New microwave heating slashes sintering time from 6 hours to 10 minutes, boosting efficiency and stability
The era of 'green hydrogen,' which produces hydrogen without emitting carbon dioxide, has moved one step closer. A domestic research team has developed an ultra-fast manufacturing technology that can complete a solid oxide electrolysis cell (SOEC), a key device, in just 10 minutes. Previously, the same process took more than 6 hours.
Professor Lee Kang-taek of Korea Advanced Institute of Science and Technology, KAIST, and his research team announced on the 28th that they successfully significantly shortened the 'sintering' process required to manufacture the electrolysis cell and lowered the temperature from 1,400°C to 1,200°C.
Sintering is a process of baking ceramic powder at high temperatures to firmly bond them together. This step must be done well to prevent hydrogen and oxygen from mixing inside the cell (preventing explosion risks), ensure smooth current flow, and extend the cell's lifespan. The issue was that this process required dozens of hours of high-temperature heating and cooling.
The research team introduced 'microwave volumetric heating' technology. By heating the cell from the inside out simultaneously rather than from the outside, it transfers heat much faster and more uniformly than conventional methods. As a result, the entire sintering process was completed in about 70 minutes, a speed over 30 times faster than the existing process.
The conventional method had an issue where the key materials of the cell, ceria (CeO₂) and zirconia (ZrO₂), mixed at excessively high temperatures, leading to reduced quality. However, the new technology successfully controlled the bonding of these two materials to adhere firmly only at appropriate temperatures, forming a flawless electrolyte layer.
The cell produced 23.7 mL of hydrogen per minute at 750°C and operated stably for over 250 hours. A 3D digital twin (virtual simulation) analysis also confirmed that ultra-fast heating regulated the material's microstructures, enhancing hydrogen production efficiency.
Professor Lee stated, "This technology is a new manufacturing paradigm that can produce high-performance electrolysis cells much faster and more efficiently," adding, "It has high potential for commercialization as it significantly saves energy and time."
The research results were published in the international academic journal 'Advanced Materials' on the 2nd of last month and were selected as the cover paper.
Reference
Advanced Materials (2025), DOI: https://doi.org/10.1002/adma.202500183