Research progress of high-performance micron-sized electrode materials for supercapacitors with a promising future

From small-scale energy storage to large-scale energy storage, supercapacitors have demonstrated their exceptional performance by enabling instantaneous power output for rapid charge and discharge. The research focus has shifted toward high-performance electrode materials, as they play a crucial role in determining the overall performance of supercapacitors. Despite the numerous reports on nanostructured electrode materials with excellent electrochemical properties over the past 30 years, the practical development of high-energy supercapacitors has been hindered by discrepancies between industrial applications that face gravimetric energy limitations and experimental studies constrained by volumetric constraints. Micron-sized electrode materials offer advantages such as high tap density, reduced specific area to minimize side reactions, increased mass loading, and enhanced volumetric capacity, making them potential candidates to bridge this gap between experimental studies and practical applications. However, challenges related to significant volume expansion and slow reaction kinetics still need to be addressed for micron-sized electrodes. This review summarizes the energy storage mechanisms of micron-sized electrode materials and recent advancements in their preparation methods aimed at improving energy density, conductivity, structural stability, and cycling stability. Furthermore, suggestions are provided regarding future developments and research directions for microscale electrode materials in supercapacitors.