Identifying the Distribution of Al 3+ in LiNi 0.8 Co 0.15 Al 0.05 O 2

The doping of Al into layered Li transition metal (TM) oxide cathode materials, LiTMO2, is known to improve the structural and thermal stability, although the origin of the enhanced properties is not well understood. We have investigated the effect of aluminum doping on layer stabilization using a c...

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Bibliographic Details
Published in:	Chemistry of materials 2016-10, Vol.28 (22)
Main Authors:	Trease, Nicole M., Seymour, Ieuan D., Radin, Maxwell D., Liu, Haodong, Liu, Hao, Hy, Sunny, Chernova, Natalya, Parikh, Pritesh, Devaraj, Arun, Wiaderek, Kamila M., Chupas, Peter J., Chapman, Karena W., Whittingham, M. Stanley, Meng, Ying Shirley, Van der Van, Anton, Grey, Clare P.
Format:	Article
Language:	eng
Subjects:	Al NMR atom probe tomography dynamic Jahn-Teller INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY MATERIALS SCIENCE NCA paramagnetic NMR
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Summary:	The doping of Al into layered Li transition metal (TM) oxide cathode materials, LiTMO2, is known to improve the structural and thermal stability, although the origin of the enhanced properties is not well understood. We have investigated the effect of aluminum doping on layer stabilization using a combination of techniques to measure the aluminum distribution in layered LiNi0.8Co0.15Al0.05O2 (NCA) over multiple length scales with 27Al and 7Li MAS NMR, local electron atom probe (LEAP) tomography, X-ray and neutron diffraction, DFT, and SQUID magnetic susceptibility measurements. LEAP tomographic maps show a homogenous distribution of Ni, Co, Al and O2 throughout the structure at the particle level in agreement with the hightemperature phase diagram. 7Li and 27Al NMR indicates that the Ni3+ ions undergo a dynamic Jahn-Teller (JT) distortion. 27Al NMR spectra indicate that the Al reduces the strain associated with the JT distortion, by preferential electronic ordering of the JT long bonds directed toward the Al3+ ion. Our ability to understand the complex atomic and orbital ordering around Al3+ demonstrated in the current method will be useful for studying the local environment of Al3+ in a range of transition metal oxide battery materials.
ISSN:	0897-4756 1520-5002