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 327Fg^-1, several times higher than that of CuCo₂O₄ nanowires (57.8Fg^-1), at a current density of 1.25Ag^-1 with excellent rate capability (90% capacitance retention at a current density of 6.25Ag^-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 714mFcm^-2 at 1mAcm^-2 is achieved, which is much higher than values reported earlier. It delivers a high energy density of 94.3Whcm^-2 at a power density of 0.4757mWcm^-2 for a voltage window of 1V. Highly stable electrochemical performance over 3000cycles 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.