High-density BaCe0.9Y0.1O3-δ obtained by solid-state reaction sintered at 1200 oC without sintering aid

Solid oxide fuel cells are the most efficient energy devices, besides being environmentally friendly. However, the high operating temperatures restrict the deployment of these cells. Therefore, efforts have focused on decreasing these temperatures using proton conductors as electrolyte, such as perovskite-type oxides ABO(3). Among them, yttrium-doped barium cerate shows high conductivity. But also, is reported in the literature that BaCe0.9Ce0.1O3-delta has low sinterability, and high sintering temperatures are required to obtain ceramic bodies with 95% of theoretical density. In this work, powders were prepared by solid-state reaction through three procedures, and it was possible to obtain dense pellets of BaCe0.9Y0.1O3-delta at sintering temperature as low as 1200 oC without sintering aid. This makes it possible to manufacture the electrolyte by co-sintering with other cell components. It was determined that the microstructural development is assisted by liquid phase, intrinsic of the system, whose efficiency for promoting densification strongly depends on the particle size and the degree of powder aggregation. In addition, the influence of microstructure on the electrical properties at low temperatures confirmed the intrinsic liquid phase in specific grain boundary conductivities.

Automated summary

Solid oxide fuel cells, being highly efficient and environmentally friendly, face limitations due to their high operating temperatures. This study focuses on reducing the temperatures by using proton conductors as the electrolyte, specifically yttrium-doped barium cerate with high conductivity. Through solid-state reaction, dense pellets of BaCe0.9Y0.1O3-delta were successfully obtained at a low sintering temperature of 1200 oC without sintering aid, enabling co-sintering with other cell components. The study also highlights the role of intrinsic liquid phase in the microstructural development and its effect on promoting densification and specific grain boundary conductivities at low temperatures.