Electrochemical properties and application of Bi-doped Ba3Ca1.18Nb1.82−xBixO9−δ electrolyte

Abstract

Ba₃Ca_1.18Nb_1.82−xBi_xO_9-δ (x = 0, 0.1, 0.2, 0.3) proton conductor materials with different Bi doping ratios are prepared. The Bi element was successfully doped into the lattice of Ba₃Ca_1.18Nb_1.82−xBi_xO_9−δ proton conductor to form a single perovskite phase. The effects of Bi doping on grain boundary are evaluated by the analysis of relaxation time distribution (DRT). The proper Bi doping ratio for Ba₃Ca_1.18Nb_1.82−xBi_xO_9−δ (x = 0, 0.1, 0.2, 0.3) can improves the grain boundaries performance. With the increase of Bi doping ratio, the conductivity of the sample increases first and then decreases. Among all the samples, Ba₃Ca_1.18Nb_1.72Bi_0.1O_9-δ (BCNB10) has the highest conductivity and satisfactory proton transport properties. In the wet air atmosphere at 700 °C, the proton transference number of BCNB10 is still higher than 0.6. The Ba₃Ca_1.18Nb_1.72Bi_0.1O_9-δ-based fuel cell has a power density of 59.7 mW cm² at 700 °C. The results show that BCNB10 is a promising fuel cell electrolyte material with high performance.