In situ amorphous-adhesive interface facilitate ionic transport in protonic ceramic fuel cells

Protonic ceramic fuel cells (PCFCs) represent a promising carbon–neutral power-generation technology, leveraging the high proton conductivity demonstrated in stable yttrium-doped barium zirconate (BZY) electrolyte, but their practical application is hindered by poor sinterability and diminished overall proton conductivity caused by resistive grain boundaries. In this work, we present a sintering-free superfast-protonic ceramic fuel cell (S-PCFC) based on BZY electrolyte enabled by an amorphous-adhesive-enabled interface. S-PCFC is fabricated in-situ via a facile and scalable dry-press process, circumventing the need for conventional high-temperature sintering in air. A molten mixture of LiOH and Li₂CO₃ is in situ embedded during electrochemical operation, forming an amorphous-adhesive interface within grain boundaries. This approach achieves a record-high power output of 866 mW·cm⁻² and the highest reported proton conductivity for BZY electrolytes (0.257 S·cm⁻¹ at 520 ℃). Density functional theory (DFT) calculations reveal the reduced migration energy barriers for proton transport, demonstrating that the in-situ formed amorphous-adhesive interface facilitates ultrafast proton conduction within the sintering-free BZY electrolyte. This S-PCFC unlocks new possibilities for superfast-protonic ceramics.