Numerical Investigations on the Damage Behaviour of a Reconstructed Anode for Solid Oxide Fuel Cell Application

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8082
Author(s):  
Katharina Steier ◽  
Vinzenz Guski ◽  
Siegfried Schmauder

This paper addresses the damage behaviour of a nickel/yttria-stabilised zirconia (Ni-YSZ) anode, in order to understand microstructural degradation processes of Solid Oxide Fuel Cells (SOFCs) during long-term operation. Numerical investigations are carried out to analyse the failure mechanisms in detail. For this purpose, finite element (FE) models are generated from focused ion beam-scanning electron microscopy 3D image data, representing the anode microstructure with varying phase compositions. A brittle model and a ductile material model were assigned to the YSZ phase and the nickel phase, respectively. The porosity is found to affect the strength of the microstructure significantly, leading to low compressive strength results. A high Ni content generally increases the toughness of the overall structure. However, the orientation and the geometry of the nickel phase is essential. When the Ni phase is aligned parallel to the loading direction, a supporting effect on the microstructure is observed, resulting in a significant high toughness. On the contrary, a rapid failure of the sample occurs when the Ni phase is oriented perpendicular to the loading direction. Two main failure mechanisms are identified: (i) cracking at the Ni/YSZ interface and (ii) cracking of struts at the location of the smallest diameter.

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5127
Author(s):  
Tomasz A. Prokop ◽  
Grzegorz Brus ◽  
Shinji Kimijima ◽  
Janusz S. Szmyd

In this work, a three-dimensional microstructure-scale model of a Solid Oxide Fuel Cell’s Positive-Electrolyte-Negative assembly is applied for the purpose of investigating the impact of decreasing the electrolyte thickness on the magnitude, and the composition of electrochemical losses generated within the cell. Focused-Ion-Beam Scanning Electron Microscopy reconstructions are used to construct a computational domain, in which charge transport equations are solved. Butler–Volmer model is used to compute local reaction rates, and empirical relationships are used to obtain local conductivities. The results point towards three-dimensional nature of transport phenomena in thin electrolytes, and electrode-electrolyte interfaces.


Catalysts ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 253 ◽  
Author(s):  
Marcin Mozdzierz ◽  
Katarzyna Berent ◽  
Shinji Kimijima ◽  
Janusz S. Szmyd ◽  
Grzegorz Brus

The models of solid oxide fuel cells (SOFCs), which are available in the open literature,may be categorized into two non-overlapping groups: microscale or macroscale. Recent progressin computational power makes it possible to formulate a model which combines both approaches,the so-called multiscale model. The novelty of this modeling approach lies in the combination ofthe microscale description of the transport phenomena and electrochemical reactions’ with thecomputational fluid dynamics model of the heat and mass transfer in an SOFC. In this work,the mathematical model of a solid oxide fuel cell which takes into account the averaged microstructureparameters of electrodes is developed and tested. To gain experimental data, which are used toconfirm the proposed model, the electrochemical tests and the direct observation of the microstructurewith the use of the focused ion beam combined with the scanning electron microscope technique(FIB-SEM) were conducted. The numerical results are compared with the experimental data fromthe short stack examination and a fair agreement is found, which shows that the proposed modelcan predict the cell behavior accurately. The mechanism of the power generation inside the SOFC isdiscussed and it is found that the current is produced primarily near the electrolyte–electrode interface.Simulations with an artificially changed microstructure does not lead to the correct prediction of thecell characteristics, which indicates that the microstructure is a crucial factor in the solid oxide fuelcell modeling.


Author(s):  
Naga Siva Kumar Gunda ◽  
Sushanta K. Mitra

The present work investigated a new method of calculating effective transport properties of solid oxide fuel cell (SOFC) electrodes from three-dimensional (3D) physically realistic network structures. These physically realistic network structures are topological equivalent representations of reconstructed microstructures in the form of spheres (nodes or bodies) and cylinders (segments or throats). Maximal ball algorithm is used to extract these physically realistic network structures from the series of two-dimensional (2D) cross-sectional images of SOFC electrodes. Dual-beam focused ion beam - scanning electron microscopy (FIB-SEM) is performed on SOFC electrodes to acquire series of 2D cross-sectional images. Finite element method is implemented to compute the effective transport properties from the network structures. As an example, we applied this method to calculate the effective gas diffusivity of lanthanum strontium manganite (LSM) of SOFC. The results obtained from physically realistic network structures are compared with reconstructed 3D microstructures.


2017 ◽  
Vol 78 (1) ◽  
pp. 2159-2170 ◽  
Author(s):  
Rubayyat Mahbub ◽  
Tim Hsu ◽  
William K Epting ◽  
Noel T. Nuhfer ◽  
Gregory A Hackett ◽  
...  

2016 ◽  
Vol 22 (6) ◽  
pp. 1261-1269 ◽  
Author(s):  
Agnieszka Priebe ◽  
Pierre Bleuet ◽  
Gael Goret ◽  
Jerome Laurencin ◽  
Dario Montinaro ◽  
...  

AbstractIn this paper the potential of time-of-flight secondary ion mass spectroscopy combined with focused ion beam technology to characterize the composition of a solid oxide fuel cell (SOFC) in three-dimension is demonstrated. The very high sensitivity of this method allows even very small amounts of elements/compounds to be detected and localized. Therefore, interlayer diffusion of elements between porous electrodes and presence of pollutants can be analyzed with a spatial resolution of the order of 100 nm. However, proper element recognition and mass interference still remain important issues. Here, we present a complete elemental analysis of the SOFC as well as techniques that help to validate the reliability of obtained results. A discussion on origins of probable artifacts is provided.


Sign in / Sign up

Export Citation Format

Share Document