Carbon-coating functionalized La0.6Sr1.4MnO4+delta layered perovskite oxide: enhanced catalytic activity for the oxygen reduction reaction

Efficient electrocatalysts for the oxygen reduction reaction (ORR) is a critical factor to influence the performance of lithium-oxygen batteries. In this study, La0.6Sr1.4MnO4+delta layered perovskite oxide as a highly active electrocatalyst for the ORR has been prepared, and a carbon-coating layer with thickness <5 nm has been successfully introduced to enhance the electronic conductivity of the as-prepared oxide. XRD, XPS, Raman, SEM and TEM measurements were carried out to characterize the crystalline structure and morphology of these samples. Rotating ring-disk electrode (RRDE) technique has been used to study catalytic activities of the as-prepared catalysts for the ORR in 0.1 M KOH media. RRDE results reveal that carbon-coated La0.6Sr1.4MnO4+delta exhibits better catalytic activity for the ORR. For the carbon-coated La0.6Sr1.4MnO4+delta, the ORR proceeds predominately via a direct four electron process, and a maximum cathodic current density of 6.70 mA cm(-2) at 2500 rpm has been obtained, which is close to that of commercial Pt/C electrocatalyst under the same testing conditions.