Polymer Electrolytes Based on Poly(vinylidenefluoride-hexafluoropropylene) and Cyanoresin

摘要

Lithium gel electrolytes based on a mixed polymer matrix consisting of poly(vinylidenefluoride-hexaflu-oropropylene) (PVDF-HFP) and cyanoresin type M (CRM) were prepared using an in situ blending process.The CRM used in this study was a copolymer of cyanoethyl pullulan and cyanoethyl poly(vinyl alcohol) (PVA) with a mole ratio of 1:1.The mixed plasticizer was ethylene carbonate (EC) and propylene carbonate (PC) with a volume ratio of 1:1.In this study,the presence of PVDF in the electrolytes helps to form a dimensionally stable film over a broad composition range,and decreases the viscosity.In addition,it provides better rheological properties that are suitable for the extrusion of thin films.However,the presence of HFP has a positive effect on generating an amorphous domain in a crystalline PVDF structure.The ionic conductivity of the polymer electrolytes was investigated in the range 298-333 K.The introduction of CRM into the PVDF-HFP/LiPF6 complex produced a PVDF-HFP/ CRM/LiPF6 complex with a higher ionic conductivity and improved thermal stability and dynamic mechanical properties than a simple PVDF-HFP/LiPF6 complex .