Investigations on electrochemical performance of La2NiO4+δ cathode material doped at A site for solid oxide fuel cells

Abstract

In this work, the perovskite compounds La1.5A0.5NiO4+δ (A = Ca, Sr or Ba), which is one kind of mixed ionic electronic conductors (MIEC) with perovskite structure, was explored as cathode materials for proton conducting solid oxide fuel cells (H-SOFCs). In order to understand how the size of A-site cations affects material properties, the electrical conductivity and the electrochemical performances of La1.5A0.5NiO4+δ (A = Ca, Sr or Ba) were compared. The results are more interesting. In the middle temperature region (600 °C–700 °C), Ca doping is the best choice among the three alkaline earth elements. In the low temperature region (300 °C–600 °C), Sr-doped single cells Sr-doped single cells have better performance. However, Ba doping easily generates BaCO3 impurities, which reduces the ion transmission capacity and increases the interface resistance, resulting in poor performance of the single cell. This work shows that La1.5A0.5NiO4+δ (A = Ca and Sr) is the main cathode candidate material for H-SOFC.