Controllable preparation of NiO macrotubes from NiC2O4 and its application in supercapacitors

In this article, the tube-like nickel oxide materials was synthesized by decomposition of nickel oxalate which was prepared by a facile hydrothermal method. Some experimental parameters affecting the morphology were studied. The electrochemical capacitive properties of the nickel oxide macrotubes were investigated using cycling voltammetry and charge/discharge techniques with KOH as electrolytes. The specific capacitance of the obtained nickel oxide macrotube electrode was measured to be as high as 701.2 F g−1 at a current density of 0.5 A g−1. The effect of calcination temperature and current density on the specific capacities were also studied. Furthermore, the obtained nickel oxide shows a good capacitive retention of ca. 93% after 1000 charge/discharge cycles.