Microwave-assisted synthesis of Fe-doped NiMnO3 as electrode material for high-performance supercapacitors

Fe-doped NiMnO3 nanosheet electrode material was successfully synthesized by convenient and efficient microwave-assisted hydrothermal method. The crystal structure, chemical composition, morphology, and specific surface area of the electrode material were analyzed by X-ray diffraction, Fourier transform infrared, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and Brunner–Emmet–Teller testing. Results showed that Fe doping changed not only the crystal structure but also the morphology of the NiMnO3 nanosheet electrode material. Moreover, the electrode material exhibited a high specific surface area and outstanding conductivity. Electrochemical performance was analyzed by cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy. The outcome of these experiments demonstrated that the Fe-doped NiMnO3 electrode material exhibited optimum electrochemical performance when the mass ratio was 15 wt%. The specific capacitance reached 732.7 F g−1 at a current density of 1 A g−1, and capacitance retention was approximately 78.3% after 10,000 cycles at 3 A g−1. The Fe-doped NiMnO3 electrode material is thus a promising next-generation supercapacitor material because of its high specific capacitance and long cycle life.