Self-propagating high-temperature synthesis of La(Sr)Ga(Mg,Fe)O _3-δ with planetary ball-mill treatment for solid oxide fuel cell electrolytes

This study investigated the combined effects of self-propagating high-temperature synthesis (SHS), planetary ball-mill (PBM) treatment, and sintering temperature on La_0.7Sr_0.3Ga_0.7Mg _0.1Fe_0.2O_3-δ (LSGMF73712) as an electrolyte material for solid oxide fuel cells (SOFC). The SHS products (SHSLSGMF73712) were compared with that prepared via solid-state reaction (SSR) in terms of sinterability and power generation performance. The SHS products were treated with PBM for 10, 30, 50, and 70 h. The SHS products contained the by-product LaSrGaO₄; however, in the SHS products treated with PBM for longer than 50 h, the by-product disappeared after sintering at 1350 °C for 3 h in air. Among the samples, SHS products treated with PBM for 70 h displayed superior sintering (1350 °C), whereas the SSR product (SSR-LSGMF73712) was successfully sintered at 1450 °C for 3 h in air. Under the cell configuration of Ni-Fe/SHS-LSGMF73712-PBM70 h (0.3 mm thick)/Sm _0.5Sr_0.5CoO₃, the maximum power density was 0.673 W/cm² at 800 °C using humidified hydrogen gas (3 mol% H₂O) as a fuel and air as an oxidizing agent at a flow rate of 100 mL/min, which was almost equivalent to that using SSR-LSGMF73712 (0.629 W/cm² at 800 °C) under the same conditions.