Supercapacitor-based ionic diode: Mechanisms, materials, and emerging applications

Abstract

Supercapacitor-based ionic diodes (CAPodes) have recently emerged as a novel class of devices that bridge energy storage with information processing. By integrating the high-frequency charge storage capability of supercapacitors with diode-like rectification, they enable unique functionalities for next-generation iontronic circuits. This review summarizes the fundamental mechanisms of ion rectification in CAPodes, surveys recent advances in electrode and electrolyte materials as well as device architectures, and highlights emerging applications in smart grids, bioelectronics, and iontronic computing. Finally, current challenges and future perspectives are discussed to provide guidance for the rational design of high-performance CAPodes and their integration into practical systems.