NiS Nanosheets Decorated on Hollow Carbon Spheres from Liquefied Wood for Supercapacitors

Carbon-based supercapacitors with high performance have a wide foreground among various energy storage devices. In this work, wood-based hollow carbon spheres (WHCS) were prepared from liquefied wood through the processes of emulsification, curing, carbonization, and activation. Then, the hydrodeposition method was used to introduce nickel sulfide (NiS) to the surface of the microspheres, obtaining NiS/WHCS as the supercapacitor electrode. The results show that NiS/WHCS microspheres exhibited a core–shell structure and flower-like morphology with a specific surface (307.55 m2 g–1) and a large total pore volume (0.14 cm3 g–1). Also, the capacitance could be up to 1533.6 F g–1 at a current density of 1 A g–1. In addition, after 1000 charge/discharge cycles, the specific capacitance remained at 72.8% at the initial current density of 5 A g–1. Hence, NiS/WHCS with excellent durability and high specific capacitance is a potential candidate for electrode materials.