Improved performance of biopolymer composite electrolyte based cellulose acetate/Zinc Oxide filler for supercapacitors

Biopolymer composite electrolytes consisting of cellulose acetate and magnesium perchlorate with different weight percent (wt.%) of Zinc Oxide fillers were prepared using the standard solution cast technique. The effect of incorporating various amounts of ZnO fillers in our composite electrolytes was investigated for their electrical and structural properties, and ion transference numbers. The ionic conductivity of 40 wt.% ZnO filler was found to be 8.75× 10⁻⁴ S/cm at 30 °C along with a 4.2 V electrochemical stability window. The ion transference number has been found to be 0.97 for CA + 40 wt.% of Mg(ClO₄)₂ + 40 wt.% with ZnO fillers. Furthermore, the electrochemical performances of the prepared electrolytes have also been investigated. The fabricated cell with this electrolyte shows an enhanced energy and high-power density of 2.78 Wh/Kg and 1000 W/Kg, respectively. An increase in the above-mentioned densities may be attributed to the high ionic conductivity ZnO fillers in the biopolymer matrix. Additionally, it shows 100% capacitance retention along with high coulombic efficiency after the 129^th cycle.