Facile and green one-step synthesis of Ni3S2@CN carbon nanosheets from sodium lignosulfonate for a supercapacitor electrode

A green and facile strategy was designed to fabricate Ni3S2-doped carbon nanosheets (Ni3S2@CN). In this strategy, sodium lignosulfonate was introduced as a sulfur source and carbon source to form the Ni3S2-doped carbon nanosheets. Nickel nitrate hexahydrate was added as a nickel source, and boric acid was used as a template agent for the formation of carbon nanosheets. As the supercapacitor electrode, Ni3S2@CN-0.4-600 exhibited a specific capacitance of 374.5 F g−1 at the current density of 1 A g−1, and achieved cyclic stability (82.9%) after 5000 charge/discharge cycles. The advantage of Ni3S2-doped carbon nanosheets compared to conventional products lies in its simplicity of the synthesis process and easily available biomass-feedstock. On the other hand, waste liquid discharge and process costs were further reduced by the recycling of boric acid templates, which provided a cost-efficient and environmentally friendly way to prepare carbon nanosheets. The facile and green one-step preparation of the Ni3S2-doped carbon nanosheet has been rarely reported previously. Thus, we wish to report the novel design and efficient electrocatalytic performance of the Ni3S2-doped carbon nanosheet in this work.