Exceptionally high proton conductivity in Eu2O3 by proton-coupled electron transfer mechanism
Shuo Wan,
M. A. K. Yousaf Shah,
Hao Wang,
Peter D. Lund,
Bin Zhu
Affiliations
Shuo Wan
Jiangsu Provincial Key Laboratory of Solar Energy Science and Technology/ Energy Storage Joint Research Center, School of Energy & Environment, Southeast University, Nanjing 210096, China
M. A. K. Yousaf Shah
Jiangsu Provincial Key Laboratory of Solar Energy Science and Technology/ Energy Storage Joint Research Center, School of Energy & Environment, Southeast University, Nanjing 210096, China
Hao Wang
Jiangsu Provincial Key Laboratory of Solar Energy Science and Technology/ Energy Storage Joint Research Center, School of Energy & Environment, Southeast University, Nanjing 210096, China
Peter D. Lund
Jiangsu Provincial Key Laboratory of Solar Energy Science and Technology/ Energy Storage Joint Research Center, School of Energy & Environment, Southeast University, Nanjing 210096, China; School of Science, Aalto University, P.O. Box 15100, 00076 Aalto, Espoo, Finland
Bin Zhu
Jiangsu Provincial Key Laboratory of Solar Energy Science and Technology/ Energy Storage Joint Research Center, School of Energy & Environment, Southeast University, Nanjing 210096, China; Corresponding author
Summary: Proton conductors are typically developed by doping to introduce structural defects such as oxygen vacancies to facilitate ionic transport through structural bulk conduction mechanism. In this study, we present a novel electrochemical proton injection method via an in situ fuel cell process, demonstrating proton conduction in europium oxide (Eu2O3) through a surficial conduction mechanism for the first time. By tuning Eu2O3 into a protonated form, H-Eu2O3, we achieved an exceptionally high proton conductivity of 0.16 S cm−1. Distribution of relaxation time (DRT) analysis was employed to investigate the proton transport behavior and reveal the significant contribution of surface proton transport to the overall conductivity of Eu2O3. Remarkably, H-Eu2O3 exhibited a low activation energy for ionic transport, comparable to the best ceramic electrolytes available. The proton-coupled electron transfer (PCET) mechanism describes this novel surficial proton conduction mechanism. These findings provide new possibilities for developing advanced proton conductors with improved performance.
