▎ 摘　　要

Ionic Liquid (IL) based polymer electrolytes using polymer poly ethylene oxide (PEO), salt lithium bis(fluoro-methylsulfonyl)imide and IL N-propyl-N-methylpyrrolidinium-bisfluorosulfonylimide (PYR13FSI) are synthesized by solution cast method. Using different experimental techniques, good thermal stability and wide electrochemical window are observed for synthesized polymer electrolytes. Maximum Li+ conductivity is found for 10% IL containing polymer electrolyte so, it is used in Li cell preparation. LiFePO4 (LFP) cathode and graphene oxide wrapped LFP cathode (GO-LFP) are also prepared to observe the effect of graphene oxide coating in electrochemical performance of the Li cell. From charge -discharge process, high specific discharge capacity (similar to 163 mAh g(-1) at 0.1 C) is found for GO-LFP as compared to LFP cathode. GO-LFP cathode shows good cyclability and Coulombic efficiency up to 100 cycles. High charge-discharge capacity of GO-LFP is noticed even at higher current rate.