Professor Park Beomkyung's Materials Engineering Team Succeeds in Converting 1400°C Multistep Process to 1250°C Single-Step Process
Cost Reduction, Performance Improvement, Long-Term Stability, and Large-Scale Production Possible... Accelerating Energy Innovation
Pusan National University (President Choi Jaewon) announced on the 20th that the research team led by Professor Park Beomkyung from the Department of Materials Science and Engineering has developed a new single-process dual-layer electrolyte technology that can maximize the industrial applicability of solid oxide cells (SOC), which are used in high-efficiency fuel cells and water electrolysis.
Water electrolysis is the process of using electrical energy to split water into hydrogen and oxygen.
This technology employs a dual-layer structure using “yttria-stabilized zirconia (YSZ)” and “Sm (samarium)-doped ceria (SDC)” as electrolyte materials, dramatically simplifying the high-temperature co-sintering process and further enhancing cell performance. An electrolyte is a material that acts as a medium for ion transport in electrochemical devices. In solid oxide cells (SOC), it mainly conducts oxygen ions, enabling the operation of fuel cells or electrolysis cells.
Solid oxide cells (SOC) are devices that convert fuel into electricity or electricity into fuel through electrochemical processes, and are largely classified into solid oxide fuel cells (SOFC) and solid oxide electrolysis cells (SOEC).
These solid oxide fuel cells and water electrolysis cells (SOFC/SOEC) are attracting attention as important technologies for achieving carbon neutrality due to their high energy conversion efficiency and the possibility of using various fuels. In particular, the dual-layer electrolyte composed of zirconia (YSZ) and ceria is an essential core component for developing high-performance fuel electrode-supported cells. However, to implement this effectively, a high-temperature (1400°C) multi-step process is required, and during the final co-sintering process, electrically insulating materials are formed, increasing cell resistance.
Additionally, due to the generally poor sinterability of ceria, the process is multi-stepped, and at high process temperatures above 1250°C, the reaction between zirconia (YSZ) and ceria is accelerated, resulting in undesirable insulating materials.
The research team led by Professor Park Beomkyung designed and applied Sm (samarium)-doped ceria (SDC) with excellent sintering properties to develop a YSZ/SDC dual-layer electrolyte, and implemented a technology that enables sintering through a single 1250°C process based on the tape casting industrial process. This process simplifies the conventional multi-step process, contributing to cost reduction and productivity improvement, while maximizing cell performance.
In particular, the single 1250°C process not only significantly reduces energy costs compared to existing methods, but also provides the dual benefit of suppressing the reactivity between zirconia (YSZ) and ceria and improving the quality of the fuel electrode pore structure, thereby enhancing cell performance. In addition, the developed electrolyte demonstrates improved interfacial conductivity characteristics compared to the conventional YSZ/GDC (gadolinium-doped ceria) combination.
The research team demonstrated the scalability of this technology by fabricating a cell with a size of 5×5 cm2, and also proved its excellent long-term stability. The cells using this technology achieved a power density of about 2.15 W/cm3 and a steam electrolysis current density of 2.95 A/cm3.
Professor Park Beomkyung stated, “The results of this study provide an important strategic direction for conventional dual-layer electrolyte compositions and process conditions, and open the way to further increase the commercial feasibility of solid oxide cells.”
This paper was authored by Professor Park Beomkyung as the corresponding author, with master's students Kim Suwan and Jung Haein as co-first authors. The research was supported by Korea Electric Power Corporation’s Power Research Institute (external basic research project) and the Korea Technology Commercialization Promotion Agency (pilot project for building an academic-industry cooperation platform) with funding from the Ministry of Science and ICT.
This research was published in the September 2nd issue of the international journal Journal of Materials Chemistry A. The title of the paper is "Improved bi-layer electrolytes of solid oxide cells: the role of a Sm0.2Ce0.8O2-δ diffusion barrier layer."
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