Rational design of metal oxide based electrode materials for high performance supercapacitors – A review

Supercapacitors have emerged as the most integral energy devices due to their unexampled countenance like high power and energy density, long cyclic life and environmentally friendly nature. Electrode materials play a critical role in determining the supercapacitor performance. Due to their rich valence states, excellent redox properties and high energy density, transition-metal oxides have demonstrated to be promising candidates for high performance supercapacitors, however, the relatively low conductivity limits their applications. Therefore, incorporating with carbon-based materials or conductive polymers is a promising strategy to further improve the performance of transition-metal oxide based supercapacitors. Here in, we have a comprehensive review on the advances and progress of transition-metal oxides materials applied in supercapacitors, such as copper oxide (CuO), nickel oxide (NiO), cobalt oxide (Co₃O₄), zinc oxide (ZnO), manganese dioxide (MnO₂), iron oxide (Fe₂O₃, Fe₃O₄, FeO), and their composites incorporated with carbon-based materials or conductive polymers. Finally, the current challenges and future perspectives of these electrode materials for supercapacitors have been summarized and anticipated.