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

Abstract

The present application provides a cathode active material composition, a cathode sheet, a battery, and a power consuming device, wherein the cathode active material composition includes a first cathode active material and a second cathode active material having a crystal form different from that of the first cathode active material, the first cathode active material including a phosphate, and the particle size distribution curve of the cathode active material composition has at least two volume distribution peaks, where the volume distribution peak with the maximum peak intensity is designated as a first peak and the volume particle size distribution corresponding to the maximum peak intensity position of the first peak is designated as Dv1, the volume distribution peak with the next maximum peak intensity is designated as a second peak and the volume particle size distribution corresponding to the maximum peak intensity position of the second peak is designated as Dv2, and 0<|Dv1-Dv2| / Dv1≦50.

Description

[Technical Field]

[0001] The present application relates to a positive electrode active material composition, a positive electrode sheet, a battery, and a power consuming device. [Background technology]

[0002] In recent years, batteries have been widely applied in energy storage power systems such as hydroelectric power, thermal power, wind power and solar power plants, as well as in multiple fields such as power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace, etc. With the continuous expansion of the application fields of batteries, the requirements for the energy density and service life of batteries are becoming increasingly higher. Summary of the Invention

[0003] The present application provides a positive electrode active material composition, a positive electrode sheet, a battery, and a power consuming device that enable the battery to combine high energy density, low cost, and good service life.

[0004] According to a first aspect of the present application, there is provided a cathode active material composition, the cathode active material composition including a first cathode active material and a second cathode active material having a crystal form different from that of the first cathode active material, the first cathode active material including a phosphate, and a particle size distribution curve of the cathode active material composition having at least two volume distribution peaks, where the volume distribution peak having the maximum peak intensity is designated as a first peak, and the volume particle size distribution corresponding to the position of the maximum peak intensity of the first peak is designated as Dv1, and the volume distribution peak having the next maximum peak intensity is designated as a second peak, and the volume particle size distribution corresponding to the position of the maximum peak intensity of the second peak is designated as Dv2, the relationship is 0<|Dv1-Dv2| / Dv1≦50.

[0005] The positive electrode active material composition includes a first positive electrode active material and a second positive electrode active material having different crystal forms, and the particle size distribution curve of the positive electrode active material composition satisfies 0<|Dv1-Dv2| / Dv1≦50, thereby allowing the first positive electrode active material and the second positive electrode active material to be closely stacked, improving the actual bulk density of the positive electrode active material composition and improving the pressed density and pressed density efficiency of the positive electrode sheet, and thereby allowing a battery using the positive electrode active material composition to have a higher energy density and a longer service life.

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

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

[0008] In any embodiment, the first positive electrode active material has a volume-based particle size distribution Dv50 of 0.25 μm to 3.5 μm, and the particle size distribution curve of the positive electrode active material composition is 0.1≦|Dv1−Dv2| / Dv1≦50, and optionally 0.46≦|Dv1−Dv2| / Dv1≦39.6; and / or 0.3 μm≦Dv1≦17.8 μm, optionally 0.35 μm≦Dv1≦12.1 μm, and / or 0.3 μm≦Dv2≦17.8 μm, and optionally 0.46 μm≦Dv2≦14.2 μm.

[0009] This allows the first and second positive electrode active materials to be stacked more tightly, further improving the actual bulk density of the positive electrode active material composition and improving the pressed density and pressed density efficiency of the positive electrode sheet, thereby allowing a battery using the positive electrode active material composition to have a higher energy density and / or a longer service life.

[0010] In any embodiment, the first positive electrode active material has a volume-based particle size distribution Dv50 of 3.5 μm to 12.5 μm, and the particle size distribution curve of the positive electrode active material composition is 0.1≦|Dv1−Dv2| / Dv1≦6.0, and optionally 0.34≦|Dv1−Dv2| / Dv1≦3.8; and / or 2.0 μm≦Dv1≦12.5 μm, optionally 3.0 μm≦Dv1≦12.3 μm, and / or 2.0 μm≦Dv2≦15.0 μm, and optionally 3.4 μm≦Dv2≦14.3 μm.

[0011] This allows the first and second positive electrode active materials to be stacked more tightly, further improving the actual bulk density of the positive electrode active material composition and improving the pressed density and pressed density efficiency of the positive electrode sheet, thereby allowing a battery using the positive electrode active material composition to have a higher energy density and / or a longer service life.

[0012] In any embodiment, the morphology of the first positive electrode active material includes one or more of monocrystalline and polycrystalline, and the morphology of the second positive electrode active material includes one or more of monocrystalline and polycrystalline.

[0013] In any embodiment, the volume-based particle size distribution Dv50 of the first positive electrode active material in single crystal form is 0.25 μm to 3.5 μm, and optionally 0.35 μm to 2.5 μm.

[0014] In any embodiment, the volume-based particle size distribution Dv10 of the first positive electrode active material in single crystal form is 0.05 μm to 1.5 μm, and optionally 0.1 μm to 1.0 μm.

[0015] In any embodiment, the volume-based particle size distribution Dv50 of the first positive electrode active material in polycrystalline form is 3.5 μm to 12.5 μm, and optionally 3.8 μm to 10.5 μm.

[0016] In any embodiment, the volume-based particle size distribution Dv10 of the first positive electrode active material in polycrystalline form is 0.1 μm to 5.0 μm, and optionally 0.5 μm to 4.5 μm.

[0017] In any embodiment, the volume-based particle size distribution Dv50 of the second positive electrode active material in single crystal form is 2.5 μm to 16.5 μm, and optionally 3.0 μm to 8.5 μm.

[0018] In any embodiment, the volume-based particle size distribution Dv10 of the second positive electrode active material in single crystal form is 0.3 μm to 8 μm, and optionally 1.0 μm to 3.5 μm.

[0019] In any embodiment, the volume-based particle size distribution Dv50 of the second positive electrode active material in polycrystalline form is 2.5 μm to 16.5 μm, and optionally 3.0 μm to 15.5 μm.

[0020] In any embodiment, the volume-based particle size distribution Dv10 of the second positive electrode active material in polycrystalline form is 0.5 μm to 12 μm, and optionally 1.0 μm to 8.5 μm.

[0021] When the volume-based particle size distribution 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 further, side reactions can be reduced and interfacial resistance can be lowered, thereby resulting in a longer service life of the battery.

[0022] In some embodiments, the weight content of the first positive electrode active material is w a and the weight content of the second positive electrode active material is w b In this case, w a is selected from the range of 0.5% to 99.5%, optionally selected from the range of 2% to 95%, and / or b is selected from the range of 0.5% to 99.5%, and optionally from the range of 5% to 98%.

[0023] When the content of the first positive electrode active material and / or the second positive electrode active material is within the above range, the battery can have a higher energy density and / or a longer service life.

[0024] In some embodiments, the first positive electrode active material has a green density P1 of 1.89 g / cm at 30,000 N. 3 or more, and optionally 1.95 g / cm 3 or more, and more selectively 1.98 g / cm 3 or more, and more selectively 2.0 g / cm 3 or more, and more selectively 2.2 g / cm 3 or more, and more selectively 2.2 g / cm 3 Above 2.8g / cm 3 or less than 2.2g / cm 3 or more and 2.65g / cm 3 The following is the result.

[0025] In some embodiments, the second positive electrode active material has a green density P2 of 2.90 g / cm at 30,000 N. 3 or more, and optionally 3.1 g / cm 3 or more, and more selectively 3.3 g / cm 3 That's all.

[0026] When the green density of the first positive electrode active material and / or the second positive electrode active material is within the above range, the battery can have a higher energy density.

[0027] In some embodiments, the second positive electrode active material has a BET specific surface area of ​​1.73 m 2 / g or less, and selectively 1.5m 2 / g or less, and more selectively 0.28m 2 / g~1.5m 2 This reduces side reactions and improves the cycle characteristics of the battery.

[0028] In some embodiments, the first positive electrode active material comprises a compound represented by Formula (I): Li a A x Mn 1-y B y P 1-z C z O 4-n D n (I) A comprises one or more elements selected from Groups IA, IIA, IIIA, IIB, VB, and VIB; B comprises one or more elements selected from Groups IA, IIA, IIIA, IVA, VA, IIB, IVB, VB, VIB, and VIII; C comprises one or more elements selected from Groups IIIA, IVA, VA, and VIA; D comprises one or more elements selected from Groups VIA and VIIA; a is selected from the range of 0.85 to 1.15; x is selected from the range of 0 to 0.1; y is selected from the range of 0.001 to 0.999; z is selected from the range of 0 to 0.5; and n is selected from the range of 0 to 0.5.

[0029] By doping the Mn site of the compound LiMnPO4, and selectively the Li site, P site, and / or O site, with a specific element in a specific amount, improved rate characteristics can be obtained, and at the same time, the elution of Mn and the doped element at the Mn site is reduced, improving cycle characteristics and / or high temperature stability, and also increasing the specific capacity and packed density of the material.

[0030] In any embodiment, A comprises 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 comprises one or more elements selected from Zn, Al, Na, K, Mg, Nb, Mo, and W.

[0031] In any embodiment, B comprises one or more elements selected from Rb, Cs, Be, Ca, Sr, Ba, In, Pb, Bi, Cd, Hf, Ta, Cr, Ru, Rh, Pd, Os, Ir, Pt, Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb, and Ge, and optionally comprises 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.

[0032] In any embodiment, C comprises one or more elements selected from B (boron), S, Si, and N.

[0033] In an optional embodiment, D comprises one or more elements selected from S, F, Cl, and Br.

[0034] In any embodiment, A includes any one element selected from Zn, Al, Na, K, Mg, Nb, Mo, and W, and optionally any one element selected from Mg and Nb.

[0035] In any embodiment, B comprises one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge, and optionally comprises at least two elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge, and further optionally comprises at least two elements selected from Fe, Ti, V, Ni, Co, and Mg, and further optionally comprises at least two elements selected from Fe, Ti, V, Co, and Mg, and further optionally comprises Fe and one or more elements selected from Ti, V, Co, and Mg.

[0036] In any embodiment, C includes any one element selected from B (boron), S, Si, and N, and is optionally S.

[0037] In any embodiment, D comprises any one element selected from S, F, Cl and Br, and optionally is F.

[0038] By selecting the Li-site dopant element within the above range, the lattice change rate during the lithium desorption process can be further reduced, thereby further improving the rate characteristics of the battery. By selecting the Mn-site dopant element within the above range, the electronic conductivity can be further improved and the lattice change rate can be further reduced, thereby improving the rate characteristics and specific capacity of the battery. By selecting the P-site dopant element within the above range, the rate characteristics of the battery can be further improved. By selecting the O-site dopant element within the above range, the interfacial side reactions can be further reduced and the high-temperature characteristics of the battery can be improved.

[0039] In any embodiment, a is selected from the range of 0.9 to 1.1, and optionally from the range of 0.97 to 1.01.

[0040] In any embodiment, x is selected from the range of 0.001 to 0.005.

[0041] In any embodiment, y is selected from the range of 0.001 to 0.5, optionally selected from the range of 0.01 to 0.5, optionally selected from the range of 0.25 to 0.5.

[0042] In any embodiment, z is selected from the range of 0.001 to 0.5, optionally selected from the range of 0.001 to 0.1, and further optionally selected from the range of 0.001 to 0.005.

[0043] In any embodiment, n is selected from the range of 0 to 0.1, and optionally from the range of 0.001 to 0.005.

[0044] By selecting the value of y within the above range, the specific capacity and rate characteristics of the first positive electrode active material can be further improved. By selecting the value of x within the above range, the dynamic characteristics of the first positive electrode active material can be further improved. By selecting the value of z within the above range, the rate characteristics of the battery can be further improved. By selecting the value of n within the above range, the high-temperature characteristics of the battery can be further improved.

[0045] 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 0.

[0046] Doping a specific element in a specific amount into the Mn site of the compound LiMnPO4, and selectively into the Li site, P site, and / or O site, in particular into the Mn site and P site of LiMnPO4 or the Li site, Mn site, P site, and O site of LiMnPO4, can improve the rate characteristics, reduce the elution of Mn and the doped element at the Mn site, improve the cycle characteristics and / or high-temperature stability, and increase the specific capacity and packed density of the first positive electrode active material.

[0047] In any embodiment, y:z is selected from the range of 0.002 to 999, optionally selected from the range of 0.025 to 999 or the range of 0.002 to 500, and further optionally selected from the range of 0.2 to 600. This can reduce defects in the first positive electrode active material, improve the integrity of the framework structure of the first positive electrode active material, effectively improve the structural stability of the first positive electrode active material, and improve the cycle stability of the battery.

[0048] 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 further optionally from the range of 0.2 to 50. This can further reduce defects in the first positive electrode active material, further improve the integrity of the framework structure of the first positive electrode active material, effectively improve the structural stability of the first positive electrode active material, and improve the cycle stability of the battery.

[0049] 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.

[0050] By simultaneously doping the Li site, Mn site, P site, and O site of the compound LiMnPO4 with specific elements in specific amounts, improved rate characteristics can be obtained, and at the same time, the elution of Mn and the doped elements from the Mn site can be reduced, improving cycle characteristics and / or high-temperature stability, and also improving the specific capacity and compressed density of the first positive electrode active material.

[0051] In any embodiment, B comprises 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 comprises one or more elements selected from Zn, Fe, Ti, V, Ni, Co, and Mg; C comprises 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.

[0052] By simultaneously doping the Mn site and P site of the compound LiMnPO4 with a specific element in a specific amount, the rate characteristics can be improved, the elution of Mn and the doped element at the Mn site can be reduced, the cycle characteristics and / or high-temperature stability can be improved, and the specific capacity and compressed density of the first positive electrode active material can be increased.

[0053] In any embodiment, (1-y):y is in the range of 0.1 to 999, optionally in the range of 0.1 to 10 or 0.67 to 999, further optionally in the range of 1 to 10, further optionally in the range of 1 to 4, and further optionally in the range of 1.5 to 3. When the above conditions are satisfied, the energy density and cycle characteristics of the first positive electrode active material can be further improved.

[0054] In any embodiment, a:x is in the range of 1 to 1200, optionally in the range of 9 to 1100, and further optionally in the range of 190 to 998. When the above conditions are satisfied, the energy density and cycle characteristics of the first positive electrode active material can be further improved.

[0055] In any embodiment, z:(1-z) is 1:9 to 1:999, and optionally 1:499 to 1:249. When the above condition is satisfied, the energy density and cycle characteristics of the first positive electrode active material can be further improved.

[0056] In any embodiment, the first positive electrode active material comprises a core and a shell coating the core, the core comprising the compound represented by Formula (I), the shell comprising one or more coating layers, each coating layer having ionic and / or electronic conductivity.

[0057] By providing a coating layer having ionic and / or electronic conductivity on the core surface, a first positive electrode active material having a core-shell structure is provided, and by applying the first positive electrode active material to a battery, the high-temperature cycle characteristics, cycle stability, and high-temperature storage performance of the battery can be improved.

[0058] In any embodiment, the one or more coating layers each independently comprise one or more selected from pyrophosphate, phosphate, carbon, doped carbon, oxide, boride, and polymer.

[0059] In any embodiment, the shell comprises one coating layer, optionally the coating layer comprises one or more selected from pyrophosphate, phosphate, carbon, doped carbon, oxide, boride, and polymer.

[0060] By using the above materials, a coating layer having ionic and / or electronic conductivity can be obtained, thereby improving the high-temperature cycle characteristics, cycle stability, and high-temperature storage performance of the battery.

[0061] In any embodiment, the shell includes a first coating layer covering the core and a second coating layer covering the first coating layer, and 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, and optionally 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. Using a first coating layer made of a specific material and a second coating layer made of a specific material can further improve rate characteristics and further reduce leaching of Mn and doped elements from Mn sites, thereby improving the cycle characteristics and / or high-temperature stability of the battery.

[0062] 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, and optionally, 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, and optionally, the first coating layer comprises pyrophosphate, the second coating layer comprises one or more selected from phosphate, oxide, and boride, and the third coating layer comprises one or more selected from carbon and doped carbon. The use of a specific material for the first coating layer, the second coating layer, and the third coating layer further improves the rate capability, further reduces the dissolution of Mn and doped elements at Mn sites, improves the cycleability and / or high-temperature stability of the battery, and further increases the specific capacity and packed density of the first positive electrode active material.

[0063] In some embodiments, the pyrophosphate salt is M b (P2O7) c and / or the phosphate is X m (PO4) q and / or the doping element in the doped carbon comprises one or more selected from group IIIA, group VA, group VIA and group VIIA, and / or the oxide is M' d Oe and / or the boride is Z v B w and / or the polymer comprises one or more selected from polysaccharides and derivatives thereof, 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; and w is selected from the range of 1 to 2.

[0064] By using the above material to form the coating layer, it is possible to further reduce the elution of Mn and doping elements at the Mn site, further improve the specific capacity and compressed density of the first positive electrode active material, and further improve the rate characteristics, high-temperature cycle characteristics, and high-temperature storage performance of the battery.

[0065] In any embodiment, M, X, and Z each independently comprise one or more elements selected from Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb, Mn, and Al.

[0066] In an optional embodiment, the doping elements in the doped carbon include one or more selected from nitrogen, phosphorus, sulfur, boron and fluorine.

[0067] In any embodiment, M′ comprises one or more elements selected from Li, Be, B, Na, Mg, Al, Si, P, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, W, La, and Ce, and optionally comprises one or more elements selected from Mg, Al, Si, Zn, Zr, and Sn.

[0068] In an optional embodiment, the polysiloxane is selected from one or more of a linear polysiloxane and a cyclic polysiloxane.

[0069] In any embodiment, the polysaccharide is selected from one or more of plant polysaccharides and marine polysaccharides.

[0070] By using the above specific materials to form the coating layer, it is possible to further reduce the elution of Mn and doping elements at the Mn site, and further improve the high-temperature cycle characteristics and high-temperature storage performance of the battery.

[0071] In any embodiment, the first positive electrode active material includes a core and a shell covering the core, and the core is Li a Mn 1-y B y P 1-z C z O4, a is selected from the range of 0.9 to 1.1, y is selected from the range of 0.001 to 0.5, z is selected from the range of 0.001 to 0.1, 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, the shell includes a first coating layer coating the core and a second coating layer coating the first coating layer, the first coating layer includes pyrophosphate MP2O7 and phosphate XPO4, 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, and the second coating layer includes carbon.

[0072] In any embodiment, the first positive electrode active material includes a core and a shell covering the core, and the core is Li a Mn 1-y B y P 1-z C zO4, 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, C includes one or more elements selected from B (boron), S, Si and N, the shell includes a first coating layer coating the core, a second coating layer coating the first coating layer, and a third coating layer coating the second coating layer, and the first coating layer is pyrophosphate Li f QP2O7 and / or Q g (P2O7) h wherein 0≦f≦2, 1≦g≦4, and 1≦h≦6; and f QP2O7 and / or Q g (P2O7) h wherein each Q independently comprises one or more elements selected from Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb, and Al, the second coating layer comprises crystalline phosphate XPO4, X comprises one or more elements selected from Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb, and Al, and the third coating layer comprises carbon.

[0073] By doping lithium manganese phosphate with specific elements and coating the surface, it is possible to effectively reduce the elution of Mn during the lithium insertion and desorption process, while at the same time promoting the migration of lithium ions, thereby improving the rate characteristics of the battery and enhancing its cycle characteristics and high-temperature properties.

[0074] In any embodiment, one or more coating layers of the shell farthest from the core each independently comprise one or more selected from polysiloxane, polysaccharide, and polysaccharide derivative, thereby improving the uniformity of the coating, effectively blocking interfacial side reactions caused by high voltage, improving the high-temperature cycle characteristics and high-temperature storage performance of the first positive electrode active material, and the coating layer has good ionic conductivity, which helps to improve the specific capacity of the first positive electrode active material and simultaneously reduces heat generation in the battery.

[0075] In an optional embodiment, the polysiloxane comprises a structural unit shown in formula (i): [ka] R1 and R2 are each independently selected from H, -COOH, -OH, -SH, -CN, -SCN, an amino group, a phosphate ester group, a carboxylate ester group, an amide group, an aldehyde group, a sulfonyl group, a polyether segment, a C1-C20 aliphatic hydrocarbon group, a C1-C20 halogenated aliphatic hydrocarbon group, a C1-C20 heteroaliphatic hydrocarbon group, a C1-C20 halogenated heteroaliphatic hydrocarbon group, a C6-C20 aromatic hydrocarbon group, a C6-C20 halogenated aromatic hydrocarbon group, a C2-C20 heteroaromatic hydrocarbon group, and a C2-C20 halogenated heteroaromatic hydrocarbon group; optionally, R1 and R2 are independently selected from H, an amino group, a phosphate ester group, a polyether segment, a C1-C8 alkyl group, a C1-C8 halogenated alkyl group, a C1-C8 heteroalkyl group, a C1-C8 halogenated heteroalkyl group, a C2-C8 alkenyl group, and a C2-C8 halogenated alkenyl group.

[0076] In an optional embodiment, the polysiloxane further comprises an end-capping group, the end-capping group comprising one or more of the functional groups polyether, C1-C8 alkyl group, C1-C8 halogenated alkyl group, C1-C8 heteroalkyl group, C1-C8 halogenated heteroalkyl group, C2-C8 alkenyl group, C2-C8 halogenated alkenyl group, C6-C20 aromatic hydrocarbon group, C1-C8 alkoxy group, C2-C8 epoxy group, hydroxy group, C1-C8 hydroxyalkyl group, amino group, C1-C8 aminoalkyl group, carboxy group, and C1-C8 carboxyalkyl group.

[0077] In any embodiment, the polysiloxane may be selected from the group consisting of polydimethylsiloxane, polydiethylsiloxane, polymethylethylsiloxane, polymethylvinylsiloxane, polyphenylmethylsiloxane, polymethylhydrogensiloxane, carboxy-functionalized polysiloxane, epoxy-terminated polysiloxane, methoxy-terminated polydimethylsiloxane, hydroxypropyl-terminated polydimethylsiloxane, polymethylchloropropylsiloxane, hydroxy-terminated polydimethylsiloxane, polymethyltrifluoropropylsiloxane, perfluorooctylmethylpolysiloxane, aminoethylaminopropylpolydimethylsiloxane, polyether-terminated polydimethylsiloxane, side chain aminopropylpolysiloxane, The polydimethylsiloxane may include one or more selected from the group consisting of cyclohexane, cyclohexane-1,3,5,7-octamethylcyclotetrasiloxane, 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, hexadecamethylcyclooctasiloxane, tetradecamethylcycloheptasiloxane, and cyclic polydimethylsiloxane.

