Positive-electrode plate, lithium-ion battery equipped with the positive-electrode plate, battery module, battery pack, and apparatus
This application discloses a positive-electrode plate, a lithium-ion battery equipped with the positive-electrode plate, a battery module, a battery pack, and an apparatus. The lithium-ion battery includes a positive-electrode plate, a negative-electrode plate, a separator, and an electrolyte. The positive-electrode plate includes a positive-electrode current collector and a positive-electrode active substance layer that is disposed on a surface of the positive-electrode current collector and that includes a positive-electrode active substance. An inorganic dielectric layer containing no binder is disposed on a surface of the positive-electrode active substance layer, and a resistance of the positive-electrode plate is not higher than 8 ohms.
1. A positive-electrode plate, comprising a positive-electrode current collector and at least one positive-electrode active substance layer disposed on a surface of the positive-electrode current collector, wherein
the positive-electrode active substance layer comprises a positive-electrode active substance represented by Formula (1):
Li x Ni y CO z M k Me p O r A m Formula (1);
in Formula (1), 0.95≤x≤1.05, 0≤y≤1, 0≤z≤1, 0≤k≤1, 0≤p≤0.1, y+z+k+p=1, 1≤r≤2, 0≤m≤2, m+r≤2, M is one or two of Mn or Al, Me is one or more of Zr, Zn, Cu, Cr, Mg, Fe, V, Ti, Y, or Nb, and A is one or more of N, F, S, or CI;
an inorganic dielectric layer is disposed on a surface of the at least one positive-electrode active substance layer that is away from the current collector, and the inorganic dielectric layer contains no binder; and
a resistance R of the positive-electrode plate is not higher than 8 ohms, and
the inorganic dielectric layer in the form of discrete lamellae covers a surface of positive-electrode active substance particles, and
a depth H by which the inorganic dielectric layer extends inside the positive-electrode active substance layer in a thickness direction of the positive-electrode active substance layer is 1/1000 to 1/10 of a thickness of the positive-electrode active substance layer.
2. The positive-electrode plate according to claim 1 , wherein the inorganic dielectric layer is formed of a plurality of nanoclusters that are closely stacked via intermolecular force.
3. The positive-electrode plate according to claim 2 , wherein the average particle diameter D 1 of the nanoclusters is 5 nm˜200 nm.
4. The positive-electrode plate according to claim 2 , wherein an average particle diameter D 1 of the nanoclusters and a thickness T of the inorganic dielectric layer covering the surface of the positive-electrode active substance layer satisfy: 0.02*T≤D 1 ≤0.5*T.
5. The positive-electrode plate according to claim 2 , wherein the thickness T of the inorganic dielectric layer covering the surface of the positive-electrode active substance layer is 50 nm˜1000 nm.
6. The positive-electrode plate according to claim 5 , wherein the thickness T of the inorganic dielectric layer is 100 nm˜600 nm.
7. The positive-electrode plate according to claim 5 , wherein the thickness T of the inorganic dielectric layer is 200 nm˜500 nm.
8. The positive-electrode plate according to claim 1 , wherein the inorganic dielectric layer comprises at least one of aluminum oxides, AlO (OH), aluminum nitrides, aluminum fluorides, silicon oxides, silicon nitrides, silicon fluorides, titanium oxide, titanium nitrides, titanium fluorides, zinc oxides, zinc nitrides, zinc fluorides, magnesium oxides, magnesium nitrides, magnesium fluorides, zirconium oxides, zirconium nitrides, zirconium fluorides, calcium oxides, calcium nitrides, calcium fluorides, barium oxides, barium nitrides, or barium fluorides.
9. The positive-electrode plate according to claim 1 , wherein the positive-electrode active substance layer further comprises a positive-electrode active substance represented by Formula (2):
Li 1+z Mn c Me′ 2-c O 4-d A′ d Formula (2);
in Formula (2), −0.1≤z≤0.2, 0≤c≤2, 0≤d<1, Me′ comprises one or more of Ni, Fe, Cr, Ti, Zn, V, Al, Mg, Zr, or Ce, and A′ comprises one or more of S, N, F, Cl, Br, or I.
10. The positive-electrode plate according to claim 1 , wherein a compacted density of the positive-electrode plate is 3.2 g/cm 3 ˜3.9 g/cm 3 , and a porosity of the positive-electrode plate is 2%˜30%.
11. The positive-electrode plate according to claim 1 , wherein an average particle diameter of the positive-electrode active substance is 5 μm˜25 μm, and a specific surface area of the positive-electrode active substance is 0.3 m 2 /g˜0.8 m 2 /g.
12. The positive-electrode plate according to claim 1 , wherein the inorganic dielectric layer also covers inner walls of at least a part of pores inside the positive-electrode active substance layer.
13. The positive-electrode plate according to claim 1 , wherein a thickness of the inorganic dielectric layer covering the inner walls of the pores inside the positive-electrode active substance layer gradually decreases from the outermost to the inside in a thickness direction of the positive-electrode active substance layer.
14. A lithium-ion battery, comprising: the positive-electrode plate according to claim 1 ; a negative-electrode plate; a separator disposed between the positive-electrode plate and the negative-electrode plate; and an electrolyte, wherein the electrolyte comprises a lithium salt and an organic solvent.
15. The lithium-ion battery according to claim 14 , wherein a second inorganic dielectric layer containing no binder is disposed on a surface of the negative-electrode plate, and a resistance of the negative-electrode plate is not higher than 3 ohms.
16. A battery module, comprising the lithium-ion battery according to claim 14 .
17. A battery pack, comprising the battery module according to claim 16 .
18. An apparatus, comprising the lithium-ion battery according to claim 14 , wherein the lithium-ion battery is used as a power supply of the apparatus.