Critical Role of Cations in Lithium Sites on Extended Electrochemical Reversibility of Co‐Rich Layered Oxide |
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| Authors: | Woongrae Cho Seungjun Myeong Namhyung Kim Sanghan Lee Youngki Kim Maengsuk Kim Seok Ju Kang Noejung Park Pilgun Oh Jaephil Cho |
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| Affiliation: | 1. Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea;2. UNIST Central Research Facilities (UCRF), Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea;3. Department of Physics, School of Natural Science, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea |
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| Abstract: | Only a very limited amount of the high theoretical energy density of LiCoO2 as a cathode material has been realized, due to its irreversible deterioration when more than 0.6 mol of lithium ions are extracted. In this study, new insights into the origin of such low electrochemical reversibility, namely the structural collapse caused by electrostatic repulsion between oxygen ions during the charge process are suggested. By incorporating the partial cation migration of LiNiO2, which produces a screen effect of cations in the 3b‐Li site, the phase distortion of LiCoO2 is successfully delayed which in turn expands its electrochemical reversibility. This study elucidates the relationship between the structural reversibility and electrochemical behavior of layered cathode materials and enables new design of Co‐rich layered materials for cathodes with high energy density. |
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| Keywords: | electrochemical reversibility layered structures phase transition mechanism screen effects |
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