The Influence of Ammonium Formate Concentration on the Electrical Performance of 2-Hydroxyethyl Cellulose Solid Biopolymer Electrolytes

Novel solid biopolymer electrolytes (SBE) with various amounts of ammonium formate (AF) salt doped into 2-hydroxyethyl cellulose (2-HEC) are fabricated by using a well-known technique, solution casting. The SBEs are developed mainly to address the leakage, toxic material issues, safety concerns, and costs associated with conventional liquid-based electrolytes. The 2-HEC-based SBE is analyzed for its ionic conductivity and electrical properties. The highest ionic conductivity achieved was 2.40 × 10-3 S/cm for AF40 (40 wt.% AF salt). The bulk resistance value obtained at ambient and elevated temperatures emphasizes its effect on ionic conductivity and electrical behavior regarding its dielectric permittivity. The activation energy from the temperature-dependent ionic conductivity indicates that activation energy decreases with increasing temperature. The two primary transport parameters affecting the system's ionic conductivity based on the Rice and Roth model are the diffusion coefficient (D) and ion mobility (µ). This study showed that the rise in ionic conductivity depends on the concentration of ammonium formate salt.