Welcome to the Amira-Avizo Software Use Case Gallery

Advanced nanotomographic analysis is still far from routine, and a number of challenges remain in data acquisition and post-processing. In this work, we present a number of techniques to improve the quality of the acquired data, together with easy-to-implement methods to obtain “advanced” microstructural quantifications. The techniques are applied to a solid oxide fuel cell cathode of interest to the electrochemistry community, but the methodologies are easily adaptable to a wide range of... Read more

The hot pressing process for fabricating membrane electrode assemblies (MEAs) has been widely adopted, yet little is known of its effects on the microstructural properties of the different components of the MEA. In particular, the interaction of the electrolyte, electrode and gas diffusion layer (GDL) due to lamination is difficult to probe as conventional imaging techniques cannot access the internal structure of the MEA. Here, a novel approach is used, which combines characterisation of hot... Read more

Composite cathodes comprising nanoscale
powders are expected to impart with high specific surface
area and triple phase boundary (TPB) density, which will lead
to better performance.

However, uniformly mixing nanosized heterophase powders remains a challenge due to their high surface energy and thus ease with which they agglomerate into their individual phases during the mixing and sintering
processes. In this study, we successfully synthesized La0.6Sr0.4Co0.2Fe... Read more

Nickel-yttria-stabilized zirconia (Ni-YSZ) cermet is widely used as an anode material in solid oxide fuel cells (SOFCs); however, Ni re-oxidation causes critical problems due to volume expansion, which causes high thermal stress. We fabricated a Ni-YSZ anode functional layer (AFL), which is an essential component in high-performance SOFCs, and re-oxidized it to investigate the related three-dimensional (3D) microstructural and thermo-mechanical effects. A 3D model of the re-oxidized AFL ... Read more

In this paper a fully three dimensional, multiphase, micro-scale solid oxide fuel cellanode transport phenomena numerical model is proposed and verified. The Butler-Volmer model was combined with empirical relations for conductivity and diffusivity – notably the Fuller-Shetler-Giddings equation, and the Fickian modelfor transport of gas reagents. FIB-SEM tomography of a commercial SOFC stack anode was performed and the resulting images were processed to acquire input data. ... Read more

This work describes the performance improvement of a polymer electrolyte fuel cell with a novel class of microporous layers (MPLs) that incorporates hydrophilic additives: one with 30 μm aluminosilicate fibers and another with multiwalled carbon nanotubes with a domain size of 5 μm. Higher current densities at low potentials were observed for cells with the additive-containing MPLs compared to a baseline cell with a conventional MPL, which correlate with improvements in water management. Th... Read more

A dendritic porous supported microstructure simultaneously creates small pore size and broad gas diffusion pathways in a solid oxide fuel cell anode membrane. This microstructure also achieves pore sizes that reduce with increasing depth within the membrane without increasing the structure tortuosity. Such a microstructure supplies high triple phase boundary density, fast gas diffusion and low polarization resistance. Here we characterise the performance of a porous anode with such a dendriti... Read more

Growing popularity and rapid development of Solid Oxide Fuel Cells (SOFCs) stem for their potential to become a gamechanger in the field of clean power generation technologies.

In this paper, a transient microstructure-oriented numerical simulation of a planar Direct Internal Reforming Solid Oxide Fuel Cell (DIR-SOFC) is delivered. The performance criteria in a direct steam reforming for a fuel starvation scenario are analyzed in order to optimize the underlying process. The proposed t... Read more

4D imaging – the three-dimensional distributions of chemical species determined using multi-energy X-ray tomography – of cathode catalyst layers of polymer electrolyte membrane fuel cells (PEM-FC) has been measured by scanning transmission x-ray microscopy (STXM) spectro-tomography at the C 1s and F 1s edges. In order to monitor the effects of radiation damage on the composition and 3D structure of the perfluorosulfonic acid (PFSA) ionomer, the same volume was measu... Read more

The performance of electrochemical devices depends on the three-dimensional (3D) distributions of microstructural features in their electrodes. Several mature methods exist to characterize 3D microstructures over the microscale (tens of microns), which are useful in understanding homogeneous electrodes. However, methods that capture mesoscale (hundreds of microns) volumes at appropriate resolution (tens of nm) are lacking, though they are needed to understand more common, less ideal electrode... Read more