[0078] In any embodiment, the number average molecular weight of the polysiloxane, the polysaccharide, and the polysaccharide derivative is independently 300,000 or less, optionally 10,000 to 200,000, further optionally 20,000 to 120,000, and further optionally 400 to 80,000.

[0079] In any embodiment, the weight percent content of polar functional groups in the polysiloxane is α, where 0≦α<50%, and optionally 5%≦α≦30%.

[0080] In some embodiments, the substituents attached to the saccharide units in the polysaccharide and polysaccharide derivative each independently comprise one or more of the functional groups: -OH, -COOH and salts thereof, -R-OH, -SOH and salts thereof, -R-OH, -R-SOH and salts thereof, sulfuric acid ester groups, and alkoxy groups, where R represents an alkylene group, and optionally represents a C1-C5 alkylene group. Optionally, the substituents attached to the saccharide units in the polysaccharide and polysaccharide derivative each independently comprise one or more of the functional groups: -OH, -COOH, -COOLi, -COONa, -COOK, -SOH, -SOHLi, -SONa, -SOK, -CH2-SOH, -CH2-SOKLi, -CH2-SONa, -CH2-SOK, methoxy groups, and ethoxy groups.

[0081] In any embodiment, the polysaccharide comprises one or more selected from pectin, carboxymethyl starch, hydroxypropyl starch, dextran, cellulose ether, carboxymethylchitosan, hydroxyethylcellulose, carboxymethylcellulose, carboxypropylmethylcellulose, guar gum, sesbania gum, gum arabic, lithium alginate, sodium alginate, potassium alginate, fucoidan, agar, carrageenan, xanthan gum, and fenugreek gum.

[0082] In any embodiment, the weight percent content of the substituents attached to the saccharide units in the polysaccharide and polysaccharide derivative is independently 20% to 85%, and optionally 30% to 78%.

[0083] In any embodiment, the lattice mismatch between the core material and the shell material is less than 10%, which ensures good contact between the core and the shell (or the covering layer) and prevents the shell (or the covering layer) from falling off.

[0084] In any embodiment, relative to the total weight of the first positive electrode active material, the manganese content is in the range of 10 wt % to 35 wt %, optionally in the range of 13.3 wt % to 33.2 wt %, further optionally in the range of 15 wt % to 30 wt %, and further optionally in the range of 17 wt % to 20 wt %; and / or the phosphorus content is in the range of 12 wt % to 25 wt %, optionally in the range of 15 wt % to 20 wt %, and further optionally in the range of 16.8 wt % to 19.5 wt %; and / or the weight ratio of manganese to phosphorus is in the range of 0.71 to 1.85, optionally in the range of 0.90 to 1.25, and further optionally in the range of 0.95 to 1.20.

[0085] By limiting the manganese content within the above range, the stability and density of the first positive electrode active material can be further improved, and the cycle, storage, compaction, and other performance of the battery can be improved, and a high potential plateau can be maintained, thereby improving the energy density of the battery.

[0086] By limiting the content of phosphorus within the above range, the influence of polaron conduction on the conductivity of the first positive electrode active material can be effectively reduced, the stability of the crystal lattice structure can be improved, and the stability of the entire first positive electrode active material can be improved.

[0087] By limiting the weight ratio of manganese to phosphorus within the above range, it is possible to further reduce manganese leaching, improve the stability and specific capacity of the first positive electrode active material, improve the cycle characteristics and storage performance of the battery, and further reduce impurity phases, so that the first positive electrode active material maintains a high discharge potential plateau and the battery has a high energy density.

[0088] In an optional embodiment, the surface of the first positive electrode active material is coated with one or more of carbon and doped carbon, and optionally, the surface of the first positive electrode active material is coated with carbon, which can improve the conductivity of the first positive electrode active material.

[0089] In an optional embodiment, the doping elements in the doped carbon include one or more selected from nitrogen, phosphorus, sulfur, boron and fluorine.

[0090] In any embodiment, the coating amount of the shell is 0.1% by weight to 6% by weight based on the weight of the core.

[0091] In any embodiment, the coating amount of the first coating layer is greater than 0 and less than 7 wt%, optionally greater than 0 and less than 6 wt%, further optionally greater than 0 and less than 5.5 wt%, or 4 to 5.6 wt%, further optionally greater than 0 and less than 2 wt%, relative to the weight of the core; and / or the coating amount of the second coating layer is greater than 0 and less than 6 wt%, optionally greater than 0 and less than 5.5 wt%, further optionally greater than 2 to 4 wt%, or 3 to 5 wt%, relative to the weight of the core; and / or the coating amount of the third coating layer is greater than 0 and less than 6 wt%, optionally greater than 0 and less than 5.5 wt%, further optionally greater than 0 and less than 2 wt%, relative to the weight of the core.

[0092] In any embodiment, the shell includes a fourth coating layer that coats the third coating layer and a fifth coating layer that coats the fourth coating layer, and the coating amounts of the fourth coating layer and the fifth coating layer are each independently 0.01 wt % to 10 wt %, optionally 0.05 wt % to 10 wt %, further optionally 0.1 wt % to 5 wt %, and further optionally 0.1 wt % to 2 wt %, relative to the weight of the core.

[0093] By having the coating weight of each coating layer preferably within the above range, the core can be sufficiently coated, and at the same time, the dynamic characteristics of the battery can be further improved without sacrificing the specific capacity of the first positive electrode active material.

[0094] In any embodiment, the shell is located on 40% to 90% of the surface of the core, and optionally on 60% to 80% of the surface, which can adequately cover the core and improve the dynamic properties of the battery.

[0095] In an optional embodiment, the shell has a thickness of 1 to 15 nm.

[0096] In any embodiment, the thickness of the first coating layer is 1 to 10 nm, optionally 2 to 10 nm, and / or the thickness of the second coating layer is 2 to 25 nm, optionally 2 to 15 nm, and further optionally 3 to 15 nm, and / or the thickness of the third coating layer is 2 to 25 nm, optionally 5 to 25 nm.

[0097] In any embodiment, the 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, and optionally the crystallinity of the pyrophosphate, phosphate, and oxide is each independently 10% to 100%, and further optionally 50% to 100%.

[0098] Pyrophosphates and phosphates having a certain degree of crystallinity not only help the pyrophosphate coating layer reduce manganese elution and fully exhibit the excellent lithium ion conductivity and the function of reducing interfacial side reactions of the phosphate coating layer, but also enable the pyrophosphate coating layer and the phosphate coating layer to achieve better lattice matching, thereby realizing a tight bond between the coating layers.

[0099] In any embodiment, the weight ratio of the pyrophosphate to the phosphate and the weight ratio of the pyrophosphate to the oxide in the shell are each independently 1:3 to 3:1, and optionally 1:3 to 1:1. Therefore, when the weight ratio of the pyrophosphate to the phosphate or the weight ratio of the pyrophosphate to the oxide is in an appropriate range, it is possible to effectively reduce not only the leaching of manganese but also the content of surface lithium impurities, reduce interfacial side reactions, and improve the high-temperature storage performance and high-temperature cycle performance of the battery.

[0100] In some embodiments, the one or more coating layers each independently comprise carbon, and the carbon is a mixture of SP2 carbon and SP3 carbon, and optionally, the molar ratio of the SP2 carbon to the SP3 carbon in the carbon ranges from 0.07 to 13, more preferably from 0.1 to 10, and even more preferably from 2.0 to 3.0. Selecting the form of carbon in the carbon coating layer can improve the overall electrical performance of the battery.

[0101] In any embodiment, the one or more coating layers each independently contain doped carbon, and the mass content of the doping element in the doped carbon is 30% or less, and optionally the mass content of the doping element in the doped carbon is 20% or less. A doping element within this content range not only sufficiently improves the conductivity of the pure carbon layer, but also effectively prevents excessive doping of the doping element from increasing surface activity, and effectively suppresses interfacial side reactions caused by excessive doping of the coating layer.

[0102] In any embodiment, the one or more coating layers each independently comprise doped carbon, wherein the doping element in the doped carbon 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.

[0103] Nitrogen atoms and sulfur atoms have atomic radii closer to those of carbon atoms and are less likely to destroy the carbon skeleton. Therefore, when the doping amounts of nitrogen atoms and sulfur atoms are within the above-mentioned relatively wide range, the doped carbon layer not only exhibits sufficient conductivity, but also promotes the transport of lithium ions and the desolvation ability of lithium ions.

[0104] The phosphorus, boron and / or fluorine atoms have different radii from carbon atoms, and excessive doping tends to destroy the carbon skeleton. Therefore, when the doping amount of phosphorus, boron and / or fluorine atoms is within the above-mentioned relatively narrow range, the doped carbon layer can not only fully exhibit its conductivity, but also promote the transport of lithium ions and the desolvation ability of lithium ions.

[0105] In any embodiment, the one or more coating layers each independently comprise a pyrophosphate, and the pyrophosphate has a crystal plane spacing in the range of 0.293 to 0.470 nm, optionally 0.297 to 0.462 nm or 0.293 to 0.326 nm, and more optionally 0.300 to 0.310 nm, and an included angle of the (111) crystal orientation in the range of 18.00° to 32.57°, optionally 18.00° to 32.00° or 26.41° to 32.57°, and more optionally 19.211° to 30.846°, and more optionally 29.00° to 30.00°.

[0106] In any embodiment, the one or more coating layers each independently comprise a phosphate, and the phosphate has a crystal plane spacing in the range of 0.244 to 0.425 nm, optionally 0.345 to 0.358 nm, and a crystal orientation (111) included angle in the range of 20.00° to 37.00°, optionally 24.25° to 26.45°.

[0107] This effectively reduces the impurity phase in the coating layer, thereby improving the specific capacity, cycle characteristics and rate characteristics of the material.

[0108] In an optional embodiment, the first coating layer or the second coating layer comprises a phosphate.

[0109] In some embodiments, the lattice change rate of the first positive electrode active material before and after complete lithium insertion and extraction is 50% or less, optionally 9.8% or less, more optionally 8.1% or less, more optionally 7.5% or less, more optionally 6% or less, more optionally 4% or less, more optionally 3.8% or less, and even more optionally 2.0 to 3.8%. By reducing the lattice change rate, the transport of Li ions can be made easier, i.e., the mobility of Li ions in the first positive electrode active material is enhanced, which helps improve the rate characteristics of the battery.

[0110] In some embodiments, the first positive electrode active material has a Li / Mn antisite defect concentration of 5.3% or less, optionally 5.1% or less, further optionally 4% or less, further optionally 2.2% or less, further optionally 2% or less, and further optionally 1.5% to 2.2%, or even 0.5% or less. Reducing the Li / Mn antisite defect concentration helps improve the specific capacity and rate performance of the first positive electrode active material.

[0111] In some embodiments, the surface oxidation state of the first positive electrode active material is −1.55 or less, optionally −1.82 or less, further optionally −1.88 or less, further optionally −1.90 or less, or −1.98 to −1.88, further optionally −1.98 to −1.89, further optionally −1.98 to −1.90. Reducing the surface oxidation state can reduce interfacial side reactions between the first positive electrode active material and the electrolyte, thereby improving the cycle characteristics and high-temperature stability of the battery.

[0112] In some embodiments, the positive electrode active material composition has a w a ×y×(3.4-V B )≦0.063, and optionally, 0.0015≦w a ×y×(3.4-V B )≦0.045, and w arepresents the weight content of the first positive electrode active material relative to the total weight of the positive electrode active material composition, y is the molar amount of B element in 1 mole of the compound represented by formula (I), and V B is the potential plateau of the B element in the compound represented by formula (I), and its unit is V (volts). If the positive electrode active material composition further satisfies the above conditions, the positive electrode sheet will have both high pressed density and high pressed density efficiency, and the battery will have both high energy density and long service life.

[0113] In some embodiments, the second positive electrode active material comprises a layered oxide. By rationally combining the first and second positive electrode active materials, the actual bulk density of the positive electrode active material composition can be further improved, and the pressed density and pressed density efficiency of the positive electrode sheet can be improved, so that a battery using the positive electrode active material composition can have a higher energy density and a longer service life.

[0114] In some embodiments, the second positive electrode active material comprises a compound represented by Formula (II): Li a1 A 1 b1 Ni c1 Co d1 B 1 e1 C 1 f1 O 2-g1 D 1 g1 , (II) A 1 contains one or more elements selected from Groups IA, IIA, VIII, VIB, and IIB; B 1 contains Mn and / or Al, and C 1 comprises one or more elements selected from Groups IA, IIA, IIIA, IVA, VA, VIA, IIB, IIIB, IVB, VB, VIB and VIII; D 1comprises one or more elements selected from Group VIA and Group VIIA, a1 is selected from the range of 0.8 to 1.2, b1 is selected from the range of 0 to 0.2, c1 is selected from the range of 0 to 1, d1 is selected from the range of 0 to 1, e1 is selected from the range of 0 to 1, f1 is selected from the range of 0 to 0.1, g1 is selected from the range of 0 to 0.1, and c1+d1+e1+f1=1.

[0115] In any embodiment, A 1 contains one or more elements selected from Na, K, Mg, Rb, Zn, and Zr.

[0116] In any embodiment, C 1 comprises 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 optionally comprises one or more elements selected from Al, Ti, Zr, Nb, Sr, Sc, Sb, Y, Ba, B.

[0117] In any embodiment, D 1 contains one or more elements selected from N, S, F, Cl and Br, and optionally contains S and / or F.

[0118] In any embodiment, a1 is selected from the range of 0.9 to 1.1.

[0119] In any embodiment, b1 is selected from the range of 0 to 0.1.

[0120] In any embodiment, c1 is selected from the range of 0.314 to 0.990, and optionally from the range of 0.500 to 0.990.

[0121] In any embodiment, d1 is selected from the range of 0 to 0.320, and optionally from the range of 0 to 0.150.

[0122] In any embodiment, e1 is selected from the range of 0.001 to 0.450, and optionally from the range of 0.005 to 0.4.

[0123] In any embodiment, f1 is selected from the range of 0.001 to 0.1, and optionally from the range of 0.001 to 0.05.

[0124] In any embodiment, g1 is selected from the range of 0 to 0.01, and optionally from the range of 0.01 to 0.05.

[0125] In any embodiment, the second positive electrode active material comprises a core and a shell coating the core, the core comprising the compound represented by Formula (II), the shell comprising one or more coating layers, each coating layer having ionic and / or electronic conductivity.

[0126] In any embodiment, in the shell of the second active cathode material, the one or more coating layers each independently comprise one or more selected from phosphate, pyrophosphate, carbon, doped carbon, oxide, and fast ion conductor, and optionally one or more selected from phosphate, pyrophosphate, and oxide.

[0127] In any embodiment, the shell of the second positive electrode active material includes one coating layer, and optionally, the coating layer includes one or more selected from phosphate, pyrophosphate, and oxide.

[0128] In any embodiment, the shell of the second positive electrode active material includes a first coating layer coating the core and a second coating layer coating the first coating layer, and optionally, the first coating layer and the second coating layer each independently include one or more selected from phosphates, pyrophosphates, and oxides, and further optionally, 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.

[0129] In any embodiment, the coating amount of the shell of the second positive electrode active material is 0.005% to 1% by weight, optionally 0.01% to 0.5% by weight, based on the weight of the core, and / or the thickness of the shell is 2 nm to 200 nm, optionally 5 nm to 50 nm.

[0130] According to the second aspect of the present application, there is provided a positive electrode sheet including a positive electrode current collector and a positive electrode film layer provided on at least one surface of the positive electrode current collector, and the positive electrode film layer includes a positive electrode active material including a positive electrode active material composition according to the first aspect of the present application.

[0131] In any embodiment, the content of the positive electrode active material composition in the positive electrode film layer is 90% to 99.5% by weight, and further optionally 95% to 99.5% by weight, based on the total weight of the positive electrode film layer.

[0132] In any embodiment, the positive electrode film layer further includes a third positive electrode active material, and the third positive electrode active material includes one or more of a lithium-excess oxide material, a lithium iron phosphate material, a spinel-structured lithium manganate material, and modified compounds thereof, and the modification method includes doping and / or surface coating modification.

[0133] In any embodiment, the third positive electrode active material includes a compound represented by formula (III), Li 1+p1 A 2 q1 B 2 r1 O s1 , (III) 0.05 ≦ p1 < 0.2, 0.10 < q1 ≦ 0.95, 0 ≦ r1 ≦ 0.2, and 2 ≦ s1 < 3, A 2 includes one or more elements selected from Co, Ni, Mn, and Al, and B 2 includes one or more elements selected from Mg, Ti, Cr, Zr, Nb, Fe, Mo, Cu, Sb, V, P, and F.

[0134] In any embodiment, the third positive electrode active material comprises a core and a shell coating the core, the core comprising the compound represented by Formula (III), the shell comprising one or more coating layers, each coating layer having ionic and / or electronic conductivity.

[0135] In any embodiment, one or more coating layers in the shell that coats the compound represented by formula (III) each independently comprise one or more selected from the group consisting of phosphates, pyrophosphates, solid electrolytes, conductive polymers, and materials capable of reversibly inserting and extracting lithium ions.

[0136] In any embodiment, the amount of the shell covering the compound represented by formula (III) is 0.1 wt % to 5 wt %, and optionally 0.5 wt % to 2 wt %, relative to the weight of the core, and / or the thickness of the shell covering the compound represented by formula (III) is 2 nm to 200 nm, and optionally 5 nm to 50 nm.

[0137] In some embodiments, the third positive electrode active material comprises a compound represented by Formula (IV): Li a2 A 3 x2 B 3 y2 P 1-z2 C 3 z2 O 4-n2 D 3 n2 , (IV) A 3 comprises one or more elements selected from groups IA, IIA, IIIA, IIB, VB and VIB, and B 3 comprises one or more elements selected from Groups IA, IIA, IIIA, IVA, VA, IIB, IVB, VB, VIB and VIII, and C 3 contains one or more elements selected from groups IIIA, IVA, VA and VIA, and D 3comprises one or more elements selected from Group VIA and Group VIIA, a2 is selected from the range of 0.85 to 1.15, x2 is selected from the range of 0 to 0.1, y2 is selected from the range of 0.001 to 0.999, z2 is selected from the range of 0 to 0.5, and n2 is selected from the range of 0 to 0.5.

[0138] In any embodiment, A 3 comprises 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 comprises one or more elements selected from Zn, Al, Na, K, Mg, Nb, Mo and W.

[0139] In any embodiment, B 3 comprises one or more elements selected from Rb, Cs, Be, Ca, Sr, Ba, In, Pb, Bi, Cd, Hf, Ta, Cr, Ru, Rh, Pd, Os, Ir, Pt, Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb and Ge, and optionally comprises 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.

[0140] In any embodiment, C 3 contains one or more elements selected from B (boron), S, Si and N.

[0141] In any embodiment, D 3 contains one or more elements selected from S, F, Cl and Br.

[0142] In any embodiment, a2 is selected from the range of 0.9 to 1.1, and optionally from the range of 0.97 to 1.01.

[0143] In any embodiment, x2 is selected from the range of 0.001 to 0.005.

[0144] In any embodiment, y2 is selected from the range of 0.001 to 0.5, optionally selected from the range of 0.01 to 0.5, optionally selected from the range of 0.25 to 0.5.

[0145] In any embodiment, z2 is selected from the range of 0.001 to 0.5, optionally selected from the range of 0.001 to 0.1, and further optionally selected from the range of 0.001 to 0.005.

[0146] In any embodiment, n2 is selected from the range of 0 to 0.1, and optionally from the range of 0.001 to 0.005.

[0147] In any embodiment, the third positive electrode active material includes a core and a shell coating the core, the core including the compound represented by Formula (IV), and the shell being the same as the shell coating the compound represented by Formula (I).

[0148] In some embodiments, the third positive electrode active material comprises a compound represented by Formula (V): LiMn t1 A 4 2-t1 O4, (V) t1 is selected from the range of 0 to 2, and A 4 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.

[0149] In any embodiment, the third positive electrode active material comprises a core and a shell coating the core, the core comprising the compound represented by Formula (V), the shell comprising one or more coating layers, each coating layer having ionic and / or electronic conductivity.

[0150] In any embodiment, one or more coating layers in the shell that coats the compound represented by formula (V) each independently comprise one or more selected from the group consisting of phosphates, pyrophosphates, solid electrolytes, conductive polymers, and materials capable of reversibly inserting and extracting lithium ions.

[0151] In any embodiment, the amount of the shell covering the compound represented by formula (V) is 0.1 wt % to 5 wt %, and optionally 0.5 wt % to 2 wt %, relative to the weight of the core, and / or the thickness of the shell covering the compound represented by formula (V) is 2 nm to 200 nm, and optionally 5 nm to 50 nm.

[0152] In an optional embodiment, the positive electrode film layer includes a positive electrode binder and / or a positive electrode conductive agent.

[0153] In an optional embodiment, the positive electrode binder comprises a vinylidene fluoride homopolymer and / or copolymer, and further optionally, the comonomer comprises one or more of tetrafluoroethylene, hexafluoropropylene, and propylene.

[0154] In any embodiment, the weight average molecular weight of the positive electrode binder is 300,000 to 2,000,000.

[0155] In any embodiment, the positive electrode film layer further comprises a functional additive, and the functional additive comprises one or more of a dispersant, a plasticizer, a pore-forming agent, a moisture scavenging additive, an acid scavenging additive, and a lithium replenisher.

[0156] In any embodiment, the positive electrode sheet further includes a functional coating layer, the functional coating layer being located between the positive electrode current collector and the positive electrode film layer and / or located on the surface of the positive electrode film layer away from the positive electrode current collector, the functional coating layer including one or more of conductive carbon, a moisture scavenging additive, an acid scavenging additive, and a lithium replenisher.

[0157] According to a third aspect of the present application, there is provided a battery including the positive electrode active material composition according to the first aspect of the present application or the positive electrode sheet according to the second aspect of the present application.

[0158] In any embodiment, the battery includes an electrolyte, the electrolyte including one or more of a liquid electrolyte, an all-solid-state electrolyte, and a gel electrolyte.

