Facile synthesis of NiMn2O4 nanosheet arrays grown on nickel foam as novel electrode materials for high-performance supercapacitors

Nanostructured spinel NiMn2O4 arrays have been fabricated by a facile hydrothermal approach and further investigated as binder-free electrode for high-performance supercapacitors. Compared with Mn3O4, NiMn2O4 exhibited higher specific capacitances (662.5 F g−1 and 370.5 F g−1 in different electrolytes at the current density of 1 A g−1) and excellent cycling stability (~96% capacitance retention after 1000 cycles) in a three-electrode system. Such a novel microstructure grown directly on the conductive substrate provided sufficient active sites for redox reaction resulting in their enhanced electrochemical behaviors. Their improved performances suggested that ultrathin sheet-like NiMn2O4 arrays on Ni foam substrate were a promising electrode material for supercapacitors.