Li-ion transport, structural and thermal studies on lithium triflate and barium titanate incorporated poly(vinylidene fluoride-co-hexafluoropropene) based polymer electrolyte

• PVdF-HFP/lithium triflate composites of several compositions are synthesized.
• Effect of lithium triflate weight fraction on the conductivity is studied.
• Crystallinity of PVdF-HFP decreases on addition of lithium/barium salts.
• Thermal stability of the composites increases by incorporation of barium titanate.

Solid polymer electrolytes (SPEs) are fabricated by incorporating lithium triflate (0–240 wt.%) into the PVdF-HFP (poly(vinylidene fluoride-hexafluoropropylene)) matrix. In the first phase, effects of lithium triflate content on ionic conductivity and structural properties of the SPEs are analysed and optimized. The ionic conductivity studies show that the AC and DC conductivities of SPEs increase with increasing the lithium triflate content and reach to orders of 10− 2 and 10− 3 S/cm, respectively. In the second phase, composite polymer electrolytes are fabricated by incorporating a ceramic filler, barium titanate (0–12 wt.%), to the optimized lithium triflate composition (15 wt.%) in PVdF-HFP matrix. The ionic conductivity of composite polymer electrolytes increases up to an order of one with the addition of filler up to 6 wt.% and decreases with further increase in the filler wt.%. Thermogravimetric analysis suggests that the thermal stability of the electrolytes enhances by the addition of ceramic filler. The structural studies of the electrolytes show that the crystallinity decreases on addition of lithium triflate and barium titanate.