Enhanced ionic conductivity in a sustainable eucalyptus gum-chitosan biopolymer electrolyte for electrochemical device applications

Polymer electrolytes, owing to their distinct characteristics, present a viable alternative to liquid electrolytes in batteries. This study presents a biodegradable polymer electrolyte membrane composed of a blend of eucalyptus gum (EG), chitosan (CS), and ammonium thiocyanate (ATC), which demonstrates enhanced ionic conductivity. The amorphous nature of the membranes was confirmed by X-ray diffraction, whereas Fourier-transform infrared spectroscopy analysis elucidated the complexation between the biopolymer blend and the salt. Our results demonstrate that a blend containing 40 wt% of ATC results in six orders of magnitude enhancement in ionic conductivity (1.41 × 10⁻³ S cm − 1 ) at ambient temperature, accompanied by a cation transfer number of 0.92. Moreover, linear sweep voltammetry indicates an electrochemical stability window of 1.93 V, and a fabricated proton battery shows an open circuit voltage of 1.79 V. These findings highlight the potential of the sustainable EG-CS blend as an efficient and eco-friendly polymer electrolyte for electrochemical device applications.