Nickel-infused silicon–nitrogen–carbon nanocomposite anodes with high rate capability and excellent cycle stability for lithium-ion batteries

Silicon (Si) is highly regarded in lithium-ion battery anode material research due to its exceptional theoretical capacity of ∼4200 mAh g⁻¹. However, its practical application is limited by severe volumetric expansion during charge and discharge cycles. This study presents a simple and efficient method by depositing a nickel oxalate (NiC₂O₄) precursor on the surface of silicon nanoparticles, followed by coating with polyaniline and then thermally decomposing to prepare nitrogen-doped Si/Ni/C composite materials (Si/Ni/NC). At a current density of 1000 mA g⁻¹, the material exhibited notable electrochemical performance, with initial charge and discharge capacities of 1786.54 mAh g⁻¹ and 2186.43 mAh g⁻¹, respectively, and a discharge capacity retention of 961.49 mAh g⁻¹ after 200 cycles. The superior performance is attributed to the multiple optimizations of the material structure: the introduction of nickel forms a silicon–nickel alloy that significantly enhances conductivity and alleviates volumetric expansion; the carbon coating enhances the stability of the SEI film, and nitrogen-doped carbon layers reduce lithium-ion migration barriers, promoting electron transport, thus ensuring high-rate performance and cycling stability.