Review-Pseudocapacitive Energy Storage Materials from Hagg-Phase Compounds to High-Entropy Ceramics

Energy storage material that provide both high power and high energy density are needed to meet current needs. Pseudocapacitive materials have become a focus of research in the field of electrochemical energy storage because of their high specific capacitance and good rate performance. To increase the energy and power density, the key lies in selecting suitable electrode material types or optimizing the electrode layer structure to increase the potential window. This review, starting from the pseudocapacitive materials, introduces the energy storage mechanism of pseudocapacitance, describes the general development of pseudocapacitive materials including oxide materials and their derivative, development of Hagg-phase compounds extended by the MXenes in the past decade, and focuses on the development of several Hagg-phase compounds and the advantages of high-entropy ceramics as future pseudocapacitive materials. Due to the high-entropy effect, high-entropy ceramics have better physical and chemical properties to become the most candidate pseudocapacitive material. Focusing on the application potential of the high-entropy ceramics in pseudocapacitive research, they will provide a new pseudocapacitive material system.

Automated summary

This review focuses on the development and characteristics of pseudocapacitive energy storage materials, as well as the potential of high-entropy ceramics as future promising pseudocapacitive materials. Increasing the power density and energy density of energy storage systems by selecting suitable electrode materials and optimizing structures is key to improving performance.