The Effect of NH4Br Composition on Electrical Behaviour of 2-Hydroxyethyl Cellulose Solid Biopolymer Electrolytes

In this study, solid biopolymer electrolytes (SBEs) were developed as an alternative to liquid electrolytes for battery applications. 2-hydroxyethyl cellulose (2HEC) served as the polymer host in the preparation of SBE films, incorporating varying amounts of ammonium bromide (NH4Br). The films were then analysed using electrical impedance spectroscopy (EIS) to investigate its electrical properties. The system containing 20 wt.% of NH4Br achieved the highest conductivity at 3.9510-5 Scm-1 at ambient temperature of 303 K. The 2HEC-NH4Br SBE film system was subjected to temperature variations between 303 K – 373 K in increments of 10 °C, revealing an increase in conductivity with rising temperature. This observation suggests that the SBE system adheres to the Arrhenius law, enabling the determination of the activation energy (Ea) through temperature dependence plotting. The Ea for the most conductive system reflects the lowest energy, indicating minimal energy required for the excitation process within the polymer chain. This Ea value offers a deeper insight into the transport parameters, including the number of mobile ions, ions mobility and diffusion coefficient, as determined through the Rice and Roth method.