Realizing fast-charging capability of silicon anode via ternary doping and structural disorder

Silicon (Si) is a potential fast-charging anode material for lithium-ion batteries (LIBs) due to its high energy density and suitable lithium insertion potential. However, the slow kinetics and significant volume changes during lithiation/delithiation hinder its practical application. High-entropy alloying of silicon enhances electronic conductivity and mitigates volume expansion, leading to improved rate performance. Nevertheless, the synergistic effects of high-entropy alloying and crystal structure on silicon-based anodes remain underexplored. Herein, a ternary doping alloy (Si-FeTiP) anode material with an amorphous structure was prepared via high-energy ball milling. The uniformly distributed microcrystalline phases of FeSi₂ and TiP enhanced the electronic conductivity and structural stability of the Si anode. The local disordered structure of the amorphous silicon phase mitigates lithiation-induced stress, while the isotropic nature of the amorphous structure facilitates excellent Li⁺ diffusion kinetics in the Si-FeTiP composite. As a result, the Si-FeTiP anode exhibits an excellent rate capability of 658 mAh g^-1 at 10 A g^-1 and a capacity retention of 80.3 % after 500 cycles at 2 A g^-1. This study enhances our understanding of how crystal structure influences ion transport and electrochemical performance. Furthermore, it provides valuable insights for the design of multivariate fast-charging silicon-based anode materials.