On the Development of Metal Supported Cell with BaZrO3-Based Proton Conducting Electrolyte

Abstract

Protonic ceramic cells (PCC) have many prospective applications in electrochemical energy conversion technologies. The promising state-of-the-art protonic ceramic electrolytes, e.g. BaZrCeO3-based perovskites has a high refractory nature which makes it difficult to develop robust electrochemical cells with high mechanical strength in a conventional cell architecture such as electrode supported cells. Utilization of a robust backbone, for example ferritic stainless steel, to support the thin functional layers will not only provide superior robustness and redox stability, but also reduce the material cost. Here we report our progress on the development of Metal Supported (MS) PCC in project DAICHI, transferring the architecture of metal supported solid oxide cells [1]. The challenge is to find a feasible process in the fabrication of gas-tight PCC electrolytes below the temperature that MS can withstand. A 20 µm-thick (La,Sr)MnO3 (LSM) layer was first laminated on ITM porous MS, onto which two intermediate electrolyte layers (IL) were sequentially fabricated. The pore size has been reduced from a few tens of µm in ITM to below hundred nm in ILs. Pulsed Laser Deposition (PLD) was employed to fabricate a 1-2 micro meter-thick BaZrO3-based electrolyte on the nano-porous ILs. A MS-PCC half cell, fabricated through processes below 1000 °C with a dense and crack-free thin-film electrolyte, is demonstrated in figure 1. It has been confirmed that surface morphology of the intermediate layer and PLD conditions such as substrate temperature have significant influence on the crystallinity of thin-film electrolyte. EIS analysis revealed Rohm of 1.5 and 0.50 ohm·cm² at 550 and 600 °C, respectively, dominated by the bulk protonic transport. Latest status in the development of MS-PCC will be presented and critically discussed.