Heterostructure engineering of transition metal dichalcogenides for high-performance supercapacitors

Layered transition metal dichalcogenides (TMDs) have emerged as promising electrode materials for supercapacitors due to their high theoretical specific capacitance, unique layered structure, large surface area, and tunable energy band structure. Substantial progress has been made in the development of TMDs for supercapacitors, with several great breakthroughs reported. However, the practical application of TMDs is still hindered by several challenges, including their susceptibility to oxidation, the tendency to restack or aggregate, structural instability, and interior electrical conductivity. To overcome these limitations, the construction of heterostructures has been identified as an effective strategy. By modulating the interface structure between different components, heterostructures can enhance overall structural stability and facilitate faster ion transport, thereby improving the efficiency of supercapacitors. This review provides a comprehensive overview of recent advances in TMD-based heterostructures for supercapacitors, focusing on their synthesis methods, the relationship between structure, properties, and electrochemical performance, as well as existing challenges. Particular emphasis is placed on heterostructure engineering strategies that integrate TMDs with materials of various dimensionalities (0D, 1D, 2D, and 3D) to enhance their electrochemical performance for supercapacitors. Finally, the review discusses critical challenges and outlines future perspectives that may guide the development of TMDs for supercapacitors and beyond.