SKKU Research Team Boosts Hydrogen Cell Efficiency and Durability via Innovative Interface Nanocoating

□ A research team led by Professor Wonyoung Lee of the School of Mechanical Engineering at Sungkyunkwan University (SKKU) has developed a technology that addresses interfacial contact resistance, a key factor limiting the performance of protonic ceramic electrochemical cells (PCECs), a next-generation clean energy technology. The new approach significantly improves both the energy efficiency and durability of the cells.

□ Protonic ceramic electrochemical cells (PCECs) are next-generation eco-friendly energy devices capable of operating in two modes within a single system: as fuel cells that generate clean electricity from hydrogen without producing pollutants, and as electrolyzers that use electricity to split water and produce hydrogen. Because PCECs can operate efficiently at relatively lower temperatures than conventional devices, they are attracting attention as a key technology for the future hydrogen economy. However, within conventional cells, the interface between the dense, smooth electrolyte and the porous, sponge-like electrode often lacks complete physical contact. This creates undesirable interfacial contact resistance, preventing the materials from fully realizing their intrinsic performance.

□ To determine how the contact area between the electrode and electrolyte affects interfacial resistance, the research team fabricated experimental model cells with varying degrees of contact and conducted detailed analyses. The results quantitatively demonstrated that interfacial resistance systematically decreases as the “contact coverage”—the proportion of the two components that are actually in physical contact—increases. Through this analysis, the researchers identified contact coverage as a key design parameter governing cell performance.

□ To implement this principle in real cells, the team applied electrostatic spray deposition (ESD), a technique that uses electrostatic forces to uniformly spray microscopic liquid droplets onto a surface. Using this method, the researchers deposited an extremely thin and dense nanometer-scale interlayer uniformly across the electrolyte surface, dramatically increasing the contact area between the electrode and electrolyte.

□ Cells incorporating the new technology demonstrated substantially improved performance over conventional cells in both power generation and hydrogen production modes. The cells also maintained stable operation under harsh conditions involving rapid temperature changes, supported by strong adhesion between the electrode and electrolyte. In addition to pure hydrogen, the cells exhibited excellent performance and stability when directly fueled with methane or ammonia, both of which are attracting attention as next-generation fuels. Furthermore, the process enabled uniform fabrication on large-area substrates, demonstrating its potential for industrial-scale commercialization beyond the laboratory.

□ Professor Wonyoung Lee said, “No matter how advanced a new material may be, it cannot deliver its full performance if the interfaces between components are not properly connected. This study is significant because it quantitatively defines microscopic contact behavior and simultaneously maximizes both cell performance and durability using a scalable precision nano-process.” He added, “We expect this technology to be widely applicable to large-scale clean energy power plants, hydrogen-powered vehicles, eco-friendly energy storage systems, and many other fields.”

□ This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (grant number 2022R1A2C3012372), the Nano & Material Technology Development Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (grant number RS-2024-00448287), the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT and MOE) (grant number RS-2026-25501632), and the Institutional Research Program of KRICT (grant number KK2513-30).