Arrays of ultrafine CuS nanoneedles supported on a CNT backbone for application in supercapacitors

Arrays of CuS ultrafine nanoneedles supported on a carbon nanotube (CNT) backbone (CNT@CuS) are fabricated by an efficient template-engaged chemical conversion route. First, the silica coated CNTs (CNT@SiO2) are introduced as the substrate for the growth of copper silicate (CuSilicate) nanoneedles to form CNT@SiO2@CuSilicate core-shell one-dimensional (1D) structures. In the second step, the CuSilicate nanoneedles are completely transformed into CuS nanoneedles via a hydrothermal treatment with Na2S. Simultaneously the intermediate silica layer is removed during the hydrothermal process, thus resulting in hierarchical CNT@CuS complex nanostructures. In virtue of the unique architecture and intrinsic properties, the as-prepared CNT@CuS hierarchical structures exhibit high capacitance and excellent cycling stability.