(174b) Structural Analysis of Lithiated Lignin-Derived Carbon Composite Anodes

Novel lignin-based carbon composite materials have been developed for use as anodes in lithium-ion batteries. The structure of the uncharged anodes has been previously characterized via pair distribution functions (PDFs) obtained from neutron scattering experiments. Computational models of the uncharged composite systems were developed and studied using classical molecular dynamics simulations. The PDFs of the model systems successfully reproduced the experimental PDFs, and the model PDFs were then decomposed into component functions to understand the origin of each characteristic feature of the overall PDF.  In this presentation, we extend our work to include an understanding of the charged and discharged anodes via the use of reactive lithium-ion simulations. The resulting change in the uncharged composite PDF due to lithiation and subsequent de-lithiation is explained by developing a relationship between the properties of the composite model (volume fraction of crystalline material, characteristic size of the crystalline domains, composite density, and ion loading) and the unique features of the PDFs, including peak height, peak location, and long-range oscillations.

N.M. was supported by a grant from the Oak Ridge Associated Universities High Performance Computing Program, by a grant from the Sustainable Energy Education and Research Center of the University of Tennessee and by a grant from the National Science Foundation (DGE-0801470). This research project used resources of the National Institute for Computational Sciences (NICS) supported by NSF under agreement number: OCI 07-11134.5.  This research at Oak Ridge National Laboratory's Spallation Neutron Source was sponsored by the U.S. Department of Energy, Office of Basic Energy Sciences.