With the growing use of X-ray computed tomography (X-ray CT) datasets for modelling of transport properties, comes the need to define the representative elementary volume (REV) if considering three dimensions or the representative elementary area (REA) if considering two dimensions. The resolution used for imaging must be suited to the features of interest in the sample and the region-of-interest must be sufficiently large to capture key information. Polymer electrolyte fuel cells have a hier... Read more

A solid oxide fuel cell (SOFC) is an electrochemical device that converts the chemical energy of hydrogen directly into electricity. A single cell usually has a form of a flat plate in which an impervious and dense ion-conducting electrolyte is sandwiched between two porous catalytic electrodes: an anode and a cathode. Fuel is fed to the anode side, and the air is supplied to the cathode. The gasses cannot mix to avoid unproductive combustion. Instead, gasses hit catalyst material, lose their... Read more

Degradation mechanisms within solid oxide fuel cells (SOFC) during thermal cycling limit operational start-up times and cell lifetime, and must therefore be better understood and mitigated. This work explores such mechanisms using digital volume correlation (DVC) techniques applied to lab-based X-ray tomograms where the microstructural evolution is evaluated during the operational cycling of a Ni–YSZ/YSZ cell. To emulate reduced start-up times, five tomograms were collected over four operat... Read more

The electrode microstructural properties significantly influence the efficiency and durability of many electrochemical devices including solid oxide fuel cells. Despite the possibility of simulating the electrochemical phenomena within real three-dimensional microstructures, the potential of such 3D microstructural information has not yet been fully exploited. We introduce here a completely new methodology for the advanced characterization of inhomogeneous current distribution base... Read more

The flow distribution behaviour of open-cell metallic foam fuel cell flow-fields are evaluated using ex-situ optical analysis and X-ray computed tomography (X-ray CT). Five different manifold designs are evaluated and flow distribution and pressure drop ... Read more

Fuel cells are electrochemical devices that convert the chemical energy of fuels into electrical energy. An ideal option for a wide variety of portable, stationary, and automotive applications is using the polymer electrolyte
fuel cells due to their modular design, high efficiency, and environmental benefits.

A 3D microstructure of the non-woven gas diffusion layers (GDLs) of polymer electrolyte fuel cells (PEFCs) is reconstructed using a stochastic method. For a commercial GDL, ... Read more

Mass transport can significantly limit the rate of reaction and lead to concentration polarization in electrochemical devices, especially under the conditions of high operating current density.

In this study we investigate hierarchically structured micro-tubular solid
oxide fuel cells (MT-SOFC) fabricated by phase inversion technique and quantitatively assess the mass transport and electrochemical performance improvement compared to a conventional tubular SOFC. We present pioneer... Read more

This study aims to correlate the active triple phase boundaries (TPBs) to the variation of as-prepared anode microstructures and Ni densifications based on the reconstructed 3D volume of an SOFC anode, providing a point of comparison with theoretical studies that reveal the relationship of TPBs and the material microstructure using randomly packed spheres models.

Nickel/zirconia-based nanostructured electrodes for solid oxide fuel cells suffer from poor stability even at intermediate temperature.

This study quantifies the electrochemical and microstructural degradation of nanostructured electrodes by combining 3D tomography, electrochemical impedance spectroscopy (EIS) and mechanistic modeling. For the first time, the electrochemical degradation of nanostructured electrodes is quantified according to the fractal nature of the three-phase bounda... Read more

A simple chemical bath deposition is used to coat a complex porous ceramic scaffold with a conformal Ni layer.

The resulting composite is used as a solid oxide fuel cell electrode, and its electrochemical response is measured in humidified hydrogen. X‐ray tomography is used to determine the microstructural characteristics of the uncoated and Ni‐coated porous structure, which include the surface area to total volume, the radial pore size, and the size of the necks between the pores.... Read more

The most common means of fabricating membrane electrode assemblies (MEAs) for polymer electrolyte fuel cells (PEFCs) involves a hot-press step. The conditions used to perform the hot-press impacts the performance and durability of the fuel cell.

However, the hot-press process is not essential for achieving operational MEAs and some practitioners dispense with the hot-press stage altogether by using a self-assembled approach. By performing the integration of the components in-situ durin... Read more