Synthesis and Physical-Chemical Study of Nanopowders and Ceramics in the Gd2O3–La2O3–SrO–Ni(Co)O3 – δ System for Cathode Fuel Cell Materials

Highly dispersed mesoporous powders of the composition Gd_1 – xSr_xCo_0.5O_3 – δ (x = 0.1, 0.15, 0.2, 0.25), Gd_0.4Sr_0.1Ni_0.5O_3 – δ, and Gd_0.125La_0.125Sr_0.25Co_0.5O_3 – δ are synthesized using the method of the cocrystallization of nitrate salts. Ceramic nanomaterials of the given composition with a CSR of ~49–62 nm (1200°С), open porosity of 17–42%, and apparent density of 5–7 g/cm³ are obtained based on them. Nanopowders and ceramics in the range of 600–1200°C have a tetragonal and orthorhombic structure of the perovskite type in the Gd₂O₃‒SrO‒Co₂O_3 – δ system. It is established that in order to obtain the optimal characteristics of density and porous structure of ceramics, combined additives of polyvinyl alcohol (PVA) are required in combination with aluminum hydroxide Al(OH)₃, acting as a pore-forming and sintering additive. The solid solutions have mixed electron-ionic conductivity with transport numbers t_e = 0.92–0.99 and t_i = 0.08–0.01. Due to their physical, chemical, and electrophysical properties associated with the structural features of solid solutions, ceramic materials obtained based on them are promising for use as solid oxide cathodes for medium-temperature fuel cells.