SECONDARY BATTERY, BATTERY MODULE, BATTERY PACK, AND ELECTRIC APPARATUS

1 . A secondary battery, comprising a positive electrode plate and a non-aqueous electrolyte, wherein

the positive electrode plate comprises a positive electrode active material, the positive electrode active material having a chemical formula of Li a A x Mn 1−y B y P 1−z C z O 4−n D n ,

wherein A comprises one or more elements selected from a group consisting of Zn, Al, Na, K, Mg, Nb, Mo, and W,

B comprises one or more elements selected from a group consisting of Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge,

C comprises one or more elements selected from a group consisting of B (boron), S, Si, and N,

D comprises one or more elements selected from a group consisting of S, F, Cl, and Br, and

a is selected from a range of 0.9 to 1.1, x is selected from a range of 0.001 to 0.1, y is selected from a range of 0.001 to 0.5, z is selected from a range of 0.001 to 0.1, n is selected from a range of 0.001 to 0.1, and the positive electrode active material is electrically neutral; and

the non-aqueous electrolyte comprises an organic solvent, the organic solvent comprises a first solvent, and the first solvent comprises one or more of compounds represented by formula 1,

wherein R 1 and R 2 are each independently one of a C1-C10 alkyl group and a C1-C10 halogenated alkyl group, and optionally, R 1 and R 2 are each independently one of a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a fluoromethyl group, a fluoroethyl group, a fluoropropyl group, a fluorobutyl group, a fluoropentyl group, and a fluorohexyl group.

2 . The secondary battery according to claim 1 , wherein the first solvent comprises at least one of the following compounds:

and

optionally, the first solvent comprises at least one of the following compounds:

3 . The secondary battery according to claim 1 , wherein based on total mass of the organic solvent, a mass percentage of the first solvent is w1, w1 ranging from 20% to 80%, and optionally, w1 ranging from 30% to 70%; and

optionally, the organic solvent further comprises a second solvent, the second solvent comprising one or more from a group consisting of linear carbonate and cyclic carbonate; and further optionally, based on the total mass of the organic solvent, a mass percentage of the second solvent is w2, w2 ranging from 20% to 80%, and optionally, w2 ranging from 30% to 70%.

4 . The secondary battery according to claim 1 , wherein the non-aqueous electrolyte further comprises a first additive, the first additive comprising one or more from a group consisting of sultone and cyclic sulfate.

5 . The secondary battery according to claim 4 , wherein the sultone comprises at least one of compounds represented by formula 2,

wherein p represents 1, 2, or 3;

R 11 represents one of a hydrogen atom, a halogen atom, a C1-C12 alkyl group, a C1-C12 halogenated alkyl group, a C1-C12 alkoxy group, and a C1-C12 halogenated alkoxy group; optionally, R 11 represents one of a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C1-C3 halogenated alkyl group, a C1-C3 alkoxy group, and a C1-C3 halogenated alkoxy group; and optionally, the alkoxy group is a linear alkoxy group or a cyclic alkoxy group, optionally, the cyclic alkoxy group shares a carbon atom with a parent ring of the sultone, and further optionally, the cyclic alkoxy group has 4, 5, or 6 carbon atoms;

each R 12 independently represents one of a hydrogen atom, a halogen atom, a C1-C12 alkyl group, a C1-C12 halogenated alkyl group, a C1-C12 alkoxy group, a C1-C12 halogenated alkoxy group, and a 4- to 7-membered sultone group, and optionally each R 12 independently represents one of a hydrogen atom, a halogen atom, a C1-C3 alkyl group, a C1-C3 halogenated alkyl group, a C1-C3 alkoxy group, a C1-C3 halogenated alkoxy group, and a 5- or 6-membered sultone group; and optionally, the sultone group shares a carbon atom with the parent ring of the sultone, and optionally, the sultone group is a 5-membered ring;

R 11 and R 12 each form a 5- to 10-membered cycloalkyl group with respective carbon atoms bonded thereto; and

R 13 represents one of a hydrogen atom, a halogen atom, a carbonyl group, a C2-C6 ester group, a C1-C12 alkyl group, a C1-C12 halogenated alkyl group, a C2-C12 alkenyl group, a C1-C12 alkoxy group, a C1-C12 halogenated alkoxy group, and a C6-C20 aryl group or benzyl group; and optionally, R 13 represents one of a hydrogen atom, a halogen atom, a carbonyl group, a C2-C3 ester group, a C1-C3 alkyl group, a C1-C3 halogenated alkyl group, a C2-C6 alkenyl group, a C1-C3 alkoxy group, a C1-C3 halogenated alkoxy group, and a C6-C10 aryl group or benzyl group;

and/or

the cyclic sulfate comprises at least one of compounds represented by formula 3,

wherein q represents 1, 2, or 3;