[0159] In any embodiment, the liquid electrolyte comprises a lithium salt, a non-aqueous solvent dissolved in the lithium salt, and optional additives, and optionally the lithium salt comprises one or more selected from LiPF, LiBF, LiN(SOF), LiN(CFSO), LiClO, LiAsF, LiB(C0), LiBFCO, and LiPOF.

[0160] In any embodiment, the concentration of the lithium salt is 0.5 to 1.5 mol / L.

[0161] In certain embodiments, the non-aqueous solvent comprises one or more selected from propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl formate, ethyl acetate, methyl butyrate, ethyl butyrate, methyl propionate, ethyl propionate, propyl propionate, methyl acrylate, ethylene sulfite, propylene sulfite, dimethyl sulfite, diethyl sulfite, acid anhydride, N-methylpyrrolidone, acetonitrile, sulfolane, dimethyl sulfoxide, methyl sulfide, γ-butyrolactone, and tetrahydrofuran.

[0162] In any embodiment, the additive may be a cyclic carbonate compound having a carbon-carbon double bond, a halogen-substituted cyclic carbonate compound, a nitrile and polynitrile compound, a phosphazene compound, an aromatic hydrocarbon and a halogenated aromatic hydrocarbon compound, an isocyanate compound, an acid anhydride compound, a sulfate ester compound, a sulfite ester compound, a sulfonate ester compound, a disulfonate ester compound, a borate ester compound, a phosphate ester compound, an amide-based compound, a carbodiimide-based compound, a crown ether and an azacrown ether-based compound, and the like. The compound may include one or more selected from the derivatives thereof, and optionally include one or more of vinylene carbonate, 1,2,3-tris(2-cyanoethoxy)propane, 1-aza-12-crown 4-ether, N,N'-dicyclohexylcarbodiimide, N,N'-diisopropylcarbodiimide, N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, tris(hexafluoroisopropyl)borate, tris(2,2,3,3-tetrafluoropropyl)borate, and tris(pentafluorophenyl)borate.

[0163] In any embodiment, the battery includes a negative electrode sheet including a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector, the negative electrode film layer including a negative electrode active material, the negative electrode active material including one or more of a carbon-based material, a silicon-based material, a tin-based material, and lithium titanate, optionally including a carbon-based material or a combination of a carbon-based material and a silicon-based material.

[0164] In an optional embodiment, the porosity of the negative electrode film layer is 20% to 50%.

[0165] In an optional embodiment, the negative electrode active material includes a carbon-based material, and the carbon-based material includes graphite or a combination of graphite and hard carbon.

[0166] In any embodiment, the negative electrode active material includes a combination of a carbon-based material and a silicon-based material, the carbon-based material includes graphite or a combination of graphite and hard carbon, and the content of the silicon element in the negative electrode active material is greater than 0 and less than or equal to 30 wt % based on the total weight of the negative electrode active material.

[0167] In any embodiment, the negative electrode sheet further comprises a functional coating layer, the functional coating layer being located between the negative electrode current collector and the negative electrode film layer and / or located on the surface of the negative electrode film layer away from the negative electrode current collector, and optionally the functional coating layer comprising carbon.

[0168] In any embodiment, the negative electrode film layer further comprises a lithium supplementary material, optionally comprising one or more of a lithium foil, a lithium tape, a lithium powder, and a lithium pre-doping reagent, optionally comprising one or more of a Li-aromatic hydrocarbon, a complex of a Li-aromatic hydrocarbon and an ether-based solvent, and optionally comprising one or more of a lithium naphthalene and a lithium biphenyl-dimethyl ether.

[0169] In any embodiment, the negative electrode sheet includes a negative electrode current collector and a first negative electrode film layer and a second negative electrode film layer respectively disposed on two surfaces of the negative electrode current collector, and optionally, the thickness ratio of the first negative electrode film layer to the second negative electrode film layer is 5:95 to 95:5.

[0170] In any embodiment, the battery includes a negative electrode sheet, and the negative electrode sheet does not include a negative electrode active material capable of inserting and extracting lithium ions.

[0171] In an optional embodiment, the negative electrode sheet comprises a lithium sheet or a lithium alloy sheet.

[0172] In an optional embodiment, the negative electrode sheet includes a three-dimensional skeleton layer in a reticulated or foamed state.

[0173] In an optional embodiment, the battery includes a separator that includes a porous substrate.

[0174] In any embodiment, the separator further comprises a coating layer located on at least one surface of the porous substrate, and optionally, the coating layer comprises one or more of inorganic heat-resistant particles, organic heat-resistant particles.

[0175] In an optional embodiment, the porosity of the separator is between 10% and 40%.

[0176] According to a fourth aspect of the present application, there is provided a power consumption device including a battery according to the third aspect of the present application.

[0177] The power consuming device of the present application includes the battery provided herein and therefore has at least the same advantages as said battery. [Brief explanation of the drawings]

[0178] In order to more clearly describe the technical solutions in the embodiments of the present application, the following briefly describes the drawings required in the embodiments of the present application. It should be understood that the drawings shown below are only some embodiments of the present application, and those skilled in the art can further obtain other drawings based on the drawings without any creative efforts.

[0179] [Figure 1] 1 is a schematic diagram of one embodiment of a battery cell of the present application. [Figure 2] 1 is an exploded schematic view of one embodiment of a battery cell of the present application. [Figure 3] 1 is a schematic diagram of a battery module according to an embodiment of the present application; [Figure 4] 1 is a schematic diagram of an embodiment of a battery pack of the present application. [Figure 5] 5 is an exploded schematic view of the battery pack shown in FIG. 4 according to the embodiment. [Figure 6] 1 is a schematic diagram of one embodiment of a power consuming device that includes a battery of the present application as a power source. [Figure 7] 10 is a particle size distribution curve of the positive electrode active material composition of Example 11.

[0180] In the drawings, the drawings are not drawn to scale. [Explanation of symbols]

[0181] 1 battery pack, 2 upper housing, 3 lower housing, 4 battery module, 5 battery cell, 51 housing, 52 electrode assembly, 53 cover plate. DETAILED DESCRIPTION OF THE INVENTION

[0182] Hereinafter, embodiments of the positive electrode active material composition, positive electrode sheet, battery, and power consuming device of the present application will be described in detail with reference to the accompanying drawings. However, unnecessary detailed description may be omitted. For example, detailed description of well-known matters and redundant description of actually identical structures may be omitted. This is to avoid unnecessary lengthening of the following description and to facilitate understanding by those skilled in the art. Note that the drawings and the following description are provided to enable those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0183] The "ranges" disclosed in this application are defined in the form of lower and upper limits, and a given range is defined by selecting one lower limit and one upper limit, with the selected lower and upper limits defining the boundaries of the particular range. Such defined ranges may be inclusive or exclusive of the endpoints and may be arbitrarily combined, i.e., any lower limit may be combined with any upper limit to form a single range. For example, if ranges of 60 to 120 and 80 to 110 are listed for a particular parameter, it is understood that ranges of 60 to 110 and 80 to 120 are also contemplated. Furthermore, if 1 and 2 are listed as minimum range values ​​and 3, 4, and 5 are listed as maximum range values, the ranges 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5 are all contemplated. In this application, unless otherwise specified, a numerical range "a to b" represents a shorthand notation for any combination of real numbers a to b, where a and b are both real numbers. For example, the numerical range "0 to 5" indicates that the present specification has already listed all real numbers between "0 and 5," and "0 to 5" is merely a shorthand representation of combinations of these numbers. Also, expressing a parameter as an integer ≧2 is equivalent to disclosing that the parameter is, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0184] All embodiments and alternative embodiments of the present application, unless otherwise specified, can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present application.

[0185] All technical features and optional technical features of the present application, unless otherwise specified, can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present application.

[0186] All steps in this application can be performed in order or randomly, and are preferably performed in order, unless otherwise specified. For example, when the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed in order, or may include steps (b) and (a) performed in order. For example, when the method described above may further include step (c), it means that step (c) may be added to the method in any order, e.g., the method may include steps (a), (b), and (c), or may include steps (a), (c), and (b), or may include steps (c), (a), and (b), etc.

[0187] The terms "comprise" and "comprises" used herein refer to both open and closed forms unless otherwise specified. For example, the terms "comprise" and "comprises" may indicate that the composition may further include or include other ingredients not listed, or may include or include only the listed ingredients.

[0188] Unless otherwise stated, in this application, the term "or" is inclusive. 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 either A being true (or present) and B being false (or absent), or A being false (or absent) and B being true (or present), or both A and B being true (or present).

[0189] Unless otherwise stated, in this application, terms such as "first," "second," "third," "fourth," "fifth," etc. are used to distinguish between different objects and are not used to describe a particular order or hierarchical relationship.

[0190] As used herein, the terms "plurality" and "plurality" mean two or more.

[0191]

[0023] At various points in this specification, substituents of compounds are disclosed in groups or in ranges. It is expressly intended that this description include each individual subcombination of the members of these groups and ranges. For example, the term "C1-C6 alkyl group" is expressly intended to individually disclose 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 groups.

[0192] Unless otherwise explained, terms used herein have the same meaning as commonly understood by one of ordinary skill in the art.

[0193] Unless otherwise specified, the values ​​of the parameters described herein can be measured by various test methods commonly used in the art, for example, by the test methods described in the examples of the present application. Unless otherwise specified, the test temperature for each parameter is 25°C.

[0194] Unless otherwise stated, all ratio parameters in this application are compared when the units are the same. For example, if the ratio of the volumetric particle size distributions of A and B is 1:1, the units of the volumetric particle size distributions of A and B are the same.

[0195] In this application, the term "pressed density efficiency" refers to the ratio of the pressed density of the membrane layer to the theoretical green density of the active material.

[0196] In the present application, the element contents of the first positive electrode active material, the second positive electrode active material, and the third positive electrode active material can be detected using inductively coupled plasma emission spectrometry (ICP).

[0197] The battery referred to in the embodiments of this application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in this application may include a battery cell, a battery module, or a battery pack.

[0198] A battery cell is the smallest unit that constitutes a battery and can independently perform charging and discharging functions. A battery cell may be cylindrical, flat, rectangular, or have other shapes, and the embodiments of the present application are not limited thereto. Figure 1 shows an example of a battery cell 5 with a rectangular parallelepiped structure.

[0199] When there are multiple battery cells, the multiple battery cells are connected in series, parallel, or series-parallel via a bus member. In some embodiments, the battery may be a battery module, and when there are multiple battery cells, the multiple battery cells are arranged and fixed to form a single battery module. In some embodiments, the battery may be a battery pack, and the battery pack includes a housing and battery cells, and the battery cells or battery modules are housed in the housing. In some embodiments, the housing may be part of a chassis structure of a vehicle. For example, a portion of the housing may be at least a portion of a bottom plate of the vehicle, or a portion of the housing may be at least a portion of a cross member and a side member of the vehicle.

[0200] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, or the like.

[0201] The battery cells referred to in the embodiments of the present application include lithium ion primary battery cells, lithium ion secondary battery cells, lithium metal battery cells, negative electrode lithium-free metal battery cells, etc., but the embodiments of the present application are not limited thereto.

[0202] A battery cell generally includes an electrode assembly, which generally includes a positive electrode sheet, a negative electrode sheet, and a separator disposed between the positive electrode sheet and the negative electrode sheet, and the electrode assembly may have a wound structure or a stacked structure, although the present application is not limited thereto.

[0203] The battery cell may further include an exterior material, which can be used to enclose the electrode assembly and the electrolyte. The exterior material may be a hard case such as a hard plastic case, an aluminum case, or a steel case. The exterior material may also be a soft pack such as a pouch-type soft pack. The material of the soft pack may be plastic, such as one or more of polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0204] In some embodiments, as shown in FIG. 2 , the exterior material may include a housing 51 and a cover plate 53. The housing 51 may include a bottom plate and side plates connected to the bottom plate, forming a storage cavity surrounded by the bottom plate and side plates. The housing 51 has an opening communicating with the storage cavity, and the cover plate 53 is used to cover the opening and seal the storage cavity. The electrode assembly 52 is enclosed in the storage cavity. The number of electrode assemblies 52 included in the battery cell 5 may be one or more and can be adjusted as needed.

[0205] In some embodiments, the battery cells can be assembled into a battery module. The battery module can include multiple battery cells, and the specific number can be adjusted depending on the application and capacity of the battery module. FIG. 3 is a schematic diagram of an example battery module 4. As shown in FIG. 3, in the battery module 4, multiple battery cells 5 can be arranged in sequence along the length of the battery module 4. Of course, any other arrangement is also possible. The multiple battery cells 5 can also be fastened together using fasteners.

[0206] Optionally, the battery module 4 may further include an outer case having an accommodating space for accommodating the plurality of battery cells 5.

[0207] In some embodiments, the battery modules can be further assembled into a battery pack, and the number of battery modules included in the battery pack can be adjusted according to the application and capacity of the battery pack.

[0208] 4 and 5 are schematic diagrams of an example battery pack 1. As shown in FIGS. 4 and 5, the battery pack 1 may include a housing and a plurality of battery modules 4 installed in the housing. The housing includes an upper housing 2 and a lower housing 3, and the upper housing 2 is used to cover the lower housing 3 and forms an enclosed space for accommodating the battery modules 4. The plurality of battery modules 4 may be arranged in the housing in any manner.

[0209] The positive electrode sheet contains a positive electrode active material, and as a key component of a battery, its performance is a key factor limiting the battery's energy density and service life. Currently, no positive electrode active material has been developed that simultaneously satisfies the requirements of low cost, high capacity, and minimal side reactions.

[0210] In view of this, the inventors provide a positive electrode active material composition that enables batteries to combine high energy density, low cost, and good service life.

[0211] A cathode active material composition according to an embodiment of the present application includes a first cathode active material and a second cathode active material having a different crystal form from that of the first cathode active material, the first cathode active material including a phosphate. The first cathode active material and the second cathode active material having different crystal forms refers to the first cathode active material and the second cathode active material having different crystal systems.

[0212] The particle size distribution curve of the positive electrode active material composition has at least two volume distribution peaks, and when the volume distribution peak having the maximum peak intensity is defined as the first peak and the volume particle size distribution corresponding to the position of the maximum peak intensity of the first peak is defined as Dv1, and the volume distribution peak having the next maximum peak intensity is defined as the second peak and the volume particle size distribution corresponding to the position of the maximum peak intensity of the second peak is defined as Dv2, then 0<|Dv1-Dv2| / Dv1≦50, and "||" represents an absolute value.

[0213] The first positive electrode active material contains a phosphate, typically has an olivine structure, and is generally inexpensive to produce. However, the first positive electrode active material has a low compaction density, making it difficult to meet the requirements for use in high-energy-density batteries. While combining it with another positive electrode active material with a high compaction density can improve the compaction density of the positive electrode sheet, simply mixing two types of positive electrode active materials generally results in poor improvements in the compaction density and compaction density efficiency of the positive electrode sheet, making it difficult to fully utilize the battery's capacity and also affecting the battery's service life.

[0214] The inventors discovered that a positive electrode active material composition includes a first positive electrode active material and a second positive electrode active material having different crystal forms, and the particle size distribution curve of the positive electrode active material composition satisfies 0<|Dv1-Dv2| / Dv1≦50, thereby allowing the first positive electrode active material and the second positive electrode active material to be closely stacked, improving the actual bulk density of the positive electrode active material composition and improving the pressed density and pressed density efficiency of the positive electrode sheet, and thereby enabling a battery using the positive electrode active material composition to have a higher energy density and a longer service life.

[0215] The particle size distribution curve of the positive electrode active material composition can be adjusted by adjusting one or more parameters of the volumetric particle size distribution, volumetric particle size distribution width, mass content, etc. of each of the first positive electrode active material and the second positive electrode active material.

[0216] In some embodiments, the first positive electrode active material has a volume-based particle size distribution Dv50 of 0.25 μm to 12.5 μm.

[0217] In some embodiments, the second positive electrode active material has a volume-based particle size distribution Dv50 of 2.5 μm to 16.5 μm.

[0218] In some embodiments, the first positive electrode active material has a volume-based particle size distribution Dv50 of 0.25 μm to 3.5 μm, and the particle size distribution curve of the positive electrode active material composition is 0.1≦|Dv1−Dv2| / Dv1≦50, and optionally 0.46≦|Dv1−Dv2| / Dv1≦39.6; and / or 0.3 μm≦Dv1≦17.8 μm, optionally 0.35 μm≦Dv1≦12.1 μm, and / or 0.3 μm≦Dv2≦17.8 μm, and optionally 0.46 μm≦Dv2≦14.2 μm.

[0219] This allows the first and second positive electrode active materials to be stacked more tightly, further improving the actual bulk density of the positive electrode active material composition and improving the pressed density and pressed density efficiency of the positive electrode sheet, thereby allowing a battery using the positive electrode active material composition to have a higher energy density and / or a longer service life.

[0220] In some embodiments, the first positive electrode active material has a volume-based particle size distribution Dv50 of 3.5 μm to 12.5 μm, and the particle size distribution curve of the positive electrode active material composition is 0.1≦|Dv1−Dv2| / Dv1≦6.0, optionally 0.34≦|Dv1−Dv2| / Dv1≦3.8, and / or 2.0 μm≦Dv1≦12.5 μm, optionally 3.0 μm≦Dv1≦12.3 μm, and / or 2.0 μm≦Dv2≦15.0 μm, and optionally 3.4 μm≦Dv2≦14.3 μm.

[0221] This allows the first and second positive electrode active materials to be stacked more tightly, further improving the actual bulk density of the positive electrode active material composition and improving the pressed density and pressed density efficiency of the positive electrode sheet, thereby allowing a battery using the positive electrode active material composition to have a higher energy density and / or a longer service life.

[0222] In some embodiments, the morphology of the first active positive electrode material includes one or more of monocrystalline and polycrystalline, and the morphology of the second active positive electrode material includes one or more of monocrystalline and polycrystalline.

[0223] The term "single crystal" also includes quasicrystals (approximate crystals), which generally refer to particles formed by the aggregation of a small number of primary particles. Polycrystals refer to secondary particles formed by the aggregation of multiple primary particles.

[0224] In some embodiments, the first positive electrode active material in single crystal form has a volume-based particle size distribution Dv50 of 0.25 μm to 3.5 μm, and optionally 0.35 μm to 2.5 μm.

[0225] In some embodiments, the volume-based particle size distribution Dv10 of the first positive electrode active material in single crystal form is between 0.05 μm and 1.5 μm, and optionally between 0.1 μm and 1.0 μm.

[0226] In some embodiments, the volume-based particle size distribution Dv50 of the first positive electrode active material in polycrystalline form is between 3.5 μm and 12.5 μm, and optionally between 3.8 μm and 10.5 μm.

[0227] In some embodiments, the volume-based particle size distribution Dv10 of the first positive electrode active material in polycrystalline form is 0.1 μm to 5.0 μm, and optionally 0.5 μm to 4.5 μm.

[0228] In some embodiments, the second positive electrode active material in single crystal form has a volume-based particle size distribution Dv50 of 2.5 μm to 16.5 μm, and optionally 3.0 μm to 8.5 μm.

[0229] In some embodiments, the volume-based particle size distribution Dv10 of the second positive electrode active material in single crystal form is between 0.3 μm and 8 μm, and optionally between 1.0 μm and 3.5 μm.

[0230] In some embodiments, the volume-based particle size distribution Dv50 of the second positive electrode active material in polycrystalline form is from 2.5 μm to 16.5 μm, and optionally from 3.0 μm to 15.5 μm.

[0231] In some embodiments, the volume-based particle size distribution Dv10 of the second positive electrode active material in polycrystalline form is 0.5 μm to 12 μm, and optionally 1.0 μm to 8.5 μm.

[0232] When the volume-based particle size distribution 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 further, side reactions can be reduced and interfacial resistance can be lowered, thereby resulting in a longer service life of the battery.

[0233] In some embodiments, the first positive electrode active material has a single crystal structure, for example, the single crystal structure may account for 80% or more, or 90% or more. The polycrystalline first positive electrode active material has a large specific surface area, which increases hygroscopicity during the production process, increases process time, and increases the production cost of the battery.

[0234] In some embodiments, the second positive electrode active material has a polycrystalline morphology, for example, the proportion of polycrystalline morphology may be 80% or more, or 90% or more. The polycrystalline second positive electrode active material may have greater granularity and higher green density, which may help improve the energy density of the battery.

[0235] In some embodiments, the weight content of the first positive electrode active material is w a In this case, w a is selected from the range of 0.5% to 99.5%, and optionally from the range of 2% to 95%.

[0236] In some embodiments, the weight content of the second positive electrode active material is w b In this case, w b is selected from the range of 0.5% to 99.5%, and optionally from the range of 5% to 98%.

[0237] When the content of the first positive electrode active material and / or the second positive electrode active material is within the above range, the battery can have a higher energy density and / or a longer service life.

[0238] In some embodiments, the first positive electrode active material has a green density P1 of 1.89 / cm at 30,000 N. 3 or more, and optionally 1.95 g / cm 3 or more, and more selectively 1.98 g / cm 3 or more, and more selectively 2.0 g / cm 3 or more, and more selectively 2.2 g / cm 3 or more, and more selectively 2.2 g / cm 3 Above 2.8g / cm 3 or less than 2.2g / cm 3 or more and 2.65g / cm 3 The following is the result.

[0239] In some embodiments, the second positive electrode active material has a green density P2 of 2.90 g / cm at 30,000 N. 3 or more, and optionally 3.1 g / cm 3 or more, and more selectively 3.3 g / cm 3 That's all.

[0240] When the green density of the first positive electrode active material and / or the second positive electrode active material is within the above range, the battery can have a higher energy density.

[0241] In some embodiments, the second positive electrode active material has a BET specific surface area of ​​1.73 m 2 / g or less, and selectively 1.5m 2 / g or less, and more selectively 0.28m 2 / g~1.5m 2 This reduces side reactions and improves the cycle characteristics of the battery.

[0242] The specific surface area of ​​a material has a meaning known in the art and can be measured using devices and methods known in the art. For example, it can be measured using the test method for analyzing specific surface area by nitrogen adsorption, as described in GB / T 19587-2017, and calculated using the Brunauer Emmett Teller (BET) method. The test device can be a Tri-Star 3020 specific surface area pore size analyzer manufactured by Micromeritics, USA.

