Interpenetrated 3D porous silicon as high stable anode material for Li-Ion battery

Confronting issues of silicon-based anode for its huge volume change (∼320%), porous silicon attracts noteworthy attention. Most previous studies are concentrated on designing various sacrificial templates to endow silicon with marvelous shapes or structures. Herein, without the assistance of sacrificial template, a template-free method is developed to fabricate interpenetrated three-dimensional porous silicon. A silica composite gel, which possesses numerous nano-pores, is primarily constructed, and the silicon can be inherently equipped with these nano-pores via modified magnesiothermic reduction. Scanning electron microscope and transmission electron microscope images illustrate that the as-prepared porous silicon possesses bi-continuous structure. It also exhibits high initial reversible capacity (∼1.41 mAh cm−2 at 0.16 mA cm−2), superior cycling stability (∼0.98 mAh cm−2 after 200 cycles), and good rate performance. In addition, analysis of cyclic voltammetry curves and electrochemical impedance spectroscopy demonstrate that this porous silicon possesses appropriate channels for rapid Li+ transport and low electrochemical reaction polarization resistance.