Protonic ceramic energy devices (PCEDs), including protonic ceramics-based membrane reactors, hydrogen-permeable membranes, fuel cells, and electrolysis cells, are energy conversion and/or storage devices working under intermediate temperature (400–700°C). These devices, along with the discovery of ceramics exhibiting high proton conductivity, have attracted substantial interest.¹

However, conventional manufacturing techniques for PCEDs commonly suffer from the challenges of the small active area, simple geometry, and low surface area/volume ratio, hindering the practical applications of PCEDs. Furthermore, conventional manufacturing techniques usually involve complicated steps. For example, the fabrication of planar protonic ceramic fuel cells requires multiple steps (e.g., tape casting, screen-printing, punching, cofiring, post-firing, sealing, and stacking), which are poorly reproducible and time-consuming as well as potential high cost.