Development of high-performance perovskite La(Mg2/3Nb1/3)O3 electrolyte with hybrid protonic/oxide ion conduction for low-temperature solid oxide fuel cells

Abstract

Perovskite structures material such as the doped barium cerate-zirconates possessing high concentration and mobility of proton defects have drawn substantial attention. However, the low thermodynamic stability of alkaline earth cations hinders it further application in solid oxide fuel cells (SOFCs). From this point of view, lanthanum-based perovskites without alkaline earth metals can be considered as suitable electrolyte material for SOFC. In this study, a new perovskite material La(Mg2/3Nb1/3)O3 (LMN) is introduced as a high performing electrolyte with considerable proton conduction conductivity of 0.0023S cm−1 at 550 °C for low temperature solid oxide fuel cells (LT-SOFCs). LMN electrolyte is characterized in terms of phase structure, morphological feature and surface properties. It is found that LMN sample is stable under fuel cell condition and deliver promising performance with a maximum output power density of 742 mW cm−2 at 550 °C. Moreover, concentration cells experiment confirmed that the LMN possessed hybrid proton/oxide conduction and was dominated by proton conduction surface properties. Our work thus vouch that LMN can be an efficient alternative electrolyte for low temperature fuel cell applications.