Self-Supported Sisal-like CuCo2O4@Ni(OH)2 Core-Shell Composites Grown on Ni Foam for High-Performance All-Solid State Supercapacitors

Construction of reasonable nanostructures for electrode materials is regarded as one critical strategy for improving capacitance and cycle life of supercapacitors (SCs). Here, self-supported, sisal-like CuCo2O4@Ni(OH)(2) composites were successfully synthesized on Ni foam using a hydrothermal treatment followed by the electrochemical deposition reaction. Scanning electron microscopy characterization of the composites verified that the sisal-like CuCo2O4@Ni(OH)(2) core-shell nanostructure comprising coating CuCo2O4 nanoneedles with Ni(OH)(2) nanoflakes. This novel structure afforded the CuCo2O4@Ni(OH)(2) composites a markedly enhanced specific capacitance of 1902 F g(-1) at 2 A g(-1) and an ultralong cycle life with a captaincy retention of 87.6% after 50 000 cycles at 10 A g(-1). Furthermore, an asymmetric solid-state supercapacitor comprising CuCo2O4@Ni(OH)(2) //activated carbon was assembled and it exhibited a high energy density of 38.6 W h kg(-1) at 800 W kg(-1). These performances strongly suggest that the self-supported sisal-like CuCo2O4@Ni(OH)(2) electrode is a very promising positive material for use in SCs.