The facile synthesis of hierarchical NiCoO2 nanotubes comprised ultrathin nanosheets for supercapacitors

Hierarchical NiCoO2 nanosheets nanotubes are successfully prepared by a mild solution method based on the template of polymeric nanotubes (PNT) followed by a thermal annealing treatment. The microstructure and chemical composition of NiCoO2 nanosheets nanotubes are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) analyzer, X-ray diffraction (XRD) and Thermogravimetric analysis (TGA). When evaluated as an electrode material for supercapacitors, the results of electrochemical test show that the unique NiCoO2 nanosheets nanotubes exhibit relatively high specific capacitance of 1468, 1352, 1233, 1178, 1020 and 672 F g−1 at the discharge current densities of 2, 4, 8, 10, 20 and 40 A g−1, respectively. They also reveal an excellent cycling stability of 99.2% retention after 3000 cycles at 10 A g−1. The smart nanostructures of the NiCoO2 nanosheets nanotubes make a prominent contribution to the excellent electrochemical performance.