Facile hydrothermal synthesis and electrochemical supercapacitor performance of hierarchical coral-like ZnCo2O4 nanowires

This paper reports a facile hydrothermal synthesis of hierarchical coral-like ZnCo2O4 nanostructures comprised of necklace type nanowires without the use surfactants. The hierarchical coral structure is composed of an interconnected necklace-type nanowire arrangement on the nanoscale, facilitating charge transportation. In addition, the coral-like ZnCo2O4 nanowires were mesoporous (2936 m(2) g(-1) and 18.96 nm), leading to large electrochemical active sites for the redox reaction and fast ion transport within the ZnCo2O4 nanowires. When used in electrochemical supercapacitors, the interconnected necklace type, coral-like ZnCo2O4 nanowires exhibited a significantly high specific capacity (694 F g(-1) at a current density of 2 A g(-1)), high rate capability (264 F g(-1) at 10 A g(-1)), and excellent cycling stability (capacitance retention of similar to 85% even after 2000 cycles at a charge-discharge current density of 10 A g(-1)). These results suggest that hierarchical coral-like ZnCo2O4 nanowires are a promising electrode material for energy storage applications in high-performance pseudocapacitors. (C) 2016 Published by Elsevier B.V.