NETL researchers are using the Lab’s cutting-edge computational tools to model thousands of simulated microstructures as they seek to boost the performance and longevity of energy-efficient, near-zero-emission solid oxide fuel cells (SOFCs).
SOFCs can efficiently convert a variety of abundant domestic fuels — including coal and natural gas — into clean power via electrochemical reactions. SOFCs are highly efficient and produce far less carbon dioxide, require very little water and use less fuel while providing the same amount of electricity, compared to today’s combustion-based fossil energy technologies.
One of the primary obstacles to widespread commercialization of SOFCs is degradation, a gradual decline in performance that limits a fuel cell’s lifespan. Several suspected contributors to performance degradation are tied to the microstructural composition of the positive and negative electrodes, which are stacked on either side of an electrolyte within an SOFC to facilitate chemical reactions.
To help optimize performance and increase longevity, NETL researchers developed an integrated model framework that aims to predict performance degradation for SOFC electrode microstructures. The model identifies performance-relevant properties based on the cell’s initial microstructure and incorporates a multiphysics model, which predicts cell performance based on its microstructure, and a coarsening model, which anticipates microstructural changes during operation.
To date, NETL has examined a vast library of 45,000 synthetic microstructures, representing the largest variety of microstructural possibilities known within the fuel cell world, using the Lab’s Joule supercomputer. Among other takeaways, preliminary results indicate that performance and degradation are contingent upon an electrode’s initial microstructure rather than changes in its microstructure over time.
Following successful pilot testing, NETL researchers are ready to tackle actual microstructure data from manufacturers and other stakeholders. Scientists are incorporating big-data analysis tools and other advanced computational techniques to investigate how specific microstructures impact whole-cell performance, study the relationship between spatial properties and fuel cell outcomes and visualize microstructural changes alongside performance data. For example, one comparison indicated that increasing the diverse mix of molecules of yttria-stabilized zirconia, an ion-conducting material in both electrodes, while decreasing that of lanthanum strontium manganite, an electron-conducting phase in SOFC cathodes, exacerbated degradation.
“Ultimately, this data and other lessons learned from NETL’s simulations will provide critical information to help industrial manufacturers design better electrodes for successful commercialization of SOFC technology,” said Billy Epting, a scientist involved with the project through NETL’s Postgraduate Research Program.
The SOFC program contributes to NETL’s mission by facilitating highly efficient, cost-effective power generation from fossil fuels with responsible stewardship of the environment, via minimal water consumption and near-zero atmospheric emissions of carbon dioxide and criteria pollutants. Collaborative research efforts are designed to accelerate technology development and transfer for public benefit.