Ionic conductivity and conduction mechanism studies on cellulose based solid polymer electrolytes doped with ammonium carbonate

Abstract

The present work deals with the formation of solid polymer electrolytes (SPE) from carboxy methylcellulose (CMC) and doped with ammonium carbonate ((NH4)2CO3). The CMC–(NH4)2CO3 SPE was characterized with electrical impedance spectroscopy (EIS) and transference number measurement (TNM) to understand its electrical and conduction mechanism. Fourier transform infrared (FTIR) were conducted to correlate the complexation of the SPE with conductivity and conduction mechanism. Complexation appears to occur mainly in CMC carboxyl group (C=O). The highest ionic conductivity obtained is 7.71 × 10−6 Scm−1 for samples incorporated with 7 wt% of (NH4)2CO3. Lowest activation energy, E a achieved is 0.21 eV corresponds to the highest conductivity sample. Ionic conductivity measurement at elevated temperature follows Arrhenius model. Dielectric study of the sample shows dependence to temperature, but not to the frequency. CMC–(NH4)2CO3 SPE sample with the highest conductivity has transference number, $$t_{ + }$$ of 0.98 proving of its conduction is predominantly cation. Quantum mechanical tunneling (QMT) was the best model to explain the conduction mechanism of the highest conductivity sample.