University of Tennessee
Materials Science & Engineering

Harvesting Switchgrass
Center for Renewable Carbon, University of Tennessee Institute for Agriculture, Knoxville, Tennessee
March 8, 2019

Professor David Harper at the UT Center for Renewable Carbon spearheads a research team to develop high-value materials from renewable resources, including switchgrass and other lignin-based feedstocks. In recent years, Prof. Harper's group has synthesized nanostructured carbon composites for use in such applications as battery anodes. In the UT Materials Science and Engineering Department, Professor David Keffer provides computational modeling to provide complementary insight into the processing-strucure-property-performance relationships of the materials. Often in a computational group, students don't always get a "hands-on" feel for the materials they are modeling. Such is not the case in this research partnership between UT Knoxville and the UT Insitute of Agriculture.

Three Materials Science and Engineering PhD students, co-advised by Profs. Harper and Keffer, harvested switchgrass grown in field trials on the Ag campus. Pictured in foreground: Valerie García-Negrón & Lu Yu; background: Dayton Kizzire.

Pyrolysis of the switchgrass transforms it into a nanostructured carbon-composite composed of graphitic nanocrystallites distributed in an amorphous carbon domain. This semester, Dayton and Lu are enrolled in Prof. Haixuan Xu's quantum materials modeling course (MSE 613) where they are investigating the locations for preferential binding of lithium and sodium ions in the composite.

Valerie has recently published a paper on a model for the hierarchical decomposition of the radial distribution function obtained from neutron and x-ray scattering, which provides experimental insight into the atomic and mesoscale structure of the composites. Currently, she is working to determine how the choice of different feedstocks, including switchgrass, impacts composite structure and thus battery performance.

This is how you develop an intimate relationship with your research!

Before the semester is out this switchgrass will be pyrolyzed and converted into a nanostructured carbon composite. After that comes battery device manufacture and electrochemical testing.

More photos on the Keffer research group site.