Electrical and electrochemical characteristics of La_0.6Sr_0.4CoO_3-δ cathode materials synthesized by a modified citrate-EDTA sol-gel method assisted with activated carbon for proton-conducting solid oxide fuel cell application

The electrical conductivity and electrochemical performance of a La_0.6Sr_0.4CoO_3-δ (LSC) cathode produced by a modified citrate-EDTA sol-gel method assisted with activated carbon are characterized for a proton-conducting solid oxide fuel cell (H⁺ −SOFC) application at intermediate temperature. Thermogravimetric analysis revealed that the decomposition of the unrequired intermediate compounds in the precalcined powder was completed at 800 °C. A single LSC perovskite phase was formed at a calcination temperature of 900 °C, as confirmed by X-ray diffraction analysis. The particle size, crystallite size, and BET-specific surface area of the powder are 219–221 nm, 18 nm, and 9.87 m² g⁻¹, respectively. The high index value of the extent of agglomeration (5.53) showed that the powder was barely agglomerated. Bulk LSC sintered at 1200 °C for 2 h showed the highest direct-current electrical conductivity (σ_d.c) compared to that of bulk LSC sintered at 1000 °C and 1100 °C. The value of σ_d.c was affected by the density and porosity of the sintered samples. The area specific resistance (ASR) of screen-printed LSC working on a proton conductor of BaCe_0.54Zr_0.36Y_0.1O_2.95 (BCZY) decreased from 5.0 Ω cm²–0.06 Ω cm² as the temperature increased from 500 °C to 800 °C with an activation energy of 1.079 eV. Overall, in this work, the LSC material produced with the aid of activated carbon meet the requirements for the application as a cathode in an intermediate temperature H⁺-SOFC.