SYNTHESIS AND FABRICATION OF SELF-HEALING SOLID POLYMER ELECTROLYTE FOR LITHIUM-ION BATTERY

Abstract

With the prompt growth and advancement of the lithium-ion battery, related safety concerns have adhered to the concern associated with the conventionally used liquid/gel electrolyte. All energy storage devices (ESDs) need electrolytes to carry charges from active materials to electrodes in a reversible manner. As the ionic conductance of an electrolyte should be high to achieve a good energy/power density in the different energy storage devices, liquid electrolytes were initially employed. These liquid electrolytes had certain drawbacks such as limited temperature range, bulky size, internal short-circuiting, thermal runaway, corrosion of electrodes, leakage of fluids and low energy density [1]. Therefore, a need for the transformation in electrolyte technology is highly required. The solid electrolyte is a potential way of overcoming all these drawbacks associated with liquid electrolytes, but lower ionic conductivity and generation of cracks with time are significant issues but this can be resolved by doing proper modification and optimization through various processes. Polymers are an emerging choice of material in the development of Solid Electrolytes as their production cost is very low, flexible and light in weight, with higher impact and tensile strength, corrosion and scratch resistance. The polymers which are being used as polymer gel electrolytes should be polar such as Polyvinylidene fluoride, Polyethylene Oxide, Polymethyl methacrylate, Polypropylene oxide, and Polyacrylonitrile [2]. All living beings in nature have self-healing mechanisms to recover from damage/injuries, which, if mimicked in electrolyte technologies, may change the future course in bendable and flexible ESDs. With the self-healing polymer electrolytes, severe cracks and fractures in the thickest layers can be intrinsically repaired [3]. Thus, we are here proposing to fabricate a self-healable solid polymer electrolyte that could be used in various energy storage devices. In this way, we have produced a series of copolymers of vinyl acetate (VA) & Diallylic disulphide (DADS) using the bulk polymerization technique through a free radical mechanism. Although PVA is already used in Solid Polymer Electrolytes, this homopolymer does not show self-healing properties [4]. The disulphide group present in the DADS is responsible for the self-recovery of the polymer due to its dynamic sulphide linkage. Therefore, the synthesized copolymer can be employed as a self-healable solid polymer electrolyte.