Lithium ion battery electrolyte containing propylene carbonate

Abstract

The invention discloses a lithium ion battery electrolyte containing propylene carbonate, which comprises a first-stage electrolyte and a second-stage solvent, wherein the first-stage electrolyte includes a first-stage solvent, a conductive lithium salt and fluoropropylene carbonate, the concentration of the conductive lithium salt in the first-stage solvent is 1.6-1.8 mol / L, the first-stage solvent comprises cyclic carbonate and chain carbonate, the mass ratio of the cyclic carbonate to the chain carbonate is 1: (4-5), the mass ratio of the first-stage solvent to the fluoropropylene carbonateis (5-6): (2-3), and the cyclic carbonate in the first-stage solvent does not contain propylene carbonate; the second-stage solvent is composed of cyclic carbonate, chain carbonate and propylene carbonate, the mass ratio of the cyclic carbonate to the chain carbonate to the propylene carbonate is 1: (4-5): (4-5), and the cyclic carbonate in the second-stage solvent does not contain the propylenecarbonate; and the mass ratio of the first-stage electrolyte to the second-stage solvent is (8-9): 1. Based on the electrolyte, the cycle performance of the lithium ion battery 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.