Grape-liked Si@Na2SiO3 composites for stable lithium storage though a metal salt-assisted chemical etching approach

Serious volume expansion for silicon-based material has extremely restricted its widespread application. Herein, Si@Na₂SiO₃ composite with grape-liked structure was fabricated by a simple metal salt-assisted chemical etching method, which is enabled by the high corrosivity of NaHCO₃. The gelatinous Na₂SiO₃ can evenly coat the surface of Si nanoparticles, then efficiently inhibiting volume expansion. Meanwhile, porous structures etched by NaHCO₃ provide more diffusion channels for Li⁺. Si@Na₂SiO₃ exhibits excellent cycling and rate properties: the discharge capacity of 1140.16mAh g⁻¹ at 0.5 A g^-1after 100th cycling and the stable discharge capacity of 1565.64 mAh g⁻¹ at 2.0 A g⁻¹. This research provides a simple and effective technology to exploit the high-capacity silicon-based anode material.