A new catalytic coating technology, developed by a team of South Korean researchers, could transform the performance of solid oxide fuel cells (SOFCs) in just four minutes. This innovation promises to enhance the energy efficiency and chemical stability of these devices, paving the way for broader industrial applications.
Dr. Yoonseok Choi of the Hydrogen Convergence Materials Laboratory at the Korea Energy Research Institute (KIER), in collaboration with other researchers, has developed a catalytic coating technology that significantly improves SOFC performance in just four minutes.
Fuel cells are increasingly recognized as highly efficient and clean energy devices, playing a key role in the hydrogen economy. Among them, SOFCs stand out for their highest power generation efficiency and their ability to use various fuels such as hydrogen, biogas and natural gas. In addition, they enable combined production of heat and electricity using the heat generated during the process.
SOFC : A type of fuel cell where the electrodes and electrolyte are solid materials, operating at high temperatures above 700 degrees Celsius.
Improvement of LSM-YSZ composite electrodes
The performance of SOFCs largely depends on the kinetics of the oxygen reduction reaction (ORR) occurring at the air electrode (cathode). Since the reaction rate at the air electrode is slower than that at the fuel electrode (anode), it limits the overall reaction rate. To overcome these slow kinetics, researchers are developing new air electrode materials with high ORR activity. However, these new materials generally lack chemical stability, requiring continued research.
Rather than focusing on new materials, the research team chose to improve the performance of the LSM-YSZ composite electrode, a material widely used in industry for its exceptional stability. They thus developed a coating process to apply nanoscale praseodymium oxide (PrOx) catalysts on the surface of the composite electrode, actively promoting the oxygen reduction reaction.
LSM-YSZ composite electrode : Composed of LSM (Lanthanum Strontium Manganite) and oxygen ion-conducting electrolyte YSZ (Yttria Stabilized Zirconia), this material is traditionally used in industry as an air electrode due to its exceptional thermal and chemical compatibility.
An innovative electrochemical deposition method
The research team introduced an electrochemical deposition method operating at room temperature and atmospheric pressure, requiring no complex equipment or processes.
By immersing the composite electrode in a solution containing praseodymium (Pr) ions and applying an electric current, hydroxide ions (OH-) generated on the surface of the electrode react with the praseodymium ions, forming a precipitate that covers the electrode evenly. This coating layer then undergoes a drying process, transforming into a stable oxide that effectively promotes the electrode’s oxygen reduction reaction in high temperature environments. The entire coating process takes just four minutes.
Cathodic electrochemical deposition (CELD) : A method using electrochemical reactions to deposit metals or metal compounds on the surface of an electrode.
Encouraging results for the industry
By operating the catalyst-coated composite electrode and the conventional composite electrode for more than 400 hours, the team observed a reduction in polarization resistance by a factor of ten. Additionally, SOFC using this coated electrode showed three times higher peak power density (142 mW/cm² → 418 mW/cm²) than that of the uncoated case, at 650 degrees Celsius. This represents the highest performance reported for SOFCs using LSM-YSZ composite electrodes in the literature.
Dr Yoonseok Choi, co-corresponding author, said: “The electrochemical deposition technique we developed is a post-process that does not significantly impact the existing SOFC manufacturing process. This makes it economically viable for the introduction of oxide nanocatalysts, thereby increasing its industrial applicability.»
He added : “We have secured a key technology that can be applied not only to SOFCs but also to various energy conversion devices, such as high temperature electrolysis (SOEC) for hydrogen production.»
Illustration caption: Photo of the joint research team (Yoon-Seok Choi, lead researcher, far right) – Credit: Korea Institute of Energy Research (KIER)
Article: “Revitalizing Oxygen Reduction Reactivity of Composite Oxide Electrodes via Electrochemically Deposited PrOx Nanocatalysts” – DOI: 10.1002/adma.202307286
