Microwave hydrothermal synthesis of -MnMoO4 nanorods for high electrochemical performance supercapacitors

Pristine -MnMoO4 nanorods were facilely prepared via co-precipitation (Cp) and microwave hydrothermal (MH) methods. X-ray diffraction (XRD) patterns showed pure monoclinic crystalline phase -MnMoO4 for the heat treated powder at 500 degrees C. Fourier Transform Infrared (FTIR) spectra showed that the chemical bond structure of -MnMoO4 corresponds to the strong vibrational modes of Mo-O-Mo, Mo-O and Mo?O. Raman spectra showed the structural bonding and crystalline nature of -MnMoO4. Field Emission Scanning Electron Microscope (FE-SEM) images exposed the nanorod shape of the -MnMoO4 powder, with diameters of approximate to 200 nm and lengths of approximate to 1.6 m. Electrochemical studies of the Cp- and MH-MnMoO4 nanorods with 2 M NaOH as the electrolyte showed specific capacitances of 143 F g(-1) and 551 F g(-1), respectively, at a 1 A g(-1) constant discharge current density. Cyclic voltammetric (CV) studies of the MH-MnMoO4 nanorods at various scan rates revealed the presence of redox pairs, suggesting a pseudocapacitive nature. The structural stability at different current densities demonstrated the high rate performances and good reversible capacity retention of the calcined MH-MnMoO4 nanorods. A cycling life stability study of MH-MnMoO4 demonstrated a good capacity retention of 89% of the initial specific capacitance at 5 A g(-1) after 1000 cycles.