Hybrid structured CoNiS/NiS nanowires with multifunctional performance for hybrid capacitor electrodes and overall water splitting.

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