Lithium ion battery electrolyte and lithium ion battery prepared therefrom

Abstract

The invention discloses a lithium ion battery electrolyte and a lithium ion battery prepared therefrom, and belongs to the technical field of lithium ion batteries. The invention aims to solve the problems that due to the accumulation of decomposed substances, the output performance degrades after high temperature storage, and the circulation performance of batteries degrades therefore. The electrolyte is characterized by comprising lithium salts, a non-aqueous organic solvent and an additive. A functional additive is dissolved in the non-aqueous organic solvent. The additive also comprises afunctional additive. The functional additive is composed of an organic substance based on trimethyl silazane and at least one lithium salt of lithium salts with an oxalic acid skeleton, lithium saltswith a phosphoric acid skeleton, and lithium salts with S=O groups. The circulation performance of a lithium ion battery is improved, after high temperature storage, the discharge capacity is well maintained, and the lithium ion battery can be applied to commercial application.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a lithium ion battery electrolyte and a lithium ion battery using the electrolyte. Background technique [0002] The electrolyte plays the role of conducting electrons between the positive and negative electrodes of the lithium-ion battery. It is generally prepared from high-purity organic solvents, electrolyte lithium salts, additives and other raw materials in a certain proportion under certain conditions. Currently, the most widely used electrolytes in commercial Li-ion batteries are those containing LiPF 6 mixture of organic solvents. Commercial LiPF 6 The electrolyte has an unavoidable trace amount of water, and the content of trace water in the electrolyte will lead to LiPF 6 Decomposition, the decomposition products and water will further react to produce hydrofluoric acid (HF); on the electrode surface, HF will react with the deposited decomposition produ...

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide a lithium-ion battery electrolyte with better cycle performance and high-temperature electrochemical performance and the prepared lithium-ion battery for the shortcomings of the current lithium-ion battery after high-temperature storage and poor output performance and cycle performance. , one is to solve the problem of LiPF caused by the trace amount of water in the electrolyte 6 Decomposition, the decomposed product further reacts with water to produce HF, which affects the surface of the electrode and the cycle performance of the battery; the second is to solve the possibility that the solvent in the electrolyte is oxidized and decomposed at high temperature, and the solvent on the positive electrode will be partly Oxidative decomposition problem while solving LiPF 6 Decomposition on the negative electrode causes the salt concentration of the main electrolyte to drop, and the accumulation of decomposition products on the electrode and the generation of gas will hinder the movement of lithium ions, affect the discharge capacity after high-temperature storage, and further affect the cycle life of the battery and other battery characteristics.

Images