Non-aqueous electrolyte and battery containing same

Abstract

The invention discloses a non-aqueous electrolyte and a battery containing the non-aqueous electrolyte. The non-aqueous electrolyte comprises an isothiazole additive and a non-isothiazole additive. According to the non-aqueous electrolyte, uniform and compact protective films can be formed on the surfaces of a positive electrode and a negative electrode through the synergistic effect of the isothiazole additive and the non-isothiazole additive, so that oxidation of the electrolyte on the surface of the positive electrode under high voltage can be inhibited, further contact between the electrolyte and the surface of a negative electrode material is avoided, and the occurrence of side reactions is reduced. Moreover, the film-forming impedance is relatively small, and the polarization of the battery is also reduced, so that the normal-temperature circulation and high-temperature storage performance of the battery are improved, and meanwhile, the battery can keep good rate capability and low-temperature discharge performance.

Description

technical field [0001] The invention belongs to the technical field of batteries, and in particular relates to a nonaqueous electrolytic solution, a preparation method thereof and a battery containing the nonaqueous electrolytic solution. Background technique [0002] There are two main ways to increase the energy density of lithium-ion batteries: 1) to increase the specific capacity of positive and negative electrode materials, such as the development of high-nickel positive electrode materials and silicon-based negative electrode materials; 2) to increase the charge cut-off voltage. Ternary layered oxides have excellent comprehensive properties such as high energy density, good cycle performance, and moderate price, and are currently the most promising type of cathode materials in lithium-ion batteries. However, with the rapid development of pure electric vehicles and hybrid electric vehicles, people put forward higher requirements on the energy density, cycle life and saf...

AI Technical Summary

Problems solved by technology

Moreover, as the charge cut-off voltage of the ternary material increases, the reactivity between the positive electrode material and the electrolyte also increases, causing the electrolyte to decompose and oxidize on the surface of the positive electrode, resulting in a ballooning effect, which leads to a normal temperature of the battery. Decreased cycle performance, high temperature cycle characteristics, safety and high temperature storage performance

However, the above problems will also reduce the interface performance between the positive electrode and the electrolyte.

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