Dual solvent step-by-step phase conversion preparation method of polymethyl methacrylate gel electrolyte microporous membrane

Abstract

The invention discloses a dual solvent step-by-step phase conversion preparation method of a polymethyl methacrylate gel electrolyte microporous membrane. The preparation method comprises the following steps: mixing a pore forming agent and a volatile solvent, dissolving polymethyl methacrylate polymer, after complete dissolution, uniformly painting the solution on a flat plate by using a scraper; allowing the flat plate to stand still for a while, after the volatile solvent is completely volatized, soaking the flat plate in deionized water, after the pore forming agent in the polymer membrane is dissolved in water, taking out the flat plate, drying the flat plate through baking, and after drying, soaking the polymer membrane into lithium salt electrolyte to obtain the PMMA gel electrolyte microporous membrane. A solvent, which can be easily dissolved in water and has a boiling point greater than 100 DEG C, is taken as the pore forming agent, the uniformity of the gel electrolyte microporous membrane is improved; compared with a conventional diaphragm, the electrochemical stability window and charge / discharge efficiency are higher; a better liquid absorbing effect is achieved, no leakage happens, the mechanical strength of the membrane is enhanced; the safety problem of liquid lithium ion batteries is solved, the problem that the conductivity of solid batteries is low is solved; and the method can be applied to industrial production easily.

Description

technical field [0001] The invention relates to a preparation method of a gel electrolyte microporous membrane, in particular to a method for preparing a polymethyl methacrylate gel electrolyte microporous membrane by step-by-step phase inversion with two solvents. Background technique [0002] Lithium-ion batteries have become widely used power products due to their high operating voltage, high energy density, small self-discharge, no memory effect, wide operating temperature range, light weight, long cycle life, and environmental friendliness. Ionic liquid electrolytes have the advantages of wide operating temperature range, high conductivity, low vapor pressure, non-volatile, low toxicity, non-explosive, low melting point, etc., but there are also many problems: high cost, high viscosity, harsh synthesis conditions, the basis of ionic liquids lack of data, etc. The all-solid polymer electrolyte is a system composed of lithium salt and polymer, and its conductivity is low...

AI Technical Summary

Problems solved by technology

Ionic liquid electrolytes have the advantages of wide operating temperature range, high conductivity, low vapor pressure, non-volatile, low toxicity, non-explosive, low melting point, etc., but there are also many problems: high cost, high viscosity, harsh synthesis conditions, the basis of ionic liquids lack of data, etc.

However, the gel electrolyte membrane prepared by this method still has the following problems: First, the porous membrane skeleton is prepared by immersion precipitation, although this method can obtain a variety of different pore structures, such as honeycomb, finger and sponge Pores, etc., but this method is not easy to achieve structural controllability and structural repeatability of the porous membrane; second, the mechanical strength of the porous membrane prepared by this method is still not ideal; third, the membrane pore size distribution is wide and difficult to adjust