Efficient Protonic Ceramic Fuel Cells' Power Source Identified in Specialized Triple Conducting Oxides Due to Their Unique Electrokinetic Proton Transport Capabilities

In a groundbreaking development, a research team led by Professor Guntae Kim from UNIST's School of Energy and Chemical Engineering has made significant strides in the field of protonic ceramic fuel cells (PCFCs). The team's findings, which were published online in March 2021 ahead of their final publication in the prestigious journal Advanced Science in June 2021, have generated a wave of excitement in the scientific community.

The study, which was carried out in collaboration with Professor Sivaprakash Sengodan from the UK's Imperial College London, Professor Meilin Liu from the Georgia Institute of Technology in the United States, and Professor Sihyuk Choi from Kumoh National Institute of Technology, focuses on the use of layered perovskites as potential cathode materials for PCFCs.

The team employed the isotope exchange diffusion profile (IEDP) method to evaluate proton kinetics in layered perovskite-type TCOs, PrBa0.5Sr0.5Co1.5Fe0.5O5+δ (PBSCF). They used heavy water (deuterium oxide, D2O) to observe proton formation and transport on both the surface and bulk of the PBSCF.

The results of the study were promising. The PBSCF cathode exhibited excellent electrochemical performance for PCFC operation at low temperatures, with a performance of 0.42 W cm-2 at 500 °C, which is the best ever reported. Furthermore, the PBSCF showed two orders of magnitude higher proton tracer diffusion coefficient (D*H) than its oxygen diffusion coefficient at higher temperature ranges.

These advancements could pave the way for PCFCs to be operated at relatively low temperatures, a significant advantage considering the critical issues faced by solid-state electrochemical devices. The research team is now focusing on quantifying proton kinetic properties of triple conducting oxides (TCOs) to further characterise the electrochemical behaviour of proton and electrode reactions.

Advantages of PCFCs include a wide range of operating temperatures and material choices, making them a promising alternative to traditional fuel cells. The team's work, therefore, represents a significant step forward in the development of eco-friendly energy conversion systems that generate electricity using the chemical energy of hydrogen or another fuel.

In addition to Professor Guntae Kim, the research team includes Choong Hoon Lee, Min Cheol Kim, and Hyeonuk Yeo from the School of Energy and Chemical Engineering at UNIST. The team's work is set to be published in its entirety in the June 2021 issue of Advanced Science.

Efficient Protonic Ceramic Fuel Cells' Power Source Identified in Specialized Triple Conducting Oxides Due to Their Unique Electrokinetic Proton Transport Capabilities