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Publication Citation: Combined NMR and XAS Study on Local Environments and Electronic Structures of the Electrochemically Li-Ion Deintercalated Li1-xCo1/3Ni1/3Mn1/302 Electrode System

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Author(s): W S. Yoon; C P. Grey; Mahalingam Balasubramanian; Xiao-Qing Yang; Daniel A. Fischer; James McBreen;
Title: Combined NMR and XAS Study on Local Environments and Electronic Structures of the Electrochemically Li-Ion Deintercalated Li1-xCo1/3Ni1/3Mn1/302 Electrode System
Published: January 01, 2004
Abstract: Combined 6Li MAS NMR, in-situ metal K-edge (hard) XAS, and O K-edge (soft) XAS have been carried out during the first charging process for the layered Li1-xCo1/3Ni1/3Mn1/3O2 cathode material. The 6Li MAS NMR results showed the prescence of Li in the Ni2+/Mn4+ layers, in addition to the expected sites for Li in the lithium layers. On charging, Li ions in both the transition metals and lithium layers are removed and no new resonances are observed. The metal K-edge XAS results suggest that the major charge compensation at the metal site during charge is achieved by the oxidation of Ni2+ ions, while the manganese ions remain mostly unchanged in the Mn4+ state. From the observation of O K-edge XAS results, we can conclude that large portion of the charge compensation during charge is achieved in the oxygen site. This work will provide the possibility of larger capacity of the electrode material by using Li in the transition metal layers and contribution of oxygen during charge.
Citation: Electrochemical and Solid State Letters
Volume: 7
Issue: No. 3
Keywords: batteries;cahtodes;lithium;NEXAFS;soft x-ray
Research Areas: Ceramics, Characterization, Energy, Energy Conversion, Storage, and Transport