Progress in Developing LnBaCo2O5+δ as an Oxygen Reduction Catalyst for Solid Oxide Fuel Cells

Abstract

Solid oxide fuel cells (SOFCs) represent a breed of eco-friendly, weather-independent, decentralized power generation technologies, distinguished for their broad fuel versatility and superior electricity generation efficiency. At present, SOFCs are impeded by a lack of highly efficient oxygen reduction catalysts, a factor that significantly constrains their performance. The double perovskites LnBaCo2O5+δ (Ln = Lanthanide), renowned for their accelerated oxygen exchange and conductivity features, are widely acclaimed as a promising category of cathode catalysts for SOFCs. This manuscript offers a novel perspective on the physicochemical attributes of LnBaCo2O5+δ accumulated over the past two decades and delineates the latest advancements in fine-tuning the composition and nanostructure for SOFC applications. It highlights surface chemistry under operational conditions and microstructure as emerging research focal points towards achieving high-performance LnBaCo2O5+δ catalysts. This review offers a comprehensive insight into the latest advancements in utilizing LnBaCo2O5+δ in the field of SOFCs, presenting a clear roadmap for future developmental trajectories. Furthermore, it provides valuable insights for the application of double perovskite materials in domains such as water electrolysis, CO2 electrolysis, chemical sensors, and metal–air batteries.

Oxygen Migration Pathways in Layered LnBaCo2O6-δ (Ln = La – Y) Perovskites

“…Layered, A-site ordered, LnBaCo 2 O 6‑δ (Ln = rare earth) double perovskites are multifunctional energy materials with promising performance as cathodes in solid oxide fuel cells, − as oxygen separation membranes, , and as catalysts for the oxygen evolution reaction in electrolysis. − The outstanding catalytic properties derive from the mixed ionic-electronic conductivity, which is advantageous as it allows chemical reaction to occur over the entire surface and not only at triple phase boundaries. The good ionic conduction in these materials has been linked to the high vacancy concentration (0 ≤ δ ≤ 1), low migration barriers for bulk oxide ion transport, and high oxygen surface exchange coefficients. ,− ,, …”

Promoting the Segregation of Sr2+ from the Perovskite Oxygen Catalyst La0.5Sr0.5Co3−δ via Quenching

“…Perovskite structure metal oxides and their derivatives are among the most researched cathode catalysts for SOFCs [4][5][6][7][8][9]. Their general formula can be represented as ABO 3 and A 2 BO 4 , where the A-site is primarily composed of lanthanides and/or alkali earth metals, and the B-site consists mainly of transition metal elements.…”