Protonic ceramic fuel cells (PCFCs) have been proposed as a ceramic fuel cell effectively operating at intermediate temperature range (IT) of 500‒700 °C (1‒5). Key to developing high performance PCFCs is the incorporation of thin protonic ceramic (PC) electrolytes as ohmic resistance by ion transport across the electrolyte membrane accounts for a significant portion of the energy loss during fuel cell operation. In order to stably accommodate the thin-film electrolyte, it is important to prepare a good anode support. Composite wafers composed of NiO and electrolyte ceramics are most commonly used as anode supports (3‒5). For example, PCFCs with yttrium-doped barium zirconate (BZY) electrolytes typically use the NiO-BZY compound as anode support. However, it is difficult to prepare NiO-PC composites because of the different sintering temperatures between NiO (~1200 °C) and PC (~1700 °C for BZY). These discrepancies tend to result in excessive growth of NiO and unevenly distributed pores, which labilize the overall stacks during fuel cell operation.

To solve this problem, we have recently proposed to use NiO-yttrium doped zirconia (YSZ) as the anode support (5). This material is the most common anode support for solid oxide fuel cells that have been proven to work effectively. This approach requires to tightly integrate the PC electrolyte onto the NiO-YSZ surface and to minimize thermal stresses at the interface. To this end, a thin NiO-PC interlayer was prepared before depositing the PC electrolyte. As a PC material, yttrium-doped barium zirconate cerate (BZCY) was used. As a result, PCFCs with Ni-YSZ anode supports tightly accommodating thin-film BZCY electrolytes have successfully demonstrated open circuit voltages (OCV) over 1 V and power outputs of 740 mW/cm²at 650 °C (5). In this presentation, we will discuss this achievement in more details and recent progresses on this topic.

1. J. H. Shim, J. S. Park, J. An, T. M. Gur, S. Kang, and F. B. Prinz, Chem. Mater., 21, (2009) 3290-3296.

2. K. Bae, D. Y. Jang, H. J. Jung, J. W. Kim, J. W. Son, and J. H. Shim, J. Power Sources, 248, (2014) 1163-1169.

3. C. Duan, J. Tong, M. Shang, S. Nikodemski, M. Sanders, S. Ricote, A. Almansoori, and R. O’Hayre, Science, 349, (2015) 1321-1326.

4. K. Bae, S. Lee, D. Y. Jang, H. J. Kim, H. Lee, D. Shin, J.-W. Son, and J. H. Shim, ACS Appl. Mater. Interfaces, 8, (2016) 9097-9103.

5. K. Bae, H.-S. Noh, D. Y. Jang, J. Hong, H. Kim, K. J. Yoon, J.-H. Lee, B.-K. Kim, J. H. Shim, and J.-W. Son, J. Mater. Chem. A, 4, (2016) 6395-6403.