Efficient Nanostructuring of Silicon by Electrochemical Alloying/Dealloying in Molten Salts for Improved Lithium Storage. (31st October 2018)

• Record Type: Journal Article
• Authors: Yuan, Yating; Xiao, Wei; Wang, Zhiyong; Fray, Derek J.; Jin, Xianbo
• Is Part Of: Angewandte Chemie. Volume 130:Number 48(2018)
• Page Start: 15969
• Page End: 15974
• Publication Date: 2018-10-31
• Subjects: Legieren/Entlegieren -- Lithiumionenbatterien -- Nanostrukturen -- Salzschmelzen -- Silicium; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201809646
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: Application of nanostructured silicon (nSi) is significantly retarded by challenges in the production of affordable nSi. We herein report a high‐yield (ca. 100 %) and low‐energy (2 kWh Kg‐nSi −1 ) nanostructuring of industrial microsized silicon (mSi) through a closed‐loop electrochemical Mg alloying/dealloying in molten MgCl2 /NaCl/KCl at 773 K. The resulting nSi unexpectedly shows a salt‐unwetted character, allowing an automatic separation from the melts. Thus water washing and accompanying oxidation of the nSi can be avoided. The final product has a nanoporous structure and comprises Si nanorods (ca. 30 nm in diameter) with an ultrathin oxide coating. It can be used for Li storage giving a combination of high initial coulombic efficiency, high specific capacity, and long cycling stability. This nanostructuring process consumes very few chemicals except for the mSi and produces almost zero waste.