Enhanced synergistic effect of NiCo sulfide nanorod arrays with high mass loading on carbon cloth for hybrid supercapacitors: The role of compositional regulation

Achieving an enhanced synergistic effect and controlling the morphology of active materials to facilitate electrolyte access are crucial for the design of high-mass-loading electrode. In this work, NiCo sulfide nanorod arrays were grown on a carbon cloth (CC) substrate via a two-step hydrothermal deposition strategy. The compositional effect was employed to modify the growth behavior, hierarchical morphology, and synergistic effect of the as-obtained electrodes. The contents of Ni-S and Co-S species and the resistance nature of the electrodes can be optimized by adjusting the Co/Ni feed ratio. The optimized Ni _1.5Co _1.5S ₄/CC electrode with a high mass loading (5.54 mg cm ⁻² ) comprises vertical nanorod arrays with open channels for electrolyte access, and exhibits a high capacity of 711 C g ⁻¹ at 2 A g ⁻¹ (3.95 C cm ⁻² at 10 mA cm ⁻²) with good cyclic stability. The as-assembled Ni _1.5Co _1.5S ₄ /CC//activated carbon cloth (ACC) hybrid supercapacitor delivers a high areal capacity of 1.96 C cm ⁻² at 5 mA cm ⁻² with excellent rate performance and achieves a high energy density of 0.49 mWh cm ⁻² at a power density of 4.5 mW cm ⁻². These achievements represent a promising concept for the practical design and regulation of NiCo sulfide electrodes at high mass loading levels.