Speaker
Description
Solid Oxide Electrolysers (SOE), due to their high operation temperature, offer high efficiency of the hydrogen production and thermal compatibility with industrial processes. In order to maximize performance of SOE and to increase their lifetime, various modifications of electrodes were proposed. The precise adjustment of the electrodes microstructural parameters such as size and distribution of pores, gives possibility to control electrochemical properties of electrodes.
In this work, the dependance of the microstructure of cathode support on the SOE performance is evaluated. Modifications of the standard Ni-8YSZ-based supports were performed twofold. The first approach involved the increase of the content of pore former (graphite) in the paste used for preparation of supports from 25 wt.% to 30 wt.% and 35 wt.%. In the other method, beside aforementioned adjustment of the content of pore former, the sintering temperature of cell was decreased. This was necessary due to the implementation of Sc- and Ce-doped zirconium electrolyte (10Sc1CeSZ) as a substitute of standard 8YSZ, which resulted in higher porosity of the support. Overall, six different batches of cells were prepared, three batches with 8YSZ electrolyte and another three batches with 10Sc1CeSZ. Same material (10Sc1CeSZ) was used in the cathode functional layer. All the cells were evaluated in terms of their microstructure and electrochemical performances with current density-voltage dependences and EIS measurements. The electrochemical tests were performed in the 700-800 °C temperature range under different composition of fuel-side inlet gases with varied H2O:H2 ratio. The recorded EIS spectra were analyzed using DRT method as well as by implementation of the equivalent circuit modeling. It made it possible to identify the limiting processes occurring in the SOE cathode and assess the effect of microstructural modification on the operation of SOE.
Acknowledgement
The research was financially supported by the National Science Centre, Poland, within project no. 2018/31/D/ST8/00123.
| Speaker Country | Poland |
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