Facile synthesis of novel metal-organic nickel hydroxide nanorods for high performance supercapacitor

Novel one-dimensional metal-organic nickel hydroxide nanorods were synthesized via a facile hydrothermal process and used as electrode materials for supercapacitors. The chemical formula of as-prepared nickel-based metal organic frameworks (MOFs) using salicylate ions as organic linkers can be denoted as [Ni(HOC6H4COO)1.48(OH)0.52·1.1H2O] by elemental and XPS analysis. The Ni-based MOF nanorods are very uniform in size with an average length of about 900 nm and diameter of 60 nm. They exhibited a high specific capacitance, exceptionally high rate capability and excellent cycling stability. Capacitances of 1698, 1385, 1278, 1068, 998 and 838 F g−1 can be achieved at rates of 1, 2, 3, 5, 7 and 10 A g−1, respectively. In the mean time, ca. 94.8% capacitance was retained after 1000 cycles at 1 A g−1. Importantly, the constructed Ni-based MOF nanorods/graphene asymmetric supercapacitor reveals outstanding capacitive behaviors with a specific capacitance of 166 F g−1 at a current density of 1 A g−1 and eminent rate capability. These outstanding electrochemical properties demonstrate that the as-prepared Ni-based MOF nanorods are efficient electrode materials for supercapacitors and have a greatly promising application in the development of high-performance electrochemical energy storage devices.