Advancements in Additive Manufacturing of Protonic Ceramic Fuel Cells

Protonic ceramic fuel cells (PCFCs), also known as proton conducting solid oxide fuel cells, are a promising low-temperature (400-600 o C) fuel cell technology. Compared to conventional oxygen-ion conducting ceramic materials, proton conducting ceramic electrolyte materials have lower activation energy (< 50 eV), which can enhance fuel cell efficiency and power output. Additive manufacturing has the potential to revolutionize PCFC manufacturing, as it enables fabrication of both dense and porous structures with desirable mechanical and electrochemical properties. In this study, we employed extrusion-based 3D printing to fabricate PCFCs using BaZr 0.3 Ce 0.5 Y 0.15 O 3-δ and BaZr 0.4 Ce 0.4 Y 0.1 Yb 0.1 O 3-δ as electrolytes, NiO as anode, and BaCo 0.4 Fe 0.4 Zr 0.1 Y 0.1 O 3-δ and Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ as cathode. For comparison, we also printed oxide conducting ceramic fuel cells using gadolinium-doped-ceria (GDC ) as electrolyte. We investigated the printable pastes' rheological properties using dynamic light scattering, viscometer, tensiometry, differential scanning calorimetry, and thermal gravimetric analysis. We also characterized the cells using current-voltage measurements, electrochemical impedance spectroscopy, and various spectroscopic and microscopic techniques (HR-TEM-EELS, SEM-EDX) to understand the underlying mechanisms. Finally, we conducted a systematic study to optimize the sintering temperature for optimal fuel cell performance and investigate degradation mechanisms to improve stability. The best printed fuel cells produced 926 mW/cm 2 with 3-layer structure and 426 mW/cm 2 with 1-layer structure at 550 o C.