Cross Linkable Polymeric Binders for Si anodes in Li Batteries for high performance and practical applications

Abstract

The electro chemical performance of Li ion battery (LIB) can be highly tuned by various factors which include morphology of anode material, nature of electrolyte and binding material, percentage of conducting materials etc. Among them, binding material have been attracted by researchers over decades, which results in the introduction of different polymeric binder, originated from nature, such as poly acrylic acid, carboxy methyl cellulose, alginic acid etc. for Si anode of LIBs. Recently several synthetic and structural modifications of these conventional polymeric binders, for example, random co polymer of polyacrylic acid with vinyl alcohol, porous scaffold of CMC, etc. has been developed by many researchers. However, the challenges of further development of Li ion rechargeable batteries still exists because of some unique property possessed by Li batteries, such as high energy density, high specific capacity and light weight to carry. Inspired from these advantages of LIBs, here in, we introduce a novel polymeric binder for Si anodes in LIB as an effort to improve the columbic efficiency and cycle durability of LIBs. We report, novel random copolymers, poly(tert-butyl acrylate-co-triethoxyvinylsilane) and Poly(acrylic acid-co-vinyl alcohol) as an efficient binders with ICE of more than 80% for LIBs. The binders form cross linking under thermal treatment, demonstrated by FT-IR, helps to minimize the pulverization of Si nano particle in the anode. In this present work we find out the optimum percentage of each monomer composition in the random co polymer by analyzing the electro-chemical-mechanical properties of series of synthesized random copolymers.