Large-Scale Fabrication, 3D Tomography, and Lithium-IonBattery Application of Porous Silicon.

Recently, silicon-based lithium-ionbattery anodes have shown encouragingresults, as they can offer high capacities and long cyclic lifetimes.The applications of this technology are largely impeded by the complicatedand expensive approaches in producing Si with desired nanostructures.We report a cost-efficient method to produce nanoporous Si particlesfrom metallurgical Si through ball-milling and inexpensive stain-etching.The porosity of porous Si is derived from particle’s three-dimensionalreconstructions by scanning transmission electron microscopy (STEM)tomography, which shows the particles’ highly porous structurewhen etched under proper conditions. Nanoporous Si anodes with a reversiblecapacity of 2900 mAh/g was attained at a charging rate of 400 mA/g,and a stable capacity above 1100 mAh/g was retained for extended 600cycles tested at 2000 mA/g. The synthetic route is low-cost and scalablefor mass production, promising Si as a potential anode material forthe next-generation lithium-ion batteries with enhanced capacity andenergy density. [ABSTRACT FROM AUTHOR]