Deconvolution of Gas Diffusion Polarization in Ni/Gadolinium-Doped Ceria Fuel Electrodes

Abstract

The deconvolution of physicochemical processes in impedance spectra of SOCs with nickel/ceria fuel electrodes is challenging as gas diffusion strongly overlaps with the electrochemical processes at fuel and air electrode. To overcome this issue, symmetrical cells were applied and the gas diffusion process at the fuel electrode was quantified by altering the inert component (nitrogen / helium) in a ternary fuel gas mixture. An effective gas transport parameter considering microstructural and geometrical features was derived, enabling a precise quantification of polarization resistances related to gas diffusion and hydrogen electrooxidation. The obtained values were applied to parameterize a dc cell model. The model validation in fuel cell and electrolyzer mode showed an excellent agreement between measured and simulated current/voltage characteristics over a wide range of technically meaningful gas compositions and operating temperatures.

Technological Pathways to Produce Compressed and Highly Pure Hydrogen from Solar Power

“…Metals, as well as glass-or metal-based sealants can be avoided in the tubular design. Operando characterization, [87,113,114] data analysis and modelling approaches [86,[115][116][117] on different scales are mandatory to understand the electrochemical processes in the cells and stacks and to improve their performance and durability. [117][118][119][120] Various SOC cell and stack designs have been used in commercial or pre-commercial SOFC-systems.…”

“…Operando characterization, [87, 113, 114] data analysis and modelling approaches [86, 115–117] on different scales are mandatory to understand the electrochemical processes in the cells and stacks and to improve their performance and durability [117–120] …”

Technologische Pfade für die Herstellung von komprimiertem und hochreinem Wasserstoff mit Hilfe von Sonnenenergie

“…Heutzutage sind planare Typen, die aus flachen Mehrschichtstrukturen bestehen, [104] (zusammen mit (mikro-) tubularen Designs), wie elektrolytgestützte (ESC), brenngaselektrodengestützte (ASC) und metallgestützte(MSC) Zellen, am weitesten verbreitet. [86,[110][111][112] Um Operando-Charakterisierung, [87,113,114] Datenanalyse und Modellierungsansätze [86,[115][116][117] auf verschiedenen Skalen sind unerlässlich, um die elektrochemischen Prozesse in den Zellen und Stacks zu verstehen und ihre Leistung und Haltbarkeit zu verbessern. [117][118][119][120] In kommerziellen oder vorkommerziellen SOFC-Systemen wurden verschiedene SOC-Zell-und Stack-Designs verwendet.…”

“…Operando‐Charakterisierung, [87, 113, 114] Datenanalyse und Modellierungsansätze [86, 115–117] auf verschiedenen Skalen sind unerlässlich, um die elektrochemischen Prozesse in den Zellen und Stacks zu verstehen und ihre Leistung und Haltbarkeit zu verbessern [117–120] …”

Quantifying the Relationship Between Microstructure and Performance in Gadolinium-Doped Ceria Infiltrated Ni/YSZ Symmetric Cells

“…Distribution of relaxation times (DRT) has been valuable in deconvoluting the electrochemical processes in electrodes with a GDC phase. Recently, Ni/GDC electrodes were analyzed with DRT to separate surface processes, bulk processes, 5 and gas diffusion processes, 6 which can strongly overlap. Particularly prudent to this work, Park et al analyzed processes of Ni/YSZ electrodes infiltrated with varying concentrations of GDC.…”