Sodium‐Ion Capacitors: Recent Development in Electrode Materials

Abstract Sodium‐ion hybrid capacitors (SICs), combining the advantages of both sodium‐ion batteries (SIBs) and electrochemical supercapacitors, have captured sustained attention in the field of energy storage devices due to their high energy and power density, long lifespan, and excellent operation stability. However, conventional SICs based on battery‐type anodes and capacitive‐type cathodes suffer from imbalance on capacity and kinetics. In this regard, rational structure design on electrode materials is still necessary for SICs. Over the past two decades, tremendous efforts have been devoted to the exploration of suitable electrode materials to fabricate high‐performance SICs. Herein, after a brief introduction on the charge storage mechanisms of SICs, the recent developments on electrode materials for SICs are summarized, especially focusing on material design strategies as well as the relationship between structure and corresponding electrochemical performances. Furthermore, the challenges and opportunities for the further development of SICs are also proposed.