[0243] The green density of the materials (for example, the first positive electrode active material, the second positive electrode active material, etc.) can be measured based on GB / T 24533-2009.

[0244] The volumetric particle size distributions Dv10 and Dv50 of a material (e.g., the first positive electrode active material, the second positive electrode active material, etc.) have meanings known in the art, indicating the particle sizes corresponding to the cumulative volume distribution percentages of the material at 10% and 50%, respectively. They can be measured using devices and methods known in the art. For example, see GB / T 19077-2016 and can be measured using a laser particle size analyzer. The testing device can be a Mastersizer 3000 laser particle size analyzer from Malvern Instruments, UK. Deionized water is used as the solvent during testing, and the material can be ultrasonically treated for 5 minutes before testing.

[0245] The particle size distribution curve of the positive electrode active material composition can be measured using a laser particle size analyzer in accordance with GB / T 19077-2016. The testing device can be a Mastersizer 3000 laser particle size analyzer from Malvern Instruments, UK. Deionized water is used as the solvent during testing, and the material can be ultrasonically treated for 5 minutes before testing.

[0246] In some embodiments, the first positive electrode active material comprises a compound represented by Formula (I): Li a A x Mn 1-y B y P 1-z C z O 4-n Dn (I) A comprises one or more elements selected from Groups IA, IIA, IIIA, IIB, VB, and VIB; B comprises one or more elements selected from Groups IA, IIA, IIIA, IVA, VA, IIB, IVB, VB, VIB, and VIII; C comprises one or more elements selected from Groups IIIA, IVA, VA, and VIA; D comprises one or more elements selected from Groups VIA and VIIA; a is selected from the range of 0.85 to 1.15; x is selected from the range of 0 to 0.1; y is selected from the range of 0.001 to 0.999; z is selected from the range of 0 to 0.5; and n is selected from the range of 0 to 0.5.

[0247] Unless otherwise specified, in the above chemical formula, when A is two or more elements, the limitation on the range of the value of x is not only a limitation on the stoichiometric number of A as an element, but also a limitation on the sum of the stoichiometric numbers of each element A. For example, when A is two or more elements A1, A2...An, the stoichiometric numbers x1, x2...xn of A1, A2...An each fall within the range of values ​​limiting x in the present application, and the sum of x1, x2...xn also falls within the same range of values.

[0248] Similarly, other symbols (e.g., B, C, D, M, M', X, Z, P, Q, A) according to the embodiments of the present application 1 , B 1 , C 1 , D 1 , A 2 , B 2 , A 3 , A 4 etc.) are two or more elements, the range limitations herein on the stoichiometric number values ​​also have the above meanings.

[0249] The first positive electrode active material is obtained by doping the compound LiMnPO4 with elements, where A, B, C, and D are elements doped into the Li site, Mn site, P site, and O site of the compound LiMnPO4, respectively. Without wishing to be bound by theory, it is currently believed that the improved performance of lithium manganese phosphate is related to a decrease in the lattice change rate and a decrease in surface activity of lithium manganese phosphate during the lithium insertion and deintercalation process. By reducing the lattice change rate, the difference in lattice constant between the two phases at the grain boundary is reduced, reducing interfacial stress and improving the Li + This enhances the transport capability at the interface, thereby improving the rate characteristics of the first positive electrode active material. However, its high surface activity can lead to severe interfacial side reactions, accelerating gas generation, electrolyte consumption, and interfacial breakdown, thereby affecting battery performance, such as cycle life. Li and / or Mn site doping can reduce the lattice change rate. Mn site doping effectively reduces surface activity, thereby reducing Mn dissolution and interfacial side reactions between the first positive electrode active material and the electrolyte. P site doping accelerates the rate of change in Mn-O bond length, lowering the polaron migration energy barrier of the material and improving electronic conductivity. O site doping effectively reduces interfacial side reactions. P site and / or O site doping further affects the dissolution of Mn from antisite defects and the dynamic properties of the material. Therefore, doping reduces the concentration of antisite defects in the material, improving the dynamic properties and specific capacity of the material, and can also change the particle morphology and improve green density. The inventors have found that by doping a specific element in a specific amount into the Mn site of the compound LiMnPO4, and selectively into the Li site, P site, and / or O site, improved rate characteristics can be obtained, and at the same time, the elution of Mn and the doped element from the Mn site can be reduced, improving cycle characteristics and / or high temperature stability, and also increasing the specific capacity and packed density of the material.

[0250] In some embodiments, A comprises 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 comprises one or more elements selected from Zn, Al, Na, K, Mg, Nb, Mo, and W; and / or B comprises 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 optionally comprises 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 comprises one or more elements selected from B (boron), S, Si and N, and / or D comprises one or more elements selected from S, F, Cl and Br.

[0251] In some embodiments, A comprises any one element selected from Zn, Al, Na, K, Mg, Nb, Mo, and W, and optionally any one element selected from Mg and Nb; and / or 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, further optionally comprising at least two elements selected from Fe, Ti, V, Ni, Co and Mg, further optionally comprising at least two elements selected from Fe, Ti, V, Co and Mg, further optionally comprising 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, and is optionally S, and / or D includes any one element selected from S, F, Cl and Br, and is optionally F.

[0252] By selecting the Li-site dopant element within the above range, the lattice change rate during the lithium desorption process can be further reduced, thereby further improving the rate characteristics of the battery. By selecting the Mn-site dopant element within the above range, the electronic conductivity can be further improved and the lattice change rate can be further reduced, thereby improving the rate characteristics and specific capacity of the battery. By selecting the P-site dopant element within the above range, the rate characteristics of the battery can be further improved. By selecting the O-site dopant element within the above range, the interfacial side reactions can be further reduced and the high-temperature characteristics of the battery can be improved.

[0253] In some embodiments, a is selected from the range of 0.9 to 1.1, optionally selected 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 selected from the range of 0.01 to 0.5, optionally selected from the range of 0.25 to 0.5, and / or z is selected from the range of 0.001 to 0.5, optionally selected from the range of 0.001 to 0.1, further optionally selected from the range of 0.001 to 0.005, and / or n is selected from the range of 0 to 0.1, and optionally from the range of 0.001 to 0.005.

[0254] By selecting the value of y within the above range, the specific capacity and rate characteristics of the first positive electrode active material can be further improved. By selecting the value of x within the above range, the dynamic characteristics of the first positive electrode active material can be further improved. By selecting the value of z within the above range, the rate characteristics of the battery can be further improved. By selecting the value of n within the above range, the high-temperature characteristics of the battery can be further improved.

[0255] In some embodiments, x is 0, z is selected from the range of 0.001 to 0.5, and n is selected from the range of 0.001 to 0.1. Or, x is selected from the range of 0.001 to 0.1, z is 0, and n is selected from the range of 0.001 to 0.1. Or, x is selected from the range of 0.001 to 0.1, z is selected from the range of 0.001 to 0.5, and n is 0. Or, x is 0, z is 0, and n is selected from the range of 0.001 to 0.1. Or, x is 0, z is selected from the range of 0.001 to 0.5, and n is 0. Or, x is selected from the range of 0.001 to 0.1, z is selected from the range of 0.001 to 0.5, and n is 0.

[0256] Thus, by doping a specific element in a specific amount at the Mn site of the compound LiMnPO4 and selectively at the Li site, P site, and / or O site, particularly by doping a specific element in a specific amount at the Mn site and P site of LiMnPO4 or the Li site, Mn site, P site, and O site of LiMnPO4, it is possible to improve the rate characteristics, reduce the elution of Mn and the doped element at the Mn site, improve the cycle characteristics and / or high-temperature stability, and increase the specific capacity and compressed density of the first positive electrode active material.

[0257] In some embodiments, y:z is selected from the range of 0.002 to 999, optionally selected from the range of 0.025 to 999 or the range of 0.002 to 500, and further optionally selected from the range of 0.2 to 600, for example, 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 a range consisting of any two of the foregoing values, thereby reducing defects in the first positive electrode active material and improving the integrity of the framework structure of the first positive electrode active material, effectively improving the structural stability of the first positive electrode active material, and improving the cycling stability of the battery.

[0258] 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 further optionally from the range of 0.2 to 50, such as 0.2, 0.8, 1, 1.25, 4, 5, 50, or a range consisting of any two of the above values, thereby further reducing defects in the first positive electrode active material, further improving the integrity of the framework structure of the first positive electrode active material, effectively improving the structural stability of the first positive electrode active material, and improving the cycling stability of the battery.

[0259] In some embodiments, (1-y):y is in the range of 0.1 to 999, optionally in the range of 0.1 to 10 or 0.67 to 999, further optionally in the range of 1 to 10, further optionally in the range of 1 to 4, further optionally 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, further optionally in the range of 190 to 998.

[0260] Here, y represents the sum of the stoichiometric numbers of the Mn site doping elements. When the above condition is satisfied, the energy density and cycle characteristics of the first positive electrode active material can be further improved.

[0261] In some embodiments, z:(1-z) is 1:9 to 1:999, and optionally 1:499 to 1:249. When the above condition is satisfied, the energy density and cycle characteristics of the first positive electrode active material can be further improved.

[0262] In some embodiments, A comprises one or more elements selected from Zn, Al, Na, K, Mg, Nb, Mo, and W; B comprises one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge; C comprises one or more elements selected from B (boron), S, Si, and N; D comprises 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.

[0263] By simultaneously doping the Li site, Mn site, P site, and O site of the compound LiMnPO4 with specific elements in specific amounts, improved rate characteristics can be obtained, and at the same time, the elution of Mn and the doped elements from the Mn site can be reduced, improving cycle characteristics and / or high-temperature stability, and also improving the specific capacity and compressed density of the first positive electrode active material.

[0264] In some embodiments, B comprises 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 comprises one or more elements selected from Zn, Fe, Ti, V, Ni, Co, and Mg; C comprises 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.

[0265] By simultaneously doping the Mn site and P site of the compound LiMnPO4 with a specific element in a specific amount, the rate characteristics can be improved, the elution of Mn and the doped element at the Mn site can be reduced, the cycle characteristics and / or high-temperature stability can be improved, and the specific capacity and compressed density of the first positive electrode active material can be increased.

[0266] In some embodiments, the first positive electrode active material comprises a core and a shell coating the core, the core comprising the compound represented by Formula (I) above. The shell comprises one or more coating layers. Each coating layer has ionic and / or electronic conductivity. In practice, each coating layer may completely or partially coat the core.

[0267] By providing a coating layer having ionic and / or electronic conductivity on the core surface, a first positive electrode active material having a core-shell structure is provided, and by applying the first positive electrode active material to a battery, the high-temperature cycle characteristics, cycle stability, and high-temperature storage performance of the battery can be improved.

[0268] In some embodiments, the one or more coating layers each independently comprise one or more selected from pyrophosphate, phosphate, carbon, doped carbon, oxide, boride, and polymer.

[0269] In some embodiments, the shell comprises one coating layer, and optionally the coating layer comprises one or more selected from pyrophosphate, phosphate, carbon, doped carbon, oxide, boride, and polymer.

[0270] By using the above materials, a coating layer having ionic and / or electronic conductivity can be obtained, thereby improving the high-temperature cycle characteristics, cycle stability, and high-temperature storage performance of the battery.

[0271] In some embodiments, the shell comprises a first coating layer coating the core and a second coating layer coating the first coating layer, and optionally, the first coating layer and the second coating layer each independently comprise one or more selected from pyrophosphate, phosphate, carbon, doped carbon, oxide, boride, and polymer.

[0272] By using the above material as the material for the coating layer and providing two coating layers, the high-temperature cycle characteristics, cycle stability, and high-temperature storage performance of the battery can be further improved.

[0273] In some embodiments, the first coating layer comprises one or more selected from pyrophosphates, phosphates, oxides, and borides, and the second coating layer comprises one or more selected from carbon and doped carbon.

[0274] By using a first coating layer made of a specific material and a second coating layer made of a specific material, it is possible to further improve the rate characteristics, further reduce the leaching of Mn and doping elements at the Mn sites, and improve the cycle characteristics and / or high-temperature stability of the battery.

[0275] In some embodiments, the shell comprises 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, and optionally, the first coating layer, the second coating layer, and the third coating layer each independently comprise one or more of pyrophosphate, phosphate, carbon, doped carbon, oxide, boride, and polymer. The "polymer" may be an oligomer or a high polymer, and the present application is not limited thereto.

[0276] By using the above materials as the coating layer material and providing three coating layers, the elution of Mn and doping elements at the Mn site can be further reduced, and the high-temperature cycle characteristics, cycle stability, and high-temperature storage performance of the battery can be further improved.

[0277] In some embodiments, the first coating layer comprises a pyrophosphate, the second coating layer comprises one or more selected from a phosphate, an oxide, and a boride, and the third coating layer comprises one or more selected from carbon and doped carbon.

[0278] By using a first coating layer made of a specific material, a second coating layer made of a specific material, and a third coating layer made of a specific material, the rate characteristics are further improved, the leaching of Mn and doping elements at the Mn sites is further reduced, the cycle characteristics and / or high-temperature stability of the battery are improved, and the specific capacity and compressed density of the first positive electrode active material are further increased.

[0279] In some embodiments, pyrophosphate is Mb (P2O7) c and / or Phosphate is X m (PO4) q and / or the doping element in the doped carbon comprises 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 Borides are Z v B w and / or the polymer comprises one or more selected from polysaccharides and derivatives thereof, and 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, and 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, and e is greater than 0 and less than or equal to 5; v is selected from the range of 1 to 7, and w is selected from the range of 1 to 2.

[0280] By using the above material to form the coating layer, it is possible to further reduce the elution of Mn and doping elements at the Mn site, further improve the specific capacity and compressed density of the first positive electrode active material, and further improve the rate characteristics, high-temperature cycle characteristics, and high-temperature storage performance of the battery.

[0281] In some embodiments, M, X, and Z each independently comprise one or more elements selected from Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb, Mn, and Al; and / or the doping element in the doped carbon comprises one or more selected from nitrogen, phosphorus, sulfur, boron and fluorine; and / or M' comprises one or more elements selected from Li, Be, B, Na, Mg, Al, Si, P, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, W, La and Ce, and / or optionally one or more elements selected from Mg, Al, Si, Zn, Zr and Sn; and / or the polysiloxane is selected from one or more of a linear polysiloxane and a cyclic polysiloxane; and / or The polysaccharide is selected from one or more of plant polysaccharides and marine polysaccharides.

[0282] By using the above specific materials to form the coating layer, it is possible to further reduce the elution of Mn and doping elements at the Mn site, and further improve the high-temperature cycle characteristics and high-temperature storage performance of the battery.

[0283] In some embodiments, the first positive electrode active material includes a core and a shell covering the core.

[0284] The core is Li a Mn 1-y B y P 1-z C z O4, a is selected from the range of 0.9 to 1.1, y is selected from the range of 0.001 to 0.5, z is selected from the range of 0.001 to 0.1, 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.

[0285] The shell includes a first coating layer coating the core and a second coating layer coating 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, and the second coating layer including carbon.

[0286] The first positive electrode active material may have a core-shell structure with two coating layers. Element B, doped into the manganese site of lithium manganese phosphate, reduces the lattice change rate of lithium manganese phosphate during lithium insertion and deintercalation, improving the structural stability of the first positive electrode active material, significantly reducing manganese dissolution, and reducing oxygen activity on the particle surface. Element C, doped into the phosphate site, modifies the difficulty of changing the Mn-O bond length, thereby lowering the lithium ion migration energy barrier, facilitating lithium ion migration, and improving the battery's rate performance. The first coating layer of the first positive electrode active material contains pyrophosphate and phosphate. The transition metal has a high migration energy barrier in pyrophosphate (>1 eV), effectively reducing transition metal dissolution. The phosphate has excellent lithium ion conductivity and can reduce the content of lithium impurities on the surface. Furthermore, the second coating layer is a carbon-containing layer, which effectively improves the conductivity and desolvation ability of LiMnPO4. Furthermore, the "barrier" effect of the second coating layer further reduces the migration of manganese ions into the electrolyte, reducing corrosion of the second active material by the electrolyte. Therefore, by doping lithium manganese phosphate with specific elements and coating the surface, it is possible to effectively reduce the elution of Mn during the lithium insertion and desorption process, while simultaneously promoting the migration of lithium ions, thereby improving the rate characteristics of the battery and enhancing its cycle and high-temperature properties.

[0287] In some embodiments, the first positive electrode active material includes a core and a shell covering the core.

[0288] The core is Li a Mn 1-y By P 1-z C z O4, a is selected from the range of 0.9 to 1.1, y is selected from the range of 0.001 to 0.5, z is selected from the range of 0.001 to 0.1, 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.

[0289] The shell includes a first coating layer that coats the core, a second coating layer that coats the first coating layer, and a third coating layer that coats the second coating layer.

[0290] The first coating layer is Li pyrophosphate f QP2O7 and / or Q g (P2O7) h wherein 0≦f≦2, 1≦g≦4, and 1≦h≦6; and wherein Li pyrophosphate f QP2O7 and / or Q g (P2O7) h wherein each Q independently comprises one or more elements selected from Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb, and Al.

[0291] The second coating layer comprises a crystalline phosphate XPO4, where X comprises one or more elements selected from Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb, and Al.

[0292] The third coating layer includes carbon.

[0293] The first positive electrode active material has a core-shell structure. Doping the manganese and phosphorus sites of the core with elements B and C, respectively, effectively reduces manganese ion dissolution, reduces manganese ion migration to the anode, and reduces electrolyte consumption due to SEI film decomposition, improving battery cycle performance. It also facilitates Mn-O bond length adjustment, lowering the lithium ion migration energy barrier, facilitating lithium ion migration, and improving battery rate performance. Coating the core with a first coating layer containing pyrophosphate significantly increases resistance to manganese migration, reducing manganese dissolution and the content of lithium impurities on the surface, reducing contact between the core and the electrolyte. This reduces interfacial side reactions, gas generation, and improves the high-temperature storage performance and cycle performance of the battery. Further coating with a phosphate coating layer with excellent lithium ion conductivity effectively reduces interfacial side reactions on the surface of the first positive electrode active material, thereby improving the high-temperature cycling and storage performance of the battery. A third coating layer, a carbon layer, further improves the dynamic performance of the battery. Furthermore, element B doped into the manganese site of the core reduces the lattice change rate of the lithium manganese phosphate during the lithium intercalation and deintercalation process, improving the structural stability of the first positive electrode active material, significantly reducing manganese leaching and oxygen activity on the particle surface. Element C doped into the phosphate site modifies the difficulty of changing the Mn-O bond length, thereby improving electronic conductivity and lowering the energy barrier for lithium ion migration, facilitating lithium ion migration and improving the rate capability of the battery.

[0294] Furthermore, the electrical neutrality of the entire core system can be maintained, thereby minimizing defects and impurity phases in the first positive electrode active material. If an excess transition metal (e.g., manganese) is present in the first positive electrode active material, the material system itself is stable, so the excess transition metal is likely to precipitate in an elemental form or form an impurity phase within the crystal lattice. However, by maintaining electrical neutrality, such impurity phases can be minimized. Furthermore, by making the system electrically neutral, lithium vacancies can be generated in the material in some circumstances, thereby improving the dynamic properties of the first positive electrode active material.

[0295] In some embodiments, one or more coating layers of the shell furthest from the core each independently comprise one or more selected from polysiloxane, polysaccharide, and polysaccharide derivative.

[0296] This improves the uniformity of the coating, effectively blocks interfacial side reactions caused by high voltage, and improves the high-temperature cycle characteristics and high-temperature storage performance of the first positive electrode active material. In addition, the coating layer has good ionic conductivity, which helps to improve the specific capacity of the first positive electrode active material and simultaneously reduces heat generation in the battery.

[0297] In some embodiments, the polysiloxane comprises a structural unit shown in formula (i): [ka] R1 and R2 are each independently selected from H, -COOH, -OH, -SH, -CN, -SCN, an amino group, a phosphate ester group, a carboxylate ester group, an amide group, an aldehyde group, a sulfonyl group, a polyether segment, a C1 to C20 aliphatic hydrocarbon group, a C1 to C20 halogenated aliphatic hydrocarbon group, a C1 to C20 heteroaliphatic hydrocarbon group, a C1 to C20 halogenated heteroaliphatic hydrocarbon group, a C6 to C20 aromatic hydrocarbon group, a C6 to C20 halogenated aromatic hydrocarbon group, a C2 to C20 heteroaromatic hydrocarbon group, and a C2 to C20 halogenated heteroaromatic hydrocarbon group; Alternatively, R1 and R2 are independently selected from H, an amino group, a phosphate ester group, a polyether segment, a C1-C8 alkyl group, a C1-C8 halogenated alkyl group, a C1-C8 heteroalkyl group, a C1-C8 halogenated heteroalkyl group, a C2-C8 alkenyl group, and a C2-C8 halogenated alkenyl group.

[0298] In some embodiments, the polysiloxane further comprises an end-capping group, which comprises one or more of the functional groups polyether, C1-C8 alkyl group, C1-C8 halogenated alkyl group, C1-C8 heteroalkyl group, C1-C8 halogenated heteroalkyl group, C2-C8 alkenyl group, C2-C8 halogenated alkenyl group, C6-C20 aromatic hydrocarbon group, C1-C8 alkoxy group, C2-C8 epoxy group, hydroxy group, C1-C8 hydroxyalkyl group, amino group, C1-C8 aminoalkyl group, carboxy group, and C1-C8 carboxyalkyl group.

[0299] In some embodiments, the polysiloxane is selected from the group consisting of polydimethylsiloxane, polydiethylsiloxane, polymethylethylsiloxane, polymethylvinylsiloxane, polyphenylmethylsiloxane, polymethylhydrogensiloxane, carboxy-functionalized polysiloxane, epoxy-terminated polysiloxane, methoxy-terminated polydimethylsiloxane, hydroxypropyl-terminated polydimethylsiloxane, polymethylchloropropylsiloxane, hydroxy-terminated polydimethylsiloxane, polymethyltrifluoropropylsiloxane, perfluorooctylmethylpolysiloxane, aminoethylaminopropylpolydimethylsiloxane, polyether-terminated polydimethylsiloxane, side chain aminopropylpolysiloxane, The polydimethylsiloxane may include one or more selected from the group consisting of cyclohexane, cyclohexane-1,3,5,7-octamethylcyclotetrasiloxane, 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, hexadecamethylcyclooctasiloxane, tetradecamethylcycloheptasiloxane, and cyclic polydimethylsiloxane.

