Date(s) - 07/11/2016
3:00 pm - 4:00 pm
220-E Hodges Library
Department of Chemical & Biomolecular Engineering
University of Tennessee, Knoxville
Advisor: Dr. David J. Keffer
3:00 p.m. Friday, July 11, 2016
220-E Hodges Library
“Lignin-based Li-Ion Anode Materials Synthesized from Low-Cost Renewable Resources”
In today’s world, the demand for novel methods of energy storage is increasing quickly, particularly with the rise of portable electronic devices, electric vehicles, and the personal consumption and storage of solar energy. While other technologies have improved rapidly, battery technology has lagged behind largely due to the difficulty in devising new electric storage systems that are simultaneously high performing, inexpensive, and safe.
In order to tackle these challenges, novel Li-ion battery anodes have been developed at Oak Ridge National Laboratory that are made from lignin, a low-cost, renewable resource that is obtained from an abundant supply of biomass. The anodes that result from the lignin manufacturing process exhibit performance comparable to that of conventional graphitic anodes for a fraction of the cost. However, these materials are unusual in that they consist solely of a mixture of amorphous and crystalline carbon, and this complex, hierarchical material is not well understood. This work reveals the mechanism behind the structural composition and the performance of these carbon composite anodes.
The anodes are investigated using two distinct approaches: 1) a computational approach, whereby atomistic models of the composite systems are created and simulated using reactive molecular dynamics, and 2) an experimental approach, whereby the small scale structure of the material is elucidated using neutron diffraction.
The computational approach reveals deep insight into the nature of Li-ion localization, and a three-dimensional, archetypal model of the local atomic environment that surrounds Li-ions at various binding energies is developed. The experimental approach is used in conjunction with the simulation results to understand the structure of the carbon composites, and how unique structural properties vary as a function of the parameters that are controlled in the manufacturing process. An understanding of the energetics and localization of Li-ions is also developed. These insights lead to the revelation that a large interfacial surface area between amorphous and crystalline carbon domains is paramount for high-capacity storage of Li-ions.
Mr. Nicholas McNutt is a PhD candidate in the Department of Chemical and Biomolecular Engineering at the University of Tennessee. He earned his B.S. in Chemical and Biomolecular Engineering at the Georgia Institute of Technology in 2012. He joined Dr. David Keffer’s group in 2012 where his work has focused mainly on molecular modeling of Li-ion battery anodes. Specifically, he studies the structure of low-cost, lignin-derived carbon composite anodes, and the storage and energetics of the Li-ions contained within them.