Conductivity and transport studies of plasticized chitosan-based proton conducting biopolymer electrolytes

This paper focuses on the conductivity and transport properties of chitosan-based solid biopolymer electrolytes containing ammonium thiocyanate (NH4SCN). The sample containing 40 wt% NH4SCN exhibited the highest conductivity value of (1.81 ± 0.50) × 10−4 S cm−1 at room temperature. Conductivity has increased to (1.51 ± 0.12) × 10−3 S cm−1 with the addition of 25 wt% glycerol. The temperature dependence of conductivity for both salted and plasticized systems obeyed the Arrhenius rule. The activation energy (Ea) was calculated for both systems and it is found that the sample with 40 wt% NH4SCN in the salted system obtained an Ea value of 0.148 eV and that for the sample containing 25 wt% glycerol in the plasticized system is 0.139 eV. From the Fourier transform infrared studies, carboxamide and amine bands shifted to lower wavenumbers, indicating that chitosan has interacted with NH4SCN salt. Changes in the C–O stretching vibration band intensity are observed at 1067 cm−1 with the addition of glycerol. The Rice and Roth model was used to explain the transport properties of the salted and plasticized systems.