Oxygen diffusion in solid oxide fuel cell cathode and electrolyte materials: mechanistic insights from atomistic simulations

Abstract

Solid oxide fuel cells are of technological interest as they offer high efficiency for energy conversion in a clean way. Understanding fundamental aspects of oxygen self-diffusion in solid state ionic systems is important for the discovery of next-generation electrolyte and cathode material compositions and microstructures that can enable the operation of SOFCs at lower temperatures more efficiently, durably, and economically. In the present perspective article, we illustrate the important role of modelling and simulations in providing direct atomic scale insights on the oxygen ion transport mechanisms and conduction properties in the cathode and electrolyte materials, and in accelerating the progress from old materials to new concepts. We first summarize the ionic transport mechanisms in the traditional cathode and electrolyte materials which have been widely studied. We then pay our attention to the non-traditional materials and their oxygen transport paths from recent studies, focusing on structural and transport anisotropy and lattice dynamics. Lastly, we highlight the new developments in the potential to increase the ionic conductivity of the traditional materials through external mechanical stimuli, bringing about the mechano-chemical coupling to drive fast ionic transport.

Porous La0.6Sr0.4CoO3−δ thin film cathodes for large area micro solid oxide fuel cell power generators

“…Thus, fabrication of large-area YSZ membranes with similar performances than those already reported was satisfactorily proven. Although film stress has a marked influence on ionic-conduction properties by affecting the charge carrier mobility [59][60][61][62][63][64], any relevant contribution of the strain on the cross-plane conductivity was observed neither in this work nor in M A N U S C R I P T…”

Impact of doping on the ionic conductivity of ceria: A comprehensive model

“…: +966(0)544700080. eters (for example, strain) on the O diffusion. [18][19][20][21][22] Andersson and co-workers have investigated the O migration and the vacancy-dopant association for low dopant concentrations. 23 Similar concentrations have been studied by Nakayama and co-workers.…”

Mechanism for enhanced oxygen reduction kinetics at the (La,Sr)CoO3−δ/(La,Sr)2CoO4+δ hetero-interface

“…The slow rate of oxygen reduction rate at the cathode has been the primary limitation to the performance of solid oxide fuel cells (SOFCs) at intermediate temperatures (500-700 °C) [1][2][3][4][5] that is important for materials stability and system cost. 1,3,5,6 This has led to an extensive search for highly active cathode materials that accelerate the kinetics of oxygen reduction reaction (ORR).…”

“…1,3,5,6 This has led to an extensive search for highly active cathode materials that accelerate the kinetics of oxygen reduction reaction (ORR). Traditionally, perovskite type transition metal oxides (ABO 3 ) have been widely investigated as SOFC cathodes.…”