Butvar

Ce_0.9Gd_0.1O_2−d (CGO91, Solvay) powders were used as the electrolyte of symmetrical half cells (Sm_1−xBaCo₂O_5+d/CGO91/Sm_1−xBaCo₂O_5+d). After weighing 2.5 g of CGO91, it was put into a metal mold and compression molding was performed by applying a force of 2 × 10³ kg/m². After that, sintering was performed at 1,450°C for 6 h in air. Cathode ink made using a-terpieal(Kanto Chemical), Butvar(Sigma Aldrich), and acetone with cathode powder; composite ink was also prepared by mixing electrolyte powder and cathode material at a weight ratio of 50:50. Both sides of the sintered electrolyte support were printed' with the prepared cathode ink, and the printed cell was sintered at 1,000°C for 1 h in the air condition. After the sintering, surface area of both sides of cathode was measured and found to be 0.785 cm². To confirm the electrical conductivity characteristics of the composites as identified through XRD analysis, a sample was prepared and the electrical conductivity was measured. After making a bar-type sample with dimensions of ~2.8 × 5.5 × 23 mm through compression molding, sample was sintered at 1,100°C for 3 h in air.

For fabrication of the electrolytes, individual samples of 2.5 g of Ce_0.9Gd_0.1O₂ (CGO91, Rhodia) powder were pressed into disc shaped metal molds at 2 × 10³ kg/m². The CGO91 electrolytes were sintered at 1450°C for 6 h and the final geometry of the sintered electrolyte pellets was approximately 22.18 mm in diameter and 0.97 mm in thickness. Inks of single-phase and composite cathodes were prepared using mixtures of SmBa_1-xCa_xCo₂O_5+d (SBCCO) cathode powders, Alpha-terpineol (KANTO CHEMICAL), Butvar (SIGMA Aldrich) and acetone. These mixtures were stirred for 1 week with a magnetic bar. Then, Ce_0.9Gd_0.1O₂ (CGO91, Rhodia) was mixed with the cathode powder at a mass ratio of 1:1 to sustain the decrease in area specific resistance (ASR). After the prepared inks were applied to the electrolytes using screen printing to fabricate symmetrical half cells, samples were heat-treated at 1000°C for 1 h at a heating rate of 5°C/min.
The area specific resistances (ASRs) of the half cells were measured using an AC impedance analyzer (Model nStat, HS Technologies); the measurements were performed in a frequency range of 0.05 Hz–2.5 MHz and temperature range of 900°C–650°C with 50 C steps in air atmosphere.
The cathode ASR was determined from the difference between the first and second intercepts of the impedance curves, divided by 2.