Electrolyte for lithium ion battery, and lithium ion battery

Abstract

The invention provides an electrolyte for a lithium ion battery, and the lithium ion battery. A first additive silicon nitrogen borane compound is added, the additive can be subjected to an oxidation reaction on the surface of a positive electrode to generate a CEI film, on one hand, the CEI film can effectively isolate side reaction between the electrolyte and a positive electrode material, and on the other hand, the generated CEI film is stable and it is ensured that the positive electrode material is not damaged and the electrolyte is not oxidized and decomposed under high voltage, so that the service life of the lithium ion battery under high voltage is prolonged. Silicon atoms and boron atoms in the first additive can also improve the migration rate of active lithium ions, so that the interface impedance is reduced; meanwhile, the silicon atoms and the boron atoms can also serve as anion receptors and can capture hydrofluoric acid generated by lithium salt and other additives, so the situation that hydrofluoric acid attacks the CEI film on the surface of the positive electrode material is avoided, the stability of the CEI membrane is ensured, and the purposes of increasing the capacity retention rate and improving high-temperature circulation and low-impedance performance are achieved.

Description

technical field [0001] The invention relates to the field of lithium batteries, in particular to an electrolyte solution for a lithium ion battery and a lithium ion battery. Background technique [0002] Lithium-ion batteries are widely used in 3C digital, new energy vehicles, energy storage base stations and aerospace fields because of their low raw material cost, good safety performance, high working voltage, large specific energy, and long cycle life. [0003] Electrolyte, as the "blood" of lithium-ion batteries, is one of the important components of lithium-ion batteries. It is responsible for the transmission of lithium ions between the positive and negative electrodes. etc. play a vital role. However, the current commercial carbonate-based solvents are prone to side reactions between the electrolyte and the surface of the positive electrode material under high-voltage and high-temperature environments, which continuously consume active lithium ions, resulting in the d...

AI Technical Summary

Problems solved by technology

[0005] One of the objectives of the present invention is to provide an electrolyte solution for lithium ion batteries, which solves the problem that the current lithium ion battery electrolyte is prone to side reactions with positive electrode materials, and the electrolyte solution of the present invention effectively isolates the electrolyte solution from positive electrode materials. side reactions, thereby effectively improving the storage and cycle performance of lithium-ion batteries under high temperature and high pressure

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