%。 71. The positive electrode active material composition according to any one of claims 47, 49, 51, and 54, wherein, The substituents attached to the sugar units in the polysaccharide 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 alkylene group.

72. The positive electrode active material composition according to claim 71, wherein, R represents a C1-C5 alkylene group.

73. The positive electrode active material composition according to claim 71, wherein, The substituents attached to the sugar units in the polysaccharide 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.

74. The positive electrode active material composition according to any one of claims 47, 49, 51, and 54, wherein 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.

75. The positive electrode active material composition according to any one of claims 47, 49, 51, and 54, wherein, The mass percentage of substituents attached to the sugar units in the polysaccharide is independently 20% to 85%.

76. The positive electrode active material composition according to claim 75, wherein, The mass percentage of substituents attached to the sugar units in the polysaccharide is independently 30% to 78%.

77. The positive electrode active material composition according to claim 46, wherein, The lattice mismatch between the material of the core and the material of the shell is less than 10%.

78. The positive electrode active material composition according to claim 1, wherein, Based on the total weight of the second positive electrode active material The manganese content is in the range of 10% to 35% by weight; and / or, The phosphorus content is in the range of 12% to 25% by weight; and / or, The weight ratio of manganese to phosphorus ranges from 0.71 to 1.

85.

79. The positive electrode active material composition according to claim 78, wherein, Based on the total weight of the second positive electrode active material, the manganese content is in the range of 13.3% to 33.2% by weight.

80. The positive electrode active material composition according to claim 78, wherein, Based on the total weight of the second positive electrode active material, the manganese content is in the range of 15%-30% by weight.

81. The positive electrode active material composition according to claim 78, wherein, Based on the total weight of the second positive electrode active material, the manganese content is in the range of 17%-20% by weight.

82. The positive electrode active material composition according to claim 78, wherein, Based on the total weight of the second positive electrode active material, the phosphorus content is in the range of 15%-20% by weight.

83. The positive electrode active material composition according to claim 78, wherein, Based on the total weight of the second positive electrode active material, the phosphorus content is in the range of 16.8% to 19.5% by weight.

84. The positive electrode active material composition according to claim 78, wherein, The weight ratio of manganese to phosphorus ranges from 0.90 to 1.

25.

85. The positive electrode active material composition according to claim 78, wherein, The weight ratio of manganese to phosphorus ranges from 0.95 to 1.

20.

86. The positive electrode active material composition according to claim 1, wherein, The surface of the second positive electrode active material is coated with one or more of carbon and doped carbon.

87. The positive electrode active material composition according to claim 86, wherein, The surface of the second positive electrode active material is coated with carbon.

88. The positive electrode active material composition according to claim 86, wherein, The doping element in the doped carbon includes one or more selected from nitrogen, phosphorus, sulfur, boron and fluorine.

89. The positive electrode active material composition according to claim 46, wherein, The shell covers an area of ​​0.1% to 6% by weight, based on the weight of the core.

90. The positive electrode active material composition according to claim 53, wherein, The coating amount of the first coating layer is greater than 0 and less than or equal to 7% 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, 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, based on the weight of the core.

91. The positive electrode active material composition according to claim 90, wherein, The coating amount of the first coating layer is greater than 0 and less than or equal to 6% by weight, based on the weight of the core.

92. The positive electrode active material composition according to claim 90, wherein, The coating amount of the first coating layer is greater than 0 and less than or equal to 5.5% by weight, based on the weight of the core.

93. The positive electrode active material composition according to claim 90, wherein, The first coating layer has a coating weight of 4-5.6% by weight, based on the weight of the core.

94. The positive electrode active material composition according to claim 90, wherein, The coating amount of the first coating layer is greater than 0 and less than or equal to 2% by weight, based on the weight of the core.

95. The positive electrode active material composition according to claim 90, wherein, The second coating layer has a coating amount greater than 0 and less than or equal to 5.5% by weight, based on the weight of the core.

96. The positive electrode active material composition according to claim 90, wherein, The second coating layer has a coating amount of 2-4% by weight, based on the weight of the core.

97. The positive electrode active material composition according to claim 90, wherein, The second coating layer has a coating amount of 3-5% by weight, based on the weight of the core.

98. The positive electrode active material composition according to claim 90, wherein, The coating amount of the third coating layer is greater than 0 and less than or equal to 5.5% by weight, based on the weight of the core.

99. The positive electrode active material composition according to claim 90, wherein, The coating amount of the third coating layer is greater than 0 and less than or equal to 2% by weight, based on the weight of the core.

