A chain fluoroester compound and its use as an electrolyte solvent for lithium ion batteries

Abstract

The invention discloses a chain-shaped fluoroester compound and the use thereof as an electrolyte solvent of a lithium ion battery. The chain fluorinated ester compound comprises a chain fluorinated carbonate compound and a chain fluorinated carboxylic acid ester compound, wherein the chain fluorinated ester compound improves the overall oxidation decomposition voltage of the electrolyte, has goodwettability, can optimize the electrode interface, reduce the impedance between the interfaces, and improves the low-temperature performance. The addition of the chain fluoroester electrolyte solventof the invention improves the high-temperature resistance and high-pressure resistance stability of the lithium ion battery, improves the rate performance of the battery, and is a novel second-generation lithium ion battery solvent.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a chain fluorinated ester compound and its use as a solvent for the electrolyte of lithium ion batteries. Background technique [0002] In recent years, the development of lithium-ion batteries has received widespread attention, and it has developed rapidly in the field of mobile phone digital, electric vehicles, electric bicycles, electric tools, and energy storage. Due to people's increasing requirements for battery life, batteries with high energy density have become a research hotspot. On the one hand, electrode materials with high energy density, such as high-nickel materials, lithium-rich manganese bases, and silicon-carbon anodes, have attracted a lot of attention; on the other hand, high-voltage lithium-ion batteries are also the main trend of current research. This poses new challenges to battery materials. [0003] At present, the high-voltage cathode materials th...

AI Technical Summary

Problems solved by technology

[0003] At present, the high-voltage cathode materials that have been reported include LiCoPO 4 、LiNiPO 4 and LiNi 0.5 mn 1.5 etc., its charging voltage platform is close to or higher than 5V, but the matching non-aqueous organic electrolyte seriously lags behind the development of high-voltage cathode materials, which limits the application of lithium-ion secondary batteries

For example, the positive electrode material has a strong oxidizing property during the charging process, and a side reaction will occur with the electrolyte during the charging process to generate CO 2 、H 2 Oxidation products such as O, CO 2 The generation of H will pose a potential threat to the safety performance of the battery; H 2 The generation of O makes the LiPF 6 / carbonate electrolyte system undergoes an autocatalytic reaction, and the generation of intermediate product HF will lead to LiMn 1.5 Ni 0.5 The dissolution of the material metal ions Mn and Ni causes the structure of the material to be distorted or collapsed, which eventually leads to a decrease in the cycle performance, volume expansion and discharge capacity of the lithium-ion secondary battery, so it cannot be applied to the high-voltage lithium-ion secondary battery system

Images