Enhanced lithium ion battery performance of nano/micro-size Si via combination of metal-assisted chemical etching method and ball-milling

Abstract Up to now, designing special Si with high coulombic efficiency and cycling stability in a bulk electrode remains a significant challenge. In this work, nano/micro-structured Si was successfully synthesized via a simple and scalable process with combination of the modified Metal-assisted chemical etching (MACE) method and ball-milling. The modified MACE method was used to purify micro-silicon (mSi) and produce porous structure. Moreover, we decrease the size of porous Si (pSi) and introduce the oxidation layer (∼3.8 nm) through simple ball-milling to prepare nano/micro-structured Si (M-pSi), which delivers a high initial coulombic efficiency of 85.2%, high capacity and good cycle performance. The initial discharge capacity of M-pSi is 2349 mA h g −1 at a current density of 0.2 C (1 C = 4200 mA g −1 ) and remains 2231 mA h g −1 after 100 cycles, suggesting an average decrease of 0.05% per cycle. Even at a higher current density of 2 C, it delivers a high discharge capacity of 750 mA h g −1 .