A new bi-directional surface modification cathode based on conventional cathode La0.6Sr0.4Co0.2Fe0.8O3-δ

Abstract

The commercialization of proton solid oxide fuel cells (H-SOFCs) is hindered by the lack of high active and durable cathode materials exposed to evil operation conditions. Here, this groundbreaking study addresses two critical challenges impeding the practicality of La0.6Sr0·4Co0·2Fe0·8O3-δ (LSCF), one of the most popular proton-conducting cathode materials contemporarily: inadequate temperature activity and durability issues stemming from surface Sr segregation. The research introduces a transformative solution through the creation of a novel nanofiber cathode, denoted as PrBaCo1.4Fe0·6O6-δ@LSCF, comprising a nanoscale LSCF FP host and PBCF NP guest. Advanced electron microscopy and scanning electron microscopy techniques confirm the seamless integration of the two phases, highlighting a distinctive fiber structure adorned with impregnated nanoparticles. Meanwhile, efficiently reducing oxygen vacancies within the LSCF bulk phase significantly suppresses Sr segregation. Systematic simulations based on density functional theory reveal that the incorporation of PSCF reduces the polarization energy barrier. In practical terms, electrochemical testing of a single cell supported by PBCF@LSCF shows a polarization resistance of only 0.053 Ω cm2 at 700 °C, translating to a remarkable fifty percent reduction. Furthermore, a sustained 100-h test reveals no notable decline in performance. Consequently, a novel dual modification approach is proposed for crafting cathodes tailored for SOFCs.