Cobalt free LaxSr1-xFe1-yCuyO3-δ (x= 0.54, 0.8, y = 0.2, 0.4) perovskite structured cathode for SOFC

Abstract

The cobalt containing cathode is always challenging because of high cost, reduction of cobalt and high thermal expansion for SOFC. Therefore, cobalt-free perovskite oxides nanostructure cathodes LaxSr1-xFe1-yCuy O3-δ (x = 0.54, 0.8, y = 0.2, 0.4) are synthesized by sol-gel method in this paper. The microstructure, electrical and transport properties of prepared nanomaterials were studied. The characterizations of synthesized materials are performed by X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The thermal effects are monitored by using Thermogravimetric analysis (TGA). The electrochemical studies of prepared cathodes are accomplished with four-probe DC method. The conductivities of La0.54Sr0.46Fe0.80Cu0.20O3-δ, La0.80 Sr0.20 Fe0.80Cu0.20 O3-δ and La0.80 Sr0.20 Fe0.60Cu0.40 O3-δ are achieved as 6.007, 3.042 and 2.002 Scm−1, respectively at 500 °C but maximum conductivities of La0.54Sr0.46Fe0.80Cu0.20O3-δ, La0.80 Sr0.20 Fe0.80Cu0.20 O3-δ and La0.80 Sr0.20 Fe0.60Cu0.40 O3-δ are obtained as 9.029, 6.237 and 5.266 Scm−1, respectively at 600 °C. The power densities are noted as 267, 201 and 156 mWcm−2 for La0.54Sr0.46Fe0.80Cu0.20O3-δ, La0.80 Sr0.20 Fe0.80Cu0.20 O3-δ and La0.80 Sr0.20 Fe0.60Cu0.40 O3-δ, respectively at 500 °C. The peak power densities are recorded as 452, 366 and 270 mWcm−2 for La0.54Sr0.46Fe0.80Cu0.20O3-δ, La0.80 Sr0.20 Fe0.80Cu0.20 O3-δ and La0.80 Sr0.20 Fe0.60Cu0.40 O3-δ, respectively at 600 °C. The current densities as 1251 mAcm−2, 1179 mAcm−2 and 1107 mAcm−2 for La0.54Sr0.46Fe0.80Cu0.20O3-δ, La0.80 Sr0.20 Fe0.80Cu0.20 O3-δ and La0.80 Sr0.20 Fe0.60Cu0.40 O3-δ are obtained, respectively at 500 °C. The significant current densities as1480 mAcm−2, 1420 mAcm−2 and 1370 mAcm−2 for La0.54Sr0.46Fe0.80Cu0.20O3-δ, La0.80 Sr0.20 Fe0.80Cu0.20 O3-δ and La0.80 Sr0.20 Fe0.60Cu0.40 O3-δ are achieved, respectively at 600 °C. The XRD data revealed the perovskite phase while results of SEM indicate that materials were homogeneous. The prepared La0.54Sr0.46Fe0.80Cu0.20O3-δ, La0.80 Sr0.20 Fe0.80Cu0.20 O3-δ and La0.80 Sr0.20 Fe0.60Cu0.40 O3-δ cathodes have maximum open circuit voltage 0.918,0.86 and 0.82 V at 600 °C.