Blends of PVdF-HFP and ionic liquids (ILs) are interesting for application as electrolytes in plastic Libatteries. They combine the advantages of the gel polymer electrolytes (GPEs) swollen by conventionalorganic liquid electrolytes with the nonflammability, and high thermal and electrochemical stability ofILs.In this work we prepared and characterized PVdF-HFP composite membranes swollen with a solutionof LiTFSI in ether-functionalized pyrrolidinium-imide ionic liquid (PYRA12O1TFSI). The membranes werefilled in with two different types of silica: (i) mesoporous SiO2 (SBA-15) and (ii) a commercial nano-sizeone (HiSilTM T700). The ionic conductivity and the electrochemical properties of the gel electrolytes werestudied in terms of the nature of the filler.The thermal and the transport properties of the composite membranes are similar. In particular, roomtemperature ionic conductivities higher than 0.25mScm−1 are easily obtained at defined filler contents.However, the mesoporous filler guarantees higher lithium transference numbers, a more stableelectrochemical interface and better cycling performances. Contrary to the HiSilTM-based membrane,the Li/LiFePO4 cells with PVdF-HFP/PYRA12O1TFSI–LiTFSI films containing 10 wt% of SBA-15 show goodcharge/discharge capacity, columbic efficiency close to unity, and low capacity losses at medium C-ratesduring 180 cycles.
|Number of pages||8|
|Journal||Journal of Power Sources|
|Publication status||Published - 2010|