Facet-Dependent Thermal Instability in LiCoO2

Soroosh Sharifi-Asl, Fernando A. Soto, Anmin Nie, Yifei Yuan, Hasti Asayesh-Ardakani, Tara Foroozan, Vitaliy Yurkiv, Boao Song, Farzad Mashayek, Robert F. Klie, Khalil Amine, Jun Lu, Perla B. Balbuena, Reza Shahbazian-Yassar

Research output: Contribution to journalArticlepeer-review

95 Scopus citations


Thermal runaways triggered by the oxygen release from oxide cathode materials pose a major safety concern for widespread application of lithium ion batteries. Utilizing in situ aberration-corrected scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS) at high temperatures, we show that oxygen release from LixCoO2 cathode crystals is occurring at the surface of particles. We correlated this local oxygen evolution from the LixCoO2 structure with local phase transitions spanning from layered to spinel and then to rock salt structure upon exposure to elevated temperatures. Ab initio molecular dynamics simulations (AIMD) results show that oxygen release is highly dependent on LixCoO2 facet orientation. While the [001] facets are stable at 300 °C, oxygen release is observed from the [012] and [104] facets, where under-coordinated oxygen atoms from the delithiated structures can combine and eventually evolve as O2. The novel understanding that emerges from the present study provides in-depth insights into the thermal runaway mechanism of Li-ion batteries and can assist the design and fabrication of cathode crystals with the most thermally stable facets.

Original languageEnglish (US)
Pages (from-to)2165-2171
Number of pages7
JournalNano letters
Issue number4
StatePublished - Apr 12 2017

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • General Chemistry
  • General Materials Science
  • Condensed Matter Physics
  • Mechanical Engineering


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