Plasticised chitosan: Dextran polymer blend electrolyte for energy harvesting application: Tuning the ion transport...

This study investigates the performance of biopolymer electrolytes based on chitosan and dextran for energy storage applications. The optimization of ion transport and performance of electric double-layer capacitors EDCL using these electrolytes, incorporating different concentrations of glycerol as a plasticizer and TiO₂ as nanoparticles, is explored. Impedance measurements indicate a notable reduction in charge transfer resistance with the addition of TiO₂. DC conductivity estimates from AC spectra plateau regions reach up to 5.6 × 10^-4 S/cm. The electric bulk resistance R_b obtained from the Nyquist plots exhibits a substantial decrease with increasing plasticizer concentration, further enhanced by the addition of the nanoparticles. Specifically, R_b decreases from ∼20 kΩ to 287 Ω when glycerol concentration increases from 10 % to 40 % and further drops to 30 Ω with the introduction of TiO₂. Specific capacitance obtained from cyclic voltammetry shows a notable increase as the scan rate decreases, indicating improved efficiency and stability of ion transport. The TiO₂-enriched EDCL achieves 12.3 F/g specific capacitance at 20 mV/s scan rate, with high ion conductivity and extended electrochemical stability. These results suggest the great potential of plasticizer and TiO₂ with biopolymers in improving the performance of energy storage systems.