Hollow NiCo₂S₄ nanotube arrays grown on carbon textile as a self-supported electrode for asymmetric supercapacitors

Although supercapacitors possess a fast charge/discharge capability, the practical application of supercapacitors is still hindered largely by their low energy density. Improving the electrochemical performance of supercapacitors depends largely on the development of novel electrode materials and hybrid systems. In this work, hollow NiCo₂S₄ nanotube arrays are successfully grown on carbon textile (CT) with robust adhesion through a two-step synthesis, involving the growth of a solid nanowire precursor and subsequent conversion into NiCo₂S₄ nanotubes using a sulfidation process. Using CT-supported NiCo₂S₄ nanotube arrays as the positive electrode and activated carbon as the negative electrode, a high-performance asymmetric supercapacitor with a maximum voltage of 1.6 V has been fabricated, which manifests high energy density (∼40.1 W h kg^-1 at 451 W kg^-1), high power density (∼4725 W kg^-1 at 21 W h kg^-1) and excellent cyclability.