NiCo2S4 nanotube arrays grown on flexible carbon fibers as battery-type electrodes for asymmetric supercapacitors

NiCo2S4 nanotube arrays grown on carbon cloth are prepared successfully by a facile two-step method. The as-prepared tubular nanoarchitecture deliver a high specific capacity of 578 C/g at a galvanostatic charge-discharge current density of 0.5 A/g with good cycling stability in 3 M KOH aqueous solution. Furthermore, the all-solidstate asymmetric supercapacitor based NiCo2S4 nanotube arrays as the positive electrode shows a superior energy density of 24.78 Wh/kg at a power density of 1770.13 W/kg. The results reveal that the as-synthesized NiCo2S4 nanotube arrays might be promising electrode materials for electrochemical energy storage.