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

Ternary NiCo 2 O 4 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 NiCo 2 S 4 nanotube arrays (NTAs) by simply treating the NiCo-precursor with Na 2 S solution based on the Kirkendall effect. The NiCo 2 S 4 NTAs grown on nickel foam substrate are directly evaluated as binder-free electrode for supercapacitors. Impressively, the NiCo 2 S 4 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 NiCo 2 O 4 nanowire array (NWA) electrode. In addition, the NiCo 2 S 4 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 NiCo 2 S 4 NTA electrode would hold great promise for high-performance supercapacitor applications in future. [ABSTRACT FROM AUTHOR]