Template-Free Electrochemical Formation of Silicon Nanotubes from Silica.

ABSTRACT: Silicon, with its elaborate microstructure, plays important roles in energy materials. In operando engineering of microstructure during extraction is an ideal protocol to develop advanced Si-based materials. A template-free electrochemical preparation of silicon nanotubes (Si-NT) is herein achieved by co-electrolysis of SiO₂ and AgCl in molten NaCl-CaCl₂ at 850 °C. The in situ electrodeposited Ag facilitates the generation of a liquid Ag-Si intermediate, triggering a liquid-solid mechanism to direct the growth of Si-NT. An automatic separation of Ag from Si then occurs in the following cooling process, resulting in Ag deposits on the Ni current collector and recycling of Ag. Such a facile and smart preparation of Si-NT from affordable silica guarantees an enhanced current efficiency of 74%, a decreased energy consumption of 12.1 kW h kg_Si ^-1, and enhanced lithium-storage capability of the electrolytic Si-NT. An in situ coating of Ag over the Si-NT can also be fulfilled by simply introducing soluble AgCl in the melts. The present study provides a template-free preparation and an in situ surface modification of Si-NT.

SUBMITTER: Weng W 

PROVIDER: S-EPMC7507395 | biostudies-literature | 2020 Sep

REPOSITORIES: biostudies-literature