Lithium ion battery electrolyte containing cyclic diketone compound

The invention discloses a lithium ion battery electrolyte containing a cyclic diketone compound, the lithium ion battery electrolyte comprises a main lithium salt, a non-aqueous solvent and additives, the additives at least comprise: a first additive which is a cyclic diketone compound; a second additive, wherein the second additive is cyclic sulfate; a third additive, wherein the third additive is cyclic sulfonate; the first additive, the second additive and the third additive respectively account for a%, b% and c% of the total mass of the electrolyte, and meet the following relational expression: b + c is more than or equal to 0.6 and less than or equal to 3; 1 < = b/c < = 10; 1 < = (b + c)/a < = 40. The electrolyte is used for the lithium ion secondary battery, the initial capacity of the battery can be effectively prevented from being reduced under the high voltage larger than or equal to 4.3 V, and meanwhile the high-temperature cycle performance and the high-temperature storage performance of the batter