Tailoring Ba3Ca1.18Nb1.82O9-δ with NiO as electrolyte for proton-conducting solid oxide fuel cells

A strategy of tailoring Ba3Ca1.18Nb1.82O9-δ (BCN) is proposed, aiming to improve the sinterability and conductivity of BCN material for fuel cell applications. The new Ba3Ca1.18Nb1.77Ni0.05O9-δ (BCNNi) material shows a significant improvement in sinterability compared with BCN, leading to a high densification for BCNNi after sintering at as low as 1400 °C. In addition, the BCNNi exhibits a conductivity of 4.59 × 10−3 S cm−1 at 700 °C that is not only higher than that for BCN which only reaches 3.45 × 10−3 S cm−1 at the same temperature but also shows a significant improvement compared with that for BCN-based materials in literature reports. As a result, the cell with the BCNNi electrolyte shows a peak power density of 84 mW cm−2 at 700 °C which is also one of the largest ever reported for this type of cells. Further electrochemical studies indicate that the high conductivity of BCNNi electrolyte membrane benefits the fuel cell performance.