Novel YBaCo3.2Ga0.8O7+δ as a cathode material and performance optimization for IT-SOFCs

•YBaCo3.2Ga0.8O7+δ (YBCGO) has been prepared, characterized and tested as cathode material for IT-SOFCs.•The average coefficient of thermal-expansion coefficient of YBCGO is 8.6 × 10−6 K−1.•YBCGO cathode gives the lowest ASR value of 0.111 Ω cm2 at 800 °C in air.•The cathode performance can be improved by adding 30 wt.% PrBaCo2O5+δ (PBCO).

The YBaCo3.2Ga0.8O7+δ (YBCGO) oxide has been developed as new cathode material based on La0.9Sr0.1Ga0.8Mg0.2O3−δ (LSGM) electrolyte for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The electrical conductivity of YBCGO sample reaches 1.4–2.1 S cm−1 in the temperature range 650–800 °C. The thermal expansion coefficient (TEC) value of YBCGO is 8.6 × 10−6 K−1 in the range of 30–1000 °C. The area specific resistance (ASR) of a YBCGO cathode with LSGM electrolyte is 0.111 Ω cm2 at 800 °C and it decreases to 0.047 Ω cm2 when PrBaCo2O5+δ (PBCO) is added to form a YBCGO–PBCO composite cathode. Peak power densities of single cells using a pure YBCGO cathode and a YBCGO–PBCO composite cathode are 395 and 531 mW cm−2 at 800 °C, respectively. The results of this study demonstrate that YBCGO can be a promising cathode material for IT-SOFCs.