Dual doping synergy: Optimizing SrMoO3 perovskite anodes via in-situ Ni exsolution and Cr doping for enhanced SOFC efficiency

Abstract

In this work, a family of SrMoO3 perovskites doped with equimolar amounts of Cr and Ni at the Mo position (SrMo1-xCrx/2Nix/2O3, x = 0.1, 0.2) was synthesised for their application as anodes in intermediate temperature solid-oxide fuel cells (IT-SOFCs). Whereas Cr doping is intended to favour the creation of oxygen vacancies in the perovskites, Ni atoms are exsolved from the perovskite crystal structure to the surface, thus favouring the electrocatalytic behaviour of the anodes. These materials have been synthesised by a sol-gel reaction and structurally characterised by laboratory X-ray diffraction (XRD), neutron powder diffraction (NPD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Additionally, physical properties such as thermal expansion behaviour, thermogravimetric analysis and electrical conductivity have been analysed and correlated to their electrochemical performance as anodes in SOFC mode, leading to maximum conductivities of 130 Scm−1 and cell performances of 862 mW/cm2 due to the synergistic action introduced by the enhanced mixed ionic and electronic conduction by Cr3+ doping at the Mo sites, and the in-situ exsolution of Ni nanoparticles that favours the electrocatalytic efficiency.