High-voltage lithium ion battery electrolyte and lithium ion battery

Abstract

A high-voltage lithium ion battery electrolyte comprises a solvent, a lithium salt and an inorganic film-forming additive, wherein the solvent comprises (2, 2, 2-trifluoroethyl) ethyl ester which accounts for 5 to 15 percent of the weight of the solvent. The high stability of the (2, 2, 2-trifluoroethyl) ethyl ester can prevent the electrolyte from being greatly oxidized on the surface of the anode, so that the high-voltage cycle performance of the electrolyte is ensured, and meanwhile, the capacity retention ratio of the battery is ensured. The addition of the lithium fluozirconate can play arole in regulating and controlling the formation of the SEI film, so that the SEI film is more uniform, the impedance of the SEI film is reduced, and the capacity retention ratio of the battery is further improved. Meanwhile, the lithium fluozirconate can further inhibit oxygenolysis of the electrolyte under high pressure.

Description

technical field [0001] The invention relates to a lithium ion battery, in particular to a high-voltage lithium ion battery electrolyte. Background technique [0002] The positive electrode material of lithium ion battery has a high voltage and is easy to react with the organic electrolyte; once the reaction occurs, the electrolyte will be consumed and the structural integrity of the positive electrode material will be destroyed, resulting in a decrease in the overall performance of the battery. For the stability of the interface between the electrolytes, it is an important means to coat and modify the positive electrode material. Common coating materials include carbon materials, oxides, fluorides and other inorganic substances, such as patent 201711230525.4, a high-voltage lithium-ion battery electrolyte and the coating materials in lithium-ion batteries are lithium carbonate, lithium oxide and potassium carbonate Wait. However, after this traditional coating material has...

AI Technical Summary

Problems solved by technology

However, after this traditional coating material has been cycled many times, for example, 200 times, the thickness of the SEI film formed on the surface of the positive electrode material is thick and uneven, and the impedance increases. The battery reflects that the cycle performance is not good.

[0003] At the same time, most of the traditional high-voltage electrolytes only pay attention to the film-forming additives and pay little attention to the solvent itself.

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