Porosity controlled synthesis of nanoporous silicon by chemical dealloying as anode for high energy lithium-ion batteries.

Silicon is regarded as the most promising electrode material to meet the high-capacity demand for lithium-ion batteries (LIBs). Nevertheless, the large volume expansion during charging/discharging process restricts its practical application. In this report, a facile chemical dealloying method is conducted to prepare porous silicon materials from Al-Si alloys with different proportions at ambient temperature. The porosity of anode materials could buffer the huge volume change of Si anode and enhance the ion transport. Finally, the optimized Si20 sample delivers a capacity of 1662 mAh g-1 after 145 cycles at 500 mA g-1 and a high rate capability up to 908 mAh g-1 at 5000 mA g-1.