Lithium-ion battery

1. A lithium-ion battery, comprising:

a positive electrode plate containing a positive electrode active material;

a negative electrode plate containing a negative electrode active material; and

an electrolyte;

wherein

the positive electrode active material comprises: a core; and a coating layer coating a surface of the core and comprising boron;

the electrolyte comprises a lithium salt, a non-aqueous organic solvent and an electrolyte additive, the electrolyte additive comprises an organic titanium compound, the organic titanium compound is one or more selected from the group consisting of compounds represented by formula 1, formula 2, formula 3, formula 4 and formula 5;

where,

R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 11 , R 12 , R 13 and R 14 each independently are one selected from C1˜C12 alkyl group substituted or unsubstituted with one or more substituent group, C1˜C12 hydroxyalkyl group substituted or unsubstituted with one or more substituent group, C2˜C12 alkenyl group substituted or unsubstituted with one or more substituent group, C2˜C12 alkynyl group substituted or unsubstituted with one or more substituent group, C1˜C12 sulfonyl substituted or unsubstituted with one or more substituent group, and metal ion;

R 8 , R 9 and R 10 each independently are one selected from C1˜C12 alkyl group substituted or unsubstituted with one or more substituent group, C2˜C12 alkenyl group substituted or unsubstituted with one or more substituent group, C2˜C12 alkynyl group substituted or unsubstituted with one or more substituent group, and halogen;

R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 and R 28 each independently are one selected from C1˜C6 alkyl group substituted or unsubstituted with one or more substituent group and C1˜C6 sulfonyl substituted or unsubstituted with one or more substituent group; and

the core is one or more selected from the group consisting of lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminium oxide and compounds obtained by adding transition metal element or non-transition metal element to the above oxides wherein a content of the organic titanium compound is 0.001%˜0.5% of a total weight of the electrolyte.

2. The lithium-ion battery according to claim 1 , wherein the substituent group is one or more selected from a group consisting of halogen atom and oxygen atom.

3. The lithium-ion battery according to claim 1 , wherein the core is lithium nickel cobalt manganese metal oxide.

4. The lithium-ion battery according to claim 3 , wherein the core is one or more selected from the group consisting of LiNi 1/3 Co 1/3 Mn 1/3 O 2 , LiNi 0.5 Co 0.2 Mn 0.3 O 2 , LiNi 0.6 Co 0.2 Mn 0.2 O 2 and LiNi 0.8 Mn 0.1 O 2 .

5. The lithium-ion battery according to claim 1 , wherein the core of the positive electrode active material includes a large particle core and a small particle core, a particle size of the large particle core ranges from 10 μm to 14 μm, a particle size of the small particle core ranges from 3 μm to 6 μm.

6. The lithium-ion battery according to claim 5 , wherein in the core of the positive electrode active material, a weight ratio of the large particle core and the small particle core is (5˜9):(1˜5).

7. The lithium-ion battery according to claim 6 , wherein

a content of nickel of the large particle core is greater than or equal to a content of nickel of the small particle core.

8. The lithium-ion battery according to claim 7 , wherein the content of nickel of the large particle core is greater than the content of nickel of the small particle core.

9. The lithium-ion battery according to claim 1 , wherein the coating layer is selected from B 2 O 3 .

10. The lithium-ion battery according to claim 1 , wherein a content of the coating layer is 0.01%˜0.2% of a total weight of the core.

11. The lithium-ion battery according to claim 10 , wherein the content of the coating layer is 0.02%˜0.1% of the total weight of the core.

12. The lithium-ion battery according to claim 1 , wherein the organic titanium compound is one or more selected from a group consisting of tetrabutyl titanate, titanium ethoxide, titanium propoxide, titanium diisopropoxide bis(acetylacetonate), titanium tetraisopropanolate, tetra-tert-butyl orthotitanate, butyl isopropyl titanate, titanium isobutoxide, tetra(3-hydroxypropoxy) titanate, titanium(IV)oxide acetylacetonate, tetrakis(2,4-pentanedionato)titanium(IV), titanocene bis(trifluoromethanesulfonate), dichlorotitanium diisopropoxide, titanium dichloride diethoxide, iodotriisopropyl titanate and tetraki s(dim ethyl amino)titanium.

13. The lithium-ion battery according to claim 12 , wherein the content of the organic titanium compound is 0.001%˜0.1% of the total weight of the electrolyte.

14. The lithium-ion battery according to claim 1 , wherein the electrolyte additive further comprises one or more selected from a group consisting of maleic anhydride, vinyl ene carbonate, 4-Vinyl-1,3-dioxolan-2-one, 4-Fluoro-1,3-dioxolan-2-one, γ-butyrolactone, dimethyl sulfite, diethyl sulfite, glycol sulfite, propyl sulfite, vinylidene sulfite, sulfolane, cyclopentyl sulfone, tetramethylene sulfoxide, cyclopentyl sulfoxide, dimethyl sulfoxide, methyl ethyl sulfoxide, diethyl sulfoxide, methyl sulfone, methyl ethyl sulfone, diethyl sulfone, divinyl sulphone, methyl methanesulfonate, ethyl methanesulfonate, propargyl methanesulfonate, methyl benzenesulfonate, 1,3-propanesultone, 1,4-butane sultone, dimethyl sulfate, diethyl sulfate, ethylene sulfate, 1,2-propanediol sulfate and prop-1-ene-1,3-sultone.