ITQ Severo Ochoa Lecture "Ion Transport in Oxide Electrolytes for Energy Conversion"

On Friday, July 5, 2024, at 12:00 p.m. in the ITQ (UPV-CSIC) Auditorium, the ITQ Severo Ochoa Lecture, titled “Ion Transport in Oxide Electrolytes for Energy Conversion,” will take place.

Manfred Martin, Professor of Physical Chemistry at the Institute of Physical Chemistry, RWTH Aachen University, and Adjunct Professor in the Department of Materials Science and Engineering at Seoul National University, has been invited to deliver the presentation.

Abstract:

Ion transport in oxides plays a significant role in energy and environmental applications. Important examples are oxygen ion and proton conducting oxides for electrolytes in electrolyzers and fuel cells.

I will present our theoretical approaches to understand these ionic transport processes in detail. We use density-functional theory (DFT) to calculate on a microscopic level defect interaction energies and migration energies of the defects that enable ionic motion. By means of Kinetic Monte Carlo (KMC) simulations we then predict macroscopic ion mobilities and ion conductivities on an ab initio level, i.e. without any adjustable parameters. As first example we will discuss rare-earth doped ceria. We show that all interactions between defects contribute to the so-called conductivity maximum of the ionic conductivity [1]. The second example concerns BaZrO₃-based oxides which are proto-type proton conductors. We show that the proton mobility is determined by nanoscale percolation of dopant ions which enables high proton mobility [2]. Finally, the understanding and comparison of the microscopic jump processes of oxygen vacancies and of protons in acceptor-doped BaZrO₃ are used to propose a simple descriptor for the influence of a dopant on the ionic conductivities, of oxygen ions and of protons as well. This new descriptor allows an easy screening of various dopants.

[1] J. Koettgen, S. Grieshammer, P. Hein, B. Grope, M. Nakayama, M. Martin,

Phys. Chem. Chem. Phys. 20, 14291 (2018).

[2] F.M. Draber, C. Ader, J.P. Arnold, S. Eisele, S. Grieshammer, S. Yamaguchi, M. Martin, Nature Mater. 19, 338 (2020).

[3] F.M. Draber, J.R. Denninger, P.C. Müller, I.K. Sommerfeld, M. Martin,

Adv. Energy Sustainability Res. (2022) 2200007.