Stabilizing porous micro-sized silicon anodes via construction of tough composite interface networks for high-energy-density lithium-ion batteries

Abstract

Compared to nanostructured Si/C materials, micro-sized Si/C anodes for lithium-ion batteries (LIBs) have gained significant attention in recent years due to their higher volumetric energy density, reduced side reactions and low costs. However, they suffer from more severe volume expansion effects, making the construction of stable micro-sized Si/C anode materials crucial. In this study, we proposed a simple wet chemistry method to obtain porous micro-sized silicon (μP-Si) from waste AlSi alloys. Then, the μP-Si@carbon nanotubes (CNT)@C composite anode with high tap density was prepared by wrapping with CNT and coated with polyvinylpyrrolidone (PVP)-derived carbon. Electrochemical tests and finite element (FEM) simulations revealed that the introduction of CNTs and PVP-derived carbon synergistically optimize the stability and overall performance of the μP-Si electrode via construction of tough composite interface networks. As an anode material for LIBs, the μP-Si@CNT@C electrode exhibits boosted reversible capacity (∼ 3500 mAh·g⁻¹ at 0.2 A·g⁻¹), lifetime and rate performance compared to pure μP-Si. Further full cell assembly and testing also indicates that μP-Si@CNT@C is a highly promising anode, with potential applications in future advanced LIBs. It is expected that this work can provide valuable insights for the development of micro-sized Si-based anode materials for high-energy-density LIBs.