Extending the lifetime of CO2 electrolyzers by improving their microstructure

Electrode microstructure optimization with GeoDict

Extending the service life of CO2 electrolyzers by improving the microstructure is the goal in the recently published article Scalability and stability in CO2 reduction via tomography-guided system design by C. P. O’Brien, D. McLaughlin, T. Böhm, Y. C. Xiao, J. P. Edwards, C. M. Gabardo, M. Bierling, J. Wicks, A. S. Rasouli, J. Abed, D. Young, C.-T. Dinh, E. H. Sargent, S. Thiele, and D. Sinton.

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C. P. O’Brien, D. McLaughlin, T. Böhm, Y. C. Xiao, J. P. Edwards, C. M. Gabardo, M. Bierling, J. Wicks, A. S. Rasouli, J. Abed, D. Young, C.-T. Dinh, E. H. Sargent, S. Thiele, and D. Sinton

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Challenges in commercialization of CO2 electrolyzers

The challenges with state-of-the-art Gas Diffusion Electrodes (GDEs) for CO2 electrolysis include managing salt precipitation and the low surface tension of the produced liquids within the GDE.

These liquids begin to wet the microporous layer (MPL) and lead to clogging of the pores, which limits the stability of commercially available GDEs for CO2 electrolysis (see Fig 1). These issues must be addressed for the successful commercial application of CO2 electrolysis.

Innovative prototype with optimized microstructure

Researchers  from the University of Toronto and the renowned Forschungszentrum Jülich, Helmholtz Institute Erlangen-Nürnberg for Renewable Energy have made significant progress in enhancing GDEs for CO2 electrolysis to C2+ products through microstructure optimization. In their study, they analyzed digital twins of a commercial GDE created using multi-modal tomography techniques—including X-ray, FIB-SEM, and EDX — and an improved digital prototype GDE. The digital twins and the simulations on these structures - carried out with GeoDict - led to an improved prototype design that was successfully scaled from the 5 cm² lab-scale starting point to 800 cm² cells.

The innovative design of the prototype incorporates a percolating network of PTFE within the MPL to tackle the challenge of salt precipitation and wetting that can clog nano-sized pores. To understand the intricacies of these electrodes, the researchers used the PoroDict module of GeoDict and analyzed grain and pore sizes, providing valuable insights into their microstructural characteristics. Following this, they determined transport parameters using the FlowDict, ConductoDict, and DiffuDict modules. While diffusion flux and permeability remained stable, there was a notable reduction in electron conduction compared to traditional designs.

In light of these findings, a new upscaled prototype was developed featuring a thinner MPL, to improve its electron conductivity. This upscaled GDL demonstrated stable operation over 240 hours in both 800 cm² and 8,000 cm² 10-cell stacks, resulting in the largest CO2 reduction to C2+ products demonstration published to date.

This research highlights the potential for advancing commercial applications in CO2 electrolysis through simulations and optimization of the microstructure of GDEs using digital material design with GeoDict.

Pathway to commercialization and author’s statement

We are pleased to report that insights from this microstructure study have led to a patent application and are planned for use by CERT Systems Inc., a company specializing in commercializing CO2 electrolysis technology.

Author David McLaughlin stated:

GeoDict contributed significantly to the findings of our study. In particular, the AI-supported segmentation was useful in obtaining high fidelity digital twins. We characterized the properties of the digital twins with digital microstructure analysis and physical simulation.

[1] C. P. O’Brien, D. McLaughlin, T. Böhm, Y. C. Xiao, J. P. Edwards, C. M. Gabardo, M. Bierling, J. Wicks, A. S. Rasouli, J. Abed, D. Young, C.-T. Dinh, E. H. Sargent, S. Thiele, D. Sinton, Joule 2024, https://doi.org/10.1016/j.joule.2024.07.004