Confining micron silicon suboxide (μ-SiOx) into an N-doped carbon matrix modified by Sn nanoparticles as a stabilized anode material for fast charging lithium-ion batteries

Abstract

The application of micron silicon suboxide (μ-SiO_x) as an anode material for commercial lithium-ion batteries (LIBs) is hindered by lower conductivity and significant volume expansion. To effectively address the inherent defects of μ-SiO_x, in this study, we developed a strategy to confine μ-SiO_x to N-doped-carbon networks modified by Sn nanoparticles to form a SiO_x@NC/Sn composite, which utilizes tin salts for protein denaturation and NaCl as a pore-forming agent. The coexistence of Sn and N with carbon forms a conductive network, facilitating the migration of lithium ions and electrons and maintaining the structural stability of the SiO_x@NC/Sn composite. SiO_x@NC/Sn with a carbon content of 50.8% as the anode for LIBs exhibits long-term stability (801.1 mA h g⁻¹ after 200 cycles at a current density of 0.2 A g⁻¹) and rate capability (401.9 mA h g⁻¹ at a current density of 5.0 A g⁻¹). Moreover, the full cell demonstrates a capacity retention rate surpassing 75% after 100 cycles at 0.5C. This work provides a simple and low-cost strategy for preparing metal-modified and nitrogen doped-carbon materials for LIBs.