100. The positive electrode active material composition according to claim 53, wherein, The shell further includes a fourth covering layer covering the third covering layer and a fifth covering layer covering the fourth covering layer; The coating amounts of the fourth and fifth coating layers are each independently between 0.01% by weight and 10% by weight, based on the weight of the core.

101. The positive electrode active material composition according to claim 100, wherein, The coating amounts of the fourth and fifth coating layers are each independently between 0.05% by weight and 10% by weight, based on the weight of the core.

102. The positive electrode active material composition according to claim 101, wherein, The coating amounts of the fourth and fifth coating layers are each independently 0.1% to 5% by weight, based on the weight of the core.

103. The positive electrode active material composition according to claim 102, wherein, The coating amounts of the fourth and fifth coating layers are each independently 0.1% to 2% by weight, based on the weight of the core.

104. The positive electrode active material composition according to claim 46, wherein, The shell is located on 40% to 90% of the surface of the core.

105. The positive electrode active material composition according to claim 104, wherein, The shell is located on 60% to 80% of the surface of the core.

106. The positive electrode active material composition according to claim 46, wherein, The thickness of the shell is 1-15 nm.

107. The positive electrode active material composition according to claim 53, wherein, The thickness of the first coating layer is 1-10 nm; and / or, The thickness of the second coating layer is 2-25 nm; and / or, The thickness of the third coating layer is 2-25 nm.

108. The positive electrode active material composition according to claim 107, wherein, The thickness of the first coating layer is 2-10 nm; and / or, The thickness of the second coating layer is 2-15 nm; and / or, The thickness of the third coating layer is 5-25 nm.

109. The positive electrode active material composition according to claim 107, wherein, The thickness of the second coating layer is 3-15 nm.

110. The positive electrode active material composition according to claim 47, wherein, Each of the one or more coating layers independently comprises one or more selected from pyrophosphates, phosphates, and oxides, and the one or more selected from the pyrophosphates, phosphates, and oxides are crystalline.

111. The positive electrode active material composition according to claim 110, wherein, The crystallinity of the pyrophosphate, the phosphate, and the oxide is each independently between 10% and 100%.

112. The positive electrode active material composition according to claim 111, wherein, The crystallinity of the pyrophosphate, the phosphate, and the oxide is independently between 50% and 100%.

113. The positive electrode active material composition according to claim 110, wherein, In the shell, the weight ratio of pyrophosphate to phosphate and the weight ratio of pyrophosphate to oxide are each independently 1:3 to 3:

1.

114. The positive electrode active material composition according to claim 113, wherein, In the shell, the weight ratio of pyrophosphate to phosphate and the weight ratio of pyrophosphate to oxide are each independently 1:3 to 1:

1.

115. The positive electrode active material composition according to claim 46, wherein, Each of the one or more coating layers independently comprises carbon, and the carbon is a mixture of SP2 carbon and SP3 carbon.

116. The positive electrode active material composition according to claim 115, wherein, In the carbon, the molar ratio of SP2 carbon to SP3 carbon is any value within the range of 0.07-13.

117. The positive electrode active material composition according to claim 116, wherein, In the carbon, the molar ratio of SP2 carbon to SP3 carbon is any value within the range of 0.1-10.

118. The positive electrode active material composition according to claim 117, wherein, In the carbon, the molar ratio of SP2 carbon to SP3 carbon is any value within the range of 2.0-3.

0.

119. The positive electrode active material composition according to claim 47, wherein, Each of the one or more coating layers independently comprises doped carbon, and the mass content of the doping element in the doped carbon is less than 30%.

120. The positive electrode active material composition according to claim 119, wherein, The mass content of the doped carbon element is less than 20%.

121. The positive electrode active material composition according to claim 47, wherein, 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%.

122. The positive electrode active material composition according to claim 47, wherein, Each of the one or more coating layers independently includes doped carbon, wherein the doping element is nitrogen, phosphorus, sulfur, boron or fluorine.

123. The positive electrode active material composition according to claim 47, wherein, Each of the one or more coating layers independently comprises pyrophosphate, the pyrophosphate having a plane spacing ranging from 0.293 to 0.470 nm and an included angle of the (111) crystal orientation ranging from 18.00° to 32.57°; and / or, 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 and the included angle of the crystal orientation (111) is in the range of 20.00°-37.00°.

