Regensburg 2025 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

MM: Fachverband Metall- und Materialphysik

MM 12: Materials for the Storage and Conversion of Energy

MM 12.2: Vortrag

Dienstag, 18. März 2025, 10:30–10:45, H22

Beyond Ion Dynamics: Efficient Charge Transport Simula- tions including Polarons at Battery Scales — •Matteo Rinaldi, Karsten Reuter, and Christian Carbogno — Fritz-Haber- Institut der MPG, Berlin

Polarons have long been recognized as fundamental for charge transport in battery materials - be it as charge carrier or as ion-transport enhancer [1]. Nonetheless, a quantitative modeling of polaron dynamics in such materials has, so far, remained elusive. On the one hand, the activated dynamics of polarons requires time and length scales that are inaccessible with first-principles methods. On the other hand, (machine learned) interatomic potentials do not capture electronic charge transport by construction. In this work, we overcome this hurdle by exploiting force-field models that explicitly account for the electronic viz. polaronic degrees of freedom in a semi-classical, adiabatic fashion. We demonstrate the viability of the approach for lithium titanium oxide (LTO), a prototypical anode material for which polaron hopping is known to play a decisive role [1]. To this end, we train an equivariant message-passing model to density-functional theory data obtained with hybrid functionals. By then performing large-scale molecular-dynamics simulations with this force-field, we investigate both ionic and polaronic transport in LTO as well as their dynamic coupling. We show that polarons diffuse orders of magnitude faster than ions and discuss the implications for the design of battery materials.

[1]M. Kick, C. Scheurer, and H. Oberhofer, ACS Appl. Energy Mater. 4, 8583 (2021).

Keywords: polaron; polaron hopping; LTO; battery materials; charge transport