Core-Shell CuCo2O4@MnO2 Nanowires on Carbon Fabrics as High-Performance Materials for Flexible, All-Solid-State, Electrochemical Capacitors

To boost the electrochemical utilization and area-specific capacitance, core–shell CuCo2O4@MnO2 heterostructured nanowire arrays on carbon fabrics are synthesized and utilized as high-performance, binder-free, positive electrodes for electrochemical capacitors. The electrode architecture takes advantage of the synergistic effects contributed from both the porous CuCo2O4 nanowire core and the MnO2 shell layer. The as-prepared electrode has a high cell-specific capacitance of 327 F g−1, several times higher than that of CuCo2O4 nanowires (57.8 F g−1), at a current density of 1.25 A g−1 with excellent rate capability (90 % capacitance retention at a current density of 6.25 A g−1) in aqueous electrolyte. A flexible, all-solid-state symmetrical supercapacitor is fabricated by assembling two CuCo2O4@MnO2 nanowire-based electrodes, a high cell-area-specific capacitance of 714 mF cm−2 at 1 mA cm−2 is achieved, which is much higher than values reported earlier. It delivers a high energy density of 94.3 W h cm−2 at a power density of 0.4757 mW cm−2 for a voltage window of 1 V. Highly stable electrochemical performance over 3000 cycles is obtained, even when the device is operated under harsh mechanical conditions. These results suggest that the as-prepared CuCo2O4@MnO2/carbon fabric composite architecture is very promising for next-generation high-performance supercapacitors, and this work opens up a novel design of advanced integrated-array electrode materials for high-performance supercapacitors.