Recently, the Institute of Process Engineering of the Chinese Academy of Sciences has made new progress in the preparation of silicon nanowire anode materials by thermal plasma. The capacity of 1000 times is still 2000mAh / g, which provides new ideas for the industrialization of silicon carbon anode materials. Related research results were published in ACS Nano.
At present, the traditional graphite negative electrode material has a theoretical specific capacity of only 372mAh / g, which cannot meet the current demand for high capacity and high performance of batteries. Silicon materials are most likely to become the next generation of negative electrode materials due to their higher specific capacity. However, silicon has problems such as severe volume expansion and poor electrical conductivity during the charge and discharge process. Nanocrystallization of silicon materials is an effective way to batch and efficient preparation Nano-silicon has become an important technical foundation for industrialization, and it is also a current problem.
The functional powder materials team of the Process Engineering Institute has been committed to the research of physical and chemical processes of high-frequency induction thermal plasma and the research and development of thermal plasma devices for many years. According to the team leader and researcher Yuan Fangli, the research team relied on a self-developed high-frequency induction thermal plasma device to prepare silicon nanospheres with a uniform diameter of about 50 nm through plasma high-temperature gasification nucleation and controlled growth.
Associate researcher Hou Guolin introduced that when studying the preparation of nano-silicon by plasma, it was found that the plasma reactor has different degrees of heat and cold, and the obtained products have different morphologies and structures. The research team introduced hot-wall reactors to extend the particle growth time, etc. The silicon nanowires were successfully prepared in batches, and the silicon nanowires were further assembled with carbon to prepare multi-scale buffered carbon-coated silicon nanowire clusters. The rich pore structure in the clusters provides space for the volume expansion of the silicon nanowires during the lithium intercalation process. It can withstand certain external forces to ensure that the structure is not damaged. It is consistent with the theoretical calculation results and provides a structure for stable cycling performance. Protection.
The mass production of nano-silicon wires produced by high-frequency thermal plasma at an ultra-kilogram level per hour has provided the basis and guidance for the industrial application of nano-silicon-based silicon carbon anode materials. Related work was supported by the National Natural Science Foundation of China and Beijing Natural Science Foundation.