AC:DC

In the project solid oxide electrolysis cells (SOECs) were tested with a new operation method called AC:DC. The operation method decrease the degradation rate for SOECs. In the graph below AC:DC operation was used on SOEC cells from DTU Energy to conduct steam electrolysis. With AC:DC operation the cell resistance was constant after a 50 hour  initiation period. In contrast, for conventional operation, the resistance increase with time.

AC:DC operation was also conducted with CO₂ electrolysis for 600 hours. Here AC:DC operation was shown to reduce the degradation rate from 39 mΩcm² per 1,000 hour to 5 mΩcm² per 1,000 hour and to increase the impurity tolerance.

Microscopy data suggests the stable resistance with AC:DC operation is related to a removal of Nickel migration, which limits the lifetime of conventional operated SOECs.

The project was completed in 2019 and 120,000 DKK was granted under the Teknologisamarbejde i Region Sjælland “DTU Risø Reaktor” (case no. RFS-17-0012) with details here: Innovation project ’AC:DC.

The AC:DC operation method is patented by Dynelectro ApS. Further info about the AC:DC operation method can be found in the published patent application.