Synthesis of ultrafine CoNi2S4 nanowire on carbon cloth as an efficient positive electrode material for high-performance hybrid supercapacitors

Abstract Rational designing and preparing of electrode materials with desirable electrochemical performance by a simple, efficient and safe method is of great significance for electrochemical energy storage devices, but it is also challenging. In this study, ultrafine CoNi2S4 nanowire arrays directly grown on carbon cloth (CC) are synthesized by sulfuration of Co–Ni hydroxide precursor. Benefiting from the high conductivity, the synergistic effect between Co and Ni ions and open self-supporting three-dimensional (3D) nanoarchitectures constructed by 1D CoNi2S4 ultrafine nanowires, the as-obtained CoNi2S4@CC electrode exhibits excellent electrochemical capacitance performances: high specific capacitance of 1872 F g −1 at 1 A g −1and 1565 F g −1 at 5 A g−1. Meanwhile, a battery-supercapacitor hybrid (BSH) device is fabricated using the as-obtained CoNi2S4@CC as the positive electrode and porous carbon nanosheets (PCNS) derived from wood fungus as the negative electrode. The constructed BSH exhibits a high energy density of 37.2 Wh kg −1 at a power density of 0.75 kW kg−1, as well as a robust long-term cycling stability (97.6% capacitance retention after 10 000 charge-discharge cycles at a constant current density of 1 A g−1). These outstanding results verify CoNi2S4 material has potential application in the energy storage field and it has been explored and expected to be the promising electrode materials for the supercapacitor.