Development and characterization of zinc ion conducting biopolymer electrolytes based on cellulose acetate for primary zinc ion batteries

Solid biopolymer electrolytes for zinc primary battery based on cellulose acetate (CA) and zinc chloride (ZnCl₂) have been prepared by solution casting technique with Dimethylformamide (DMF) as the solvent. X-ray diffraction analysis provides that biopolymer membrane 40 wt% of CA:60 wt% of ZnCl₂ shows very high amorphous nature. Complex formation between biopolymer CA with ZnCl₂ has been confirmed by FTIR measurements. Biopolymer membrane 40 wt% of CA:60 wt% of ZnCl₂ shows a high zinc ionic conductivity of 3.04 × 10^–3 S/cm calculated from impedance measurements. Wagner’s Polarization measurements indicates that charge carriers are ions and the highest zinc ionic conductivity membrane has got low glass transition temperature 35 °C determined by DSC studies. The electrochemical stability of the highest zinc ion conductivity membrane is found to be 2.15 V by LSV technique. The cyclic stability of the prepared membrane has been determined by cyclic voltammetry analysis. Transport parameters such as Diffusion constant (D), mobility (μ) and relaxation time (τ) have been calculated for the biopolymer electrolytes. A primary zinc ion battery has been constructed using zinc plate as anode, highest zinc ion conducting membrane as an electrolyte and MnO₂ as cathode shows an open-circuit voltage 1.55 V. The performance of the battery has been studied with various loads.