Biomass absorption of nickel salt derived carbon wrapped NiS/Ni3S4 nanocomposite as efficient electrode for supercapacitors

Transition metal sulfides (TMSs) are utilized in supercapacitors as electrode materials for their high theoretical capacity. The fabrication of TMSs/carbon composite for supercapacitors has gained much interest because of its favorable electron conductivity, and mechanical strength. Herein, the biomass absorption method is applied to fabricate NiS/Ni 3 S 4 carbon composite. Carbon-wrapped nickel (Ni@C) is obtained through the carbonization of Ni 2+ absorbed biomass. The wrapping structure can prevent nanoparticles from stacking and structure collapse. In the following process, utilizing Na 2 SO 4 as activator and sulfur source, it etches the carbon surface to create multistage pore structure, and meanwhile, the carbon matrix reduced part of SO 4 2- to form S 2- /S that can be captured by the available active sites, leading to produce S-S/C-S bond. Subsequently, A-NiS/Ni 3 S 4 @C and NiS/Ni 3 S 4 @C were effectively obtained after sulfuring A-Ni@C and Ni@C in the condition of hydrothermal, respectively. Benefitting from the bonding structure and coating characteristics, A-NiS/Ni 3 S 4 @C presented better ion diffusion behavior and exhibited a specific capacity of 560.6 F g -1 at 1 A g -1 , 242.5 F g -1 higher than that of NiS/Ni 3 S 4 @C. Furthermore, the A-NiS/Ni 3 S 4 @C was also assembled into a hybrid supercapacitor and showed a specific capacity of 118.6 F g -1 at 1 A g -1 . • Biomass-derived carbon well confined NiS/Ni 3 S 4 nanoparticles was successfully prepared. • Nanoparticles can be obtained efficiently via biomass absorption method. • Na 2 SO 4 can enhance the property in a mild way by etching the carbon surface physically and form C-S/S-S. • Offering a new method for the fabrication of nanocomposite and mild way for polish the properties of carbon.