Optimization of PVDF-based polymer electrolytes.

An attempt was made to synthesise PVdF-based polymer electrolytes containing 1:1 EC:PC plasticiser in various salts such as LiAsF6, LiPF6 and LiBF4 at different rations using PVdF as homopolymer. Though having a high ionic conductivity, certain films were found to be fragile, an indication of poor mechanical strength. Therefore, PVdF-PVC blend polymers were prepared using different rations of PVdF-PVC as well as with differents amount of plasticiser mixture. Film charecterisation was attempted using XRD, DSC, impedance and conductivity measurements. A particular combination of PVdF-PVC in the ratio 25:5 was observed to have high ionic conductivity and good mechanical strength. The electrochemical stability and the stability of lithium-polymer interface of the prepared polymer electrodes were checked in terms of charge-discharge and impedance studies. Effect of storage time and cyclability are discussed