Free Volume Controlled Ionic Conductivity in Poly Vinyl Alcohol/Zinc Acetate Solid Polymer Electrolytes
E. Kavya Valsan, Anju John, M. Raghavendra, H.B. Ravikumar
Abstract
Poly vinyl alcohol (PVA)/ Zinc acetate (ZnAc) Solid Polymer Electrolytes (SPEs) of different ZnAc weight percentage (5%, 10%, 15%, 20%) were prepared. Positron Lifetime Spectroscopy (PLS) studies reveal the increased fractional free volume (F v ) from 1.93% to 2.16% for 20 wt% of ZnAc loading. The increased ionic conductivity of PVA/ZnAc SPEs for 20 wt% of ZnAc loading suggests the increased concentration of Zn 2+ cations and acetate anions. The ionic conductivity of PVA/ZnAc SPEs increases at higher frequencies of the applied electric field due to the increased polarization of dipoles. The increased ionic conductivity of PVA/ZnAc SPEs with increased fractional free volume suggests that the mobility of Zn 2+ and acetate ions is favored by the amorphous phase of the SPEs. The XRD results justify the increased amorphousness of PVA/ZnAc SPEs. FTIR studies confirm the formation of polymer salt complexes due to chemical bonding between C–H group of PVA and carbonyl group of (C=O) of ZnAc salt.