Revitalizing interface in protonic ceramic cells by acid etch

Protonic ceramic electrochemical cells hold promise for operation below 600 degrees C (refs.(1,)(2)). Although the high proton conductivity of the bulk electrolyte has been demonstrated, it cannot be fully used in electrochemical full cells because of unknown causes(3). Here we show that these problems arise from poor contacts between the low-temperature processed oxygen electrode-electrolyte interface. We demonstrate that a simple acid treatment can effectively rejuvenate the high-temperature annealed electrolyte surface, resulting in reactive bonding between the oxygen electrode and the electrolyte and improved electrochemical performance and stability. This enables exceptional protonic ceramic fuel-cell performance down to 350 degrees C, with peak power densities of1.6 W cm(-2) at 600 degrees C, 650 mW cm(-2) at 450 degrees C and 300 mW cm(-2) at 350 degrees C, as well as stable electrolysis operations with current densities above 3.9 A cm(-2) at 1.4 V and 600 degrees C. Our work highlightsthe critical role of interfacial engineering in ceramic electrochemical devices and offers new understanding and practices for sustainable energy infrastructures.

Automated summary

Researchers improved the electrochemical performance and stability of protonic ceramic fuel cells by acid treatment, enabling exceptional performance at lower temperatures.