Synthesis of nanocrystalline lanthanum manganite with tailored particulate size and morphology using a novel spray pyrolysis technique for application as the functional solid oxide fuel cell cathode

Nanocrystalline strontium doped lanthanum manganite (La0.65Sr0.3MnO3) having variable particulate sizes and morphology is synthesized by a novel spray pyrolysis (SP) technique for solid oxide fuel cell (SOFC) cathode. Precalcined nanopowders received from the first SP run are added as the seeding agent in the subsequent runs for their in-situ growth inside the reactor. The suitability of the nano and micro particulates having interconnected porosity are examined as cathode functional and current collection layers. Detailed physical, microstructural and bulk electrical characterizations of such nanopowders are studied. Cathode polarization behavior and the associated rate limiting steps are characterized using AC impedance spectroscopy in the symmetric cell configurations. The optimization of the cathode processing conditions has brought the interfacial polarization down to ∼0.2 Ω-cm2 and thereby increases the cell performance from 2.0 to 3.2 A.cm−2 (0.7 V, 800 °C). Such improvement in anode-supported SOFC is correlated with the cathode processing conditions, particulate size, morphology and cathode microstructure. ► Spray pyrolysed nanocrystalline LSM possess tailored particulate size and morphology. ► Precalcined LSM nanoparticles used as seeding agent for in-situ particle growth. ► Tailored morphology of functional cathode results in lowest polarization (0.4 Ω-cm2). ► Functional cathode enhances cell performance appreciably (3.2 A cm−2, 0.7 V & 800 °C). ► Functional cathode also reduces cell ASR down to 0.109 Ω-cm2 at 800 °C.