Electrolyte for lithium-ion battery, lithium-ion battery, battery module, battery pack, and apparatus

1. An electrolyte for a lithium-ion battery, comprising:

an organic solvent;

an electrolyte lithium salt dissolved in the organic solvent; and

an additive;

wherein the additive is a compound represented by following formula I:

wherein

R 1 is a C1-10 alkylidene group, and optionally, one or more hydrogen atoms in the alkylidene group is substituted with one or more of phenyl, halogen, nitrogen, oxygen, sulfur, silicon, boron, or phosphorus;

R 2 and R 3 each are independently selected from halogen, a saturated or unsaturated C1-10 alkyl group or alkoxy group, R—NR 4 —, or —R 1 —NR 4 R 5 , and optionally, one or more hydrogen atoms in the saturated or unsaturated alkyl group or alkoxy group is substituted with one or more of halogen, nitrogen, oxygen, sulfur, silicon, boron, or phosphorus; and

R is a saturated or unsaturated C1-10 alkyl group, optionally, one or more hydrogen atoms in the saturated or unsaturated alkyl group is substituted with one or more of halogen, nitrogen, oxygen, sulfur, silicon, boron, or phosphorus, and R 4 and R 5 each are independently selected from H or halogen.

2. The electrolyte according to claim 1 , wherein R 1 in the compound of the formula I is selected from a C1-4 alkylidene group, and optionally, one or more hydrogen atoms in the alkylidene group is substituted with one or more of phenyl, fluorine, chlorine, bromine, iodine, nitrogen, oxygen, sulfur, silicon, boron, or phosphorus.

3. The electrolyte according to claim 2 , wherein R 1 in the compound of the formula I is selected from —CH 2 —, —CH 2 CH 2 —, —CH 2 CH 2 CH 2 —, —CH 2 (CH 2 ) 2 CH 2 —, or —CH 2 —CHPh-.

4. The electrolyte according to claim 1 , wherein R 2 and R 3 in the compound of the formula I each are independently selected from F, Cl, Br, a C1-4 alkyl group or alkoxy group, R—NR 4 —, or —R 1 —NR 4 R 5 , and optionally, one or more hydrogen atoms in the alkyl group or alkoxy group is substituted with one or more of fluorine, chlorine, bromine, iodine, nitrogen, oxygen, sulfur, silicon, boron, or phosphorus; and

R is independently selected from a C1-4 alkyl group, and R 4 and R 5 each are independently selected from H.

5. The electrolyte according to claim 4 , wherein R 2 and R 3 in the compound of the formula I each are independently selected from F, Cl, —CH 3 , —CH 2 CH 3 , —CH 2 CH 2 CH 3 , —CH 2 (CH 2 ) 2 CH 3 , —OCH 3 , —OCH 2 CH 3 , —OCH 2 CH 2 CH 3 , —OCH 2 (CH 2 ) 2 CH 3 , —CF 3 , —CF 2 CF 3 , —CF 2 CF 2 CF 3 , —CF 2 (CF 2 ) 2 CF 3 , —CH 2 CF 3 , —CH(CF 3 ) 2 , CH 3 NH—, CF 3 NH—, CH 3 CH 2 NH—, CH 3 (CH 2 ) 2 NH—, CH 3 (CH 2 ) 2 NH—, —CH 2 NH 2 , or —CH 2 CH 2 NH 2 .

6. The electrolyte according to claim 5 , wherein the compound of the formula I is selected from following compounds:

7. The electrolyte according to claim 1 , wherein a concentration of the compound of the formula I in the electrolyte is 0.1 wt % to 15 wt %.

8. The electrolyte according to claim 7 , wherein a concentration of the compound of the formula I in the electrolyte is 0.5 wt % to 10 wt %.

9. The electrolyte according to claim 1 , wherein the electrolyte lithium salt is selected from at least one of LiPF 6 , LiBF 4 , LiTFSI, LiFSI, LiClO 4 , LiAsF 6 , LiPO 2 F 2 , LiBOB, LiDFOB, LiTFOP, LiN(SO 2 R F ) 2 , or LiN(SO 2 F)(SO 2 R F ), wherein a substituent group R F =C n F 2n+1 , and n is an integer from 1 to 10.

10. The electrolyte according to claim 9 , wherein the electrolyte salt is selected from at least one of LiTFSI and LiFSI.

11. The electrolyte according to claim 9 , wherein a concentration of the electrolyte lithium salt in the electrolyte is 0.5 mol/L to 10 mol/L.

12. The electrolyte according to claim 11 , wherein a concentration of the electrolyte lithium salt in the electrolyte is 1 mol/L to 5 mol/L.

13. The electrolyte according to claim 1 , wherein the electrolyte further comprises at least one of a solid electrolyte interface (SEI) film forming additive, a flame retardancy additive, an overcharge protection additive, and a conductive additive.

14. A lithium-ion battery, comprising a positive electrode, a negative electrode, a separator provided between the positive electrode and the negative electrode, and the electrolyte according to claim 1 ;

optionally, the positive electrode comprises a positive active material represented by formula II:

Li 1+x Ni a Co b M 1−a−b O 2−y A y   (II),

wherein

0.1≤x≤0.2, 0<a<1, 0≤b<1, 0<a+b<1, 0≤y<0.2,

M is selected from at least one of Mn, Fe, Cr, Ti, Zn, V, Al, Zr, or Ce, and

A is selected from S, N, F, Cl, Br, or I.

15. The lithium-ion battery according to claim 14 , wherein 0.5≤a<1.

16. The lithium-ion battery according to claim 14 , wherein 0.6≤a<1, M is selected from Mn and Al, and A is selected from S and F.

17. An apparatus, comprising the lithium-ion battery according to claim 14 , wherein the lithium-ion battery is used as a power supply for the apparatus.

18. The apparatus according to claim 17 , wherein the apparatus comprises an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, an electric vessel, or an energy storage system.