[0300] In some embodiments, the number average molecular weight of the polysiloxane, polysaccharide, and polysaccharide derivative is each independently 300,000 or less, optionally 10,000 to 200,000, further optionally 20,000 to 120,000, and further optionally 400 to 80,000.

[0301] The number average molecular weight of polysiloxanes, polysaccharides, and polysaccharide derivatives can be measured by methods known in the art, such as gel permeation chromatography (GPC), using a PL-GPC 220 high temperature gel permeation chromatograph.

[0302] In some embodiments, the weight percent content of polar functional groups in the polysiloxane is α, where 0≦α<50%, and optionally 5%≦α≦30%.

[0303] The "mass percent content of polar functional groups in the polysiloxane" refers to the mass percentage of polar functional groups in the polysiloxane, including R1, R2, and end-capping groups. The polar functional groups include one or more of -COOH, -OH, -SH, -CN, -SCN, amino groups (including -NH2 and -NH-), phosphate ester groups, carboxylic acid ester groups (-COO-), amide groups (-CONH-), aldehyde groups (-CHO), sulfonyl groups (-S(=O)2-), polyether segments, halogens, alkoxy groups, and epoxy groups. When the polar functional group is directly bonded to the silicon atom, α represents the mass fraction of the polar functional group in the polysiloxane. When the polar functional group is not directly bonded to the silicon atom, α represents the sum of the mass fractions of the polar functional group and the divalent to tetravalent methyl (e.g., -CH2, -CH-, -C-, etc.) directly bonded to it in the polysiloxane. Here, "divalent to tetravalent methyl" refers to the carbon atom directly bonded to the polar functional group and located between the polar functional group and the silicon atom, as well as other non-polar functional groups bonded to the carbon atom. Taking polymethyltrifluoropropylsiloxane as an example, α represents the mass percent content of -CF3 therein, excluding ethylene. Taking polymethylchloropropylsiloxane as an example, α represents the mass percent content of -CH2Cl therein, excluding ethylene. Taking hydroxypropyl-terminated polydimethylsiloxane as an example, α represents the mass percent content of -CH2OH therein. The weight percent content of polar functional groups in a polysiloxane can be measured by methods known in the art, such as titration methods (e.g., acid-base titration, redox titration, precipitation titration), infrared spectroscopy, and nuclear magnetic resonance spectroscopy.

[0304] In some embodiments, the substituents attached to the saccharide units in the polysaccharides and polysaccharide derivatives each independently comprise one or more of the functional groups -OH, -COOH and salts thereof, -R-OH, -SOH and salts thereof, -R-OH, -R-SOH and salts thereof, sulfuric acid ester groups, and alkoxy groups, where R represents an alkylene group, and optionally a C1-C5 alkylene group.

[0305] Optionally, the substituents attached to the saccharide units in the polysaccharides and polysaccharide derivatives each independently comprise one or more of the following functional groups: -OH, -COOH, -COOLi, -COONa, -COOK, -SOH, -SOLi, -SONa, -SOK, -CH-SOH, -CH-SOLi, -CH-SONa, -CH-SOK, methoxy, and ethoxy.

[0306] The term "substituents attached to a sugar unit" includes all groups attached to the backbone of the sugar unit.

[0307] In some embodiments, the polysaccharide comprises one or more selected from pectin, carboxymethyl starch, hydroxypropyl starch, dextran, cellulose ether, carboxymethylchitosan, hydroxyethylcellulose, carboxymethylcellulose, carboxypropylmethylcellulose, guar gum, sesbania gum, gum arabic, lithium alginate, sodium alginate, potassium alginate, fucoidan, agar, carrageenan, xanthan gum, and fenugreek gum.

[0308] In some embodiments, the weight percent content of the substituents attached to the saccharide units in the polysaccharides and polysaccharide derivatives is independently 20% to 85%, and optionally 30% to 78%. The weight percent content of the substituents attached to the saccharide units in the polysaccharides and polysaccharide derivatives can be measured by methods known in the art, such as titration methods (e.g., acid-base titration, redox titration, precipitation titration), infrared spectroscopy, and nuclear magnetic resonance spectroscopy.

[0309] In some embodiments, the lattice mismatch between the core material and the shell material is less than 10%, which provides good contact between the core and the shell (or the covering layer) and prevents the shell (or the covering layer) from falling off.

[0310] In some embodiments, based on the weight of the positive electrode active material, The manganese element content is in the range of 10% to 35% by weight, optionally in the range of 13.3% to 33.2% by weight, further optionally in the range of 15% to 30% by weight, further optionally in the range of 17% to 20% by weight, and / or The phosphorus content is in the range of 12% to 25% by weight, optionally in the range of 15% to 20% by weight, and more optionally in the range of 16.8% to 19.5% by weight, and / or The weight ratio range of elemental manganese to elemental phosphorus is 0.71 to 1.85, optionally 0.90 to 1.25, and more optionally 0.95 to 1.20.

[0311] When manganese is contained only in the core of the first positive electrode active material, the manganese content may correspond to the content of the core.

[0312] By limiting the manganese content within the above range, the stability and density of the first positive electrode active material can be further improved, and the cycle, storage, compaction, and other performance of the battery can be improved, and a high potential plateau can be maintained, thereby improving the energy density of the battery.

[0313] By limiting the content of phosphorus within the above range, the influence of polaron conduction on the conductivity of the first positive electrode active material can be effectively reduced, the stability of the crystal lattice structure can be improved, and the stability of the entire first positive electrode active material can be improved.

[0314] By limiting the weight ratio of manganese to phosphorus within the above range, it is possible to further reduce manganese leaching, improve the stability and specific capacity of the first positive electrode active material, improve the cycle characteristics and storage performance of the battery, and further reduce impurity phases, so that the first positive electrode active material maintains a high discharge potential plateau and the battery has a high energy density.

[0315] The manganese and phosphorus elements can be measured using conventional technical means in this field. In particular, the manganese and phosphorus contents can be measured using the following method: Dissolve the material in dilute hydrochloric acid (concentration 10-30%), use the content of each element in the ICP test solution, and then measure and convert the manganese content to obtain its weight percentage.

[0316] In some embodiments, the surface of the first positive electrode active material is coated with one or more of carbon and doped carbon, and optionally the surface of the first positive electrode active material is coated with carbon, which can improve the conductivity of the first positive electrode active material.

[0317] In some embodiments, the doping element in the doped carbon comprises one or more selected from nitrogen, phosphorus, sulfur, boron, and fluorine, which makes it easier to control the performance of the doped carbon layer.

[0318] In some embodiments, the coating amount of the shell (only one coating layer) is 0.1 wt % to 6 wt % of the weight of the core. When the coating amount is preferably within this range, the core can be sufficiently coated, and at the same time, the dynamic characteristics of the battery can be further improved without sacrificing the specific capacity of the first positive electrode active material.

[0319] In some embodiments, the coating amount of the first coating layer is greater than 0 and less than 7 wt%, alternatively greater than 0 and less than 6 wt%, further alternatively greater than 0 and less than 5.5 wt%, or 4-5.6 wt%, further alternatively greater than 0 and less than 2 wt%, relative to the weight of the core; and / or The amount of the second coating layer is greater than 0 and less than 6% by weight, optionally greater than 0 and less than 5.5% by weight, and further optionally 2 to 4% by weight or 3 to 5% by weight, relative to the weight of the core; and / or The coverage of the third coating layer is greater than 0 and less than 6% by weight, optionally greater than 0 and less than 5.5% by weight, and further optionally greater than 0 and less than 2% by weight, based on the weight of the core.

[0320] In some embodiments, the shell further comprises a fourth coating layer overlying the third coating layer and a fifth coating layer overlying the fourth coating layer.

[0321] The coating amounts of the fourth coating layer and the fifth coating layer are each independently 0.01% by weight to 10% by weight, optionally 0.05% by weight to 10% by weight, further optionally 0.1% by weight to 5% by weight, and further optionally 0.1% by weight to 2% by weight, relative to the weight of the core.

[0322] By having the coating weight of each coating layer preferably within the above range, the core can be sufficiently coated, and at the same time, the dynamic characteristics of the battery can be further improved without sacrificing the specific capacity of the first positive electrode active material.

[0323] In some embodiments, the shell is located on 40% to 90% of the surface of the core, and optionally on 60% to 80% of the surface, which provides sufficient coverage of the core and improves the dynamic properties of the battery.

[0324] In some embodiments, the thickness of the shell (only one coating layer) is 1 to 15 nm.

[0325] In some embodiments, the thickness of the first coating layer is 1 to 10 nm, optionally 2 to 10 nm, and / or the thickness of the second coating layer is 2 to 25 nm, optionally 2 to 15 nm, and further optionally 3 to 15 nm; and / or The thickness of the third coating layer is 2 to 25 nm, and optionally 5 to 25 nm.

[0326] In some embodiments, the thickness of the first coating layer can 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 any range between any of the foregoing values.

[0327] In some embodiments, the thickness of the second coating layer is 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 between any of the foregoing values.

[0328] In some embodiments, the thickness of the third coating layer is 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 can be within any range of any of the foregoing values.

[0329] When the first coating layer has a thickness in the above range, the adverse effects on the dynamic properties of the first positive electrode active material can be further reduced.

[0330] When the second coating layer has a thickness within the above range, the surface structure of the second coating layer is stabilized and side reactions with the electrolyte are reduced, thereby effectively reducing interfacial side reactions and improving the high-temperature characteristics of the battery.

[0331] When the third coating layer has a thickness in the above range, the conductive performance of the first positive electrode active material can be improved, and the compressed density of a positive electrode sheet manufactured using the first positive electrode active material can be improved.

[0332] The thickness of the coating layer is measured primarily using FIB, and the specific method involves the following steps: randomly selecting a single particle from the first positive electrode active material powder to be measured, cutting a thin slice approximately 100 nm thick from the middle or near the middle position of the selected particle, then subjecting the slice to a TEM test, measuring the thickness of the coating layer, and taking the average value from three to five positions.

[0333] In some embodiments, the one or more coating layers each independently comprise one or more selected from pyrophosphates, phosphates, and oxides, and the one or more selected from pyrophosphates, phosphates, and oxides are crystalline.

[0334] Alternatively, the crystallinity of the pyrophosphate, phosphate and oxide is each independently 10% to 100%, preferably 50% to 100%.

[0335] In this specification, the term "crystalline" means that the degree of crystallinity is 50% or more, i.e., 50% to 100%. In other words, when the crystalline pyrophosphate and crystalline phosphate of the present application appear, this indicates that the degree of crystallinity is 50% to 100%.

[0336] Pyrophosphates and phosphates having a certain degree of crystallinity not only help the pyrophosphate coating layer reduce manganese elution and fully exhibit the excellent lithium ion conductivity and the function of reducing interfacial side reactions of the phosphate coating layer, but also enable the pyrophosphate coating layer and the phosphate coating layer to achieve better lattice matching, thereby realizing a tight bond between the coating layers.

[0337] The crystallinity can be adjusted by, for example, adjusting the process conditions of the sintering process, such as the sintering temperature and time. The crystallinity can be measured by methods known in the art, such as X-ray diffraction, density measurement, infrared spectroscopy, differential scanning calorimetry, and nuclear magnetic resonance spectroscopy. A method for measuring the crystallinity of the first positive electrode active material by X-ray diffraction specifically includes the following steps.

[0338] A certain amount of the first positive electrode active material powder is taken and the total scattering intensity is measured by X-ray. This is the sum of the scattering intensity of the entire space material, and is related only to the intensity of the primary radiation, the chemical structure of the first positive electrode active material powder, and the total number of electrons involved in diffraction, i.e., the mass, and is unrelated to the order of the sample. Next, crystalline scattering and non-crystalline scattering are separated from the diffraction pattern, and the crystallinity is the ratio of the crystalline partial scattering to the total scattering intensity.

[0339] In some embodiments, the weight ratio of the pyrophosphate to the phosphate and the weight ratio of the pyrophosphate to the oxide in the shell are each independently 1:3 to 3:1, and optionally 1:3 to 1:1. Therefore, by ensuring that the weight ratio of the pyrophosphate to the phosphate or the weight ratio of the pyrophosphate to the oxide is in an appropriate range, it is possible to effectively reduce not only the leaching of manganese but also the content of surface lithium impurities, reduce interfacial side reactions, and improve the high-temperature storage performance and high-temperature cycle performance of the battery.

[0340] In some embodiments, one or more coating layers each independently comprise carbon, and the carbon is a mixture of SP2 and SP3 carbon forms, and optionally, the molar ratio of the SP2 and SP3 carbon forms in the carbon is any value in the range of 0.07 to 13, further optionally, any value in the range of 0.1 to 10, and further optionally, any value in the range of 2.0 to 3.0.

[0341] In some embodiments, the molar ratio of SP2 carbon to SP3 carbon can 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 can range within any of the above values.

[0342] In this application, a numerical value followed by "about" indicates a range, indicating a range of ±10% of the numerical value.

[0343] Selecting the carbon morphology in the carbon coating layer improves the overall electrical performance of the battery. Specifically, by using a mixture of SP2 and SP3 carbon morphologies and limiting the ratio of SP2 to SP3 carbon within a certain range, it is possible to avoid the situation where the carbon in the coating layer is all amorphous SP3 carbon, which has poor electrical conductivity, and the situation where the carbon in the coating layer is all graphitized SP2 carbon, which has good electrical conductivity but few lithium ion channels, which is unfavorable for lithium insertion and extraction. Furthermore, limiting the molar ratio of SP2 to SP3 carbon within the above range not only achieves good electrical conductivity but also promotes lithium ion transport, which is advantageous for the battery's function and cycle characteristics.

[0344] The mixing ratio of SP2 and SP3 forms of carbon can be controlled by sintering conditions, such as sintering temperature and sintering time. The molar ratio of SP2 and SP3 forms of carbon can be measured by Raman spectroscopy, and the specific test method is as follows: The Raman energy spectrum is peak-split to obtain Id / Ig (where Id is the peak intensity of SP3 carbon and Ig is the peak intensity of SP2 carbon), and the molar ratio of the two forms can be determined.

[0345] In some embodiments, one or more coating layers each independently contain doped carbon, and the doped carbon has a doping element content of 30% or less by mass, or optionally, the doped carbon has a doping element content of 20% or less by mass. The doping element content within this range not only sufficiently improves the conductivity of the pure carbon layer, but also effectively prevents excessive doping of the doping element from increasing surface activity, and effectively suppresses interfacial side reactions caused by excessive doping of the coating layer.

[0346] In some embodiments, the one or more coating layers each independently comprise 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 wherein the doping element is nitrogen, phosphorus, sulfur, boron, or fluorine.

[0347] Nitrogen atoms and sulfur atoms have atomic radii closer to those of carbon atoms and are less likely to destroy the carbon skeleton. Therefore, when the doping amounts of nitrogen atoms and sulfur atoms are within the above-mentioned relatively wide range, the doped carbon layer not only exhibits sufficient conductivity, but also promotes the transport of lithium ions and the desolvation ability of lithium ions.

[0348] The phosphorus, boron and / or fluorine atoms have different radii from carbon atoms, and excessive doping tends to destroy the carbon skeleton. Therefore, when the doping amount of phosphorus, boron and / or fluorine atoms is within the above-mentioned relatively narrow range, the doped carbon layer can not only fully exhibit its conductivity, but also promote the transport of lithium ions and the desolvation ability of lithium ions.

[0349] In some embodiments, the one or more coating layers each independently comprise a pyrophosphate, wherein the pyrophosphate has a crystallographic spacing in the range of 0.293 to 0.470 nm, alternatively 0.297 to 0.462 nm or 0.293 to 0.326 nm, and further alternatively 0.300 to 0.310 nm; the included angle of the (111) crystal orientation in the range of 18.00° to 32.57°, alternatively 18.00° to 32.00° or 26.41° to 32.57°, further alternatively 19.211° to 30.846°, and further alternatively 29.00° to 30.00°; and / or the one or more coating layers each independently comprise a phosphate, the phosphate having a crystal plane spacing in the range of 0.244 to 0.425 nm, optionally 0.345 to 0.358 nm, and a crystal orientation (111) having an included angle in the range of 20.00° to 37.00°, optionally 24.25° to 26.45°; Optionally, the first coating layer or the second coating layer comprises a phosphate.

[0350] The first and second coating layers of the first positive electrode active material are both made of crystalline materials, and their crystal plane spacing and included angle ranges are within the above ranges, which can effectively reduce impurity phases in the coating layers and thereby improve the specific capacity, cycle performance, and rate performance of the material.

[0351] In some embodiments, the lattice change rate of the first positive electrode active material before and after complete lithium insertion and extraction is 50% or less, optionally 9.8% or less, further optionally 8.1% or less, further optionally 7.5% or less, further optionally 6% or less, further optionally 4% or less, further optionally 3.8% or less, and further optionally 2.0 to 3.8%.

[0352] By reducing the lattice change rate, the transport of Li ions can be made easier, i.e., the mobility of Li ions in the first positive electrode active material is enhanced, which helps to improve the rate performance of the battery. The lattice change rate can be measured by a method known in the art, such as X-ray diffraction (XRD).

[0353] In some embodiments, the first positive electrode active material has a Li / Mn antisite defect concentration of 5.3% or less, optionally 5.1% or less, further optionally 4% or less, further optionally 2.2% or less, further optionally 2% or less, further optionally 1.5% to 2.2%, or further optionally 0.5% or less.

[0354] The so-called Li / Mn antisite defect is a defect in the LiMnPO4 crystal lattice where Li + and Mn 2+The concentration of Li / Mn antisite defects refers to the exchange of positions of Mn in the first positive electrode active material. 2+ Replaced by Li + Li + The percentage of Mn in the total amount of antisite defects is 2+ Li + This inhibits the transport of Li and Mn antisite defects, thereby reducing the concentration of Li / Mn antisite defects, thereby improving the specific capacity and rate performance of the first positive electrode active material. The concentration of Li / Mn antisite defects can be measured by methods known in the art, such as XRD.

[0355] In some embodiments, the surface oxidation state of the first positive electrode active material is −1.55 or less, optionally −1.82 or less, further optionally −1.88 or less, further optionally −1.90 or less, or −1.98 to −1.88, further optionally −1.98 to −1.89, further optionally −1.98 to −1.90.

[0356] By reducing the surface oxidation state, side reactions at the interface between the first positive electrode active material and the electrolyte can be reduced, thereby improving the cycleability and high-temperature stability of the battery. The surface oxidation state can be measured by methods known in the art, such as electron energy loss spectroscopy (EELS).

[0357] In some embodiments, the positive electrode active material composition has a value of 0.0004≦w a ×y×(3.4-V B )≦0.063, and optionally, 0.0015≦w a ×y×(3.4-V B )≦0.045.

[0358] w a represents the weight content of the first positive electrode active material relative to the total weight of the positive electrode active material composition.

[0359] y is the molar amount of the B element in 1 mole of the compound represented by formula (I), and the element content of y can be detected using inductively coupled plasma emission spectrometry (ICP).

[0360] V B is the potential plateau of the B element in the compound represented by formula (I), and its unit is V (volt). B can be measured by the following method: At 25°C, the battery is allowed to stand for 10 minutes, discharged at 0.33C to the lower cutoff voltage, and after 10 minutes of standing, the battery is charged at a constant current of 0.33C to the upper cutoff voltage, followed by a constant voltage charge until the current is ≦0.05C. After 10 minutes of standing, the battery is discharged at 0.33C to the lower cutoff voltage, and the discharge capacity of the battery is obtained and designated as C0. After 10 minutes of standing, the battery is charged at a constant current of 0.04C0 to the upper cutoff voltage, followed by a constant voltage charge until the current is ≦0.05C. After 10 minutes of standing, the battery is discharged at 0.04C0 to the lower cutoff voltage, and the discharge capacity of the battery is designated as C1. A discharge differential capacitance dQ / dV curve is created based on the discharge curve, and the peak in the dQ / dV curve below 3.4V is designated as the peak of element B. The voltage corresponding to this peak is V. B is.

[0361] The battery is a battery that includes a positive electrode active material composition.

[0362] If the positive electrode active material composition further satisfies the above conditions, the positive electrode sheet will have both high pressed density and high pressed density efficiency, which will help the battery have both high energy density and long service life.

[0363] In some embodiments, the second positive electrode active material comprises a layered oxide.

[0364] Although the second positive electrode active material has a high pressed density, it is expensive, and generally has many side reactions during use in a battery and a poor crystalline structure stability. By rationally combining the first and second positive electrode active materials, the actual bulk density of the positive electrode active material composition can be further improved, and the pressed density and pressed density efficiency of the positive electrode sheet can be improved, so that a battery using the positive electrode active material composition can have a higher energy density and a longer service life.

[0365] In some embodiments, the second positive electrode active material comprises a compound represented by Formula (II): Li a1 A 1 b1 Ni c1 Co d1 B 1 e1 C 1 f1 O 2-g1 D 1 g1 , (II) A 1 contains one or more elements selected from Groups IA, IIA, VIII, VIB, and IIB; B 1 contains Mn and / or Al, and C 1 comprises one or more elements selected from Groups IA, IIA, IIIA, IVA, VA, VIA, IIB, IIIB, IVB, VB, VIB and VIII; D 1 comprises one or more elements selected from Group VIA and Group VIIA, a1 is selected from the range of 0.8 to 1.2, b1 is selected from the range of 0 to 0.2, c1 is selected from the range of 0 to 1, d1 is selected from the range of 0 to 1, e1 is selected from the range of 0 to 1, f1 is selected from the range of 0 to 0.1, g1 is selected from the range of 0 to 0.1, and c1+d1+e1+f1=1.

[0366] In some embodiments, A 1 contains one or more elements selected from Na, K, Mg, Rb, Zn, Zr, and / or C 1 comprises 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 comprising one or more elements selected from Al, Ti, Zr, Nb, Sr, Sc, Sb, Y, Ba, B; and / or D 1 contains one or more elements selected from N, S, F, Cl and Br, optionally containing 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, and optionally from the range of 0.01 to 0.05.

[0367] In some embodiments, the second active cathode material comprises a core and a shell coating the core, wherein the core comprises a compound represented by Formula (II), and the shell comprises one or more coating layers, each coating layer having ionic and / or electronic conductivity.

