Protonic ceramic electrochemical cells (PCECs) function as fuel cells, converting hydrogen into electricity, or as electrolysers, where electricity is used to split water into hydrogen and oxygen. This makes them useful in hydrogen energy systems because excess wind and solar power can be converted into hydrogen, stored, and later converted back into electricity. Inside PCECs, two electrodes are separated by a ceramic electrolyte that controls the movement of hydrogen ions, which are protons.

Unfortunately, manufacturing the proton-conducting ceramic electrolyte layer is cumbersome. Long processing times involve multiple steps, including intensive ball-milling and high-temperature sintering, making protonic ceramics expensive to produce. In this work, the researchers investigated how PCECs could be manufactured more cheaply, more quickly and with improved performance.

Instead of using larger precursor particles and grinding them for many hours, they started with nano-sized precursor powders. This enabled them to remove the ball-milling step entirely and reduce production time from 85 hours to 33 hours. In addition, it produced a finer electrolyte powder whose smaller particles packed together and sintered more easily, allowing the ceramic to become dense at temperatures around 100 °C lower than those required by the conventional method. The resulting electrolytes had lower electrical resistance, improving efficiency.

Compared with cells made using the conventional synthesis method, the new cells delivered up to 32% higher peak power density in fuel cell mode and 40% higher electrolysis current density at 600 °C, while maintaining stable operation for more than 500 hours. The process also reduced manufacturing costs by 25-29% and was successfully demonstrated in larger-area cells. This work could help accelerate the deployment of protonic ceramic electrochemical technologies for hydrogen production and energy conversion.

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Focus on Protonic Ceramics: A Promising Class of Materials for Energy Conversion and Storage – Guest Editors: Sandrine Ricote and Aayan Banerjee