Method for preparing ionic liquid plasticized composite polymer electrolyte for lithium ion battery

Abstract

The invention relates to a method for preparing ionic liquid plasticized composite polymer electrolyte for a lithium ion battery. In the invention, the conductivity of a polymer electrolyte membrane is increased, meanwhile, the electrochemical stability window and the mechanical properties of the membrane are also further enhanced. The method comprises two parts. The first part is to prepare an inorganic particle doped polymer-matrix microporous membrane with a steam bath exchange method and mainly comprises the following steps of: firstly, uniformly dispersing inorganic particles in an organic solvent; then, dissolving a polymer matrix and a pore forming agent in the uniform organic solvent to form transparent gel under the condition of agitation; and finally, preparing the inorganic particle doped polymer-matrix microporous membrane through casting membrane formation and with the steam bath exchange method. The second part is to prepare the ionic liquid plasticized gel-like composite polymer electrolyte and mainly comprises the following steps of: directly soaking the prepared doped polymer-matrix microporous membrane in a mixed solution of imidazole ionic liquid and lithium salt so as to swell and plasticize the polymer-matrix microporous membrane. Because steam bath is adopted to form the membrane and the imidazole ionic liquid is introduced to perform plasticization, the prepared electrolyte membrane has good mechanical strength and flexibility, high ionic conductivity, wide electrochemical stability window and simple preparation process and is easy for realization of industrial production.

Description

technical field [0001] The invention relates to an ionic liquid plasticized composite polymer electrolyte for a lithium ion battery and a preparation method thereof, belonging to the field of polymer material preparation. Background technique [0002] Lithium-ion batteries have been a hot spot in the research and development of chemical power sources since their introduction in the early 1990s due to their significant advantages such as high operating voltage, high energy density, long cycle life, low self-discharge rate, low pollution, and no memory effect. At present, in order to solve the explosion hazard caused by liquid leakage in traditional liquid lithium-ion batteries, polymer lithium-ion batteries are increasingly favored because of their high specific energy, safety, flexible shape, ability to inhibit dendrite growth, and buffer charging. The advantages of electrode volume change during discharge and the elimination of battery safety issues related to liquid electr...

AI Technical Summary

Problems solved by technology

[0003] All-solid electrolytes can maintain good mechanical properties, but cannot meet the conductivity requirements of the used

Although the electrolyte membrane prepared by the traditional phase inversion method can meet the requirements of electrical conductivity, it has obvious disadvantages such as poor mechanical properties of the membrane.

At present, the industrialized polymer electrolyte preparation is mainly the Bellcore extraction / activation two-step production method proposed by Gozdz et al. Although this method can prepare an electrolyte membrane that meets the practical conductivity, the whole process involves a large amount of organic solution. Applicable but there are problems such as harm to the environment

Electrolyte membranes prepared by electrospinning are limited in their use due to cumbersome preparation process, immature process and high cost.

The idea of ​​using the addition of inorganic particles to improve the mechanical properties of the electrolyte membrane proposed by Professor Scrosati of the First University of Rome in Italy has been unanimously recognized. However, due to the involvement of organic plasticizers in the entire electrolyte membrane preparation process, it is easy to cause its Decomposition occurred during use and a series of safety accidents occurred

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