S-Space College of Engineering/Engineering Practice School (공과대학/대학원) Dept. of Chemical and Biological Engineering (화학생물공학부) Journal Papers (저널논문_화학생물공학부)
Entropymetry for non-destructive structural analysis of LiCoO2 cathodes
- Kim, Hye Jin; Park, Youngkyu; Kwon, Yoonjin; Shin, Jaeho; Kim, Young-Han; Ahn, Hyun-Seok; Yazami, Rachid; Choi, Jang Wook
- Issue Date
- Energy and Environmental Sciences, Vol.13 No.1, pp.286-296
- Upon the emergence of electric vehicles, accurate and non-destructive monitoring of battery electrode materials during operation is highly desirable. Structural degradation of widely adopted intercalation-based materials constitutes the origin of their capacity fading and safety deterioration. Here, we introduce entropymetry to monitor the structural changes of LiCoO2 (LCO) and its nickel (Ni)-doped derivatives at different states of charge (SOC). While simple lithium (Li) extraction on charging gives a monotonic decline of entropy change (Delta S) based on progressive vacancy occupation over Li sites, the presence of a monoclinic intermediate phase inverses the slope of the Delta S profile to reflect its limited atomic configurations with high ordering. Furthermore, Ni-doping lessens the ordering of the monoclinic phase, decreasing the height amplitude of Delta S profile in the monoclinic regime. The increased disorder by Ni-doping enhances the stability of the lattice framework, extending the cycle life with high voltage cut-off (4.6 V vs. Li/Li+). The present study highlights entropymetry as a unique, non-destructive tool in monitoring the structural ordering and relevant degradation of electrode materials in lithium-ion batteries.
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