Spinel LiMn2O4 nanohybrid as high capacitance positive electrode material for supercapacitors

A LiMn2O4 nanohybrid consisting of nanotubes, nanorods and nanoparticles has been synthesized using alpha-MnO2 nanotubes from hydrothermal reaction as a precursor. It is characterized with X-ray diffraction, field emission scanning electron and transmission electron microscopy. A formation mechanism is proposed. As a positive electrode material for supercapacitors, it exhibits a high specific discharge capacitance of 415 F g(-1) at 0.5 A g(-1) in 0.5 mol l(-1) Li2SO4 aqueous solution. Even at 10 A g(-1), it still has a specific discharge capacitance of 208 F g(-1). The energy density of the asymmetric supercapacitor using activated carbon as the negative electrode and LiMn2O4-nanohybrid as the positive electrode in the aqueous solution in the voltage range of 0-1.8 V presents 29.8 Wh kg(-1) at power density of 90 W kg(-1). In addition, the cycling behavior of the asymmetric supercapacitor is good. (C) 2013 Elsevier B.V. All rights reserved.