ReaxFF molecular dynamics simulations on lithium sulfur batteries

Understanding of the structural, and kinetic behavior of the sulfur cathode materials are crucial for designing high performance Li-S batteries. In a recent study, ReaxFF molecular dynamics simulations has been utilized to study sulfur cathode materials. Upon lithiation, the sulfur cathode undergoes significant volume expansion and ReaxFF simulations nicely captures this phenomenon. A grand canonical Monte Carlo (GCMC) scheme was employed to calculate the open circuit voltage profile during cell discharge. The diffusion coefficients of both lithium and sulfur at various stages of Li-loading in the sulfur cathode provides significant information about reaction kinetics and diffusion induced stress generation during cell operation.

These very first reactive MD simulations for studying Li-S battery cathode materials will eventually allow multi-scale simulations in a reactive environment on the charge and discharge process of Li-S batteries, which are necessary for designing improved energy materials.

ReaxFF simulation results for lithiated sulfur cathode materials: S diffusion in Li₂S (left) and discharge voltage profile (right).

Try it yourself: Discharge voltage profiles, Li-Ion Diffusion Coefficients Tutorial

See also: ReaxFF tutorials, ReaxFF training course, parametrization with MCFF, GCMC with ReaxFF, reparametrization tutorial.

M. M. Islam, A. Ostadhossein, O. Borodin, A. T. Yeates, W. W. Tipton, R. G. Hennig, N. Kumar, and A. C. T. van Duin, ReaxFF molecular dynamics simulations on lithiated sulfur cathode materials, Phys. Chem. Chem. Phys. 17, 3383-3393 (2015)