Porous silicon from the magnesiothermic reaction as a high-performance anode material for lithium ion battery applications

Abstract

Porous silicon (PSi) is one of the most promising anode materials for next generation lithium ion batteries. Additionally, good cycling stability and rate capability are expected for PSi-based anode because of its possible accommodation of volume change during the charge/discharge process. In this work, we have demonstrated that PSi with tunable pore diameters and specific surface areas up to 303.2m2g−1 can be synthesized with a magnesiothermic reaction of silicon monoxide. The result indicates that pore structure can be largely controlled by the reaction temperature while the electrochemical performance of PSi is found to be closely related with their pore structure. The anode based on PSi with the optimized pore structure exhibits a reversible specific capacity of 1045.6mAhg−1 at a specific current of 1000mAg−1. To further demonstrate the potential of PSi from magnesiothermic reaction as high-performance anode material, a conductive carbon layer has been wrapped around the periphery of PSi particles. At a specific current of 1000mAg−1, carbon wrapped PSi retains a reversible capacity of 1639.0mAhg−1, 84.5% of the initial capacity after 200 cycles. The performance is much better than those of naked PSi or infiltrated carbon coated PSi due to its effective accommodation of the volume change during the charge/discharge process.