Hybrid structured CoNi₂S₄/Ni₃S₂ nanowires with multifunctional performance for hybrid capacitor electrodes and...

Rational design of electrode materials plays a significant role in potential applications such as energy storage and conversion. In this work, CoNi₂S₄/Ni₃S₂ nanowires grown on Ni foam were synthesized through a facile hydrothermal approach, revealing a large capacitance of 997.2 F g^-1 and cycling stability with 80.3% capacitance retention after 5000 cycles. The device was prepared using CoNi₂S₄/Ni₃S₂//AC as the positive electrode and active carbon as the negative electrode, and delivered an energy density of 0.4 mW h cm^-3 at a power density of 3.99 mW cm^-3 and an excellent cycle life with 79.2% capacitance retention after 10 000 cycles. In addition, the hybrid CoNi₂S₄/Ni₃S₂ nanowires demonstrate excellent OER performance with low overpotential of 360 mV at 30 mA cm^-2 and overpotential of 173.8 mV at -10 mA cm^-2 for the HER, a cell voltage of 1.43 V, and excellent cycle stability.