The fabrication and characterization of bimodal nanoporous silicon films with retained magnesium, achieved through a novel approach utilizing free corrosion dealloying of precursor Si–Mg films in distilled water, is studied. Investigation of film structure and chemical composition using various techniques reveals important characteristics potentially relevant to lithium-ion battery applications. Dealloying of precursor films results in a hierarchal structure, where larger ligaments have an average width of 83 nm and smaller ligaments an average width of 19 nm. A thin, porous surface layer is present on most dealloyed films and is largely composed of magnesium and silicon oxides, as verified by XPS surface analysis. TEM studies reveal that as-dealloyed films are amorphous, but nanocrystalline silicon grains form after vacuum annealing at 500 °C. EDS mapping and XPS reveal three distinct chemical composition regions through the film thickness, where residual magnesium generally increases as a function of film thickness, with the highest amount of retained magnesium at the surface. The ligament size, composition, and structure, combined with the simple, non-hazardous nature of the dealloying method, make this an attractive material and processing technique for efficient and scalable production of lithium-ion battery anode material.
|Journal||Advanced Engineering Materials|
|State||Published - Feb 1 2018|
Bibliographical noteFunding Information:
This material is based upon work supported by the National Science Foundation under Grant No. CMMI-1301184. Use of the XPS was also supported by the National Science Foundation under Cooperative Agreement No. 1355438. The authors acknowledge support of the Electron Microscopy Center at the University of Kentucky.
© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
- lithium-ion battery
- thin film
ASJC Scopus subject areas
- Materials Science (all)
- Condensed Matter Physics