Rational Synthesis of Branched CoMoO₄@CoNiO₂ Core/Shell Nanowire Arrays for All-Solid-State Supercapacitors with Improved Performance

Effectively composite materials with optimized structures exhibited promising potential in continuing improving the electrochemical performances of supercapacitors in the past few years. Here, we proposed a rational design of branched CoMoO₄@CoNiO₂ core/shell nanowire arrays on Ni foam by two steps of hydrothermal processing. Owing to the high activity of the scaffold-like CoMoO₄ nanowires and the well-defined CoNiO₂ nanoneedles, the three-dimensional (3D) electrode architectures achieved remarkable electrochemical performances with high areal specific capacitance (5.31 F/cm² at 5 mA/cm²) and superior cycling stability(159% of the original specific capacitance, i.e., 95.7% of the maximum retained after 5000 cycles at 30 mA/cm²). The all-solid-state asymmetric supercapacitors composed of such electrode and activated carbon (AC) exhibited an areal specific capacitance of 1.54 F/cm² at 10 mA/cm² and a rate capability (59.75 Wh/kg at a 1464 W/kg) comparable with Li-ion batteries. It also showed an excellent cycling stability with no capacitance attenuation after 50000 cycles at 100 mA/cm². After rapid charging (1 s), such supercapacitors in series could lighten a red LED for a long time and drive a mini motor effectively, demonstrating advances in energy storage, scalable integrated applications, and promising commercial potential.