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Kinetic Stability of Bulk LiNiO 2 and Surface Degradation by Oxygen Evolution in LiNiO 2 ‐Based Cathode Materials
Author(s) -
Kong Fantai,
Liang Chaoping,
Wang Luhua,
Zheng Yongping,
Perananthan Sahila,
Longo Roberto C.,
Ferraris John P.,
Kim Moon,
Cho Kyeongjae
Publication year - 2019
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201802586
Subject(s) - materials science , oxygen , oxygen evolution , kinetic energy , cathode , thermodynamics , phase (matter) , work (physics) , chemical engineering , chemical physics , chemistry , electrochemistry , electrode , physics , organic chemistry , quantum mechanics , engineering
Capacity degradation by phase changes and oxygen evolution has been the largest obstacle for the ultimate commercialization of high‐capacity LiNiO 2 ‐based cathode materials. The ultimate thermodynamic and kinetic reasons of these limitations are not yet systematically studied, and the fundamental mechanisms are still poorly understood. In this work, both phenomena are studied by density functional theory simulations and validation experiments. It is found that during delithiation of LiNiO 2 , decreased oxygen reduction induces a strong thermodynamic driving force for oxygen evolution in bulk. However, oxygen evolution is kinetically prohibited in the bulk phase due to a large oxygen migration kinetic barrier (2.4 eV). In contrast, surface regions provide a larger space for oxygen migration leading to facile oxygen evolution. These theoretical results are validated by experimental studies, and the kinetic stability of bulk LiNiO 2 is clearly confirmed. Based on these findings, a rational design strategy for protective surface coating is proposed.