Preparation and electrochemical properties of La_0.5Sr_0.5Co_0.2Fe_0.8O₃ oxides as bifunctional catalysts for reversible single-component cells

La_0.5Sr_0.5Co_0.2Fe_0.8O₃ (LSCF) perovskite materials were prepared by hard template method with SBA-15 as the template in methanol and ethanol solvents and the electrochemical properties of LSCF were investigated. It is found that LSCF prepared with ethanol solvent has larger specific surface area and more oxygen vacancy concentration, which in turn exhibits higher electrical conductivity and better catalytic activity towards oxygen reduction reaction (ORR) and hydrogen oxidation reaction (HOR). This is because the LSCF prepared by the ethanol solvent has more Co^{2 +} /Co^{3 +} and Fe^{2 +} /Fe^{3 +} electron pairs, which promotes the electronic conduction of the material. In addition, for HOR, the rate determining step (RDS) is the transfer of adsorbed H to the reaction site, and for ORR, the RDS is the reduction of the adsorbed oxygen atom on LSCF. In addition, the reversible single-component cell (RSCC) composed of LSCF prepared by ethanol solvent shows better performance for discharge and water electrolysis. The maximum power density (P_max) of the RSCC is 232.9 mW/m², and the current density at 1.3 V is −398.3 mA/cm² at 700 ℃.