Morphology control of Ni₃S₂ multiple structures and their effect on supercapacitor performances

In this work, the Ni₃S₂ multiple structures are prepared on Ni foam (Ni₃S₂@NF) by a mass production one-step hydrothermal method. The prepared Ni₃S₂@NF multi-structured materials can expose more electroactive sites for fast electron transport owing to their intimate contact with electrolyte. By precisely controlling the proportion of glycerin in the reaction solution, the desired Ni₃S₂@NF core–shell structure can be synthesized with a high specific capacitance of 736.64 F g⁻¹ at 0.8 A g⁻¹ (7.36 F cm⁻² at 8 mA cm⁻²), which is about one order of magnitude higher than other structures. The role of glycerin for controlling the sample morphology is attributed to its ability to absorb hydrogen sulfide for further reaction to produce nano-sized Ni₃S₂ structures. The Ni₃S₂@NF core–shell sample also exhibits good cycling stability of 82% after 1000 cycles. This is because the intertwined nanostructures can accelerate ion transport and protect internal Ni₃S₂ from degrading. Our work provides a new and efficient mass production method for obtaining energy storage materials with micro-sheet and nano-plated multiple structures.