Effects of grain boundary structure on lithium transport in graphite

Abstract

Molecular dynamics simulations are used to investigate lithium (Li) transport rates in symmetric tilt graphite grain boundaries (GBs). Experiments have quantified highly varied diffusion rates of Li in graphite and recent computational work exposed similar differences in Li intercalation rates into GBs from a free surface. This work extends findings of intercalation studies to provide explanations for various rates and uses said differences to predict bulk GB transport behavior. Various structural properties are presented for graphite GBs, including bond angles, bond order, and free volume analysis which is rarely presented in covalent systems. The importance of free volume connectivity is also discussed as is Li structure in GBs.

Keywords:

• Diffusion
• lithium
• graphite
• grain boundary

Acknowledgements

The authors are grateful for the support of the NSF XSEDE Program TG-CTS140059 (Molecular Dynamics Study of Lithium-ion Diffusion Rates in Graphite Grain Boundaries) and Lehigh University’s High Performance Computing resources.

Notes

No potential conflict of interest was reported by the authors.