Microscopic Observation of Solid Electrolyte Interphase Bilayer Inversion on Silicon Oxide

Caleb Stetson, Manuel Schnabel, Zhifei Li, Steven Harvey, Chun-Sheng Jiang, Andrew Norman, Steven DeCaluwe, Mowafak Al-Jassim, Anthony Burrell

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Silicon has been investigated in recent years as an alloying anode material to enhance gravimetric energy density in lithium-ion batteries. While recent developments have suggested that silicon oxides exhibit improved cycling stability over pure Si, the origin of the improved cycling performance is still poorly understood. The initial solid electrolyte interphase (SEI) formation mechanisms on Si wafers with both native oxide and chemically etched thermal oxide coatings are investigated structurally, chemically, and morphologically in the nanoscale. After one electrochemical cycle, microscopy reveals that SEI formed on native SiOx features the typical SEI bilayer structure with a carbon-rich outer SEI layer and an inorganic-rich inner SEI layer. In contrast, the SEI formed on chemically etched thermal oxide shows an inversion in the structure. This work observes distinct initial SEI formation mechanisms on the HF-etched SiO2 surface, which may be partially responsible for improved cycle life observed in SiOx-based anode materials.

Original languageAmerican English
Pages (from-to)3657-3662
Number of pages6
JournalACS Energy Letters
Issue number12
StatePublished - 11 Dec 2020

Bibliographical note

Publisher Copyright:

NREL Publication Number

  • NREL/JA-5K00-77261


  • lithium-ion battery
  • scanning transmission electron microscopy
  • silicon anode
  • solid electrolyte interphase


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