Large-scale preparation of amorphous silicon materials for high-stability lithium-ion battery anodes

Silicon (Si) anodes have emerged as promising candidates in the field of high-energy-density lithium-ion batteries (LIBs) due to their exceptionally high theoretical specific capacity. However, the practical application of Si anodes has been severely hindered by the cracking and pulverization caused by the anisotropic volume expansion of crystalline Si during the lithiation process. Here, we have developed an efficient and cost-effective method for preparing amorphous Si materials. This method utilizes electron beam-induced direct heating to provide ultra-high temperatures (>3000 °C), driving the evaporation of Si sources and forming non-crystalline Si materials during rapid quenching. Simultaneously, the unevaporated Si can be deeply purified to prepare high-purity Si (purity greater than 99.9999 %) for use in photovoltaic solar cells. The isotropic characteristics of non-crystalline Si during lithium insertion significantly alleviate Si particle fragmentation and enhance lithium-ion transport rates. As a LIB anode, it exhibits excellent long-term cycling stability, with 1200 cycles at 0.5 A/g, and a reversible capacity of more than 88.8 %. The capacity retention of the full cell assembled with LiFePO₄ cathode is greater than 80 % after 300 cycles at 0.5 C. The results presented in this article confirm the significant applicability of the developed method in large-scale synthesis of amorphous Si.