Nanoporous LiMn2O4 spinel prepared at low temperature as cathode material for aqueous supercapacitors

LiMn2O4 spinel was prepared by a hydrothermal method using alpha-MnO2 nanotubes as precursor at 180 degrees C, a temperature much lower than that in previously reported methods. It is nanoporous with a pore size of about 40-50 nm and a BET surface area of 9.76 m(2) g(-1). It exhibits a high specific capacitance of 189 F g(-1) at 0.3 A g(-1) as a cathode for an aqueous supercapacitor. Even at 12 A g(-1), it still has a capacitance of 166 F g(-1). After 1500 cycles, there is no evident capacity fading. The LiMn2O4 cathode can deliver an energy density of 31.9 Wh kg(-1) at 3480W kg(-1) and even maintain 19.4 Wh kg(-1) at about 5100 W kg(-1) based on the mass of LiMn2O4. (C) 2013 Elsevier B.V. All rights reserved.