Harnessing the Benefits of PEDOT : PSS Conductive Coating for Prolonged Cycle Life of Copper Hexacyanoferrate in Aqueous Zinc-Ion Batteries

The utilization of copper hexacyanoferrate (CuHCF) as positive electrode material in aqueous zinc-ion batteries (ZIBs) has gained significant attention due to its efficient (de-)intercalation of Zn2+ ions, cost-effective synthesis, low toxicity, and high working potential. One approach to improve its electrochemical performance is to coat the CuHCF particles with conductive polymers, such as poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT : PSS). In this study, we investigated the impact of the PEDOT : PSS as a coating on the electrochemical behavior and the cycle life of CuHCF for aqueous ZIB applications. Galvanostatic cycling performed at a current rate of 1 C relevant for the stationary application of the CuHCF/PEDOT : PSS electrodes having high mass loadings (10 mg cm(-2) of active material) revealed significantly longer cycle life while maintaining a high Coulombic efficiency (>= 99.5 %). The longest cycle life was achieved with CuHCF coated using a 4.5 wt. % PEDOT : PSS aqueous coating dispersion. These findings demonstrate the potential of conductive polymer coatings as a practical approach to enhance the electrochemical performance of positive electrode materials in aqueous Zinc-ion batteries.