POSITIVE ELECTRODE MATERIAL PLATE AND PREPARATION METHOD THEREOF, SECONDARY BATTERY, BATTERY MODULE, BATTERY PACK, AND ELECTRIC APPARATUS

1 . A positive electrode material plate, comprising:

an electrode plate substrate; and

a coating layer arranged on a surface of the electrode plate substrate;

wherein the coating layer is a three-dimensional network lithium phosphate layer with a thickness of 10 nm to 20 nm, and a percentage of lithium phosphate is 20% to 30%.

2 . The positive electrode material plate according to claim 1 , wherein the coating layer is a three-dimensional network lithium phosphate layer with a thickness of 12 nm to 13 nm.

3 . The positive electrode material plate according to claim 1 , wherein the coating layer is a three-dimensional network lithium phosphate layer with a thickness of 12.4 nm to 12.8 nm.

4 . The positive electrode material plate according to claim 1 , wherein the percentage of lithium phosphate is 22% to 26%.

5 . The positive electrode material plate according to claim 1 , wherein the electrode plate substrate comprises a compound of formula I:

LiNi x Co y M 1-x-y O 2   formula I,

wherein 0.6≤x<1, 0≤y≤0.2, and M is at least one of Mn, Al, Ti, Zr, Mg, W, and Mo.

6 . A secondary battery, comprising the positive electrode material plate according to claim 1 .

7 . A battery module, comprising the secondary battery according to claim 6 .

8 . A battery pack, comprising the secondary battery according to claim 6 .

9 . An electric apparatus, comprising the secondary battery according to claim 6 , wherein the secondary battery is used as a power source of the electric apparatus or an energy storage unit of the electric apparatus.

10 . A method for preparing a positive electrode material plate, comprising:

providing a mixture of a nickel source, a cobalt source, and a metal M source, wherein M is at least one of Mn, Al, Ti, Zr, Mg, W, and Mo, and mixing the mixture with urea and deionized water, followed by stirring and performing a hydrothermal reaction to obtain a precursor;

reacting the precursor with a lithium source, and performing sintering to obtain a positive electrode material, wherein the positive electrode material has formula I:

LiNi x Co y M 1-x-y O 2   formula I,

wherein 0.6≤x<1, 0≤y≤0.2, and M is at least one of Mn, Al, Ti, Zr, Mg, W, and Mo; and

applying the positive electrode material on a positive electrode current collector, and performing a treatment to obtain the positive electrode material plate.

11 . The method according to claim 10 , wherein the treatment comprises:

adding a phytic acid solution dropwise onto a surface of the positive electrode material plate to form a coating layer on the surface of the positive electrode material plate, wherein:

the coating layer is a three-dimensional network lithium phosphate layer with a thickness of 12 nm to 13 nm, and a percentage of lithium phosphate is 20% to 30%; and

a ratio of an amount of the phytic acid solution used to an area of the positive electrode material plate is 0.2 mL/cm 2 to 0.45 mL/cm 2 .

12 . The method according to claim 11 , wherein the ratio of the amount of the phytic acid solution used to the area of the positive electrode material plate is 0.2 mL/cm 2 to 0.3 mL/cm 2 .

13 . The method according to claim 12 , wherein the ratio of the amount of the phytic acid solution used to the area of the positive electrode material plate is 0.25 mL/cm 2 .

14 . The method according to claim 11 , wherein a surface treatment time of the surface of the positive electrode material plate is 20 minutes to 45 minutes.

15 . The method according to claim 4 , wherein the surface treatment time of the positive electrode material plate is 20 minutes to 30 minutes.

16 . The method according to claim 15 , wherein the surface treatment time of the positive electrode material plate is 25 minutes.