R 14 represents one of a hydrogen atom, a halogen atom, a carbonyl group, a C1-C12 alkyl group, a C1-C12 halogenated alkyl group, a C2-C12 alkenyl group, a C1-C12 alkoxy group, a C1-C12 halogenated alkoxy group, a C2-C6 ester group, and a 4- to 7-membered cyclic sulfate group; optionally, R 14 represents one of a hydrogen atom, a halogen atom, a carbonyl group, a double bond, a C1-C6 alkyl group, a C1-C3 halogenated alkyl group, a C1-C3 alkoxy group, a C1-C3 halogenated alkoxy group, a C2-C3 ester group, and a 4- or 5-membered cyclic sulfate group; and optionally, the cyclic sulfate group shares a carbon atom with the cyclic sulfate; and

each R 15 independently represents one of a hydrogen atom, a halogen atom, a C1-C12 alkyl group, a C1-C12 halogenated alkyl group, a C1-C12 alkoxy group, a C1-C12 halogenated alkoxy group, and a C6-C20 aryl group; and optionally, each R 15 independently represents one of a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C1-C3 halogenated alkyl group, a C1-C3 alkoxy group, a C1-C3 halogenated alkoxy group, and a C6-C10 aryl group; or

R 14 and R 15 each form a 4- to 7-membered cyclic sulfate group together with respective carbon atoms bonded thereto, and further optionally, R 14 and R 15 each form a 5-membered cyclic sulfate group together with respective carbon atoms bonded thereto;

optionally, the sultone comprises at least one of the following compounds:

optionally, the cyclic sulfate comprises at least one of the following compounds:

further optionally, the sultone comprises at least one of the following compounds:

and

further optionally, the cyclic sulfate comprises at least one of the following compounds:

6 . The secondary battery according to claim 4 , wherein based on total mass of the non-aqueous electrolyte, a percentage of the first additive is W3, and 0.01%≤W3≤20% optionally, 0.1%≤W3≤10% and further optionally, 0.2%≤W3≤5%.

7 . The secondary battery according to claim 1 , wherein the non-aqueous electrolyte further comprises a second additive, the second additive comprising one or more from a group consisting of a sulfite compound, a disulfonate compound, a nitrile compound, an aromatic compound, a phosphazene compound, a cyclic anhydride compound, a phosphite compound, a phosphate compound, and a borate compound.

8 . The secondary battery according to claim 7 , wherein based on total mass of the non-aqueous electrolyte, a percentage of the second additive is W4, and 0.01%≤W4≤20%, optionally, 0.05%≤W4≤5%, and further optionally, 0.1%≤W4≤3%.

9 . The secondary battery according to claim 1 , wherein A, C, and D are each independently any one element within their respective ranges described above, and B comprises at least two elements within its range; and

optionally,

A is any one element selected from Mg and Nb, and/or

B is at least two elements selected from Fe, Ti, V, Co, and Mg, optionally Fe and more than one element selected from Ti, V, Co, and Mg, and/or

C is S, and/or

D is F.

10 . The secondary battery according to claim 1 , wherein

x is selected from a range of 0.001 to 0.005; and/or

y is selected from a range of 0.01 to 0.5, optionally from a range of 0.25 to 0.5; and/or

z is selected from a range of 0.001 to 0.005; and/or

n is selected from a range of 0.001 to 0.005.

11 . The secondary battery according to claim 1 , wherein (1−y):y is within a range of 1 to 4, optionally within a range of 1.5 to 3, and a:x is within a range of 9 to 1100, optionally within a range of 190 to 998.

12 . The secondary battery according to claim 1 , wherein a lattice change rate of the positive electrode active material is below 8%, optionally below 4%.

13 . The secondary battery according to claim 1 , wherein a Li/Mn antisite defect concentration of the positive electrode active material is below 2%, optionally below 0.5%.

14 . The secondary battery according to claim 1 , wherein a surface oxygen valence of the positive electrode active material is below −1.82, optionally from −1.89 to −1.98.

15 . The secondary battery according to claim 1 , wherein a compacted density under 3 T of the positive electrode active material is above 2.0 g/cm 3 , optionally above 2.2 g/cm 3 .

16 . The secondary battery according to claim 1 , wherein a surface of the positive electrode active material is coated with carbon.

17 . A battery module, comprising a secondary battery, wherein the secondary battery is the secondary battery according to claim 1 .

18 . A battery pack, comprising a battery module, wherein the battery module is the battery module according to claim 17 .

19 . An electric apparatus, comprising a secondary battery according to claim 1 .