Hierarchical CoNi2S4 nanosheet/nanotube array structure on carbon fiber cloth for high-performance hybrid supercapacitors

Well-defined nanostructures are attractive due to their excellent advantages in enhancing the performance of electrochemical energy storage. In this work, a kind of hybrid structure of hierarchical CoNi2S4 nanosheet/nanotube array directly assembled on carbon fiber cloth has been designed and developed for high-performance supercapacitors. CoNi2S4 nanosheet/nanotube arrays are fabricated through orderly electrodeposition of ZnO nanorod arrays and CoNi2S4 nanosheets, followed by removing ZnO nanorods template. Benefiting from the unique hollow nanostructure with abundant electrochemical active sites, the specific capacitance of this electrode can reach up to 995.8 C g(-1) at a current density of 2 A g(-1), along with excellent rate capability (740 C g(-1) at 50 A g(-1)). Moreover, the hybrid supercapacitors are prepared by using hierarchical CoNi2S4 nanosheet/nanotube arrays as positive electrode and reduced graphene oxide-carbon nanotubes as negative electrode for energy storage application, which demonstrate a high energy density of 35 Wh kg(-1) at a power density of 3 kW kg(-1) and excellent cycle stability with 96.9% capacitance retention after 10000 cycles. This work provides a feasible and a practical approach to fabricate CoNi2S4 hollow nanostructures and its huge potential in energy storage. (C) 2019 Elsevier Ltd. All rights reserved.