Developing Protonic Ceramic Cells on Porous Metal Supports

Kurzfassung

Perovskite oxides, such as BaZrO3, demonstrate high proton conductivity at intermediate temperatures when aliovalent cations are doped. Proton conduction in the operational temperature range of 400-600 °C is attractive for variety of applications, including fuel cells, steam electrolysis and electrochemical hydrogen pump, that are important technologies in hydrogen economy. The state-of-the-art electrolytes, Y/Yb doped Ba(Zr,Ce)O3-d, have been intensively studied to develop Protonic Ceramic Cells (PCC) of good performance and stability, which promises their potential for electrochemical devices. In the conventional ceramic process, sintering temperature needs to be very high (> 1400 °C) to densify the PCC electrolytes, making it challenging to up-scale PCCs by industrial technologies and planar PCCs are not yet commercially available unlike the solid oxide cells. Porous substrates made of Ni-cermet are typically used as PCC supports. As an alternative architecture, a porous metal supported PCC (MS-PCC) is proposed. The high robustness of MS architecture under redox and thermal cycling has been successfully demonstrated for solid oxide fuel cells. MS architecture has high mechanical stabilities, allows to reduce the cost and ceramic material consumption, and makes the stack integration and up-scaling easier. Those advantages are very attractive for PCCs, whereas the major challenge is to find a manufacture route to achieve dense and stable PCC electrolyte layer on the porous metal. Finding good material combination is important that would result in high performance and mitigate the risk of cell degradation. The microstructures as well as the electrochemical properties of the component layers are also crucial. The key issues are the component materials and the scalable technologies. By utilizing commercial porous metal support and ceramic membrane lamination technique to down-size the pores from 30 micro-m to ~100 nm, 1 micro-m-thick gas tight PCC was achieved by Pulsed Laser Deposition. The MS-PCC concept was successfully demonstrated by Fuel cell and steam electrolysis operation [1]. In this talk, the achievement and the issues in the MS-PCC development at DLR will be presented and the challenges towards up-scaling will be discussed. [1] H. Zheng et al. ACS Energy Letters, 2024, 10.1021/acsenergylett.4c01173 Our current challenge in up-scaling MS-PCC is supported by the project Hy-SPIRE (HORIZON-JTI-CLEANH2 #101137866).