Research progress of transition metal compounds and composites in the field of supercapacitors

Supercapacitors are widely used in the field of energy storage because of their high power density and good cycle stability. The energy storage mechanism of different electrode materials is different, and the corresponding supercapacitors are also obviously different. In recent years, transition metallic compounds with high energy density and capacitance have attracted extensive attention. In this paper, the energy storage principles and research results of three main transition metal-based electrode materials (transition metal oxide (TMOs), Layered double hydroxides (LDHs) and transition metal sulfide (TMDs)) and the research progress of their composites are reviewed, and the future of transition metal-based electrode materials is prospected.