Simple ball milling-assisted method enabling N-doped carbon embedded Si for high performance lithium-ion battery anode

Si has been regarded as a hopeful advanced anode of lithium-ion batteries due to its features such as ultrahigh theoretical specific capacity and high natural abundance. But, it suffers from electrochemical irreversibility because of large volumetric change and poor conductivity during cycle. In spite of obtaining enhanced lithium storage performance after compositing with carbon materials, most of the reported Si/C composite anodes lack a simple preparation process. For the new anode materials, the simple preparation process is as important as showing high performance. Herein, an efficient simple method is developed to prepare a composite of N-doped carbon embedding Si nanoparticles (Si@C) to response to the above Si faced challenges. Its preparation process just consists of very simple ball milling and pyrolysis carbonization, showing great simplicity. The findings confirm that the combination of the ball-milling mixing and the use of PVP carbon precursor enables the optimal Si@C-2 composite to have a N-doped carbon embedding structure and a robust interface Si-O-C chemical bond bonding, hence obtaining enhanced conductivity, high electrochemical kinetics and superb structure stability during cycling process. Therefore, the Si@C-2 anode exhibits excellent performance, with 1542 and 794.7 mA h g-1 after 100 and 1000 cycles at 100 and 1000 mA g-1, respectively, superior to many reported Si/C composites. The simple, scalable preparation method and superb performances offer Si@C-2 great promising in advanced LIB anode applications.

Automated summary

A simple method was developed to prepare a composite of N-doped carbon embedding Si nanoparticles (Si@C) to address the challenges faced by Si materials. The Si@C-2 composite exhibited excellent electrochemical performance and structure stability after a simple ball milling and pyrolysis carbonization process. The findings suggest that Si@C-2 has great potential for advanced LIB anode applications.