A kind of method for preparing sei film by magnetization

Abstract

The invention relates to the field of new energy materials, in particular to a method for preparing an SEI film by magnetization. The preparation method includes the following preparation steps: assembling the cathode sheet, the anode sheet and the separator into a bare battery cell, injecting an electrolyte solution after the bare cell outer packaging shell, and standing until the cathode sheet and the anode sheet are fully soaked to obtain Prefabricated cells: place the prefabricated cells in a chemical formation machine, apply a magnetic field to the prefabricated cells during the formation, and perform a chemical conversion process under the action of the magnetic field. After the chemical conversion process, an SEI film is formed on the surface of the anode sheet. When the SEI film prepared by the method of the present invention is used in a battery, the charge and discharge efficiency, cycle performance and rate performance can all be significantly optimized and improved.

Description

technical field [0001] The invention relates to the field of new energy materials, in particular to a method for preparing an SEI film by magnetization. Background technique [0002] The development of lithium-ion batteries has provided rapid advances in portable electronic devices and enabled the realization of electric vehicles. However, the low reduction potential of graphite requires the formation of a solid electrolyte phase (SEI) to passivate the electrode surface for long-term cycling. [0003] SEI film, the full name of solid electrolyte interface, solid electrolyte interface (membrane), as the name implies, it is a passivation film layer with solid electrolyte properties. SEI is Li + It is an excellent conductor, which can allow lithium ions to be transported in it, enter the graphite surface, and perform lithium deintercalation work. At the same time, it is also a good electronic insulator, which can effectively reduce the probability of internal short circuit a...

AI Technical Summary

Problems solved by technology

[0009] In order to solve the problem that the existing SEI film has low charge and discharge efficiency when used, and the amount of lithium ions intercalated on the SEI film is large after long-term cycling, resulting in a large irreversible capacity loss, and the existing improved processes cannot effectively solve the problem , the invention provides a method for preparing SEI film by magnetization

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