Exceptional catalytic activity of hollow structured La0.6Sr0.4CoO3−δ perovskite spheres in aqueous media and aprotic Li–O2 batteries

Abstract

Hollow structured La_0.6Sr_0.4CoO_3−δ (HS-LSC) perovskite spheres are synthesised via a template assisted approach and utilized as a bi-functional catalyst in both aqueous and non-aqueous media. Optimization of the calcination temperature has been performed to yield a single-phase HS-LSC. Rotating ring disk electrode measurements of HS-LSC in 0.1 M KOH exhibit two-fold higher (apex of limiting current is 4.974 mA cm⁻²) oxygen evolution reaction (OER) capability than that of the commercial RuO₂ (1.84 mA cm⁻²). The excellent oxygen reduction reaction (ORR) activity and durability up to 5400 s of HS-LSC also registered as comparable to those of Pt/C. The organic medium OER and ORR activities of the catalyst were explored from a Li–O₂ battery perspective. The HS-LSC catalyst based Li–O₂ battery delivered a deep discharge capacity of ∼4895 mA h g⁻¹ with high coulombic efficiency (∼82%), and rate capability. Excellent cycling stability is also evidenced for a limited capacity of 500 mA h g⁻¹. Unprecedentedly, the favourable structural and morphological features facilitate O₂ transport, electrolyte immersion and ion diffusion processes promoting the catalytic reaction kinetics on the electrode.