[0368] In some embodiments, the one or more coating layers each independently comprise one or more selected from phosphate, pyrophosphate, carbon, doped carbon, oxide, and fast ion conductor, and optionally one or more selected from phosphate, pyrophosphate, and oxide.

[0369] In some embodiments, one or more coating layers each independently comprise one or more elements selected from Al, Zr, Mg, Ba, Cd, Zn, Ti, Co, W, Y, Si, Sn, B, P, S, and C.

[0370] In some embodiments, the fast ion conductor is Li 3x3 La 2 / 3-x3 M 2 a3 TiN 2 z3 O3, Li 2+2x4 Zn 1-x4GeO4, LiM 3 2(PO4)3, 2 contains one or more elements selected from Ba and Sr, and N 2 contains one or more elements selected from Al and Zr, and M 3 is one or more elements of Zr, Ti, Ge, and Hf, and 0.04≦x3≦0.167, 0≦a3≦1, 0≦z3≦1, and −0.3≦x4≦0.8.

[0371] In some embodiments, the shell of the second positive electrode active material includes a coating layer, and optionally, the coating layer includes one or more selected from a phosphate, a pyrophosphate, and an oxide.

[0372] In some embodiments, the shell of the second positive electrode active material includes a first coating layer coating the core and a second coating layer coating the first coating layer, and optionally, the first coating layer and the second coating layer each independently include one or more selected from a phosphate, a pyrophosphate, and an oxide.

[0373] Optionally, 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. Optionally, the oxide in the first coating layer is an oxide of one or more elements selected from Al, Zr, Mg, Ti, Co, Y, Ba, and Cd. Optionally, the oxide in the second coating layer is an oxide of one or more elements selected from B, Sn, S, and P.

[0374] In some embodiments, the coating amount of the shell of the second positive electrode active material is 0.005 wt % to 1 wt %, and optionally 0.01 wt % to 0.5 wt %, relative to the weight of the core.

[0375] In some embodiments, the shell of the second positive electrode active material has a thickness of 2 nm to 200 nm, and optionally 5 nm to 50 nm.

[0376] The first positive electrode active material and the second positive electrode active material can be manufactured by a sintering method. The shells of the first positive electrode active material and the second positive electrode active material can be manufactured by a liquid phase coating method.

[0377] [Positive electrode sheet] The positive electrode sheet provided by the embodiments of the present application includes a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector, and the positive electrode film layer includes a positive electrode active material including the positive electrode active material composition. The positive electrode current collector has two surfaces facing each other in its own thickness direction, and the positive electrode film layer is provided on one or both of the two opposing surfaces of the positive electrode current collector.

[0378] In some embodiments, based on the total weight of the positive electrode film layer, the content of the positive electrode active material composition in the positive electrode film layer is 50 to 99.5% by weight, optionally 90 to 99.5% by weight, 95 to 99.5% by weight.

[0379] In some embodiments, the positive electrode film layer further includes a third positive electrode active material, and the third positive electrode active material includes one or more of a lithium peroxide material, a lithium iron phosphate material, a spinel structured lithium manganate material, and their respective modified compounds, and the modification method includes doping and / or surface coating modification.

[0380] In some embodiments, the third positive electrode active material includes a compound represented by formula (III), Li 1+p1 A 2 q1 B 2 r1 O s1 , (III) 0.05 ≦ p1 < 0.2, 0.10 < q1 ≦ 0.95, 0 ≦ r1 ≦ 0.2, and 2 ≦ s1 < 3, A 2 includes one or more elements selected from Co, Ni, Mn, and Al, and B 2 includes one or more elements selected from Mg, Ti, Cr, Zr, Nb, Fe, Mo, Cu, Sb, V, P, and F.

[0381] In some embodiments, the third positive electrode active material is Li 1.11 Ni 0.22 Mn 0.58 Ti 0.02 O2, Li 1.2 Mn 0.6 Ni 0.2 O2, Li 1.16 Ni 0.22 Mn 0.6 O2, Li 1.16 Ni 0.13 Co 0.06 Mn 0.59 O2 and Li 1.1 Ni 0.2 Co 0.2 Mn 0.48 O2.

[0382] In some embodiments, the third active cathode material comprises a core and a shell coating the core, wherein the core comprises a compound represented by Formula (III), and the shell comprises one or more coating layers, each coating layer having ionic and / or electronic conductivity.

[0383] In some embodiments, the one or more coating layers each independently comprise one or more selected from the group consisting of a phosphate, a pyrophosphate, a solid electrolyte, a conductive polymer, and a material capable of reversibly inserting and extracting lithium ions.

[0384] The phosphate, pyrophosphate, and solid electrolyte can improve the ion transport performance of the third positive electrode active material.

[0385] Conductive polymers can form uniform thin films with high electronic conductivity, improving charge transfer at the cathode / electrolyte interface. At the same time, they can accommodate volume changes in the material, thereby reducing crack formation.

[0386] The material capable of reversibly inserting and extracting lithium ions may include different types of positive electrode active materials.

[0387] In some embodiments, the amount of the shell covering the compound represented by formula (III) is 0.1 wt % to 5 wt %, and optionally 0.5 wt % to 2 wt %, based on the weight of the core.

[0388] In some embodiments, the thickness of the shell covering the compound represented by formula (III) is from 2 nm to 200 nm, and optionally from 5 nm to 50 nm.

[0389] In some embodiments, the third positive electrode active material comprises a compound represented by Formula (IV): Li a2 A 3 x2 B 3 y2 P 1-z2 C 3 z2 O 4-n2 D 3 n2 , (IV) A 3 comprises one or more elements selected from groups IA, IIA, IIIA, IIB, VB and VIB, and B 3 comprises one or more elements selected from Groups IA, IIA, IIIA, IVA, VA, IIB, IVB, VB, VIB and VIII, and C 3 contains one or more elements selected from groups IIIA, IVA, VA and VIA, and D 3 comprises one or more elements selected from Group VIA and Group VIIA, a2 is selected from the range of 0.85 to 1.15, x2 is selected from the range of 0 to 0.1, y2 is selected from the range of 0.001 to 0.999, z2 is selected from the range of 0 to 0.5, and n2 is selected from the range of 0 to 0.5.

[0390] In some embodiments, A 3 comprises 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 optionally comprises one or more elements selected from Zn, Al, Na, K, Mg, Nb, Mo and W; and / or B 3 comprises one or more elements selected from Rb, Cs, Be, Ca, Sr, Ba, In, Pb, Bi, Cd, Hf, Ta, Cr, Ru, Rh, Pd, Os, Ir, Pt, Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb and Ge, optionally comprising 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 3 contains one or more elements selected from B (boron), S, Si and N, and / or D 3 contains one or more elements selected from S, F, Cl and Br, and / or a2 is selected from the range of 0.9 to 1.1, optionally selected from the range of 0.97 to 1.01, and / or x2 is selected from the range of 0.001 to 0.005, and / or y2 is selected from the range of 0.001 to 0.5, optionally selected from the range of 0.01 to 0.5, optionally selected from the range of 0.25 to 0.5, and / or z2 is selected from the range of 0.001 to 0.5, optionally selected from the range of 0.001 to 0.1, further optionally selected from the range of 0.001 to 0.005, and / or n2 is selected from the range of 0 to 0.1, and optionally from the range of 0.001 to 0.005.

[0391] In some embodiments, the third positive electrode active material includes a core and a shell coating the core, the core includes a compound represented by Formula (IV), and the shell is the same as the shell coating the compound represented by Formula (I), and the description thereof is omitted here.

[0392] In some embodiments, the third positive electrode active material comprises a compound represented by Formula (V): LiMn t1 A 4 2-t1 O4, (V) t1 is selected from the range of 0 to 2, and A 4 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.

[0393] In some embodiments, the third active cathode material comprises a core and a shell coating the core, wherein the core comprises a compound represented by Formula (V), and the shell comprises one or more coating layers, each coating layer having ionic and / or electronic conductivity.

[0394] In some embodiments, the one or more coating layers each independently comprise one or more selected from the group consisting of a phosphate, a pyrophosphate, a solid electrolyte, a conductive polymer, and a material capable of reversibly inserting and extracting lithium ions.

[0395] The phosphate, pyrophosphate, and solid electrolyte can improve the ion transport performance of the third positive electrode active material.

[0396] Conductive polymers can form uniform thin films with high electronic conductivity, improving charge transfer at the cathode / electrolyte interface. At the same time, they can accommodate volume changes in the material, thereby reducing crack formation.

[0397] The material capable of reversibly inserting and extracting lithium ions may include different types of positive electrode active materials.

[0398] In some embodiments, the amount of the shell covering the compound represented by formula (V) is 0.1 wt % to 5 wt %, and optionally 0.5 wt % to 2 wt %, based on the weight of the core.

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

[0400] The third positive electrode active material can be produced by a sintering method, and the shell can be produced by a liquid phase coating method.

[0401] In some embodiments, the positive electrode film layer may include a positive electrode binder.

[0402] In some embodiments, the positive electrode binder may include vinylidene fluoride homopolymer and / or copolymer. Optionally, the comonomer may include one or more of tetrafluoroethylene, hexafluoropropylene, and propylene. Optionally, the weight percentage of the comonomer is ≦1%. For example, the positive electrode binder may include one or more of polyvinylidene fluoride (PVDF), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, and vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer.

[0403] In some embodiments, the positive electrode binder may include one or more of polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylic resin.

[0404] In some embodiments, the weight average molecular weight of the positive electrode binder may be 300,000 to 2,000,000.

[0405] In some embodiments, the positive electrode film layer may include a positive electrode conductive agent, for example, one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers, but examples of the present application are not limited thereto.

[0406] In some embodiments, the positive electrode film layer may further include a functional additive, which may include one or more of a dispersant, a plasticizer, a pore-forming agent, a moisture scavenging additive, an acid scavenging additive, and a lithium replenisher.

[0407] The dispersant may include an abc block copolymer, wherein the a block includes polyvinylpyrrolidone, the b block includes polyacrylic acid, and the c block includes one or more of a polytetrahydrofuran chain, a polyethylene oxide chain, a polyethylene glycol chain, a polypropylene glycol chain, and a polyoxypropylene triol chain. Optionally, the ratio of the average degree of polymerization of the a block to the b block is greater than 10:1. Optionally, the ratio of the average degree of polymerization of the a block to the c block is (0.1 to 10:1). Optionally, the weight-average molecular weight of the dispersant is 2,000 to 100,000.

[0408] The plasticizer may include one or more of a strong solvent type (PP-SS) plasticizer, a low temperature resistant type (PP-LT) plasticizer, a low volatility (PP-LV) plasticizer, a low diffusivity (SP-LD) plasticizer, a heat stabilized type (SP-Stab) plasticizer, and a flame retardant (SP-FR) plasticizer.

[0409] Strong solvent type (PP-SS) plasticizers can provide strong plasticizing properties and may include, for example, phthalates, non-phthalates (eg, benzoates, tricresyl phosphate, etc.).

[0410] Low temperature resistant (PP-LT) plasticizers can provide good low temperature resistance and may include, for example, aliphatic dibasic acid esters.

[0411] Low volatility (PP-LV) plasticizers have low volatility and may include, for example, trimellitates and polyesters.

[0412] Low diffusivity (SP-LD) plasticizers have low diffusivity and may include, for example, polyesters.

[0413] The heat-stabilized (SP-Stab) plasticizer has a heat stabilizing function and may include, for example, an epoxy compound.

[0414] Flame retardant (SP-FR) plasticizers have flame retardant functionality and may include, for example, phosphate esters and halogenated hydrocarbons.

[0415] The lithium replenisher may include one or more of lithium excess oxides (e.g., Li2NiO2, Li5FeO4, etc.), nanocomposites, and binary lithium compounds, and optionally, the number of Li atoms in the molecular formula of the lithium replenisher is ≧1.5.

[0416] In some embodiments, the positive electrode current collector can be a metal foil or a composite current collector. The metal foil can be, for example, aluminum foil. The composite current collector can include a polymer base layer and a metal layer formed on at least one surface of the polymer base layer. The composite current collector can be formed by forming a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, or silver alloy) on a polymer substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), or polyethylene (PE)).

[0417] The positive electrode sheet does not exclude additional functional layers other than the positive electrode film layer. For example, in some embodiments, the positive electrode sheet may further include a functional coating layer, which may be located between the positive electrode current collector and the positive electrode film layer and / or on the surface of the positive electrode film layer away from the positive electrode current collector. For example, the functional coating layer may include one or more of conductive carbon, a moisture scavenging additive, an acid scavenging additive, and a lithium supplement, although the embodiments of the present application are not limited thereto. In some embodiments, the thickness of the functional coating layer may be 0.1 μm to 10 μm.

[0418] The positive electrode sheet can be produced by the following method: Components for producing the positive electrode sheet, such as a positive electrode active material composition, a conductive agent, a binder, and any other components, are dispersed in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode paste, which is then applied to a positive electrode current collector, followed by processes such as drying and cold pressing, to obtain a positive electrode sheet.

[0419] [Negative electrode sheet] In some embodiments, the negative electrode sheet includes a negative electrode current collector and a negative electrode film layer including a negative electrode active material and disposed on at least one surface of the negative electrode current collector. For example, the negative electrode current collector has two opposing surfaces in its thickness direction, and the negative electrode film layer is disposed on either or both of the two opposing surfaces of the negative electrode current collector.

[0420] In some embodiments, the negative electrode current collector can be a metal foil or a composite current collector. The metal foil can be, for example, a copper foil. The composite current collector can include a polymer substrate layer and a metal layer formed on at least one surface of the polymer substrate. The composite current collector can be formed by forming a metal material (e.g., copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, silver alloy, etc.) on a polymer substrate (e.g., a substrate such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), or polyethylene (PE)).

[0421] In some embodiments, the thickness of the negative electrode current collector may be 3 μm to 20 μm.

[0422] In some embodiments, the negative electrode active material may include one or more of a carbon-based material, a silicon-based material, a tin-based material, and lithium titanate. The carbon-based material may include one or more of graphite (e.g., artificial graphite, natural graphite, etc.), soft carbon, and hard carbon. The silicon-based material may include one or more of elemental silicon, silicon oxide, silicon carbon composite, silicon nitrogen composite, and silicon alloy. The tin-based material may include one or more of elemental tin, tin oxide, and tin alloy.

[0423] In some embodiments, the negative electrode active material may include a carbon-based material or a combination of a carbon-based material and a silicon-based material.

[0424] In some embodiments, the negative electrode active material may include a carbon-based material, and the carbon-based material may include graphite or a combination of graphite and hard carbon. Optionally, the graphite may have a porous structure. Optionally, the graphite may have a specific capacity of 340 mAh / g or greater.

[0425] In some embodiments, the negative electrode active material comprises a combination of a carbon-based material and a silicon-based material, the carbon-based material comprises graphite or a combination of graphite and hard carbon, and the content of the silicon element in the negative electrode active material is greater than 0 and less than or equal to 30 wt % based on the total weight of the negative electrode active material.

[0426] In some embodiments, the negative electrode film layer may include a negative electrode binder. For example, the negative electrode binder may include one or more of styrene butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS), although examples of the present application are not limited thereto.

[0427] In some embodiments, the negative electrode film layer may further include a negative electrode conductive agent, for example, superconducting carbon, conductive graphite, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers, but the embodiments of the present application are not limited thereto.

[0428] In some embodiments, the negative electrode film layer may further include other additives, such as a thickener (eg, sodium carboxymethyl cellulose (CMC)).

[0429] In some embodiments, the porosity of the negative electrode film layer is between 20% and 50%.

[0430] The negative electrode sheet does not exclude additional functional layers other than the negative electrode film layer. In some embodiments, the negative electrode sheet may further include a functional coating layer, which may be located between the negative electrode current collector and the negative electrode film layer and / or on the surface of the negative electrode film layer away from the negative electrode current collector. Optionally, the functional coating layer may include carbon.

[0431] In some embodiments, the negative electrode film layer may further include a lithium supplement material. Optionally, the lithium supplement material may include one or more of lithium foil, lithium tape, lithium powder, and a lithium pre-doping reagent. Optionally, the lithium pre-doping reagent may include one or more of Li-aromatic hydrocarbons, complexes of Li-aromatic hydrocarbons and ether-based solvents, and optionally, one or more of lithium naphthalene and lithium biphenyl-dimethyl ether (DME).

[0432] In some embodiments, the negative electrode sheet may include a negative electrode current collector and a first negative electrode film layer and a second negative electrode film layer disposed on two surfaces of the negative electrode current collector, respectively. The first negative electrode film layer and the second negative electrode film layer may have the same or different compositions, and the first negative electrode film layer and the second negative electrode film layer may have the same or different thicknesses.

[0433] In some embodiments, the thickness ratio of the first negative electrode film layer to the second negative electrode film layer is 5:95 to 95:5.

[0434] The negative electrode sheet can be manufactured by the following method: Components for manufacturing the negative electrode sheet, such as a negative electrode active material, a negative electrode conductive agent, a negative electrode binder, and any other components, are dispersed in a solvent (e.g., deionized water) to form a negative electrode paste, which is then applied to a negative electrode current collector, followed by processes such as drying and cold pressing, to obtain a negative electrode sheet.

[0435] In some embodiments, the negative electrode sheet may not include a negative electrode active material capable of inserting and extracting lithium ions. For example, the negative electrode sheet may include a lithium sheet or a lithium alloy sheet, or may include a mesh-like or foam-like three-dimensional skeletal layer, or may include a negative electrode current collector and a lithium-containing layer disposed on at least one surface of the negative electrode current collector.

[0436] [Electrolyte] The electrolyte serves to conduct ions between the positive electrode sheet and the negative electrode sheet. The present application does not particularly limit the type of electrolyte, and it can be selected as needed. For example, the electrolyte may include one or more of a liquid electrolyte (or electrolytic solution), an all-solid electrolyte, and a gel electrolyte. In some embodiments, the electrolyte is liquid and includes a lithium salt, a non-aqueous solvent in which the lithium salt is dissolved, and optional additives.

[0437] In some embodiments, the lithium salt may include one or more selected from LiPF6, LiBF4, LiN(SO2F)2, LiN(CF3SO2)2, LiClO4, LiAsF6, LiB(C2O4)2, LiBF2C2O4, and LiPO2F2.

[0438] In some embodiments, the concentration of the lithium salt may be 0.5 to 1.5 mol / L.

[0439] In some embodiments, the non-aqueous solvent may include one or more selected from propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl formate, ethyl acetate, methyl butyrate, ethyl butyrate, methyl propionate, ethyl propionate, propyl propionate, methyl acrylate, ethylene sulfite, propylene sulfite, dimethyl sulfite, diethyl sulfite, acid anhydride, N-methylpyrrolidone, acetonitrile, sulfolane, dimethyl sulfoxide, methyl sulfide, γ-butyrolactone, and tetrahydrofuran.

[0440] In some embodiments, the additive may include one or more of an anode film-forming additive, a cathode film-forming additive, an additive that improves the overcharge characteristics of the battery, an additive that improves the high temperature performance of the battery, an additive that improves the low temperature power performance of the battery, a moisture scavenging additive, an acid scavenging additive, an additive capable of complexing ions of a transition metal, etc. By way of example, the additive may include: One or more selected from cyclic carbonate compounds having a carbon-carbon double bond, halogen-substituted cyclic carbonate compounds, nitrile and polynitrile compounds, phosphazene compounds, aromatic hydrocarbons and halogenated aromatic hydrocarbon compounds, isocyanate compounds, acid anhydride compounds, sulfate ester compounds, sulfite ester compounds, sulfonate ester compounds, disulfonate ester compounds, borate ester compounds, phosphate ester compounds, amide compounds, carbodiimide compounds, crown ether and azacrown ether compounds, and derivatives thereof and optionally one or more of vinylene carbonate (VC), 1,2,3-tris(2-cyanoethoxy)propane (TCP), 1-aza-12-crown 4-ether (A12C4), N,N'-dicyclohexylcarbodiimide, N,N'-diisopropylcarbodiimide, N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, tris(hexafluoroisopropyl)borate, tris(2,2,3,3-tetrafluoropropyl)borate, tris(pentafluorophenyl)borate.

[0441] In some embodiments, the content of the additive may be 10% or less based on the total weight of the electrolyte.

[0442] [Separator] In some embodiments, the battery cell further includes a separator. The present application does not particularly limit the type of separator, and any known porous structure separator with good chemical stability and mechanical stability can be selected.

[0443] In some embodiments, the separator includes a porous substrate. The material of the porous substrate may include 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, and is not particularly limited. When the porous substrate is a multi-layer composite film, the materials of each layer may be the same or different, and are not particularly limited.

[0444] In some embodiments, the separator may further include a coating layer disposed on at least one surface of the porous substrate. Optionally, the coating layer includes one or more of inorganic refractory particles, organic refractory particles.

[0445] In some embodiments, the porosity of the separator is between 10% and 40%.

[0446] In some embodiments, the thickness of the separator may be between 3 μm and 20 μm.

[0447] The present application further provides a power consuming device including at least one of the battery cells, battery modules, or battery packs according to the present application. The battery cells, battery modules, or battery packs may be used as a power source for the power consuming device or as an energy storage element for the power consuming device. The power consuming 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.), trains, ships, satellites, energy storage systems, etc.

[0448] The power consumption device can select a battery cell, a battery module, or a battery pack depending on its usage conditions.

[0449] 6 shows an example of a power consuming device, such as a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the high power and high energy density requirements of the power consuming device, a battery pack or a battery module can be used.

[0450] Other examples of power consuming devices include mobile phones, tablet computers, laptop computers, etc. Such power consuming devices are generally required to be lightweight and thin, and can use battery cells as a power source.

[0451] Example The following examples more specifically describe the contents disclosed herein, but since various modifications and variations within the scope of the contents disclosed herein will be apparent to those skilled in the art, these examples are for illustrative purposes only. Unless otherwise specified, all parts, percentages, and ratios reported in the following examples are by weight, and all reagents used in the examples are commercially available or synthesized according to conventional methods and can be used directly without treatment, and all equipment used in the examples is commercially available.

[0452] The batteries of Examples 1 to 26 and Comparative Example 3 were all manufactured by the following method.

