Bond Pathway Analysis of NMR Spectra for Li1.2Mn0.4Co0.4O2: Pristine Material

Tuesday, 26 May 2015: 09:20
Continental Room B (Hilton Chicago)
H. Iddir (Materials Science Division, Argonne National Laboratory), B. Key, F. Dogan (Argonne National Laboratory), J. Russell (Argonne National laboratory), B. R. Long, J. Bareno, and R. Benedek (Argonne National Laboratory)
NMR has been applied extensively to lithium ion battery cathode materials, of which layered-layered composites xLi2MnO3•(1-x)LiMO2 (M=Mn,Co,Ni)  are of particular interest, owing to their high energy density. In this work, NMR spectra are measured for the model layered-layered system xLi2MnO3•(1-x)LiCoO2  and Bond-Pathway-model analysis is applied to elucidate the atomic arrangement and domain structure of this material (in its pristine state, before electrochemical cycling). The simplest structural element of a domain consists of a stripe of composition LiMn2 parallel to an in-layer crystallographic axis in a metal layer of the composite.  A simple model of the composite structure may be constructed by a superposition of such stripes in an LiCoO2 background. We show that such a model can account for most of the features of the observed NMR spectra.

Support from the Vehicle Technologies Program U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy.