Synthesis And Properties Of Novel Ionic Liquid Polymer Electrolyte

The development of novel highly ion-conducting polymer electrolytes for potential application in a wide variety of solid-state electrochemical devices has received an upsurge of interest, driven by the intrinsic properties of the polymer electrolytes, such as thin-film forming ability, flexibility, as well as the relatively high ionic conductivity and wide electrochemical window.Ionic liquids, due to their immeasurably low vapor pressure, high ionic conductivity, and greater thermal and electrochemical stability,are considered to be suitable electrolyte salts for polymer-in-salt systems.In this dissertation, the polymer electrolytes comprising a blend of PMMA or P(MMA-VBIMBr) as a host polymer and BMIMBF4as plasticizer were studied,and the results as follows:(1)1-Vinyl-3-Butylimidazolium bromide(VBIMBr) was synthesized using N-Vinylimidazole and bromic normal butane,and then poly-methyl methacrylate-1-vinyl-3-butylimidazolium bromide was synthesized via radical solution copolymerization with methyl methacrylate (MMA) and VBIMBr as monomers.Products were studied by FTIR,1H NMR.and The reaction condition were optimized. The best synthetic conditions of VBIMBr:reaction time is6h,temperature is80℃, and feed ratio is1:1.1. The yield of VBIMBr is91.30%;The optimum conditions of P(MMA-VBIMBr):copolymerization was run with chloroform as solvent at70℃for6h.The yield of P(MMA-VBIMBr) is92.74%.(2)The ionic liquids polymer electrolytes comprising a blend of PMMA or P(MMA-VBIMBr) as a host polymer and BMIMBF4as plasticizer were prepared by solution casting technique and studied by by FTIR,1H NMR,XRD,SEM,TG and EIS.According to these studies, it was found that polymer electrolytes based on PMMA and P(MMA-VBIMBr) had high thermal stability,the decomposition temperature are250℃and270℃respectively;polymer electrolytes based on P(MMA-VBIMBr) possess more excellent thermal stability and mechanical performance than PMMA-based electrolytes; and electrolyte membrane shows best comprehensive performance with BMIMBF4/polymer mass ratio of2:1and MMA/VBIMBr ratio of7:3,which ionic conductivity reached up to 0.50×10-3S/cm and2.77×10-3S/cm at20℃;and electrochemical window is3.5V and2V,respectively.The temperature dependence of the polymer electrolyte complexes appeared to obey Arrhenius equation.The innovation of this theme is a new kind of ionic liquid polymer electrolyte based on P(MMA-VBIMBr),which was synthesized via the free radical copolymerization reaction for the first time. The structural of ionic liquid was introduced in polymer matrix,which can change the motion of the polymer chain,decrease the crystallinity and Tg,and provide more carriers,are beneficial for further improving ionic conductivity.