Impacts of ceramic filler and the crystallite size of polymer matrix on the ionic transport properties of lithium triflate/poly (vinylidene fluoride-co-hexafluoropropene) based polymer electrolytes

- Lithium triflate/PVDF-HAF SPEs with optimized Li-salt loading are synthesized.
- Incorporation of BaTiO3 enhances the σDC of SPEs by one order of magnitude.
- Li-ion conductivity increases with decreasing crystallite size of polymer matrix.

Solid polymer electrolytes (SPEs) have wide-scale applications in the fields of energy storage (capacitors and batteries), power conversion (fuel cells), electrochemical sensing etc. In the present work, poly(vinylidene fluoride-co-hexafluoropropene) (PVDF-HFP) based SPEs with varying concentration of lithium triflate and composite solid polymer electrolytes (CSPEs) composed of BaTiO3 in addition to the optimised loading of lithium triflate in PVDF-HFP matrix are synthesized by solution casting technique. SPE with 10 wt.% lithium triflate shows highest DC conductivity of 2.19 × 10−6 S cm−1 at 300 K, which enhances to 8.89 × 10−6 S cm−1 by adding 4 wt.% of BaTiO3. X-Ray diffraction (XRD) and scanning electron microscopy (SEM) analysis shows that the reduction in crystallite size of the polymeric matrix assists in enhancing the conductivity. Hence, the crystallite size, by altering the arrangement of the non-conducting polymeric chains, affects the ionic conductivity of the composites significantly.

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