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Critical Role of Cations in Lithium Sites on Extended Electrochemical Reversibility of Co‐Rich Layered Oxide
Author(s) -
Cho Woongrae,
Myeong Seungjun,
Kim Namhyung,
Lee Sanghan,
Kim Youngki,
Kim Maengsuk,
Kang Seok Ju,
Park Noejung,
Oh Pilgun,
Cho Jaephil
Publication year - 2017
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201605578
Subject(s) - electrochemistry , materials science , cathode , lithium (medication) , ion , oxide , density functional theory , chemical physics , phase (matter) , chemical engineering , inorganic chemistry , electrode , chemistry , computational chemistry , metallurgy , organic chemistry , medicine , engineering , endocrinology
Only a very limited amount of the high theoretical energy density of LiCoO 2 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 LiNiO 2 , which produces a screen effect of cations in the 3 b ‐Li site, the phase distortion of LiCoO 2 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.