A kind of medium electrolyte, lithium ion battery and preparation method thereof

Abstract

The invention discloses a medium electrolyte, which includes the following substances according to the mass fraction: 6% to 24% conductive lithium salt; 70% to 90% polymer electrolyte matrix; 3% to 6% plasticizer; the invention also discloses the use of the The lithium-ion battery of medium electrolyte, comprises the positive pole piece that the surface is coated with quasi-solid electrolyte and lithium negative pole piece, and lithium negative pole piece surface is coated with described medium electrolyte; Preferably described quasi-solid state electrolyte comprises methyl methacrylate, Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 and mesoporous molecular sieve; the present invention also discloses the preparation method of the medium electrolyte; the present invention utilizes the state of the medium electrolyte semi-solid gel to have good chemical stability to lithium metal, suppresses the growth of lithium dendrites, and thus obtains lithium metal with excellent performance ion battery.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a medium electrolyte, a lithium ion battery using the medium electrolyte and a preparation method of the medium electrolyte. Background technique [0002] With the popularization of electric vehicles, the safety issues of high energy density lithium batteries are becoming increasingly severe. Especially in recent years, the electric vehicle fire incidents reported internationally and domestically have become more and more frequent, which highlights the challenge of designing batteries with both safety and energy density. [0003] In order to further improve the energy density and safety performance of lithium-ion batteries, solid-state batteries have become the only way. The conductivity of all-solid-state batteries cannot meet the requirements, and more exploration is needed to achieve mass production. Industrialized lithium-ion batteries, including global power b...

AI Technical Summary

Problems solved by technology

Lithium dendrites may appear in liquid lithium-ion batteries working at high currents, which can pierce the diaphragm and cause short-circuit damage; the electrolyte is an organic liquid, which will intensify the tendency of side reactions, oxidative decomposition, gas generation, and combustion at high temperatures

When the liquid lithium-ion battery is subjected to severe impact or the battery temperature is too high, the electrolyte is very easy to burn, causing the battery to catch fire and more serious safety accidents

[0005] Liquid batteries are eagerly changing to solid-state batteries, but the conductivity of all-solid-state electrolytes is not ideal now, so it will slowly transition from quasi-solid-state batteries to all-solid-state batteries

For solid-state batteries, metal lithium is the most ideal negative electrode material, but side reactions between the liquid electrolyte and lithium metal are prone to occur, resulting in the growth of lithium dendrites and reducing the Coulombic efficiency of the battery. It is currently the development of quasi-solid-state batteries. bottleneck

[0006] The publication number is CN103855427A invention patent application discloses a solid electrolyte, the main technical problem to be solved is to provide a modified polymethyl methacrylate electrolyte with high mechanical strength and electrical conductivity, and its specification records the prepared lithium ion battery The charge and discharge efficiency of the 0.1C charge and discharge test does not improve significantly, and the application effect of high energy density lithium batteries needs further research

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