Researchers at South Korea’s Hanbat National University have developed a new method to enhance the performance and stability of solid oxide fuel cells, a clean-energy technology crucial to the global energy transition.
The team, led by Professor Junghyun Kim from Hanbat’s Department of Advanced Materials Engineering, demonstrated cobalt exsolution in fuel cell cathodes under oxidizing conditions, a finding that overturns long-standing assumptions in fuel cell research.
Cobalt exsolution refers to the process where nanoparticles spontaneously come out or “exsolve” from ceramic materials such as perovskite oxide to the fuel cell’s cathode. These cobalt nanoparticles improve oxygen reduction at the cathode, making the fuel cell more efficient and stable.
“We have presented the first experimental evidence of cobalt exsolution occurring in a high-temperature oxidizing atmosphere, challenging the conventional paradigm,” Kim said.
Their findings were published online in May 2025 and later featured in Volume 648 of the Journal of Power Sources.
Testing New Cathode Structures
The researchers studied the electrochemical properties and oxygen content of two-layered perovskite oxide structures, SBSCF 1.9 and SBSCF 2.05.
They found that two specific samples, with 30 percent Fe substitution in SBSCF 1.9-0.3 and 50 percent Fe substitution in SBSCF 2.05-0.5, delivered the best electrochemical performance.
When heated above 700 degrees Celsius in oxidizing atmospheres, both samples exhibited cobalt exsolution, with particle formation peaking at 900 degrees Celsius.
The team explained that under high-temperature oxidizing conditions, weaker cobalt–oxygen bonds break, while stronger ferrous-oxygen bonds remain intact.
The freed oxygen atoms then move toward the surface, creating vacancies that attract cobalt atoms. These migrate and form cobalt nanoparticles on the electrode surface.
As the temperature rises, more cobalt particles form, further improving the electrode’s activity.
Promising Results
Among the samples, SBSCF 1.9-0.3 produced smaller but more numerous Co particles, reducing area-specific resistance and boosting oxygen reduction reaction activity. The team attributed this to its higher cobalt content and surface oxygen vacancy concentration.
“Our results show that finely dispersed Co particles are key to enhancing SOFC cathode performance,” Kim said. “Beyond SOFCs, this discovery could also advance oxygen separation membranes and clean-air catalytic systems.”
The findings could reshape fuel cell design and efficiency, paving the way for broader adoption of clean, high-performance energy technologies.
Also Read:
Leicester Univ Scientists Pioneer Eco-Friendly Fuel Cell Recycling Method
Hanbat Researchers Unveil Breakthrough Technique to Boost Fuel Cell Efficiency
