Project Details
Projekt
Overcoming Charge Transport Limitations: From Fundamental Mechanisms to Advanced Technologies
Applicant
Dr. Manuel Dillenz
Subject Area
Theoretical Chemistry: Electronic Structure, Dynamics, Simulation
Term
since 2025
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 570433177
Overcoming kinetic limitations is a fundamental challenge in materials science constraining the performance of energy storage technologies. These limitations significantly impact efficiency and rate capabilities across numerous functional materials, particularly those relying on polaron-mediated transport mechanisms. In transition metal-based compounds, charge carriers interact strongly with the host lattice, inducing local structural distortions termed polarons. Simultaneously, Jahn-Teller active centers in materials based on Mn, Fe, and Ni undergo dynamic pseudo-rotations on femtosecond to picosecond timescales - matching the timescale of polaron mobility. Despite directly influencing macroscopic charge transport properties, the mechanistic correlation between these phenomena remains insufficiently understood. To investigate these phenomena, I focus on LiMn2O4 (LMO) as model system, where Mn3+ ions create JT distortions that undergo an order-disorder transition at 290K, within typical battery operating ranges. This transition involves frequent pseudo-rotations leading to a time-averaged cubic structure, making LMO an ideal case study for investigating how dynamic structural processes affect charge transfer in sustainable battery materials. I suggest examining how thermally activated pseudo-rotations of Jahn-Teller distortion axes govern short-timescale structural evolution in LMO. This aims to elucidate the fundamental mechanism of charge transport in related materials governed by the critical interplay between JT dynamics and polaron migration. The objectives include determining how JT distortion orientations affect polaron migration barriers, examining how JT center concentration influences ordering transitions across the Li intercalation range, and integrating these kinetic and thermodynamic insights to explain charge transfer in JT-active materials with applications across battery technologies. To achieve these objectives, I aim to develop a novel framework based on ML-accelerated extended Hubbard functionals that balances accuracy and computational efficiency. This addresses a critical limitation in computational materials science by accurately capturing both localized and partially delocalized electronic states while avoiding spurious energy penalties typically applied to transition states. Ultimately, this work addresses a critical knowledge gap in charge transport kinetics of JT-active materials, with direct applications to fast-charging capabilities and rational design of sustainable battery technologies for the green transition. The methodological innovations developed here extend beyond battery materials to other fields requiring accurate modeling of correlated electron systems, including heterogeneous catalysis and transition metal oxide interfaces where similar challenges in describing partially delocalized transition states exist.
DFG Programme
WBP Fellowship
International Connection
Denmark
