Processing Ceramic Proton Conductor Membranes for Use in Steam Electrolysis.

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• Protonic ceramic electrolysis cells (PCECs) offer efficient hydrogen production via steam electrolysis.
• Lowering operating temperatures is key for PCECs, achievable with ceramic proton-conducting electrolytes.
• Upscaling robust planar PCECs remains a significant fabrication challenge due to sintering-induced defects.

Purpose of the Study:

• To develop a scalable fabrication process for large-area (50x50 mm²) electrode-supported protonic ceramic electrolysis cells.
• To optimize sintering parameters for defect-free barium cerium yttrium zirconate (BZCY) half-cells with minimal warping.
• To demonstrate the performance of a complete PCEC using optimized components.

Main Methods:

• Sequential tape casting for fabricating large planar BZCY half-cells.
• Optimization of sintering parameters to achieve dense, gas-tight electrolyte layers.
• Screen printing of a Ba_0.5La_0.5CoO_3-δ steam electrode onto the BZCY electrolyte.
• Electrochemical characterization and microstructural analysis (HAADF-STEM, EDX) of the fabricated cells.

Main Results:

• Successfully processed defect-free 50x50 mm² BZCY half-cells with reduced warping via optimized sintering.
• Achieved dense and gas-tight 15 μm BZCY electrolyte layers by co-sintering at 1350 °C for 5 hours.
• Demonstrated a PCEC performance of 1.4 V at 500 mA·cm⁻² with ~84% Faradaic efficiency at 600 °C using 80% steam.
• Microstructural analysis confirmed the integrity of the layered cell structure.

Conclusions:

• A feasible and scalable approach for low-cost fabrication of large-area PCECs has been established.
• The developed method overcomes challenges in upscaling planar ceramic electrolysis devices.
• This work paves the way for efficient industrial-scale hydrogen production using advanced ceramic electrolytes.