Electrolyte additive, high-voltage electrolyte and lithium ion battery containing electrolyte additive

The invention discloses an electrolyte additive, a high-voltage electrolyte and a lithium ion battery containing the electrolyte additive. The high-voltage electrolyte is prepared by adding the electrolyte additive into the conventional electrolyte; the conventional electrolyte comprises a non-aqueous organic solvent and lithium salt, wherein the content of the non-aqueous organic solvent is 80-85 percent of the total mass; the mass of the electrolyte additive is 0.01-10 percent of the total mass; and the electrolyte additive is maleic anhydride C4H2O3 or one of derivatives thereof and has the structure formula as shown in the abstract. According to the high-voltage electrolyte, a stable interfacial film can be formed on the surfaces of a positive electrode and a negative electrode, the reaction activity on the electrode surface is inhibited, oxidative decomposition of the electrolyte is reduced, and gas swelling is effectively inhibited, so that the safety performance and the cycle performance of the lithium ion battery under normal pressure and high voltage are improved and the service life of the lithium ion battery under normal pressure and high voltage is prolonged. The electrolyte is simple in preparation process and is suitable for industrial production.