Construction of an inert framework in porous SiOx/Si anodes for high-performance Li-ion batteries

Abstract

Si-based anodes with porous structures demonstrate improved electrochemical performance in Li-ion batteries; however, the collapse of pores during cycling remains a major challenge for practical applications. Herein, we report the construction of a hierarchical porous SiO_x/Si composite anode with an inert Mg₂SiO₄ skeleton to stabilize the porous structure during reversible Li-storage. The Li-active components SiO_x/Si are dispersed within a continuous rigid framework, enabling more effective confinement of volume changes and better preservation of structural integrity. The successful synthesis of porous SiO_x/Si with an inert Mg₂SiO₄ framework is confirmed by XRD and XPS, indicating uniform distribution of active components within the framework. As a result, the specific capacity is improved from 519 mAh g⁻¹ to 775 mAh g⁻¹ after 100 cycles. The lithium-ion diffusion coefficient (D_Li⁺) reaches 3.42 × 10⁻¹⁰ cm² s⁻¹, indicating that the stabilized hierarchical porous structure promotes efficient Li⁺ transport throughout repeated charge–discharge processes. The inert Mg₂SiO₄ framework remains stable even after long-term cycling. This study offers a new material design strategy for Si-based anodes, which will promote the practical application of porous structured Si anodes.