Lithium-ion battery electrolyte applicable to high nickel positive electrode material and silicon-carbon negative electrode material and preparation method thereof

Abstract

The invention discloses a lithium-ion battery electrolyte applicable to a high nickel positive electrode material and a silicon-carbon negative electrode material and a preparation method thereof, andbelongs to the technical field of lithium-ion battery electrolytes. Main points of the technical scheme of the invention are that the lithium-ion battery electrolyte is composed of an organic solvent, lithium salt and an additive, the organic solvent is composed of a carbonic ester solvent, the lithium salt is composed of lithium hexafluorophosphate LiPF6 and lithium difluorooxalate borate LiDFOB, and the additive is composed of N,N'-sulfonyldiimidazole SDI, fluoroethylene carbonate FEC and tris(trimethylsilyl) phosphite TMSPi. N,N'-sulfonyldiimidazole SDI and fluoroethylene carbonate FEC form a good SEI film at the negative electrode in the first charging and discharging process of a lithium-ion battery, so that the capacity, cycle performance and high temperature laying performance of the battery are improved. N,N'-sulfonyldiimidazole SDI and tris(trimethylsilyl) phosphite TMSPi form a dense passivation layer at the positive electrode, so that the dissolution of transition metal inthe positive electrode material is prevented, and the cyclic stability of the positive electrode material is improved.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion battery electrolyte, and in particular relates to a lithium-ion battery electrolyte suitable for high-nickel positive electrode materials and silicon-carbon negative electrode materials and a preparation method thereof. Background technique [0002] Lithium-ion batteries have been widely used in portable consumer electronics, power tools, medical electronics and other fields because of their advantages such as high energy density, high power density, long cycle life, no memory effect, safety and reliability, and environmental friendliness. However, in recent years, with the rapid increase in the demand for battery energy density in its application fields, it is urgent to further increase its energy density. [0003] High-nickel cathode materials generally refer to nickel-containing cathode materials with a nickel mole fraction greater than 0.6. Such materials have the characteristics of high s...

AI Technical Summary

Problems solved by technology

Such as fluoroethylene carbonate (FEC), which has good film-forming properties and oxidation resistance, can be added to the electrolyte to effectively improve the battery cycle performance, but the storage performance and cycle performance of the battery are not good under high temperature conditions

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