Perovskite Sr0.95Ce0.05CoO3−δ loaded with copper nanoparticles as a bifunctional catalyst for lithium-air batteries

Abstract

Sr_0.95Ce_0.05CoO_3−δ (SCCO) particles loaded with copper nanoparticles on their surface are shown to be excellent, low-cost, and stable bifunctional catalysts for the oxygen-reduction and oxygen-evolution reactions (ORR and OER) in aqueous solution. Evidence for the presence of Ce³⁺ and Co²⁺ as well as Co⁴⁺ and Co³⁺ ions revealed by XPS measurements as well as XRD analysis indicates that a CeCoO_2.5 brownmillerite phase may be extruded to the surface. A surface Co⁴⁺/Co³⁺ couple is known to be a good OER catalyst. The performance of the SCCO-based catalysts is better at higher current rates (>0.1 mA cm⁻²) than that of Vulcan XC-72 and even close to that of the 50% Pt/carbon-black catalyst. This catalyst could be used in a metal/air battery or a PEM fuel cell as an efficient and stable bifunctional catalyst.