Mechanism research progress on transition metal compound electrode materials for supercapacitors

Abstract Supercapacitors (SCs) have remarkable energy storage capabilities and have garnered considerable interest due to their superior power densities and ultra‐long cycling characteristics. However, their comparatively low energy density limits their extensive application in large‐scale commercial applications. Electrode materials directly affect the performance of SCs. Thus, the development of cutting‐edge electrode materials and modification of their morphological and structural properties are vital for advancing the performance of SCs. Transition metal compounds have a high specific capacity and good cycling durability, making them the most promising electrode active materials for high‐energy density SCs. Nevertheless, their inadequate conductivity, unfavorable ion diffusion rates, substantial volume expansion and phase transitions during charging and discharging are obstacles to their stable and efficient integration into SCs. To address these challenges, this study provides a comprehensive summary of the current advancements in transition metal nanomaterials as electrode materials for SCs, an overview of the current research status, and the prevailing challenges. Furthermore, this study highlights synthetic techniques and management strategies for electrode materials derived from transition metal compounds, targeting the resolution of the aforementioned challenges. Finally, a concise discussion is provided on the future directions of SC development, with an emphasis on the utilization of transition metal compound electrode materials.