Researchers in South Korea have developed a new type of air electrode that could dramatically improve the performance and durability of reversible solid oxide cells (RSOCs), an important technology for the future of clean hydrogen energy.
The study, published in Nature Energy, was led by Jun-Young Park from Sejong University, together with researchers from Chonnam National University and Seoul National University.
RSOCs are advanced energy devices that can work in two ways.
They can generate electricity like a fuel cell, or they can use electricity to produce hydrogen from water through electrolysis. Because of this dual function, they are considered a promising technology for storing renewable energy and supporting a future hydrogen economy.
One of the key parts of these systems is the air electrode, where important chemical reactions take place.
For more than four decades, scientists have commonly used a material called gadolinium-doped ceria, or GDC, in these electrodes. However, GDC limits the reactions to very small regions inside the material, reducing overall efficiency.
The research team decided to try a different material called BCZYYb, which had previously been known mainly as a proton conductor.
Surprisingly, they discovered that the material could also transport oxygen ions and electronic charges very effectively under operating conditions. This balanced behavior allowed the material to support reactions across a much larger area of the electrode.
The team then combined BCZYYb with another specially designed catalyst called GCCCO. When the two materials were joined together, they formed a unique electric structure at their interface that helped chemical reactions happen more quickly and efficiently.
The shape of the GCCCO material also played an important role. Its thin, plate-like structure allowed gases to move more easily through the electrode while remaining stable at extremely high temperatures.
The results were impressive. At 800 degrees Celsius, the new electrode achieved record-breaking performance in both fuel-cell mode and electrolysis mode, outperforming all previously reported composite air electrodes.
The researchers also tested the system for 200 hours under repeated high-stress conditions. Even after long operation, the electrode showed almost no loss in performance, suggesting excellent long-term durability.
The team found that replacing GDC with BCZYYb improved the performance of several existing electrode systems by 38% to 129%, showing that the approach could be widely applied across many solid oxide technologies.
According to the researchers, the study shows that choosing the right ionic conductor may be much more important than scientists previously believed.
They hope the new design strategy will help speed up the commercialization of hydrogen energy systems and support the transition to cleaner energy worldwide.
