Optimisation of PVdF-based polymer electrolytes

An attempt was made to synthesise PVdF-based polymer electrolytes containin g 1:1 EC:PC plasticiser in various salts such as LiAsF6, LiPF6 and LiBF4 at different ratios using PVdF as homopolymer. Though, having a high ionic co nductivity, certain films were found to be fragile, an indication of poor m echanical strength. Therefore, PVdF-PVC blend polymers were prepared using different ratios of PVdF-PVC as well as with different amounts of plasticis er mixture. Film characterisation was attempted using XRD, DSC, impedance a nd conductivity measurements. A particular combination of PVdF-PVC in the r atio 25:5 was observed to have high ionic conductivity and good mechanical strength. The electrochemical stability and the stability of lithium-polyme r interface of the prepared polymer electrolytes were checked in terms of c harge-discharge and impedance studies. Effect of storage time and cyclabili ty are discussed. (C) 2001 Elsevier Science B.V. All rights reserved.