Effective coating of Si@NiO nanoflowers with nitrogen-doped wheat protein-derived biochar for efficient lithium-ion and lithium-sulfur batteries anode materials

As the most promising anode material for ultra-high specific capacity lithium-ion batteries, Si has been hindered from widespread use by large volume effects and limited electrical conductivity during cycling. In this study, NiO nanoflowers were coated onto the exterior of Si NPs by hydrothermal method. Si@NiO was then mixed and annealed with natural biomass gel extracted from moldy wheat to produce Si@NiO@Biochar ternary composites, which were prepared. Si NPs are the source of high specific capacity of anode materials. The carbon layer minimizes the electrode bulk effect and enhances cycling stability, while the NiO flowers expand the lithium-ion transport channel and reduce Si NPs bulk effect. Furthermore, the N element from wheat protein in the carbon layer enhances the electrical conductivity of the material. After 100 cycles at 0.1 A g−1 and 1000 cycles at 1 A g−1, the capacity of the electrode rose to 952.12 mAh g−1 and 1098.05 mAh g−1, respectively. The Si@NiO@Biochar material showed remarkable electrochemical stability at various current densities and the thickness grew by just 27.97% after 500 cycles. It can also be utilized in lithium-sulfur batteries because of its microporous structure and capacity to transport sulfur. The reversible capacity was 388.21 mAh g−1 after 70 cycles at 1 C. Biomass carbon from biomass gels coated on Si@NiO reduces biomass energy waste. This research is a significant step for commercializing Si anode materials and providing an eco-friendly new method for storing energy.