124. The positive electrode active material composition according to claim 123, wherein, Each of the one or more coating layers independently comprises pyrophosphate, wherein the interplanar spacing of the pyrophosphate is in the range of 0.297-0.462 nm.

125. The positive electrode active material composition according to claim 123, wherein, Each of the one or more coating layers independently comprises pyrophosphate, wherein the interplanar spacing of the pyrophosphate is in the range of 0.293-0.326 nm.

126. The positive electrode active material composition according to claim 123, wherein, Each of the one or more coating layers independently comprises pyrophosphate, wherein the interplanar spacing of the pyrophosphate is in the range of 0.300-0.310 nm.

127. The positive electrode active material composition according to claim 123, wherein, Each of the one or more coating layers independently comprises pyrophosphate, the crystal orientation (111) of which has an included angle ranging from 18.00° to 32.00°.

128. The positive electrode active material composition according to claim 123, wherein, Each of the one or more coating layers independently comprises pyrophosphate, the crystal orientation (111) of which has an included angle ranging from 26.41° to 32.57°.

129. The positive electrode active material composition according to claim 123, wherein, Each of the one or more coating layers independently comprises pyrophosphate, the crystal orientation (111) of which has an included angle ranging from 19.211° to 30.846°.

130. The positive electrode active material composition according to claim 123, wherein, Each of the one or more coating layers independently comprises pyrophosphate, the crystal orientation (111) of which has an included angle ranging from 29.00° to 30.00°.

131. The positive electrode active material composition according to claim 123, wherein, Each of the one or more coating layers independently comprises a phosphate, wherein the interplanar spacing of the phosphate is in the range of 0.345-0.358 nm.

132. The positive electrode active material composition according to claim 123, wherein, Each of the one or more coating layers independently comprises a phosphate, wherein the included angle of the crystal orientation (111) of the phosphate is in the range of 24.25°-26.45°.

133. The positive electrode active material composition according to claim 50 or 53, wherein, The first or second coating layer contains phosphate.

134. The positive electrode active material composition according to claim 1, wherein, The lattice change rate of the second positive electrode active material before and after complete lithium insertion / extraction is less than 50%; and / or, The concentration of Li / Mn antisite defects in the second positive electrode active material is below 5.3%; and / or, The surface oxygen valence state of the second positive electrode active material is below -1.

55.

135. The positive electrode active material composition according to claim 134, wherein, The lattice change rate of the second positive electrode active material before and after complete lithium insertion / extraction is less than 9.8%.

136. The positive electrode active material composition according to claim 134, wherein, The lattice change rate of the second positive electrode active material before and after complete lithium insertion / extraction is less than 8.1%.

137. The positive electrode active material composition according to claim 134, wherein, The lattice change rate of the second positive electrode active material before and after complete lithium insertion / extraction is less than 7.5%.

138. The positive electrode active material composition according to claim 134, wherein, The lattice change rate of the second positive electrode active material before and after complete lithium insertion / extraction is less than 6%.

139. The positive electrode active material composition according to claim 134, wherein, The lattice change rate of the second positive electrode active material before and after complete lithium insertion / extraction is less than 4%.

140. The positive electrode active material composition according to claim 134, wherein, The lattice change rate of the second positive electrode active material before and after complete lithium insertion / extraction is less than 3.8%.

141. The positive electrode active material composition according to claim 134, wherein, The lattice change rate of the second positive electrode active material before and after complete lithium insertion / extraction is 2.0-3.8%.

142. The positive electrode active material composition according to claim 134, wherein, The concentration of Li / Mn antisite defects in the second positive electrode active material is below 5.1%.

143. The positive electrode active material composition according to claim 134, wherein, The concentration of Li / Mn antisite defects in the second positive electrode active material is below 4%.

144. The positive electrode active material composition according to claim 134, wherein, The concentration of Li / Mn antisite defects in the second positive electrode active material is below 2.2%.

145. The positive electrode active material composition according to claim 134, wherein, The concentration of Li / Mn antisite defects in the second positive electrode active material is below 2%.

146. The positive electrode active material composition according to claim 134, wherein, The concentration of Li / Mn antisite defects in the second positive electrode active material is 1.5%-2.2%.

147. The positive electrode active material composition according to claim 134, wherein, The concentration of Li / Mn antisite defects in the second positive electrode active material is below 0.5%.

148. The positive electrode active material composition according to claim 134, wherein, The surface oxygen valence state of the second positive electrode active material is below -1.

82.

149. The positive electrode active material composition according to claim 134, wherein, The surface oxygen valence state of the second positive electrode active material is below -1.

