Revitalizing interface in protonic ceramic cells by acid etch

• Published in: Nature (London) 2022-04, Vol.604 (7906), p.479-485
• Main Authors: Bian, Wenjuan, Wu, Wei, Wang, Baoming, Tang, Wei, Zhou, Meng, Jin, Congrui, Ding, Hanping, Fan, Weiwei, Dong, Yanhao, Li, Ju, Ding, Dong
• Format: Article
• Language: English
• Subjects: 08 HYDROGEN; 639/301/299/893; 639/4077/893; Acids; Ceramics; Electrochemical analysis; Electrochemical cells; Electrochemistry; Electrodes; Electrolysis; Electrolytes; Electrolytic cells; Energy; Etching; fuel cells; High temperature; Humanities and Social Sciences; HYDRO ENERGY; Hydrogen; hydrogen production; interface engineering; Interfacial bonding; Low temperature; Microscopy; multidisciplinary; Oxygen; protonic ceramic electrochemical cells; Protons; Science; Science (multidisciplinary); Sintering; Surface chemistry; Sustainable energy; Sustainable practices
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/s41586-022-04457-y

Protonic ceramic electrochemical cells hold promise for operation below 600 °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 °C, with peak power densities of 1.6 W cm −2 at 600 °C, 650 mW cm −2 at 450 °C and 300 mW cm −2 at 350 °C, as well as stable electrolysis operations with current densities above 3.9 A cm −2 at 1.4 V and 600 °C. Our work highlights the critical role of interfacial engineering in ceramic electrochemical devices and offers new understanding and practices for sustainable energy infrastructures. A simple acid treatment can improve high-temperature annealed electrolyte surfaces, resulting in improved performance and stability at lower temperatures for protonic ceramic fuel/electrolysis cells, offering new understanding for sustainable energy infrastructures.