Energy Landscapes for Lithium Incorporation and Diffusion in Multidomain Silicon Suboxide Anode Materials

Somin Chae, Hyung Kyu Lim, Sangheon Lee

Research output: Contribution to journalArticlepeer-review

Abstract

In-depth understanding of the lithium interaction characteristics within multidomain silicon suboxide is indispensable for optimizing the electrochemical performance of silicon suboxide anode materials for lithium-ion batteries. In this study, we investigate the domain-dependent thermodynamic and kinetic properties of lithium atoms within systematically designed multidomain silicon suboxide models composed of Si, SiO2, and Si/SiO2 interface by performing a series of computational simulations combined with a unique tomography-like sampling scheme. We find that the Si/SiO2 interfacial region exhibits preferential thermodynamics and kinetics for lithiation and can serve as a critical lithium transport channel during charge-discharge cycles, while the SiO2 domain is likely to be excluded from lithiation due to its high resistance to lithium diffusion. Consequently, a significant fraction of lithium is expected to be trapped at the Si/SiO2 interface during the discharge process, which ultimately contributes to a low initial Coulombic efficiency. This theoretical understanding suggests that the formation of continuously connected lithium-transportable Si/SiO2 interfacial channels surrounding the Si domains, along with a well-structured shallow SiO2 framework through the use of appropriate synthesis methods, is essential for maximizing the electrochemical performance of silicon suboxide anode materials.

Original languageEnglish
JournalACS Applied Materials and Interfaces
DOIs
StateAccepted/In press - 2023

Bibliographical note

Publisher Copyright:
© 2023 American Chemical Society.

Keywords

  • Si/SiO interface
  • density functional theory
  • diffusion
  • initial Coulombic efficiency
  • lithium-ion battery
  • phase separation
  • silicon suboxide

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