88.

150. The positive electrode active material composition according to claim 134, wherein, The surface oxygen valence state of the second positive electrode active material is below -1.

90.

151. The positive electrode active material composition according to claim 134, wherein, The surface oxygen valence state of the second positive electrode active material is -1.98 to -1.

88.

152. The positive electrode active material composition according to claim 134, wherein, The surface oxygen valence state of the second positive electrode active material is -1.98 to -1.

89.

153. The positive electrode active material composition according to claim 134, wherein, The surface oxygen valence state of the second positive electrode active material is -1.98 to -1.

90.

154. The positive electrode active material composition according to claim 1, wherein, The first positive electrode active material has a powder compaction density P1 of 30000N. 3 The above; and / or, The second positive electrode active material has a powder compaction density P2 of 1.89 g / cm³ at 30000 N. 3 above.

155. The positive electrode active material composition according to claim 154, wherein, The first positive electrode active material has a powder compaction density P1 of 30000N. 3 above.

156. The positive electrode active material composition according to claim 154, wherein, The first positive electrode active material has a powder compaction density P1 of 30000N. 3 above.

157. The positive electrode active material composition according to claim 154, wherein, The first positive electrode active material has a powder compaction density P1 of 30000N. 3 above.

158. The positive electrode active material composition according to claim 154, wherein, The first positive electrode active material has a powder compaction density P1 of 30000N. 3 above.

159. The positive electrode active material composition according to claim 154, wherein, The second positive electrode active material has a powder compaction density P2 of 1.95 g / cm³ at 30000 N. 3 above.

160. The positive electrode active material composition according to claim 154, wherein, The second positive electrode active material has a powder compaction density P2 of 1.98 g / cm³ at 30000 N. 3 above.

161. The positive electrode active material composition according to claim 154, wherein, The second positive electrode active material has a powder compaction density P2 of 2.0 g / cm³ at 30000 N. 3 above.

162. The positive electrode active material composition according to claim 154, wherein, The second positive electrode active material has a powder compaction density P2 of 2.2 g / cm³ at 30000 N. 3 above.

163. The positive electrode active material composition according to claim 154, wherein, The second positive electrode active material has a powder compaction density P2 of 2.2 g / cm³ at 30000 N. 3 Above and 2.8 g / cm 3 the following.

164. The positive electrode active material composition according to claim 154, wherein, The second positive electrode active material has a powder compaction density P2 of 2.2 g / cm³ at 30000 N. 3 Above and 2.65 g / cm 3 the following.

165. The positive electrode active material composition according to claim 1, wherein, The first positive electrode active material includes the compound shown in 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 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.

166. The positive electrode active material composition according to claim 165, wherein, A 1 Includes one or more elements selected from Na, K, Mg, Rb, Zn, and Zr; and / or, 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; and / or, D 1 Includes 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 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 selects the range from 0 to 0.

01.

167. The positive electrode active material composition according to claim 166, wherein, C 1 Includes one or more elements selected from Al, Ti, Zr, Nb, Sr, Sc, Sb, Y, Ba, and B; and / or, D 1 Including 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 selects a range from 0.01 to 0.

05.

168. The positive electrode active material composition according to claim 165, wherein, The first positive electrode active material includes a core and a shell covering the core. The core comprises the compound represented by formula (II); The shell includes one or more covering layers; each covering layer has ionic conductivity and / or electronic conductivity.

169. The positive electrode active material composition according to claim 168, wherein, The shell's coverage is from 0.005% to 1% by weight, based on the weight of the core; and / or, The thickness of the shell is 2 nm to 200 nm.

170. The positive electrode active material composition according to claim 169, wherein, The shell's coverage is from 0.01% to 0.5% by weight, based on the weight of the core; and / or, The thickness of the shell is 5 nm to 50 nm.

171. The positive electrode active material composition according to claim 1, wherein, The first positive electrode active material includes the compound shown in 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 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.

172. The positive electrode active material composition according to claim 171, wherein, The first positive electrode active material includes a core and a shell covering the core. The core comprises the compound represented by formula (III); The shell includes one or more covering layers; each covering layer has ionic conductivity and / or electronic conductivity.

173. The positive electrode active material composition according to claim 172, wherein, The shell's coverage is from 0.1% to 5% by weight, based on the weight of the core; and / or, The thickness of the shell is 2 nm to 200 nm.