[0453] Positive electrode sheet manufacturing The first and second positive electrode active materials shown in Tables 1 and 2, the conductive agent acetylene black, and the binder polyvinylidene fluoride (PVDF) were thoroughly mixed in a mass ratio of 96:2:2 in an appropriate amount of NMP solvent to form a uniform positive electrode paste. The positive electrode paste was uniformly applied to the two surfaces of aluminum foil positive electrode current collectors, dried, and cold-pressed to obtain a positive electrode sheet.

[0454] Manufacture of negative electrode sheets The negative electrode active material graphite, binder styrene butadiene rubber (SBR), thickener sodium carboxymethyl cellulose (CMC-Na), and conductive agent carbon black (Super P) are mixed in a mass ratio of 96.2:1.8:1.2:0.8 in an appropriate amount of deionized water as a solvent and stirred thoroughly to form a uniform negative electrode paste. The negative electrode paste is then evenly applied to the copper foil surface of the negative electrode current collector, dried, and cold-pressed to obtain a negative electrode sheet.

[0455] Electrolyte production Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) are mixed in a volume ratio of 1:1:1 to obtain an organic solvent, and then thoroughly dried LiPF6 is dissolved in the organic solvent to prepare an electrolyte solution with a concentration of 1 mol / L.

[0456] Separator manufacturing A porous polyethylene film is used as the separator.

[0457] Battery manufacturing The positive electrode sheet, separator, and negative electrode sheet are laminated and wound in this order to obtain an electrode assembly, which is then placed in a housing and dried, followed by the injection of an electrolyte solution, vacuum sealing, standing, chemical formation, shaping, and other processes to obtain a battery.

[0458] Comparative Example 1 The manufacturing method of the battery was the same as that of Example 1, except for the manufacturing method of the positive electrode sheet.

[0459] The second positive electrode active material shown in Table 1, the conductive agent acetylene black, and the binder polyvinylidene fluoride (PVDF) are thoroughly mixed and stirred in an appropriate amount of NMP solvent in a mass ratio of 96:2:2 to form a uniform positive electrode paste. The positive electrode paste is uniformly applied to the two surfaces of the aluminum foil positive electrode current collector, dried, and cold-pressed to obtain a positive electrode sheet.

[0460] Comparative Example 2 The manufacturing method of the battery was the same as that of Example 1, except for the manufacturing method of the positive electrode sheet.

[0461] The first positive electrode active material shown in Table 1, the conductive agent acetylene black, and the binder polyvinylidene fluoride (PVDF) are thoroughly mixed and stirred in an appropriate amount of NMP solvent in a mass ratio of 96:2:2 to form a uniform positive electrode paste. The positive electrode paste is uniformly applied to the two surfaces of aluminum foil positive electrode current collectors, dried, and cold-pressed to obtain a positive electrode sheet.

[0462] In Tables 1 and 2, NCM523 is LiNi 0.5 Co 0.2 Mn 0.3 O2, and LMFP is carbon-coated LiMn 0.7 Fe 0.3 It is PO4.

[0463] The NCM523 and LMFP in each example and comparative example were obtained by purchasing commercially available products, sieving the commercially available materials using an appropriate sieve, and then mixing them in a predetermined ratio. Alternatively, commercially available materials were ball milled to an appropriate size, sieved using an appropriate sieve, and then mixed in a predetermined ratio. Alternatively, the NCM523 and LMFP were obtained by using a sintering method, adjusting sintering process parameters (e.g., sintering temperature, sintering time, sintering atmosphere, etc.) and grinding parameters (e.g., grinding speed, grinding time, etc.), and then sieving using an appropriate sieve. Alternatively, the NCM523 and LMFP were obtained by mixing materials of different sizes produced by a sintering method in a predetermined ratio.

[0464] w a represents the weight content of the first positive electrode active material relative to the total weight of the positive electrode active material composition. b represents the weight content of the second positive electrode active material relative to the total weight of the positive electrode active material composition.

[0465] P1 is the green density of the first positive electrode active material at 30,000 N. P2 is the green density of the second positive electrode active material at 30,000 N.

[0466] PD represents the compressed density of the positive electrode film layer.

[0467] Positive electrode sheet compression density efficiency = PD / [(P1 × W a )+(P2×W b )]. (P1×W a )+(P2×W b ) represents the theoretical compressed density of the positive electrode active material composition.

[0468] y is the molar amount of Fe element in LMFP, i.e., 0.3.

[0469] V B is the potential plateau of the Fe element in the LMFP, and its unit is V (volts).

[0470] In the particle size distribution curve of the positive electrode active material composition, the volume distribution peak having the maximum peak intensity is defined as the first peak, and the volume-based particle size distribution corresponding to the maximum peak intensity position of the first peak is defined as Dv1, and the volume distribution peak having the next maximum peak intensity is defined as the second peak, and the volume-based particle size distribution corresponding to the maximum peak intensity position of the second peak is defined as Dv2.

[0471] FIG. 7 is a particle size distribution curve of the positive electrode active material composition of Example 11. As shown in FIG. 7, in the particle size distribution curve of the positive electrode active material composition, the peak on the left side is the second peak (i.e., the volume distribution peak having the next maximum peak intensity), and the peak on the right side is the first peak (i.e., the volume distribution peak having the maximum peak intensity).

[0472] Each of the above parameters can be measured according to the test methods described above.

[0473] In Table 1, the first positive electrode active material is mainly single-crystal, and the proportion thereof is 90% or more. The second positive electrode active materials of Examples 1 to 11 are mainly polycrystalline, and the proportion thereof is 90% or more. The second positive electrode active materials of Examples 12 to 16 are mainly single-crystal, and the proportion thereof is 90% or more.

[0474] In Table 2, the first positive electrode active material is mainly polycrystalline and accounts for 90% or more. The second positive electrode active materials of Examples 17 to 21 are mainly single-crystalline and account for 90% or more. The second positive electrode active materials of Examples 22 to 26 are mainly polycrystalline and account for 90% or more.

[0475] Exam section At 25°C, the battery was charged at a constant current of 1C to 4.3V, then at a constant voltage of 0.05C, at which point the battery was fully charged. The charge capacity at this point was recorded, i.e., the first-cycle charge capacity. After allowing the battery to rest for 5 minutes, it was discharged at a constant current of 1C to 2.8V, which constitutes one charge-discharge cycle. The discharge capacity at this point was recorded, i.e., the first-cycle discharge capacity. The battery was subjected to a charge-discharge cycle test using the above method, and the discharge capacity after each cycle was recorded until the battery's discharge capacity decayed to 80% of the first-cycle discharge capacity. The number of cycles at this point characterizes the battery's cycle characteristics. The higher the number of cycles, the longer the service life.

[0476] As can be seen from the test results in Tables 1 and 2, when the particle size distribution curve of a positive electrode active material composition satisfies 0<|Dv1-Dv2| / Dv1≦50, a positive electrode sheet using the positive electrode active material composition can have both high compaction density and high compaction density efficiency, thereby enabling the secondary battery to have a high energy density and a long service life.

[0477] The manufacturing method of the batteries of Examples 27 to 31 was the same as that of Example 4, except that the type of the first positive electrode active material was different, as specifically shown in Table 3.

[0478] The first positive electrode active materials of Examples 27 to 31 are 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 selecting an appropriate sieve for sieving, or by mixing materials with different particle sizes produced by a sintering method in a predetermined ratio.

[0479] As can be seen from the test results in Table 3, by doping a specific element into the Mn site of LiMnPO4 and into the Li site, P site, and / or O site, and by selectively doping a specific element into the Mn site and P site of LiMnPO4, and further selectively doping a specific element into the Li site, Mn site, P site, and O site of LiMnPO4, the compression density of the positive electrode sheet can be further improved, and the energy density and cycle characteristics of the battery can be improved.

[0480] It should be noted that the present application is not limited to the above-described embodiments. The above-described embodiments are merely examples, and any embodiment that has substantially the same configuration as the technical idea and achieves the same effects within the scope of the technical solution of the present application is included within the technical scope of the present application. Furthermore, various modifications conceivable by those skilled in the art to the embodiments, as well as other forms constructed by combining some of the components of the embodiments, are also included within the scope of the present application, as long as they do not deviate from the gist of the present application.

[0481] [Table 1-1] [Table 1-2]

[0482] [Table 2]

[0483] [Table 3]

Claims

1. A 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 that of the first positive electrode active material, The first positive electrode active material contains a phosphate, and the particle size distribution curve of the positive electrode active material composition has at least two volume distribution peaks, where the volume distribution peak with the maximum peak intensity is defined as a first peak, and the volume-based particle size distribution corresponding to the position of the maximum peak intensity of the first peak is defined as Dv1, and the volume distribution peak with the next maximum peak intensity is defined as a second peak, and the volume-based particle size distribution corresponding to the position of the maximum peak intensity of the second peak is defined as Dv2, and the relationship is 0<|Dv1-Dv2| / Dv1≦50.

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

3. The first positive electrode active material has a volumetric particle size distribution Dv50 of 0.25 μm to 3.5 μm, and the particle size distribution curve of the positive electrode active material composition is 0.1≦|Dv1−Dv2| / Dv1≦50, and optionally 0.46≦|Dv1−Dv2| / Dv1≦39.6; and / or 0.3 μm≦Dv1≦17.8 μm, optionally 0.35 μm≦Dv1≦12.1 μm, and / or 3. The positive electrode active material composition according to claim 1, wherein 0.3 μm≦Dv2≦17.8 μm, and optionally 0.46 μm≦Dv2≦14.2 μm, is satisfied.

4. The first positive electrode active material has a volume-based particle size distribution Dv50 of 3.5 μm to 12.5 μm, and the particle size distribution curve of the positive electrode active material composition is 0.1≦|Dv1−Dv2| / Dv1≦6.0, and optionally 0.34≦|Dv1−Dv2| / Dv1≦3.8; and / or 2.0 μm≦Dv1≦12.5 μm, optionally 3.0 μm≦Dv1≦12.3 μm, and / or 3. The positive electrode active material composition according to claim 1, wherein Dv2 satisfies 2.0 μm≦Dv2≦15.0 μm, and optionally 3.4 μm≦Dv2≦14.3 μm.

5. the first positive electrode active material has a morphology of one or more of a single crystal and a polycrystal, and the second positive electrode active material has a morphology of one or more of a single crystal and a polycrystal; Alternatively, the volume-based particle size distribution Dv50 of the first positive electrode active material in single crystal form is 0.25 μm to 3.5 μm, and optionally 0.35 μm to 2.5 μm; and / or Alternatively, the volume-based particle size distribution Dv10 of the first positive electrode active material in single crystal form is 0.05 μm to 1.5 μm, and optionally 0.1 μm to 1.0 μm; and / or Alternatively, the volume-based particle size distribution Dv50 of the first positive electrode active material in polycrystalline form is 3.5 μm to 12.5 μm, and optionally 3.8 μm to 10.5 μm; and / or Alternatively, the volume-based particle size distribution Dv10 of the first positive electrode active material in polycrystalline form is 0.1 μm to 5.0 μm, and optionally 0.5 μm to 4.5 μm; and / or Alternatively, the volume-based particle size distribution Dv50 of the second positive electrode active material in single crystal form is 2.5 μm to 16.5 μm, and optionally 3.0 μm to 8.5 μm; and / or Alternatively, the volume-based particle size distribution Dv10 of the second positive electrode active material in single crystal form is 0.3 μm to 8 μm, and optionally 1.0 μm to 3.5 μm; and / or Alternatively, the volume-based particle size distribution Dv50 of the second positive electrode active material in polycrystalline form is 2.5 μm to 16.5 μm, and more preferably 3.0 μm to 15.5 μm; Optionally, the volume-based particle size distribution Dv10 of the second positive electrode active material in polycrystalline form is 0.5 μm to 12 μm, and optionally 1.0 μm to 8.5 μm. The positive electrode active material composition of any one of claims 1 to 4.

6. The weight content of the first positive electrode active material relative to the total weight of the positive electrode active material composition is w ａ and the weight content of the second positive electrode active material is w ｂ In this case, w ａ is selected from the range of 0.5% to 99.5%, optionally selected from the range of 2% to 95%, and / or w ｂ The positive electrode active material composition according to any one of claims 1 to 5, wherein is selected from the range of 0.5% to 99.5%, and optionally selected from the range of 5% to 98%.

7. The green density P of the first positive electrode active material at 30,000 N １ is 1.89 g / cm ３ or more, and optionally 1.95 g / cm ３ or more, and more preferably 1.98 g / cm ３ or more, and more preferably 2.0 g / cm ３ or more, and more preferably 2.2 g / cm ３ or more, and more preferably 2.2 g / cm ３ or more and 2.8 g / cm ３ or less than 2.2 g / cm ３ or more and 2.65 g / cm ３ and / or The green density P of the second positive electrode active material at 30,000 N ２ is 2.90 g / cm ３ or more, and optionally 3.1 g / cm ３ or more, and more preferably 3.3 g / cm ３ or more; and / or The BET specific surface area of ​​the second positive electrode active material is 1.73 m ２ / g or less, and optionally 1.5m ２ / g or less, and more preferably 0.28 m ２ / g to 1.5m ２ The positive electrode active material composition according to any one of claims 1 to 6, wherein the SiO2 content is 1 / g.

8. the first positive electrode active material comprises a compound represented by formula (I), Li ａ A ｘ Mn １－ｙ B ｙ P １－ｚ C ｚ O ４－ｎ D ｎ (I) 8. The positive electrode active material composition according to claim 1, wherein A comprises one or more elements selected from Group IA, Group IIA, Group IIIA, Group IIB, Group VB, and Group VIB; B comprises one or more elements selected from Group IA, Group IIA, Group IIIA, Group IVA, Group VA, Group IIB, Group IVB, Group VB, Group VIB, and Group VIII; C comprises one or more elements selected from Group IIIA, Group IVA, Group VA, and Group VIA; D comprises one or more elements selected from Group VIA and Group VIIA; a is selected from the range of 0.85 to 1.15; x is selected from the range of 0 to 0.1; y is selected from the range of 0.001 to 0.999; z is selected from the range of 0 to 0.5; and n is selected from the range of 0 to 0.

5.

9. A comprises 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 comprises one or more elements selected from Zn, Al, Na, K, Mg, Nb, Mo and W; and / or B comprises 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 optionally comprises 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 includes one or more elements selected from B (boron), S, Si and N, and / or 9. The positive electrode active material composition of claim 8, wherein D comprises one or more elements selected from S, F, Cl, and Br.

10. 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 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, further optionally comprising at least two elements selected from Fe, Ti, V, Ni, Co and Mg, further optionally comprising at least two elements selected from Fe, Ti, V, Co and Mg, further optionally comprising 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, and is optionally S, and / or 10. The positive electrode active material composition according to claim 8, wherein D comprises any one element selected from S, F, Cl and Br, and optionally is F.

11. a is selected from the range of 0.9 to 1.1, optionally selected 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 selected from the range of 0.01 to 0.5, optionally selected from the range of 0.25 to 0.5; and / or z is selected from the range of 0.001 to 0.5, optionally selected from the range of 0.001 to 0.1, further optionally selected from the range of 0.001 to 0.005; and / or 11. The positive electrode active material composition according to claim 8, wherein n is selected from the range of 0 to 0.1, and optionally selected from the range of 0.001 to 0.

005.

12. 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 12. The positive electrode active material composition according to claim 8, wherein 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.

13. y:z is selected from the range of 0.002 to 999, optionally selected from the range of 0.025 to 999 or the range of 0.002 to 500, further optionally selected from the range of 0.2 to 600. The positive electrode active material composition according to any one of claims 8 to 12.

14. The positive electrode active material composition according to any one of claims 8 to 13, wherein z:n is selected from the range of 0.002 to 500, optionally selected from the range of 0.2 to 100, and further optionally selected from the range of 0.2 to 50.

15. 15. The positive electrode active material composition according to claim 8, 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 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.

16. 15. The positive electrode active material composition according to claim 8, 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, 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.

17. (1-y): y is in the range of 0.1 to 999, optionally in the range of 0.1 to 10 or in the range of 0.67 to 999, further optionally in the range of 1 to 10, further optionally in the range of 1 to 4, further optionally 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 further optionally in the range of 190 to 998. The positive electrode active material composition according to any one of claims 8 to 16.

18. The positive electrode active material composition of any one of claims 8 to 17, wherein z:(1-z) is from 1:9 to 1:999, and optionally from 1:499 to 1:

249.

19. the first positive electrode active material includes a core and a shell covering the core, The core comprises a compound represented by formula (I), The positive electrode active material composition according to any one of claims 8 to 18, wherein the shell comprises one or more coating layers, each coating layer having ionic conductivity and / or electronic conductivity.

20. 20. The cathode active material composition of claim 19, wherein the one or more coating layers each independently comprise one or more selected from pyrophosphates, phosphates, carbon, doped carbon, oxides, borides, and polymers.

21. the shell comprises one coating layer; 21. The cathode active material composition of claim 19 or 20, wherein the coating layer optionally comprises one or more selected from pyrophosphates, phosphates, carbon, doped carbon, oxides, borides, and polymers.

22. the shell includes a first coating layer that coats the core and a second coating layer that coats the first coating layer, Optionally, the first coating layer and the second coating layer each independently comprise one or more selected from pyrophosphate, phosphate, carbon, doped carbon, oxide, boride, and polymer; 21. The positive electrode active material composition of claim 19, wherein the first coating layer further optionally comprises one or more selected from pyrophosphates, phosphates, oxides, and borides, and the second coating layer further optionally comprises one or more selected from carbon and doped carbon.

23. the shell includes a first coating layer that coats the core, a second coating layer that coats the first coating layer, and a third coating layer that coats the second coating layer; Optionally, 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; 21. The positive electrode active material composition of claim 19 or 20, further optionally, wherein the first coating layer comprises a pyrophosphate, the second coating layer comprises one or more selected from a phosphate, an oxide, and a boride, and the third coating layer comprises one or more selected from carbon and doped carbon.

24. The pyrophosphate salt is M ｂ (P ２ O ７ ) ｃ and / or The phosphate is X ｍ (P.O. ４ ) ｑ and / or the doping elements in the doped carbon include 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 derivatives thereof, and 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; The positive electrode active material composition according to any one of claims 20 to 23, wherein w is selected from the range of 1 to 2.

25. M, X and Z each independently comprise one or more elements selected from Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb, Mn and Al; and / or the doping element in the doped carbon comprises one or more selected from nitrogen, phosphorus, sulfur, boron and fluorine; and / or M' comprises one or more elements selected from Li, Be, B, Na, Mg, Al, Si, P, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, W, La and Ce, and / or optionally one or more elements selected from Mg, Al, Si, Zn, Zr and Sn; and / or the polysiloxane is selected from one or more of a linear polysiloxane and a cyclic polysiloxane; and / or 25. The cathode active material composition of claim 24, wherein the polysaccharide is selected from one or more of plant polysaccharides and marine polysaccharides.

26. the first positive electrode active material includes a core and a shell covering the core, The core is Li ａ Mn １－ｙ B ｙ P １－ｚ C ｚ O ４ wherein 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 comprises one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb and Ge, and C comprises one or more elements selected from B (boron), S, Si and N; The shell includes a first coating layer that coats the core and a second coating layer that coats the first coating layer, and the first coating layer is pyrophosphate MP ２ O ７ and phosphate XPO ４ wherein M and X each independently comprise one or more elements selected from Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb, and Al, and the second coating layer comprises carbon.

27. the first positive electrode active material includes a core and a shell covering the core, The core is Li ａ Mn １－ｙ B ｙ P １－ｚ C ｚ O ４ wherein 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 comprises one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb and Ge, and C comprises one or more elements selected from B (boron), S, Si and N; the shell includes a first coating layer that coats the core, a second coating layer that coats the first coating layer, and a third coating layer that coats the second coating layer; The first coating layer is Li pyrophosphate ｆ QP ２ O ７ and / or Q ｇ (P ２ O ７ ) ｈ wherein 0≦f≦2, 1≦g≦4, and 1≦h≦6, and said Li pyrophosphate ｆ QP ２ O ７ and / or Q ｇ (P ２ O ７ ) ｈ wherein each Q independently comprises one or more elements selected from Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb, and Al; The second coating layer is made of crystalline phosphate XPO ４ wherein X comprises one or more elements selected from Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb, and Al; The positive electrode active material composition according to any one of claims 19 to 20 and 23 to 25, wherein the third coating layer contains carbon.

28. 26. The positive electrode active material composition according to claim 19, wherein one or more coating layers in the shell farthest from the core each independently comprise one or more selected from the group consisting of polysiloxane, polysaccharide, and polysaccharide derivative.

29. The polysiloxane comprises a structural unit shown in formula (i): 【Chemistry 1】 R １ and R ２ are each independently selected from H, —COOH, —OH, —SH, —CN, —SCN, an amino group, a phosphate ester group, a carboxylate ester group, an amide group, an aldehyde group, a sulfonyl group, a polyether segment, a C1 to C20 aliphatic hydrocarbon group, a C1 to C20 halogenated aliphatic hydrocarbon group, a C1 to C20 heteroaliphatic hydrocarbon group, a C1 to C20 halogenated heteroaliphatic hydrocarbon group, a C6 to C20 aromatic hydrocarbon group, a C6 to C20 halogenated aromatic hydrocarbon group, a C2 to C20 heteroaromatic hydrocarbon group, and a C2 to C20 halogenated heteroaromatic hydrocarbon group; Optionally, R １ and R ２ are independently selected from H, an amino group, a phosphate ester group, a polyether segment, a C1 to C8 alkyl group, a C1 to C8 halogenated alkyl group, a C1 to C8 heteroalkyl group, a C1 to C8 halogenated heteroalkyl group, a C2 to C8 alkenyl group, and a C2 to C8 halogenated alkenyl group.

30. 30. The positive electrode active material composition according to any one of claims 19 to 25 and 28 to 29, wherein the polysiloxane further comprises an end-capping group, and the end-capping group comprises one or more functional groups selected from the group consisting of polyether, a C1 to C8 alkyl group, a C1 to C8 halogenated alkyl group, a C1 to C8 heteroalkyl group, a C1 to C8 halogenated heteroalkyl group, a C2 to C8 alkenyl group, a C2 to C8 halogenated alkenyl group, a C6 to C20 aromatic hydrocarbon group, a C1 to C8 alkoxy group, a C2 to C8 epoxy group, a hydroxy group, a C1 to C8 hydroxyalkyl group, an amino group, a C1 to C8 aminoalkyl group, a carboxy group, and a C1 to C8 carboxyalkyl group.

