Facile synthesis of iron[sbnd]nickel[sbnd]cobalt ternary oxide (FNCO) mesoporous nanowires as electrode material for supercapacitor application

Abstract

Transition Metal Oxides have drawn significant attention due to their reversible chemical redox reaction and long-life stability. Inexorable agglomeration and shrinkage/expansion of transition metal oxides in the nanosize regime have a noticeable effect on their electrochemical properties. Here in this work, mesoporous nanowires (NWs) with a typical composition of iron-nickel-cobalt ternary oxide (FNCO) are synthesized using a simple, facile and cost-effective hydrothermal process followed by furnace annealing. These NWs are then extensively investigated as an electrode material for supercapacitor application. To compare the electrochemical properties, nanowires of nickel-cobalt oxide (NCO), iron-cobalt oxide (FCO) and cobalt oxide (CO) were also produced by following the same protocol. The FNCO NWs are found to overcome the shortcomings in the electrochemical energy storage devices by exhibiting higher values of specific capacitance (2197 Fg-1) and energy density (109 Whkg−1) at 1 Ag-1 current rate. Moreover, the FNCO NWs also showed a cyclic charge/discharge stability of 96% even up to 20,000 cycles. Furthermore, a FNCO//graphene asymmetric device, fabricated with FNCO NWs and graphene as positive and negative electrodes, respectively, which exhibit high energy density (47 Whkg−1), power density (375 Wkg-1) and excellent capacitance retention (86%) after 15,000 cycles.