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Operando Lithium Dynamics in the Li‐Rich Layered Oxide Cathode Material via Neutron Diffraction
Author(s) -
Liu Haodong,
Chen Yan,
Hy Sunny,
An Ke,
Venkatachalam Subramanian,
Qian Danna,
Zhang Minghao,
Meng Ying Shirley
Publication year - 2016
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.201502143
Subject(s) - materials science , neutron diffraction , lithium (medication) , oxygen , lattice constant , analytical chemistry (journal) , oxide , cathode , transition metal , diffraction , crystal structure , crystallography , chemistry , physics , metallurgy , catalysis , medicine , biochemistry , organic chemistry , chromatography , optics , endocrinology
Neutron diffraction under operando battery cycling is used to study the lithium and oxygen dynamics of high Li‐rich Li(Li x /3 Ni (3/8‐3 x /8) Co (1/4‐ x /4) Mn (3/8+7 x /24) O 2 ( x = 0.6, HLR) and low Li‐rich Li(Li x /3 Ni (1/3‐ x /3) Co (1/3‐ x /3) Mn (1/3+ x /3) O 2 ( x = 0.24, LLR) compounds that exhibit different degrees of oxygen activation at high voltage. The measured lattice parameter changes and oxygen position show largely contrasting changes for the two cathodes where the LLR exhibits larger movement of oxygen and lattice contractions in comparison to the HLR that maintains relatively constant lattice parameters and oxygen position during the high voltage plateau until the end of charge. Density functional theory calculations show the presence of oxygen vacancy during the high voltage plateau; changes in the lattice parameters and oxygen position are consistent with experimental observations. Lithium migration kinetics for the Li‐rich material is observed under operando conditions for the first time to reveal the rate of lithium extraction from the lithium layer, and transition metal layer is related to the different charge and discharge characteristics. At the beginning of charging, the lithium extraction predominately occurs within the lithium layer. Once the high voltage plateau is reached, the lithium extraction from the lithium layer slows down and extraction from the transition metal layer evolves at a faster rate.