Perovskite nanocomposite and self-assembled nanoparticle-decorated cathode for low temperature SOFCs

Abstract

One-pot route synthesis of A-site Sm-doped simple perovskite with nominal composition Sm0.10Ba0.90Co0.8Fe0.2O3-δ leads to a novel perovskite nanocomposite containing ~ 90% A-site cation deficient cubic simple perovskite Ba_0.925 〖(Co/Fe)〗_0.962 Sm_0.038 O_(3-δ) and ~ 10% orthorhombic layered perovskite 〖SmBa(Co/Fe)〗_2 O_(5+δ). The cubic perovskite enables isotropic 3-D oxygen ion diffusion, enhancing ionic conductivity while orthorhombic layered perovskite provides high electrical conductivity. The synergetic combination of the two phases results in high oxygen reduction reaction activity at low temperatures. With the novel perovskite nanocomposite, surface nanoparticle-decorated nanocomposite cathode is self-assembled in one-step sintering process. The corresponding anode-supported cell delivers a peak power density of 1271 mW cm-2 at 650 oC. The cell also demonstrates long-term stability (~ 333 h) under the current load of 600 mA cm2 and shows short-term stability (~ 16 h) under an alternating large current load between 600 and 1700 mA cm2 at 600 oC. The novel perovskite nanocomposite developed in this paper is among the best in open literature for the cathode of low temperature SOFCs.