Rational design of NiMn-based electrode materials for high-performance supercapacitors

Supercapacitors have attracted extensive attention due to their advantages of high energy density, low cost and long cycle life. However, the key to affect the performance of supercapacitors lies in the electrode materials. The layered bimetallic hydroxides (LDHs), transition metal sulfides (TMSs), transition metal phosphides (TMPs) and transition metal oxides (TMOs) dominated by Ni and Mn elements have good electrochemical performance when they are used as electrode materials. The preparation methods of NiMn-based electrode materials, including hydrothermal method, electrodeposition method, sol-gel method, metal-organic frameworks (MOFs) derivation method, coprecipitation method, electrospinning method and so on, are reviewed in this paper. The carbon material modification of NiMn-based electrode materials is introduced from aspects such as graphene and its derivatives, carbon nanotubes, activated carbon, and biomass derived carbon. At the same time, the structure control strategies of NiMn-based composites are introduced, and the design strategies of two-dimensional and three-dimensional materials are systematically discussed, such as layer structure, heterostructure, Nano-flower structure, core-shell structure, etc. In particular, the research progress of NiMn-based electrode materials for asymmetric supercapacitors is introduced in detail, and their electrochemical properties in different applications are discussed. Finally, the current challenges and future development directions of NiMn-based electrode materials are discussed.