Solid Electrolyte Interphase

Solid Electrolyte Interphase (SEI) is formed on electrode surfaces from decomposition products of electrolytes. The SEI allows Li+ transport and blocks electrons in order to prevent further electrolyte decomposition and ensure continued electrochemical reactions.

  • prevents further electrolyte decomposition
  • protects the negative electrode from large overpotentials during fast charging
  • allows lithium-ion transport while blocking electron flow

The SEI layer formation can be improved with electrolyte additives.

  • Solid Electrolyte Interphase: forms on the anode, primarily during the first cycle, and is essential for stability.
  • Cathode Electrolyte Interphase: forms on the cathode, is generally thinner, less stable, and more complex than the SEI.

SEI Growth

Continued SEI growth occurs throughout the battery’s life, particularly during cycling, and if excessive leads to capacity fade, increased resistance, and possible safety hazards. See SEI Growth for detail and references.

SEI Mathematical Models

SEI mathematical models [3] based on physics can be broadly classified into three categories:

  1. density functional theory (DFT) models
  2. continuum-level models
  3. zero-dimensional models

References

  1. Shan Yan, Amy C. Marschilok, Conversion-Type Electrodes for Rechargeable Lithium Based Batteries: Case Studies of Iron Based Conversion Materials for Lithium-Ion Batteries and Molybdenum Disulfides for Lithium-Sulfur Batteries, Editor(s): Luisa F. Cabeza, Encyclopedia of Energy Storage, Elsevier, 2022, Pages 36-46, ISBN 9780128197301
  2. S. Hamidreza Beheshti, Mehran Javanbakht, Hamid Omidvar, Md Sazzad Hosen, Annick Hubin, Joeri Van Mierlo, Maitane Berecibar, Development, retainment, and assessment of the graphite-electrolyte interphase in Li-ion batteries regarding the functionality of SEI-forming additives, iScience, Volume 25, Issue 3, 2022
  3. Kawa Manmi, Marcus Tuchel, Emma Kendrick and Ferran Brosa Planella, A Comparison of Standard SEI Growth Models in the Context of Battery Formation, 2024 J. Electrochem. Soc. 171 100530

See also

Cobalt-Free, Anode-Free: A Simpler Route to High-Energy Cells?, Electrolyte Additives, Self-Healing Binders, Prelithiation