Facile and Scalable Synthesis of Si@void@C Embedded in Interconnected 3D Porous Carbon Architecture for High Performance Lithium-Ion Batteries

Si-based materials possess huge potential as an excellent anode material for Li-ion batteries. However, how to realize scalable synthesis of Si-based anode with a long cycling life and high-performance is still a critical challenge. Here a water-in-oil microemulsion process followed by UV illumination, calcination, and hydrothermal method to produce yolk-shell Si@void@C embedded in interconnected 3D porous carbon network architecture using silicon nanoparticles is reported. As a result, the sample Si@void@C/C-2 electrode has achieved a reversible capacity of 1160 mA h g⁻¹ at 0.2 A g⁻¹ after 300 cycles and a stable long cycling life of 480 mA h g⁻¹ at 1 A g⁻¹ after 1000 cycles. A full battery with the synthesized anode shows a capacity of 128 mA h g⁻¹ at 0.2 A g⁻¹ as well as good cycling stability after 1100th cycles. Such excellent electrochemical performance is ascribed to its unique structure, the yolk-shell void space, highly robust carbon shells and interconnected porous carbon nets that can improve the conductivity of the electrode, buffer the volume expansion, and also suppress Si nanoparticles stress variation. This water-in oil system makes it possible for mass production of environmentally friendly synthesis of core–shell structure.