Electrolyte and secondary battery

Abstract

The invention provides an electrolyte and a secondary battery. The electrolyte comprises an electrolyte salt, an organic solvent and an additive. The additive comprises tertiary thiophene and derivatives thereof as well as compounds represented by Formula 1. In Formula 1, R7, R8, R9, R10 are each independently selected from H or a halogen atom, and at least one of R7, R8, R9, R10 is selected froma halogen atom. As that tertiary thiophene and the derivative thereof and the compound represen by the formula 1 are added into the electrolyte, the problem of high-temperature gas production of the secondary battery can be remarkably improve, and the cycle performance and the storage performance of the secondary battery can be simultaneously improved.

Description

technical field [0001] The invention relates to the battery field, and more specifically, the invention relates to an electrolyte solution and a secondary battery. Background technique [0002] Lithium-ion battery, as the most commonly used secondary battery, has been extensively studied and developed in recent years because of its advantages such as high specific energy, high working voltage, wide application temperature range, low self-discharge rate, long cycle life, no pollution and good safety performance. It is widely used in mobile electronic devices such as mobile phones, portable computers, video cameras, cameras, etc., and gradually replaces traditional nickel-metal hydride batteries and nickel-cadmium batteries in the fields of communication equipment such as aviation, aerospace, navigation, artificial satellites, and small medical instruments. [0003] In order to pursue high energy density, existing lithium-ion batteries often choose a high-nickel cathode materi...

AI Technical Summary

Problems solved by technology

[0003] In order to pursue high energy density, existing lithium-ion batteries often choose a high-nickel cathode material / silicon-doped anode material system. During the charging and discharging process of lithium-ion batteries, the electrolyte is easy to oxidize and decompose with the high-nickel cathode material with a large amount of delithiation. reaction, there is a problem of gas production, especially in a high temperature environment, in LiPF 6 The decomposition product of PF 5 Under the catalysis, it is easy to accelerate the oxidative decomposition of the electrolyte and release a large amount of reaction heat and gas. Therefore, there is a serious problem of gas production in lithium-ion batteries in high-temperature environments.

[0004] In addition, when high-nickel cathode materials are used in lithium-ion batteries, as the nickel content increases, the oxidative properties of the high-nickel cathode materials in the delithiated state are significantly enhanced, and the electrolyte is easily absorbed on the surface of the high-nickel cathode materials in the delithiated state. Oxidative decomposition occurs, aggravating the gas production problem of lithium-ion batteries, and further deteriorating the cycle performance of lithium-ion batteries

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