Modeling Li-metal plating at the graphene surface
Graphitic electrode materials are central to Li-ion battery technology because of their high electron conductivity, high surface area for Li intercalation, and thermal and chemical stability. Li-intercalated graphite has large specific capacity that can be modulated by the introduction of point defects and dopants. Upon charge/discharge cycles, metallic lithium can accumulate at the electrode/electrolyte interface, which prevents the intercalation of Li ions and degrades the overall battery performances. This phenomena is known as Li plating. Atomistic simulations are critical to understand better the interaction between Li ions and graphene in order to develop next-generation anode materials. However, such simulations require the description of charged electrode and electron transfer. Thanks to eReaxFF it is now possible to describe explicitly the reduction of Li ions at the graphene interface and to observe the dynamics of Li plating of the anode. These state-of-the-art simulations bring us a step closer to modeling an entire battery at the atomic scale.
A recent research paper reports a new eReaxFF reactive force field to describe electron conduction and non-zero voltage simulations of graphitic anode materials. It is demonstrated that the eReaxFF description, using explicit electrons, captures the correct behavior of electron conduction in the graphite plane while restricting through-plane motion. The developed force field captures the correct trends of electron motion and localization in both pristine as well as defective graphene at different applied temperatures and voltages. The force field can simulate lithium-graphene interaction and the consequent lithium metal plating and nucleation driven by electron transfer from the negatively charged graphene surface to the exposed lithium ions.
With the Amsterdam Modeling Suite, you can perform eReaxFF simulations to study Li-plating on graphene using PLAMS. Let us know if you would like the try the python script (tar) to calculate electron affinities or to setup Li-plating simulations.
