Hybrid Transition-Metal Oxide and Nitride@N-Doped Reduced Graphene Oxide Electrodes for High-Performance, Flexible,...

Nanoscale composites for high-performance electrodes employed in flexible, all-solid-state supercapacitors are being developed. A series of binder-free composites, each consisting of a transition bimetal oxide, a metal oxide, and a metal nitride grown on N-doped reduced graphene oxide (rGO)-wrapped nickel foam are obtained by using a universal strategy. Three different transition metals, Co, Mo, and Fe, are separately compounded with nickel ions, which originate from the nickel foam, to form three composites, NiCoO₂ @Co₃ O₄ @Co₂ N, NiMoO₄ @MoO₃ @Mo₂ N, and NiFe₂ O₄ @Fe₃ O₄ @Fe₂ N, respectively. These as-prepared active materials have similar regular variation patterns in their properties, including better conductivity and battery-mimicking pseudocapacitance, which result in their high whole-electrode capacitance performance [2598.3 F g^-1 (39.85 F cm^-2 ), 3472.6 F g^-1 (41.43 F cm^-2 ) and 1907.5 F g^-1 (3.41 F cm^-2 ) for the composites incorporating Co, Mo, and Fe, respectively]. The as-assembled flexible, all-solid-state NiCoO₂ @Co₃ O₄ @Co₂ N//KOH/PVA//NiCoO₂ @Co₃ O₄ @Co₂ N device can be easily bent and exhibits high energy density and power density of 92.8 Wh kg^-1 and 1670.4 W kg^-1 , respectively. The universality of this design strategy could allow it to be employed in producing hybrid materials for high-performance energy-storage devices.