Enhanced Electrochemical Performance of Double Perovskites as Cathodes in Reversible Ceramic Electrochemical Cells through Nb Doping

Abstract

Efficient and cost-effective generation of electricity and hydrogen holds promise through reversible protonic ceramic electrochemical cells (R-PCECs). However, the successful commercialization of R-PCECs depends on the advancement of air electrodes that are both highly active and durable. Here, we made an air electrode material with two phases of double perovskite and single perovskite by doping Nb into B-site of the traditional PrBaCo2O6 double perovskite. The coexistence of the mixed double perovskite and single perovskite phases demonstrates superior electrochemical performance and durability compared to pristine double perovskite and single perovskite materials when employed as cathode materials. X-ray photoelectron spectroscopy (XPS), synchrotron radiation X-ray absorption spectroscopy (XAS) and neutron diffraction analysis reveal that this enhancement is primarily attributed to the introduction of high-valence Nb5+, resulting in an increased number of oxygen vacancies and structural stability. The findings presented in this study contribute valuable insights into the design and development of advanced cathode materials for solid oxide fuel cells and electrolyzers, with the potential for applications in sustainable energy conversion and storage technologies.