Stable proton-conducting Ca-doped LaNbO₄ thin electrolyte-based protonic ceramic membrane fuel cells by in situ screen printing

In order to develop a simple and cost-effective route to fabricate protonic ceramic membrane fuel cells (PCMFCs), a stable proton-conducting La_0.99Ca_0.01NbO₄ (LCN) thin electrolyte was fabricated on a porous NiO-La_0.5Ce_0.5O_1.75 (NiO-LDC) anode by in situ screen printing. The key part of this process is to directly print well-mixed ink of La₂O₃, CaCO₃ and Nb₂O₅ instead of pre-synthesized LCN ceramic powder on the anode substrate. After sintering at 1400 °C for 5 h, the full dense electrolyte membrane in the thickness of 20 μm was obtained. A single cell was assembled with (La_0.8Sr_0.2)_0.9MnO_3-δ-La_0.5Ce_0.5O_1.75 (LSM-LDC) as cathode and tested with humidified hydrogen as fuel and static air as oxidant. The open circuit voltage (OCV) and maximum power density respectively reached 0.98 V and 65 mW cm^-2 at 800 °C. Interface resistance of cell under open circuit condition was also investigated.