Propylene carbonate based electrolyte and lithium ion battery containing same

Abstract

The invention discloses a propylene carbonate based electrolyte and a lithium ion battery containing the same, the electrolyte comprises a propylene carbonate solvent, a lithium salt and a diluent, and the diluent is a chain solvent with weak polarity. The diluent is one or more of trimethyl borate, triethyl borate, tripropyl borate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl butyl ether, ethyl butyl ether, propyl butyl ether, methyl ethyl ether and ethylene glycol dimethyl ether. The propylene carbonate based electrolyte and the lithium ion battery containing the propylene carbonate based electrolyte have the characteristics of high conductivity, excellent low-temperature performance and good high-voltage stability.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a propylene carbonate-based electrolyte and a lithium ion battery containing the electrolyte. Background technique [0002] Lithium-ion batteries have the advantages of high energy density, high operating voltage, long cycle life, and no memory effect, and are widely used in portable electronic devices, electric vehicles, and large-scale energy storage. Nowadays, people have higher requirements for the energy density of lithium-ion batteries; in addition, the low-temperature charge and discharge performance of lithium-ion batteries has also attracted much attention. [0003] At present, the composition of the commercial lithium-ion battery electrolyte is lithium hexafluorophosphate as the lithium salt, ethylene carbonate with high viscosity and high freezing point (>35°C) as the solvent, and some chain carbonate solvents. Among them, ethylene carbonate can form ...

AI Technical Summary

Problems solved by technology

However, the high-concentration lithium salt electrolyte has extremely high viscosity, low conductivity and high price, which is extremely unfavorable for the commercial application of this electrolyte

[0005] Adding non-polar solvents that do not coordinate with lithium ions, such as fluoroethers, halogenated alkanes, etc., into high-concentration lithium salt electrolytes to form local high-concentration electrolytes can effectively reduce the concentration and viscosity of lithium salts in the electrolyte, but these Non-polar solvents do not complex with lithium ions and cannot increase the degree of dissociation of lithium salts, so they cannot improve the low conductivity of high-concentration electrolytes

In addition, the boiling point of these non-polar solvents is usually only 30~60°C, and they are very volatile, which is extremely unfavorable for the accurate preparation of the electrolyte and the problem of flatulence during the use of lithium-ion batteries.

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