Densification and electrical conducting behavior of BaZr0.9Y0.1O3-δ proton conducting ceramics with NiO additive

Abstract In this study, the NiO additive was employed as a sintering aid to prepare dense BaZr 0.9 Y 0.1 O 3-δ (BZY10) ceramics for proton ceramic fuel cell (PCFC) and electrolysis cell (PCEC) applications. It was found that the NiO additive contributed to facilitating the grain growth and enhancing the proton conductivity of BZY10 ceramics. However, the subsequent studies on the transport number reveal a detrimental effect of NiO additive on increasing the electronic leakage of BZY10 ceramics under humid oxidizing atmosphere. This is expected to cause the misdiagnosis of the electrocatalytic activity of PCFC cathodes and a lower Faraday efficiency of PCECs. Considering the utilization of BZY10 ceramics as the proton conducting electrolyte, it is preferred to obtain a high density (∼95%) and applicable proton conductivity at the minimum NiO usage. This strategy was achieved by sintering the nanocrystalline BZY10 powders with 0.2 wt% NiO additive at 1500 °C for 6 h in air, of which the usage is 80% lower than that in the well-known solid state reactive sintering approach.