31. Polysiloxanes include polydimethylsiloxane, polydiethylsiloxane, polymethylethylsiloxane, polymethylvinylsiloxane, polyphenylmethylsiloxane, polymethylhydrogensiloxane, carboxy-functionalized polysiloxane, epoxy-terminated polysiloxane, methoxy-terminated polydimethylsiloxane, hydroxypropyl-terminated polydimethylsiloxane, polymethylchloropropylsiloxane, hydroxy-terminated polydimethylsiloxane, polymethyltrifluoropropylsiloxane, perfluorooctylmethylpolysiloxane, aminoethylaminopropylpolydimethylsiloxane, polyether-terminated polydimethylsiloxane, side-chain aminopropylpolysiloxane, aminopropyl-terminated polydimethylsiloxane.

31. The positive electrode active material composition according to any one of claims 19 to 25 and 28 to 30, comprising one or more selected from the group consisting of cyclohexylsiloxane, 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, hexadecamethylcyclooctasiloxane, tetradecamethylcycloheptasiloxane, and cyclic polydimethylsiloxane.

32. The positive electrode active material composition according to any one of claims 19 to 25 and 28 to 31, wherein the number average molecular weights of the polysiloxane, the polysaccharide, and the polysaccharide derivative are each independently 300,000 or less, optionally 10,000 to 200,000, further optionally 20,000 to 120,000, and further optionally 400 to 80,000.

33. The mass percent content of polar functional groups in the polysiloxane is α, where 0≦α<50%, and optionally 5%≦α≦30%. The positive electrode active material composition of any one of claims 19 to 25 and 28 to 32.

34. The substituents bonded to the saccharide units in the polysaccharide and polysaccharide derivative are each independently a functional group such as -OH, -COOH and salts thereof, -R-OH, -SO ３ H and its salts, —R—OH, —R—SO ３ H and its salts, sulfuric acid ester groups, alkoxy groups, wherein R represents an alkylene group, optionally a C1-C5 alkylene group; Optionally, the substituents attached to the sugar units in the polysaccharide and polysaccharide derivative are each independently a functional group such as -OH, -COOH, -COOLi, -COONa, -COOK, -SO ３ H, -SO ３ Li, -S.O. ３ Na, -SO ３ K, -CH ２ -SO ３ H, —CH ２ -SO ３ Li, -CH ２ -SO ３ Na, -CH ２ -SO ３ The positive electrode active material composition according to any one of claims 19 to 25 and 28 to 33, comprising one or more of the group consisting of K, a methoxy group, and an ethoxy group.

35. 35. The positive electrode active material composition according to any one of claims 19 to 25 and 28 to 34, wherein the polysaccharide comprises one or more selected from pectin, carboxymethyl starch, hydroxypropyl starch, dextran, cellulose ether, carboxymethychitosan, hydroxylethyl cellulose, carboxymethyl cellulose, carboxypropyl methyl cellulose, guar gum, sesbania gum, gum arabic, lithium alginate, sodium alginate, potassium alginate, fucoidan, agar, carrageenan, xanthan gum, and fenugreek gum.

36. The positive electrode active material composition according to any one of claims 19 to 25 and 28 to 35, wherein the mass percent content of the substituents attached to the saccharide units in the polysaccharide and the polysaccharide derivative is each independently 20% to 85%, and optionally 30% to 78%.

37. The positive electrode active material composition according to any one of claims 19 to 36, wherein a lattice mismatch between the core material and the shell material is less than 10%.

38. relative to the total weight of the first positive electrode active material, the content of elemental manganese is in the range of 10% to 35% by weight, alternatively in the range of 13.3% to 33.2% by weight, further alternatively in the range of 15% to 30% by weight, further alternatively in the range of 17% to 20% by weight; and / or the phosphorus content is in the range of 12% to 25% by weight, alternatively in the range of 15% to 20% by weight, and further alternatively in the range of 16.8% to 19.5% by weight; and / or The weight ratio range of elemental manganese to elemental phosphorus is 0.71 to 1.85, optionally 0.90 to 1.25, and further optionally 0.95 to 1.

20. The positive electrode active material composition according to any one of claims 8 to 37.

39. 19. The positive electrode active material composition according to claim 1, wherein a surface of the first positive electrode active material is coated with one or more of carbon and doped carbon, and optionally, the surface of the first positive electrode active material is coated with carbon.

40. 40. The cathode active material composition of claim 39, wherein the doping element in the doped carbon comprises one or more selected from nitrogen, phosphorus, sulfur, boron, and fluorine.

41. The positive electrode active material composition according to any one of claims 19 to 21, 24 to 25, and 28 to 40, wherein the coating amount of the shell is 0.1 wt% to 6 wt% relative to the weight of the core.

42. The coating amount of the first coating layer is greater than 0 and not greater than 7 wt%, alternatively greater than 0 and not greater than 6 wt%, further alternatively greater than 0 and not greater than 5.5 wt%, or 4 to 5.6 wt%, further alternatively greater than 0 and not greater than 2 wt%, relative to the weight of the core; and / or The amount of the second coating layer is greater than 0 and less than 6% by weight, optionally greater than 0 and less than 5.5% by weight, and further optionally 2-4% by weight or 3-5% by weight, relative to the weight of the core; and / or 39. The positive electrode active material composition according to claim 19, wherein the coating amount of the third coating layer is greater than 0 and less than 6 wt %, optionally greater than 0 and less than 5.5 wt %, and further optionally greater than 0 and less than 2 wt %, relative to the weight of the core.

43. the shell further includes a fourth coating layer coating the third coating layer and a fifth coating layer coating the fourth coating layer; The positive electrode active material composition according to any one of claims 19 to 20, 23 to 25, 27 to 38, and 42, wherein the coating amounts of the fourth coating layer and the fifth coating layer are each independently 0.01 wt% to 10 wt%, selectively 0.05 wt% to 10 wt%, further selectively 0.1 wt% to 5 wt%, and further 0.1 wt% to 2 wt%, relative to the weight of the core.

44. The positive electrode active material composition according to any one of claims 19 to 43, wherein the shell is located on 40% to 90% of the surface of the core, and selectively on 60% to 80% of the surface of the core.

45. The positive electrode active material composition according to any one of claims 19 to 21, 24 to 25, 28 to 41, and 44, wherein the shell has a thickness of 1 to 15 nm.

46. the thickness of the first coating layer is between 1 and 10 nm, optionally between 2 and 10 nm; and / or the thickness of the second coating layer is between 2 and 25 nm, optionally between 2 and 15 nm, and further optionally between 3 and 15 nm; and / or The positive electrode active material composition according to any one of claims 19 to 20, 22 to 38, and 42 to 45, wherein the thickness of the third coating layer is 2 to 25 nm, and optionally 5 to 25 nm.

47. the 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; Optionally, the crystallinity of the pyrophosphate, the phosphate, and the oxide is each independently 10% to 100%, preferably 50% to 100%.

48. 48. The positive electrode active material composition according to claim 19, 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, and optionally 1:3 to 1:

1.

49. the one or more coating layers each independently comprise carbon, and the carbon is a mixture of SP2 carbon and SP3 carbon; Optionally, in the carbon, the molar ratio of the SP2 form carbon to the SP3 form carbon is any value within a range of 0.07 to 13, further optionally any value within a range of 0.1 to 10, and further optionally any value within a range of 2.0 to 3.

0.

50. 50. The cathode active material composition according to claim 19, wherein the one or more coating layers each independently comprise doped carbon, and the doped carbon has a mass content of the doping element of 30% or less, and optionally the doped carbon has a mass content of 20% or less.

51. The one or more coating layers each independently comprise doped carbon, wherein the doped carbon comprises: 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.

52. the one or more coating layers each independently comprise a pyrophosphate, wherein the pyrophosphate has a crystallographic spacing in the range of 0.293 to 0.470 nm, alternatively 0.297 to 0.462 nm or 0.293 to 0.326 nm, and further alternatively 0.300 to 0.310 nm, and an included angle of the (111) crystallographic orientation in the range of 18.00° to 32.57°, alternatively 18.00° to 32.00° or 26.41° to 32.57°, further alternatively 19.211° to 30.846°, and further alternatively 29.00° to 30.00°; and / or the one or more coating layers each independently comprise a phosphate, the phosphate having a crystal plane spacing in the range of 0.244 to 0.425 nm, optionally 0.345 to 0.358 nm, and a crystal orientation (111) having an included angle in the range of 20.00° to 37.00°, optionally 24.25° to 26.45°; Optionally, the first coating layer or the second coating layer comprises a phosphate.

53. The lattice change rate of the first positive electrode active material before and after complete lithium intercalation and deintercalation is 50% or less, optionally 9.8% or less, further optionally 8.1% or less, further optionally 7.5% or less, further optionally 6% or less, further optionally 4% or less, further optionally 3.8% or less, further optionally 2.0 to 3.8%, and / or The first positive electrode active material has a Li / Mn antisite defect concentration of 5.3% or less, optionally 5.1% or less, further optionally 4% or less, further optionally 2.2% or less, further optionally 2% or less, further optionally 1.5% to 2.2% or 0.5% or less; and / or The cathode active material composition according to any one of claims 1 to 52, wherein the surface oxidation state of the first cathode active material is -1.55 or less, optionally -1.82 or less, further optionally -1.88 or less, further optionally -1.90 or less, or -1.98 to -1.88, further optionally -1.98 to -1.89, further optionally -1.98 to -1.

90.

54. The positive electrode active material composition has a value of 0.0004≦w ａ ×y×(3.4-V Ｂ )≦0.063, and optionally, 0.0015≦w ａ ×y×(3.4-V Ｂ )≦0.045; w ａ represents the weight content of the first positive electrode active material relative to the total weight of the positive electrode active material composition, y is the molar amount of B element in 1 mole of the compound represented by formula (I), and V Ｂ is a potential plateau of the B element in the compound represented by formula (I), and the unit is V (volts).

55. 55. The positive electrode active material composition of claim 1, wherein the second positive electrode active material comprises a layered oxide.

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

57. A １ contains one or more elements selected from Na, K, Mg, Rb, Zn, Zr, and / or C １ comprises 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 optionally comprises one or more elements selected from Al, Ti, Zr, Nb, Sr, Sc, Sb, Y, Ba, B; and / or D １ contains one or more elements selected from N, S, F, Cl and Br, optionally containing 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 57. The positive electrode active material composition of claim 56, wherein g1 is selected from the range of 0 to 0.01, and optionally selected from the range of 0.01 to 0.

05.

58. the second positive electrode active material includes a core and a shell covering the core, The core comprises a compound represented by formula (II), 58. The positive electrode active material composition of claim 56 or 57, wherein the shell comprises one or more coating layers, each coating layer having ionic and / or electronic conductivity.

59. 59. The cathode active material composition of claim 58, wherein the one or more coating layers each independently comprise one or more selected from phosphate, pyrophosphate, carbon, doped carbon, oxide, fast ion conductor, and optionally one or more selected from phosphate, pyrophosphate, and oxide.

60. the shell comprises one coating layer; 60. The cathode active material composition of claim 58 or 59, wherein the coating layer optionally comprises one or more selected from a phosphate, a pyrophosphate, and an oxide.

61. the shell includes a first coating layer that coats the core and a second coating layer that coats the first coating layer, Optionally, the first coating layer and the second coating layer each independently comprise one or more selected from phosphate, pyrophosphate, and oxide; 60. The positive electrode active material composition of claim 58 or 59, wherein the first coating layer further optionally comprises one or more selected from a phosphate and an oxide, and the second coating layer further optionally comprises one or more selected from a pyrophosphate and an oxide.

62. The coating amount of the shell is 0.005% to 1% by weight, and optionally 0.01% to 0.5% by weight, relative to the weight of the core; and / or The cathode active material composition according to any one of claims 58 to 61, wherein the shell has a thickness of 2 nm to 200 nm, and optionally 5 nm to 50 nm.

63. 63. A positive electrode sheet comprising a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector, wherein the positive electrode film layer comprises a positive electrode active material comprising the positive electrode active material composition according to any one of claims 1 to 62, and optionally, the content of the positive electrode active material composition in the positive electrode film layer is 90 wt% to 99.5 wt%, and further optionally, 95 wt% to 99.5 wt%, based on the total weight of the positive electrode film layer.

64. 64. The positive electrode sheet of claim 63, wherein the positive electrode film layer further comprises a third positive electrode active material, the third positive electrode active material comprising one or more of a lithium excess oxide material, a lithium iron phosphate material, a spinel-structured lithium manganese oxide material, and respective modified compounds, and the modification manner comprises doping and / or surface coating modification.

65. the third positive electrode active material comprises a compound represented by formula (III), Li １＋ｐ１ A ２ ｑ１ B ２ ｒ１ O ｓ１ 、 (III) 0.05≦p1<0.2, 0.10<q1≦0.95, 0≦r1≦0.2, and 2≦s1<3, and A ２ contains one or more elements selected from Co, Ni, Mn and Al, and B ２ 65. The positive electrode sheet of claim 64, wherein Mg, Ti, Cr, Zr, Nb, Fe, Mo, Cu, Sb, V, P, and F comprise one or more elements selected from the group consisting of Mg, Ti, Cr, Zr, Nb, Fe, Mo, Cu, Sb, V, P, and F.

66. the third positive electrode active material includes a core and a shell covering the core, The core comprises a compound represented by formula (III), 66. The cathode active material composition of claim 65, wherein the shell comprises one or more coating layers, each coating layer having ionic and / or electronic conductivity.

67. 67. The positive electrode sheet according to claim 66, wherein the one or more coating layers each independently comprise one or more selected from the group consisting of phosphates, pyrophosphates, solid electrolytes, conductive polymers, and materials capable of reversibly inserting and extracting lithium ions.

68. The coating amount of the shell is 0.1% to 5% by weight, and optionally 0.5% to 2% by weight, relative to the weight of the core; and / or The positive electrode sheet according to claim 66 or 67, wherein the thickness of the shell is 2 nm to 200 nm, and optionally 5 nm to 50 nm.

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

5. The positive electrode sheet according to claim 64.

70. A ３ comprises 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 optionally comprises one or more elements selected from Zn, Al, Na, K, Mg, Nb, Mo and W; and / or B ３ comprises 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 optionally comprises 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 ３ contains one or more elements selected from B (boron), S, Si and N, and / or D ３ comprises one or more elements selected from S, F, Cl and Br, and / or a2 is selected from the range of 0.9 to 1.1, optionally selected from the range of 0.97 to 1.01; and / or x2 is selected from the range of 0.001 to 0.005, and / or y2 is selected from the range of 0.001 to 0.5, optionally selected from the range of 0.01 to 0.5, optionally selected from the range of 0.25 to 0.5; and / or z2 is selected from the range of 0.001 to 0.5, optionally selected from the range of 0.001 to 0.1, further optionally selected from the range of 0.001 to 0.005; and / or The positive electrode sheet according to claim 69, wherein n2 is selected from the range of 0 to 0.1, and optionally selected from the range of 0.001 to 0.

005.

71. the third positive electrode active material includes a core and a shell covering the core, The core comprises a compound represented by formula (IV), The positive electrode sheet according to claim 69 or 70, wherein the shell is a shell according to any one of claims 19 to 52.

72. the third positive electrode active material comprises a compound represented by formula (V), LiMn ｔ１ A ４ ２－ｔ１ O ４ 、 (V) t1 is selected from the range of 0 to 2, and A ４ 65. The positive electrode sheet of claim 64, wherein 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.

73. the third positive electrode active material includes a core and a shell covering the core, The core comprises a compound represented by formula (V), 73. The cathode active material composition of claim 72, wherein the shell comprises one or more coating layers, each coating layer having ionic and / or electronic conductivity.

74. 74. The positive electrode sheet according to claim 73, wherein the one or more coating layers each independently comprise one or more selected from the group consisting of phosphates, pyrophosphates, solid electrolytes, conductive polymers, and materials capable of reversibly inserting and extracting lithium ions.

75. The coating amount of the shell is 0.1% to 5% by weight, and optionally 0.5% to 2% by weight, based on the weight of the core; and / or The positive electrode sheet according to claim 73 or 74, wherein the thickness of the shell is 2 nm to 200 nm, optionally 5 nm to 50 nm.

76. the positive electrode film layer includes a positive electrode binder and / or a positive electrode conductive agent, Optionally, the positive electrode binder comprises a vinylidene fluoride homopolymer and / or copolymer, and further optionally, the comonomer comprises one or more of tetrafluoroethylene, hexafluoropropylene, propylene, and / or Optionally, the weight average molecular weight of the positive electrode binder is 300,000 to 2,000,000, the positive electrode sheet according to claim 75.

77. The positive electrode film layer further comprises a functional additive, the functional additive comprising one or more of a dispersant, a plasticizer, a pore-forming agent, a moisture scavenging additive, an acid scavenging additive, and a lithium replenisher; and / or 77. The positive electrode sheet according to claim 75 or 76, wherein the positive electrode sheet further comprises a functional coating layer, the functional coating layer being located between the positive electrode current collector and the positive electrode film layer and / or located on a surface of the positive electrode film layer away from the positive electrode current collector, the functional coating layer comprising one or more of conductive carbon, a moisture scavenging additive, an acid scavenging additive, and a lithium replenisher.

78. A battery comprising the positive electrode active material composition according to any one of claims 1 to 62 or the positive electrode sheet according to any one of claims 63 to 77.

79. 79. The battery of claim 78, comprising an electrolyte, wherein the electrolyte comprises one or more of a liquid electrolyte, an all-solid-state electrolyte, and a gel electrolyte.

80. the liquid electrolyte includes a lithium salt, a non-aqueous solvent in which the lithium salt is dissolved, and optional additives; Optionally, the lithium salt is LiPF ６ , LiBF ４ , LiN(SO ２ F) ２ , LiN(CF ３ SO ２ ) ２ , LiClO ４ , LiAsF ６ , LiB(C ２ O ４ ) ２ , LiBF ２ C ２ O ４ , LiPO ２ F ２ and / or Alternatively, the concentration of the lithium salt is 0.5 to 1.5 mol / L; and / or Optionally, the non-aqueous solvent comprises one or more selected from propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl formate, ethyl acetate, methyl butyrate, ethyl butyrate, methyl propionate, ethyl propionate, propyl propionate, methyl acrylate, ethylene sulfite, propylene sulfite, dimethyl sulfite, diethyl sulfite, acid anhydride, N-methylpyrrolidone, acetonitrile, sulfolane, dimethyl sulfoxide, methyl sulfide, γ-butyrolactone, tetrahydrofuran, and / or Alternatively, the additive may be selected from cyclic carbonate compounds having a carbon-carbon double bond, halogen-substituted cyclic carbonate compounds, nitrile and polynitrile compounds, phosphazene compounds, aromatic hydrocarbons and halogenated aromatic hydrocarbon compounds, isocyanate compounds, acid anhydride compounds, sulfate compounds, sulfite compounds, sulfonate compounds, disulfonate compounds, borate compounds, phosphate compounds, amide compounds, carbodiimide compounds, crown ether and azacrown ether compounds, and derivatives thereof.

80. The battery of claim 79 comprising one or more selected from the group consisting of vinylene carbonate, 1,2,3-tris(2-cyanoethoxy)propane, 1-aza-12-crown 4-ether, N,N'-dicyclohexylcarbodiimide, N,N'-diisopropylcarbodiimide, N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, tris(hexafluoroisopropyl)borate, tris(2,2,3,3-tetrafluoropropyl)borate, and tris(pentafluorophenyl)borate.

81. The battery includes a negative electrode sheet including a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector, the negative electrode film layer including a negative electrode active material, the negative electrode active material including one or more of a carbon-based material, a silicon-based material, a tin-based material, and lithium titanate; Optionally, the negative electrode active material comprises a carbon-based material or a combination of a carbon-based material and a silicon-based material; Optionally, the negative electrode film layer has a porosity of 20% to 50%.

82. The negative electrode active material includes a carbon-based material, and the carbon-based material includes graphite or a combination of graphite and hard carbon, or 82. The battery of claim 81 , wherein the negative electrode active material comprises a combination of a carbon-based material and a silicon-based material, the carbon-based material comprising graphite or a combination of graphite and hard carbon, and a content of the silicon element in the negative electrode active material is greater than 0 and less than or equal to 30 wt %, based on a total weight of the negative electrode active material.

83. The negative electrode sheet further comprises a functional coating layer, the functional coating layer being located between the negative electrode current collector and the negative electrode film layer, and / or located on the surface of the negative electrode film layer remote from the negative electrode current collector, optionally the functional coating layer comprising carbon, and / or The battery of claim 81 or 82, wherein the negative electrode film layer further comprises a lithium supplementary material, and optionally the lithium supplementary material comprises one or more of the following: lithium foil, lithium tape, lithium powder, and lithium pre-doping reagent; and optionally the lithium pre-doping reagent comprises one or more of Li-aromatic hydrocarbon, complex of Li-aromatic hydrocarbon and ether solvent, and further optionally comprises one or more of lithium naphthalene, lithium biphenyl-dimethyl ether.

84. 84. The battery of claim 81, wherein the negative electrode sheet includes a negative electrode current collector and a first negative electrode film layer and a second negative electrode film layer respectively disposed on two surfaces of the negative electrode current collector, and optionally, the thickness ratio of the first negative electrode film layer to the second negative electrode film layer is 5:95 to 95:

5.

85. The battery includes a negative electrode sheet, and the negative electrode sheet does not include a negative electrode active material capable of inserting and extracting lithium ions; Alternatively, the negative electrode sheet comprises a lithium sheet or a lithium alloy sheet, or The battery according to any one of claims 78 to 80, wherein the negative electrode sheet comprises a mesh-like or foam-like three-dimensional skeleton layer.

86. 86. The battery of any one of claims 78 to 85, wherein the battery comprises a separator comprising a porous substrate.

87. 87. The battery of claim 86, wherein the separator further comprises a coating layer located on at least one surface of the porous substrate, optionally wherein the coating layer comprises one or more of inorganic heat-resistant particles, organic heat-resistant particles.

88. 88. The battery of claim 86 or 87, wherein the porosity of the separator is between 10% and 40%.

89. A power consuming device comprising a battery according to any one of claims 78 to 88.

Images