Facet-Dependent Thermal Instability in LiCoO ₂

Journal Article · Wed Mar 01 00:00:00 EST 2017 · Nano Letters

DOI:https://doi.org/10.1021/acs.nanolett.6b04502· OSTI ID:1462493

Sharifi-Asl, Soroosh  ^[1]; Soto, Fernando A. ^[2]; Nie, Anmin  ^[3]; Yuan, Yifei ^[4]; Asayesh-Ardakani, Hasti ^[1]; Foroozan, Tara ^[1]; Yurkiv, Vitaliy ^[1]; Song, Boao ^[1]; Mashayek, Farzad ^[1]; Klie, Robert F. ^[5]; Amine, Khalil  ^[6]; Lu, Jun  ^[6]; Balbuena, Perla B.  ^[2]; Shahbazian-Yassar, Reza  ^[1]

---

1. Mechanical and Industrial Engineering Department, University of Illinois at Chicago, Chicago, Illinois 60607, United States
2. Department of Chemical Engineering, Texas A&,M University, College Station, Texas 77843, United States
3. Materials Genome Institute, Shanghai University, Shanghai 200444, China
4. Mechanical and Industrial Engineering Department, University of Illinois at Chicago, Chicago, Illinois 60607, United States; Chemical Science and Engineering Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, United States
5. Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
6. Chemical Science and Engineering Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, United States

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 degrees 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 O-2. The novel understanding that emerges from the present study piovides 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.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: Ibero-American University
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 1462493
• Journal Information: Nano Letters, Vol. 17, Issue 4; ISSN 1530-6984
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

LiCoO2 degradation
Lithium-ion batteries
ab initio molecular dynamics
in situ STEM/EELS
oxygen release
thermal stability