Composite electrolyte membrane and preparation method and application thereof

Abstract

The invention discloses a composite electrolyte membrane and a preparation method and application thereof. The composite electrolyte membrane comprises a porous membrane substrate which is filled withhot-melt polymer filling particles, an organic-inorganic electrolyte filling layer which is arranged on at least part of the surface of the porous membrane substrate and comprises organic-inorganic electrolyte of which at least part fills the porous membrane substrate, and a polymer electrolyte buffer layer which is arranged on at least part of the organic-inorganic electrolyte filling layer andcovers the porous membrane substrate as a surface in contact with electrodes. The composite electrolyte membrane has the advantages of high safety performance, excellent mechanical strength, high conductivity at room temperature and good interface compatibility with positive and negative electrodes.

Description

technical field [0001] The invention belongs to the technical field of solid electrolytes, in particular, the invention relates to a composite electrolyte membrane and its preparation method and application. Background technique [0002] All-solid polymer electrolytes and fast ion conductor composite electrolytes can effectively solve the shortcomings of traditional liquid electrolytes and improve the safety performance of lithium-ion batteries. High ionic conductivity, good compatibility with electrodes, excellent mechanical properties, and wide electrochemical window are the characteristics that an ideal solid-state polymer electrolyte should have, but currently commonly used all-solid-state polymer electrolytes are difficult It has the above characteristics at the same time. For example, the traditional PEO system lithium-ion battery solid electrolyte has insufficient room temperature ionic conductivity and mechanical strength. One method to improve the room temperature ...

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Problems solved by technology

However, the method of introducing carbonate-based solid electrolytes is generally copolymerization or mixing. The copolymerization method is easy to change the flexibility of the molecular chain, reducing the mobility of the molecular chain and thus weakening the ion conductivity, while the mixing method has compatibility problems and is easy to reduce the mechanical strength of the electrolyte. and energy density

Based on this, a large number of experimental studies have been carried out in the industry by coating the surface of the porous membrane carrier with an electrolyte gel layer. This kind of electrolyte membrane with the help of a porous carrier can improve the strength and flexibility of the electrolyte membrane, but due to the porous carrier The thickness of the electrolyte is generally relatively thick, and the pores are mostly non-through holes with large pore diameters. If the control is not good, it will easily lead to micro-short circuit. The surface coating technology cannot ensure that the electrolyte material is completely filled. In the actual application process, there will be a hollow phenomenon, resulting in ion conduction. Impossible, battery impedance increases, unable to work normally

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