Composite polymer electrolyte film for lithium ion battery and preparation method thereof

Abstract

The invention relates to a composite polymer electrolyte film for a lithium ion battery and a preparation method thereof. Electrolyte takes polymers as matrix material, and is evenly filled with lithium conductive ceramic powder, wherein the quality of the lithium conductive ceramic powder is 1-20% of that of polymer electrolyte; the lithium conductive ceramic powder is one of LISICON ceramic, NASICON ceramic, perovskite ceramic and lithium BPO4 ceramic at least, the polymers include polyoxyethylene, polyacrylonitrile, polymethylmethacrylate, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymers and blending and copolymerization systems of the matrixes. The prepared composite polymer electrolyte film for the lithium ion battery can be used as polymer electrolyte for a lithium ion secondary battery, improves the safety performance of the lithium ion battery, and has high mechanical performance and strong operability, and the polymers obtain good elasticity and processability and the lithium conductive ceramic has high ionic conductivity and lithium ion migration number.

Description

technical field [0001] The invention relates to a composite polymer electrolyte membrane for a lithium ion battery and a preparation method thereof. Background technique [0002] As a green chemical power source with high energy density, high output voltage, no memory effect, and environmental friendliness, lithium-ion batteries have good economic benefits, social benefits, and strategic significance, and have been widely used in mobile communications, digital Products, aerospace and other fields, and is considered to be the most promising power battery for electric vehicles. However, there are many safety problems caused by the use of flammable, volatile, and highly reactive organic liquid electrolytes in lithium-ion batteries. For example, the main component of liquid electrolyte is carbonate, which has a very low flash point and a low boiling point, and will burn or even explode under certain conditions. At present, the solution is to use other electrolyte materials ins...

AI Technical Summary

Problems solved by technology

[0003] Polymer electrolyte is a kind of electrolyte material that realizes ion conduction by adding lithium salt in the polymer matrix, and the directional movement of lithium ions in the polymer matrix. Because the polymer material has good viscoelasticity and plasticity, it is easy to process, and The cost is low, and it has become the most likely electrolyte material to replace organic liquid electrolytes. However, it is difficult to obtain high room temperature ion conductivity for pure solid polymer electrolytes, and the lithium ion migration number is low (generally less than 0.4). Electrode polarization occurs, which limits the practical application of polymer electrolytes

Lithium conductive ceramic solid electrolyte has high room temperature ionic conductivity, lithium ion migration number is close to 1, and has good high temperature resistance, but its mechanical strength is poor, the interface impedance when in contact with the electrode active material is large, and the electrochemical window is relatively small. narrow

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