Long-Term Cycle Behavior of Nano-LiCoO₂ and Its Postmortem Analysis

Journal Article · Thu Jan 17 04:00:00 EST 2019 · Journal of Physical Chemistry. C

DOI:https://doi.org/10.1021/acs.jpcc.8b10099· OSTI ID:1495451

Ashuri, Maziar ^[1]; He, Qianran ^[1]; Shi, Zhepu ^[1]; Chen, Changlong ^[1]; Yao, Weiliang ^[1]; Kaduk, James ^[1]; Segre, Carlo ^[1]; Shaw, Leon ^[1]

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1. Illinois Institute of Technology, Chicago, IL (United States)

In this study, the long-term cycle behavior of nano-LiCoO₂ cathodes over 500 cycles at high rates is investigated. Furthermore, the postmortem analysis of the cycled nano-LiCoO₂ cathodes using a combination of X-ray absorption spectroscopy and X-ray diffraction is also conducted to shed light on the capacity decay mechanisms. It is found that crystalline nano-LiCoO₂ after 500 charge/discharge cycles at 10C becomes amorphous, exhibits Co²⁺ species rather than the expected Co³⁺ at the fully lithiated condition, has longer Co–O bond length than that of pristine nano-LiCoO₂ and micro-LiCoO₂, and exhibits 53% specific capacity loss over 500 cycles at 10C. In addition, slow Li-ion intercalation and deintercalation at the electrode/electrolyte interface are found to be the rate-limiting step for nano-LiCoO₂ during discharge and charge, respectively. Furthermore, to achieve the high-rate capability of LiCoO₂, not only LiCoO₂ particle sizes should be reduced to nanoscales but also the Li-ion intercalation and deintercalation rates at the electrode/electrolyte interface need to be enhanced. Since the capacity decay induced by the structural damage and the formation of CoO-like phases starts at the surface of nano-LiCoO₂, proper surface coatings have the potential to solve the capacity decay problem faced by nano-LiCoO₂, enabling it for high-rate applications.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• Sponsoring Organization: Wanger Inst. for Sustainable Energy Research (WISER); Rowe Family Endowment Fund
• OSTI ID: 1495451
• Journal Information: Journal of Physical Chemistry. C, Journal Name: Journal of Physical Chemistry. C Journal Issue: 6 Vol. 123; ISSN 1932-7447
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
electrodes
intercalation
interfaces
ions
nanoparticles