Efficient Nanostructuring of Silicon by Electrochemical Alloying/Dealloying in Molten Salts for Improved Lithium Storage

Yating Yuan, Wei Xiao, Zhiyong Wang, Derek J. Fray, Xianbo Jin

Research output: Contribution to journalArticlepeer-review

53 Scopus citations

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.

Original languageEnglish
Pages (from-to)15743-15748
Number of pages6
JournalAngewandte Chemie - International Edition
Volume57
Issue number48
DOIs
StatePublished - Nov 26 2018
Externally publishedYes

Keywords

  • alloying/dealloying
  • lithium-ion batteries
  • molten salts
  • nanostructuring
  • silicon

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