High performance tubular protonic ceramic fuel cells via highly-scalable extrusion process

Abstract We report an effective method to fabricate long, anode-supported tubular protonic ceramic fuel cells (PCFCs) and test cells in single-cell and short-stack mode. Further, we use our tubular PCFC platform to directly compare three high performance cathodes reported in literature: BaCo0·4Fe0·4Zr0·1Y0·1O3-δ (BCFZY), Ba0·5Sr0·5Co0·8Fe0·2O3-δ (BSCF), and PrBa0.5Sr0·5Co1·5Fe0·5O6-δ (PBSCF) using indentical preparation methods, which can minimize effects from variation of materials either due to suppliers or subsequent processing and testing from different research labs. Using a BCFZY cathode, the maximum power density of our tubular PCFC reaches 164, 308, and 517 mW cm−2 at 500, 550, and 600 °C, respectively. A 2-cell tubular short stack provides a total power of 2.3 W at 600 °C with tube diameters of 0.82 cm and a total tube active length of 3.2 cm. At 600 °C, the maximum power density reaches, 534, 517, and 326 mw cm−2 for the BSCF, BCFZY, and PBSCF cathodes, respectively. Under the same conditions, the BSCF-based cell shows the lowest total resistance mostly due to the lowest ohmic resistance and modest polarization resistance. The BCFZY-based cell has the lowest polarization resistance but larger ohmic resistance leading to a slightly higher total resistance than BSCF. The PBSCF cell has an ohmic resistance close to BSCF but a total polarization resistance much larger than either BSCF or BCFZY cell which results in the lowest overall performance.