Nickel‐Doping Modified Interface Synergized With Hollow Confinement Constructs Highly Stable Silicon Anodes for Long Cycling Lithium‐Ion Batteries

Silicon-based materials possess a theoretical specific capacity of 4200 mAh g^-1, making them an ideal anode material for current high-energy-density lithium-ion batteries. However, their significant volume expansion (>300%) and inherently poor electrical conductivity limit their large-scale application. In this study, an innovative synergistic design approach was employed to propose a nickel (Ni)-doped hollow carbon-coated silicon composite material (Ni/HSi@C). This material integrates structural engineering with a carbon layer coating the hollow silicon structure, thereby facilitating volume changes toward internal expansion. Additionally, phase state regulation and interface optimization were integrated, with Ni-doping introduced to promote the formation of amorphous silicon while inducing the formation of a stable solid electrolyte interface film rich in LiF during charge-discharge cycles, thereby achieving synergistic optimization. Experimental results indicate that after 1000 cycles at a current density of 1000 mA g^-1, the specific capacity of Ni/HSi@C remains at 1318 mAh g^-1. Furthermore, the pouch cell achieves an energy density of 379 Wh kg^-1. In situ impedance and distribution of relaxation times analysis demonstrate that Ni-doping significantly reduces interfacial impedance and suppresses electrolyte decomposition.