title: Critical Role of Cations in Lithium Sites on Extended Electrochemical Reversibility of Co-Rich Layered Oxide.
abstract: Only a very limited amount of the high theoretical energy density of LiCoO2as 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 LiCoO2is 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.
authors.affiliation: Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 689-798, Republic of Korea.
authors.forename: Woongrae
authors.initials: W
authors.lastname: Cho
authors.affiliation: Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 689-798, Republic of Korea.
authors.forename: Seungjun
authors.initials: S
authors.lastname: Myeong
authors.affiliation: Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 689-798, Republic of Korea.
authors.forename: Namhyung
authors.initials: N
authors.lastname: Kim
authors.affiliation: Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 689-798, Republic of Korea.
authors.forename: Sanghan
authors.initials: S
authors.lastname: Lee
authors.affiliation: UNIST Central Research Facilities (UCRF), Ulsan National Institute of Science and Technology (UNIST), Ulsan, 689-798, Republic of Korea.
authors.forename: Youngki
authors.initials: Y
authors.lastname: Kim
authors.affiliation: Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 689-798, Republic of Korea.
authors.forename: Maengsuk
authors.initials: M
authors.lastname: Kim
authors.affiliation: Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 689-798, Republic of Korea.
authors.forename: Seok Ju
authors.initials: SJ
authors.lastname: Kang
authors.affiliation: Department of Physics, School of Natural Science, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 689-798, Republic of Korea.
authors.forename: Noejung
authors.initials: N
authors.lastname: Park
authors.affiliation: Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 689-798, Republic of Korea.
authors.forename: Pilgun
authors.initials: P
authors.lastname: Oh
authors.affiliation: Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 689-798, Republic of Korea.
authors.forename: Jaephil
authors.initials: J
authors.lastname: Cho
keywords: electrochemical reversibility; layered structures; phase transition mechanism; screen effects