174. The positive electrode active material composition according to claim 173, wherein, The shell covers an area of ​​0.5% to 2% by weight, based on the weight of the core; and / or, The thickness of the shell is 5 nm to 50 nm.

175. The positive electrode active material composition according to claim 1, wherein, The first positive electrode active material includes the compound shown in formula (IV). LiMn t1 A 3 2-t1 O4(IV) t1 is selected from the range 0 to 2, A 3 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.

176. The positive electrode active material composition according to claim 175, wherein, The first positive electrode active material includes a core and a shell covering the core. The core comprises the compound represented by formula (IV); The shell includes one or more covering layers; each covering layer has ionic conductivity and / or electronic conductivity.

177. The positive electrode active material composition according to claim 176, wherein, The shell covers an area of ​​0.1% to 3% by weight, based on the weight of the core; and / or, The thickness of the shell is 2 nm to 200 nm.

178. The positive electrode active material composition according to claim 177, wherein, The shell covers an area of ​​0.2% to 1.5% by weight, based on the weight of the core; and / or, The thickness of the shell is 5 nm to 50 nm.

179. A positive electrode sheet, comprising 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 comprising the positive electrode active material composition according to any one of claims 1 to 178.

180. The positive electrode sheet according to claim 179, wherein, The content of the positive electrode active material composition in the positive electrode film is 90-99.5% by weight, based on the total weight of the positive electrode film.

181. The positive electrode sheet according to claim 180, wherein, The content of the positive electrode active material composition in the positive electrode film is 95-99.5% by weight, based on the total weight of the positive electrode film.

182. The positive electrode sheet according to claim 179, wherein, The positive electrode sheet satisfies 0.23 ≤ (h1 × N1) / (CW / PD / 10000) < 1, where h1 represents the average size of the first positive electrode active material particles along the thickness direction of the positive electrode film, in μm; N1 represents the number of first positive electrode active material particles contained in the positive electrode film along the thickness direction; and CW represents the areal density of the positive electrode film, in g / cm³. 2 ; PD represents the compaction density of the positive electrode film, in g / cm³. 3 .

183. The positive electrode sheet according to claim 182, wherein, The positive electrode sheet satisfies 0.63≤(h1×N1) / (CW / PD / 10000)≤0.

87.

184. The positive electrode sheet according to claim 182, wherein, Along the thickness direction of the positive electrode film, the average size h1 of the first positive electrode active material particles is 0.5-20 μm; and / or, Along the thickness direction of the positive electrode film, the number N1 of the first positive electrode active material particles contained in the positive electrode film is 5-25; and / or, The areal density (CW) of the positive electrode film is 0.01-0.05 g / cm³. 2 ; and / or, The compaction density (ρD) of the positive electrode film is 1.8-3.6 g / cm³. 3 .

185. The positive electrode sheet according to claim 184, wherein, Along the thickness direction of the positive electrode film, the average size h1 of the first positive electrode active material particles is 2.8-9.2 μm; and / or, Along the thickness direction of the positive electrode film, the number N1 of the first positive electrode active material particles contained in the positive electrode film is 6-20; and / or, The areal density (CW) of the positive electrode film is 0.015-0.035 g / cm³. 2 ; and / or, The compaction density (ρD) of the positive electrode film is 2.0-3.4 g / cm³. 3 .

186. The positive electrode sheet according to claim 182, wherein, The positive electrode also satisfies 0.5≤α1+(PD / ρ1)≤1.5, where α1 represents the porosity of the positive electrode film.

187. The positive electrode sheet according to claim 186, wherein, The porosity α1 of the positive electrode film is 0.28-0.

50.

188. The positive electrode sheet according to claim 187, wherein, The porosity α1 of the positive electrode film is 0.30-0.

39.

189. The positive electrode sheet according to claim 182, wherein, Based on the total mass of the positive electrode active material composition, the mass percentage of the first positive electrode active material is denoted as W1, the mass percentage of the second positive electrode active material is denoted as W2, the powder compaction density of the first positive electrode active material at 30000N is denoted as P1, and the powder compaction density of the second positive electrode active material at 30000N is denoted as P2. All units are g / cm³. 3 If so, then ΡD / [(P1×W1)+(P2×W2)] is over 89%.

190. The positive electrode sheet according to claim 189, wherein, The percentage of ΡD / [(P1×W1)+(P2×W2)] is over 92%.

191. A battery comprising a positive electrode active material composition according to any one of claims 1 to 178, or a positive electrode sheet according to any one of claims 179 to 190.

192. An electrical device comprising the battery of claim 191.

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