Lithium ion battery electrolyte considering high-temperature and low-temperature properties

Abstract

The invention discloses a lithium ion battery electrolyte considering both high-temperature performance and low-temperature performance. The composition is prepared from the following components in percentage by mass: 20-40% of a surfactant and the balance of water, the electrolyte comprises 10%-15% of an electrolyte lithium salt, 80%-85% of a non-aqueous organic solvent and 3%-5% of an additive,wherein the electrolyte lithium salt comprises lithium tetrafluoroborate LiBF4, lithium bis (oxalato) borate LiBOB and lithium bis (fluoromalonic acid) borate LiBFMB; wherein the non-aqueous organic solvent comprises ethylene carbonate EC, propylene carbonate PC, ethyl methyl carbonate EMC and ethyl acetate EA, and the additive comprises fluoroethylene carbonate FEC and ethylene sulfate DTD. By adopting the lithium salt, the non-aqueous organic solvent and the additive in a proper proportion, the electrolyte has a wide temperature window, good charging and discharging performance and good cycling stability, and the battery accommodating the electrolyte can have good cycling performance and electrochemical performance at high temperature and low temperature.

Description

technical field [0001] The invention belongs to the field of lithium-ion batteries, and in particular relates to a lithium-ion battery electrolyte that takes into account both high-temperature and low-temperature performances. Background technique [0002] Lithium-ion batteries have the advantages of high energy density, high working voltage, long cycle life, less environmental pollution, and no memory effect, and are considered to be one of the most promising secondary batteries. As the carrier of lithium-ion battery ion transmission, the electrolyte plays an important role in the cycle stability, rate performance and safety performance of the lithium-ion battery. The performance of the electrolyte will also determine the performance of the lithium-ion battery. [0003] With the rapid development of science and technology and the continuous deterioration of the earth's environment, human demand for green energy products is also increasing. There are more and more usage sce...

AI Technical Summary

Problems solved by technology

Under high temperature conditions, general commercial lithium-ion batteries will accelerate the decomposition of the electrolyte and increase the internal resistance of the battery, resulting in poor battery cycle performance, low capacity retention, and serious safety accidents such as fire and explosion. Under low temperature conditions for ion batteries, the viscosity of the electrolyte increases, the conductivity of ions and electrons becomes lower, the transfer of ions between the positive and negative electrodes is restricted, and the activity of the battery is reduced, resulting in a very low capacity released, or even unable to discharge. call out

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