Effects of Composite Electrode Structure on Performance of Intermediate-Temperature Solid Oxide Electrolysis Cell

Abstract

The composite electrode structure plays an important role in the optimization of performance of the intermediate-temperature solid oxide electrolysis cell (IT-SOEC). However, the structural influence of the composite electrode on the performance of IT-SOEC is not clear. In this study, we developed a three-dimensional macroscale model coupled with the mesoscale model based on percolation theory. We describe the electrode structure on a mesoscopic scale, looking at the electrochemical reactions, flow, and mass transport inside an IT-SOEC unit with a composite electrode. The accuracy of this multi-scale model was verified by two groups of experimental data. We investigated the effects of operating pressure, volume fraction of the electrode phase, and particle diameter in the composite electrode on electrolysis reaction rate, overpotential, convection/diffusion flux, and hydrogen mole fraction. The results showed that the variation in the volume fraction of the electrode phase had opposite effects on the electrochemical reaction rate and multi-component diffusion inside the composite electrode. Meanwhile, an optimal range of 0.8–1 for the particle diameter ratio was favorable for hydrogen production. The analysis of IT-SOEC with composite electrodes using this multi-scale model enables the subsequent optimization of cell performance and composite electrode structure.

High Temperature Solid Oxide Electrolysis – Technology and Modeling

“…Nano-particle infiltrated electrodes were characterized in [121]. A combination of percolation theory with a mesoscale microstructure model was presented in [92,122].…”

“…One possibility is to extend the NSE with a Darcy's law term [52,53,57,62,65,86,91,137,138,[140][141][142][143]. [58,88,90,91,122,144,145] apply forms of Brinkman equation, while [60,71,79,146] replace NSE with Darcy's law and [83,147] rely on the implementation in the dusty-gas model. The permeability needed for the Darcy's law term is determined via the Kozeny-Carman equation [51,88,141,148,149].…”

“…The good balance between computational complexity and accurate predictions is also reflected in the high number of recent publications applying the DGM to describe mass transport in porous electrodes [76,79,83,91,115,122,172].…”

Oxygen Electrode PrBa0.5Sr0.5Co1.5Fe0.5O5+δ–BaZr0.1Ce0.7Y0.1Yb0.1O3−δ with Different Composite Proportions for Proton-Conducting Solid Oxide Electrolysis Cells

“…To address the above issues, compounding PBSCF and proton conductor is a simple and effective optimization method . Regarding composite optimization strategies, many researchers have achieved the optimization of perovskite materials and good electrochemical performance.…”

“…To address the above issues, compounding PBSCF and proton conductor is a simple and effective optimization method. 22 Regarding composite optimization strategies, many researchers have achieved the optimization of perovskite materials and good electrochemical performance. Park et al 23 proposed an optimization process based on PBSCF-Ce 0.9 Gd 0.1 O 1.95 (GDC) x, (x = 0, 20, 40, 50, and 60 wt %) composite electrodes to effectively expand the electrochemical reaction zone.…”