Durability challenges key to SOC technology
Solid oxide cells play a central role in low-carbon energy systems, enabling highly-efficient production of electricity and hydrogen. However, their use is limited due to a lack of durability over time: during operation, electrode materials become altered with a gradual decline in performance.
Nickel, used in Ni-YSZ electrodes, plays a key part in these mechanisms. Its microstructure is affected by operating conditions: particles migrate and aggregate, reducing the active surface area and directly impacting electrochemical activity.
Advanced modeling to better understand these mechanisms
To analyze these mechanisms, researchers developed a multi-physics approach combining an electrochemical model with phase-field simulations. This method uses 3D modeling to monitor internal changes in the electrodes and link the microstructure to overall performance, at scales difficult to achieve through experimentation.
The results have demonstrated the crucial role of the initial microstructure: large nickel particles facilitate migration and accelerate degradation, while a finer microstructure improves long-term stability.
The study has also shown that these mechanisms vary depending on the operating mode: in electrolysis mode, nickel migration is largely prevalent and accelerates degradation, while in fuel cell mode, agglomeration is the predominant factor.
Developing more durable electrodes for low-carbon hydrogen production
This research has identified several concrete indications for improving SOC durability: optimizing the microstructure from the design phase, extending lifespan, maintaining performance, and reducing operating costs.
This work contributes to the development of more robust technologies for low-carbon hydrogen production. Research is ongoing to refine these models, incorporate new phenomena, and conduct comparisons with experimental data. These methods could ultimately be used to optimize the design of materials according to specific application constraints.