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

Abstract

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.