Boron-doped porous Si anode materials with high initial coulombic efficiency and long cycling stability

Silicon is regarded as a promising next-generation anode material to replace carbon-based materials in lithium-ion batteries. However, the poor conductivity and dramatic volume changes of Si anode materials lead to their low initial coulombic efficiency and unsatisfactory cycling stability. Herein, highly crystalline B-doped porous Si (B-doped pSi) nanoplates were designed and prepared via the air-oxidation demagnesiation of Mg2Si from p-type Si wafers. Doping with B greatly decreased the resistance and surface oxidation compared to the raw materials, and the high-temperature synthetic process resulted in high crystallinity. As a result, the obtained material exhibits a high initial coulombic efficiency of 89% and a superior rate capability of 1107 mA h g(-1) at 6.4 A g(-1). Furthermore, the unique porous plate-like structure provides free space for the volumetric expansion of Si, which results in good cycling performance (reversible capacity of 1500 mA h g(-1) at 2 A g(-1) after 300 cycles) in the B-doped porous Si.