Scalable and Cost‐Effective Preparation of Hierarchical Porous Silicon with a High Conversion Yield for Superior Lithium‐Ion Storage

Although some reported porous silicon‐based anode materials manifest excellent lithium‐ion storage properties, their scalable and economical synthesis remains a large obstacle to their industrial application. This work presents a scalable and efficient preparation of hierarchical porous silicon by using cost‐effective porous SiO 2 as raw material through a modified magnesiothermic reduction approach, in which a rotatable furnace was employed and the hydrofluoric acid (HF) etching treatment was avoided. Moreover, the reaction has a high conversion yield (>95 %). Subsequently, a carbon layer with a thickness of 7 nm has been conformally wrapped onto the surface of the porous silicon through a chemical vapor deposition (CVD) process. The obtained porous Si@C composite exhibits a high reversible capacity at 0.3 A g −1 , and retained ca. 40 % of its capacity even at 8 A g −1 . Moreover, it has an excellent capacity retention over 300 cycles. The strategies disclosed in the present work and the novel porous Si@C composite may have great potential for the next generation of lithium‐ion batteries.