LaScO3-based electrolyte for protonic ceramic fuel cells: Influence of sintering additives on the transport properties and electrochemical performance

In this work, the effect of the content of CuO, ZnO, Al2O3, NiO, Fe2O3, Co3O4 and MoO3 additives on the sinterability, microstructure, and electrical properties of La0.9Sr0.1ScO3-α proton-conducting oxide in a form of tubes produced by slip casting is studied. It is shown that the relative density of La0.9Sr0.1ScO3-α tubes without sintering aids is ~86%. The introduction of 1.0 wt % ZnO, Al2O3, NiO or 0.5 ÷ 1.0 wt % Co3O4 leads to a relative density of ceramics higher than 95%. Among dense ceramic tubes, LSS +0.5 wt % Co3O4 has the highest electrical conductivity. The introduction of 1 wt % Fe2O3 additive does not affect the sinterability of the LSS, and 1 wt % CuO and MoO3 inhibits LSS sintering. Single protonic ceramic fuel cells based on LSS +0.5 wt % Co3O4 and LSS +1.0 wt % NiO supporting electrolyte tubes with a thickness of 300 μm are studied. The maximum power density of about 30 mW/cm2 at 800 °C was obtained for a cell based on LSS +0.5 wt % Co3O4 using wet hydrogen as fuel and air as an oxidizing gas. [Display omitted] •Co3O4 recognized to be the best sintering additive for La0.9Sr0.1ScO3-δ electrolyte.•The way of sintering additive introduction affects microstructure in case of Co3O4.•The optimal amount of Co3O4 additive was found to be 0.5 wt%.•Highly dense ceramic tubes of proton-conducting electrolyte were obtained.