| abstract |
The invention provides an electrolyte comprising lithium salt, a non-aqueous solvent and a first additive, wherein the first additive is selected from compounds adopting a structure shown in a formula (I). An ionic liquid oligomer with an amphiphilic function is added into the electrolyte to serve as the first additive. This type of ionic liquid oligomer can be taken as a surfactant and can effectively improve the wettability of the electrolyte on a diaphragm and an electrode material when the adding amount is controlled within a certain composition, and the initial efficiency and the charge-discharge capacity of a lithium ion battery are further improved. As a matter of fact that an ionic liquid can be also taken as a solvent of the lithium salt, the solubility of the lithium salt cannot be affected by addition of the ionic liquid. Besides, a second additive is added while the first additive is added. The second additive can participate in formation of an interfacial film in charge-discharge processes of the battery, so that the stable interfacial film can be formed between the electrolyte and the electrode material, thereby avoiding a side reaction between the electrolyte and the electrode material, and further improving the cycle stability of the lithium ion battery. |