Tailoring barium doped cobalt-free nanocomposite cathodes for high-performance solid oxide fuel cells

The development of high-performing cathode materials for operation at intermediate temperatures is essential to advancing solid oxide fuel cells (SOFCs) applications. Herein, an in-situ self-assembled cobalt-free nanocomposite cathode for SOFCs is designed and developed through a straightforward barium (Ba) doping strategy on SrFe_0.9Ti_0.1O_3-δ (SFT) perovskite. The original material with the nominal composition of Ba_0.25Sr_0.75Fe_0.9Ti_0.1O_3-δ (BSFT25) is synthesized. The resulting nanocomposite consists of two phases. The surface of the primary cubic perovskite phase (C-BSFT25) is decorated with a minor fraction of spinel phase (S-BSFT25) nanoparticles. The Ba dopant within the major C-BSFT25 phase enhances oxygen transport kinetics, while the S-BSFT25 nanoparticles improve the surface exchange process, thus resulting in enhanced oxygen reduction reaction activity. The SOFC with BSFT25 nanocomposite cathode achieved an impressive performance (a peak power density of 1.2 W cm⁻² at 600 °C) and encouraged operational durability (410 h at 600 °C).