Details

Autor(en) / Beteiligte

• Ashuri, Maziar
• He, Qianran
• Shi, Zhepu
• Chen, Changlong
• Yao, Weiliang
• Kaduk, James
• Segre, Carlo
• Shaw, Leon

Titel

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

Ist Teil von

• Journal of physical chemistry. C, 2019-02, Vol.123 (6), p.3299-3308

Ort / Verlag

United States: American Chemical Society

Erscheinungsjahr

2019

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• 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. Thus, 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.