Nickel-Manganese Binary Metal Oxide as Electrode Materials for Supercapacitors

Pseudocapacitors have a higher specific capacitance than electrochemical double-layer capacitors (about 10 similar to 100 times). Since the Faraday reactions are simultaneously occur on the surface and inside of the electrode material during charging/discharging process. More electrons are generated and have a larger specific capacitance. At present, research on pseudocapacitance electrode materials mainly focuses on metal oxides and conductive polymers. Nickel-manganese-based metal oxides, as one of them, have the advantages of high theoretical specific capacitance, low cost, non-toxicity and environmental friendliness. However, its actual electrochemical performance is much lower than the theoretical value. Therefore, in order to improve the electrochemical performance of electrode materials. Some researchers have proposed many effective strategies, such as prepared of different kinds of metal oxides as electrode materials, use of different synthesis processes to prepare high specific surface area materials, the synergetic effect between the different materials and so on. In this paper, the application progress of nickel-manganese based binary metal oxides (NiMnO3, NiMn2O4 and Ni6MnO8) as pseudocapacitance electrode materials in supercapacitors has reviewed. At the same time, the future research directions of metal oxide electrode materials are further proposed.