Construction of desirable NiCo2S4 nanotube arrays on nickel foam substrate for pseudocapacitors with enhanced performance

Ternary NiCo2O4 synthesized via annealing NiCo-precursor has been extensively studied as an advanced electrode material for high-performance supercapacitors. In this work, we demonstrate a facile hydrothermal synthesis of NiCo2S4 nanotube arrays (NTAs) by simply treating the NiCo-precursor with Na2S solution based on the Kirkendall effect. The NiCo2S4 NTAs grown on nickel foam substrate are directly evaluated as binder-free electrode for supercapacitors. Impressively, the NiCo2S4 NTA electrode delivers an ultrahigh capacitance of 15.58 F cm(-2) at a current density of 10 mA cm(-2), which is much higher than 3.63 F cm(-2) of the mesoporous NiCo2O4 nanowire array (NWA) electrode. In addition, the NiCo2S4 NTA electrode also exhibits good cycling stability with 79.3% capacitance retention at high current density of 60 mA cm(-2) after 2000 cycles. In view of the excellent electrochemical performance and the facile and cost-effective synthesis, such NiCo2S4 NTA electrode would hold great promise for high-performance supercapacitor applications in future. (C) 2014 Elsevier Ltd. All rights reserved.