Li-ion battery electrolyte containing propylene carbonate

Abstract

The invention discloses a lithium ion battery electrolyte containing propylene carbonate, comprising: a first-level electrolyte, including a first-level solvent, a conductive lithium salt and fluoropropylene carbonate, and the conductive lithium salt is in the first-level solvent The concentration is 1.6~1.8mol / L, the first grade solvent is composed of cyclic carbonate and chain carbonate, the mass ratio of cyclic carbonate and chain carbonate is 1:4~5, the first grade solvent and The mass ratio of fluorinated propylene carbonate is 5~6:2~3, and the cyclic carbonate in the first-level solvent does not include propylene carbonate; the second-level solvent is composed of cyclic carbonate, chain carbonate and carbonic acid Composed of propylene carbonate, the mass ratio of cyclic carbonate, chain carbonate and propylene carbonate is 1:4~5:4~5, and the cyclic carbonate in the second-stage solvent does not include propylene carbonate; the first-stage electrolysis The mass ratio of liquid to secondary solvent is 8-9:1. Based on this electrolyte, the cycle performance of lithium-ion batteries can be improved.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a lithium ion battery electrolyte containing propylene carbonate. Background technique [0002] Lithium-ion battery is a secondary battery (rechargeable battery) that mainly relies on the movement of lithium ions between the positive and negative electrodes to work. During the charging and discharging process, lithium ions intercalate and deintercalate back and forth between the two electrodes: during charging, lithium ions are deintercalated from the positive electrode, inserted into the negative electrode through the electrolyte, and the negative electrode is in a lithium-rich state; the opposite is true during discharge. As the application of lithium-ion batteries becomes more and more common, the requirements for the cycle performance and high and low temperature performance of lithium-ion batteries are also getting higher and higher. At present, in order to im...

AI Technical Summary

Problems solved by technology

However, propylene carbonate is easy to co-intercalate to graphite electrodes, resulting in a decrease in the cycle performance of lithium-ion batteries.