Hydrogen production performance of 3-cell flat-tubular solid oxide electrolysis stack

Flat-tubular solid oxide electrolysis cells have been manufactured with a ceramic interconnector in a body to minimize the stack volume and eliminate metallic components. The NiO–YSZ supports are prepared by the extrusion method, and the other cell components, which included the electrolyte, air electrode, and ceramic interconnector, are fabricated by slurry coating methods. The active area of a single cell is 30 cm2, and the gas tightness of the stack is checked in the range below 2 bars. The effects of the operating conditions on the performance of a solid oxide electrolysis stack are investigated using electrochemical impedance spectroscopy and the I–V test. Consequently, it is confirmed that sufficient steam content stimulates the electrochemical splitting of water and decreases the activation energy for water electrolysis at a high temperature. In our 3-cell stack test, the hydrogen production rate is 4.1 lh−1, and the total hydrogen production was 144.32 l during 37.1 h of operation.

► Flat-tubular solid oxide electrolysis cells for high-temperature electrolysis.
► The effects of the operating temperature and the humidity on the performance of high-temperature electrolysis.
► Cross-check between the electrochemical impedance spectroscopy and the I–V performance results.
► High steam content enhances the electrochemical splitting of water at high temperature.
► Evaluation of the performance and durability of 3-cell flat-tubular solid oxide electrolysis stack.