Synergistic effect of sodium content for tuning Sm2O3 as a stable electrolyte in proton ceramic fuel cells

Abstract

Samarium oxide (Sm2O3), a rare earth sesquioxide, shows that a great potential in proton-conducting fuel cells. However, the stability of Sm2O3 based cell remains a challenge. Herein we reported a facile method for enhancing the stability via the incorporation of sodium content into Sm2O3. This study discloses that the existence of sodium induces phase transition of Sm2O3 from monoclinic to cubic phase beneficial for fast proton transportation. Further mechanism investigation reveals that the cubic phase structure of Sm2O3 is stabilized resulting from substitution of sodium. Compared with commercial Sm2O3 (CSM), the fuel cell employing Na–Sm2O3 (NSM) as electrolyte delivers an improved peak power density of 570 mW cm−2 and the extended stability over 100 h under 130 mWcm−2 at 520 °C. In this study, NSM is successfully developed as a stable electrolyte material for proton conduct fuel cells, expanding its application in electrochemical devices.