Electrolyte solution capable of improving high temperature cycling and storing performances of lithium secondary battery

Abstract

The invention discloses an electrolyte solution capable of improving high temperature cycling and storing performances of a lithium secondary battery. The electrolyte solution is prepared by lithium salt, an organic solvent and an addition agent, wherein the electrolyte solution also comprises a high temperature film-forming agent; the high temperature film-forming agent is one or any combinations of delta-valerolactone, gamma-valerolactone, gamma-caprolactone and epsilon-caprolactone; and the mass percentage of the high temperature film-forming agent accounts for 0.5%-15% of the total amount of the electrolyte solution. The high temperature film-forming agent is added into the electrolyte solution of the lithium secondary battery, a passivating film with excellent stability can be formed on the surface of a lithium secondary battery positive pole, a contact interface of the positive pole and the electrolyte solution can be improved, the decomposition reaction of the electrolyte solution on the positive pole material in the high temperature is inhibited, and the disadvantages that the existing lithium secondary battery is quick in storage capacity loss, low in recovery rate and quick in battery thickness swelling when being used under high temperature environments are overcome, so that the high temperature cycling and storing performances are improved.

Description

technical field [0001] The invention relates to the technical field of lithium secondary batteries, in particular to an electrolyte capable of improving the high-temperature cycle and storage performance of lithium secondary batteries. Background technique [0002] Lithium secondary battery is a high-energy battery that appeared in the 1990s. It has the advantages of green environmental protection, high working voltage, no memory effect, long life, and safety. It has been widely used in military and civilian electrical appliances, such as mobile phones, notebook computers, broadcast Devices, etc., and gradually develop into other product areas. At the same time, users have higher and higher requirements for battery life and ambient temperature. [0003] Electrolyte is an important part of lithium secondary batteries, and its performance greatly affects the electrochemical performance of lithium secondary batteries, such as cycle performance, capacity retention, high tempera...

AI Technical Summary

Problems solved by technology

However, during the cycle and storage process of lithium secondary batteries at high temperature, the electrochemical performance of lithium secondary batteries gradually decreases, and the battery will also swell.

This is mainly because the reaction of the electrolyte on the positive electrode active material is also accelerated in a high-temperature (45-60°C) environment for lithium secondary batteries, resulting in battery swelling, reduced cycle performance, and safety risks.

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