Cobalt‐Free Perovskite Cathodes for Solid Oxide Fuel Cells

Abstract

The past decade has observed rapid growth in the development of cobalt-free perovskite cathodes, which provide enhanced structure and operational stability at the operating temperature of intermediate temperature solid oxide fuel cells (IT-SOFC, 600-800°C) compared to its cobalt-containing counterpart. This Review aims to present a comprehensive overview on the status and advances of the existing cobalt-free perovskite cathodes for IT-SOFCs by discussing electrochemical behaviors, thermal expansion properties, stabilities as well as the oxygen ionic and the electronic transport properties of these cobalt-free perovskite cathode compositions, with primary emphasis on the relationship between the electrochemical performances and the materials science-related factors. Among various cobalt-free perovskite cathodes presented in this Review, niobium-doped compositions generally show lower polarization resistances relative to other cathode compositions.[a] Dr. performance and materials science-related factors. The review is divided into four sections. This first section justifies the SOFC technology significance and its context. The second section features the pertaining aspects on the development of cobaltfree perovskite cathodes according to electrochemical performance, chemical compatibility with electrolytes, thermal expansion mismatch, and overview of the composite perovskite cathodes. The third section provides comparative insights into the performances of single, double, and composite cobalt-free perovskite cathodes focusing into thermal and electrochemical parameters, i. e., thermal expansion coefficient (TEC), total electrical conductivity, polarization resistance and its corresponding activation energy. Synthesis routes, lattice cell parameters, oxygen content, and other available data are also included. The fourth section, in turn, overviews, challenges and outlook for further research and development of cobalt-free perovskite cathodes and concludes the review.

Promotion of oxygen reduction and evolution by applying a nanoengineered hybrid catalyst on cobalt free electrodes for solid oxide cells

“…The here prepared hybrid-catalyst-coated LSF electrode is among the fastest ones reported on cobalt-free materials. 18,36 Even though it is LSF based and cobalt-free, its performance matches those of the high-performance cobalt-containing electrodes reported recently, including LSCF or LSCF nanofiber 9 , BSCF-CGO10 mixture or nanofibers 12 , SrTi0.3Fe0.63Co0.07O3−δ (STFC-07) 37 and PBCC 14 as well as several representative surface-coated-electrodes such as PrSrCoMnO6-δ (PSCM)coated LSCF 38 , multi-phase catalysts (composed of BaCoO3−x (BCO) and PrCoO3−x (PCO) nanoparticles and a conformal PBCC thin film)-coated LSCF 39 , SSC-coated LSCF/CGO10 40 , PrNi0.5Mn0.5O3 (PNM) thin film and PrOx nanoparticles-coated LSCF 21 , and cobaltite-coated PBCC 41 (Fig. 2c).…”

Cobalt‐Free Pr0.5Ba0.4Sr0.1FeO3–δ as a Highly Efficient Cathode for Commercial YSZ‐Supported Solid Oxide Fuel Cell

“…Among the various cobalt-free perovskite oxides, iron-based perovskite oxides are promising candidates for SOFC cathode materials owing to their affordable electrical conductivity, longterm cell operation durability and great chemical compatibility with the YSZ electrolyte. [22][23][24][25] One of the representative materials achieving the above demands is Pr 0.5 Ba 0.5 FeO 3-δ (PBF). [26,27] Even though the PBF material could be directly applied onto the YSZ electrolyte, this material tend to show insufficient electro-catalytic activity toward ORR compared to cobalt-based perovskite oxides.…”

“…Among the various cobalt‐free perovskite oxides, iron‐based perovskite oxides are promising candidates for SOFC cathode materials owing to their affordable electrical conductivity, long‐term cell operation durability and great chemical compatibility with the YSZ electrolyte [22–25] . One of the representative materials achieving the above demands is Pr 0.5 Ba 0.5 FeO 3– δ (PBF) [26,27] .…”

Characterization of SrFe0.9‐xCuxMo0.1O3‐δ (x = 0, 0.1 and 0.2) as cathode for intermediate‐temperature solid oxide fuel cells

“…18 In view of these situations, further developing of cobaltfree SOFC cathodes with high electrochemical activity in the intermediate temperature range is imperative. 19,20 In comparison with cobalt-based MIECs, iron-based MIECs are more stable as IT-SOFC cathodes because of the relatively high stability of electronic configuration of Fe ions than that of Co ions. 21,22 SrFeO 3 -based perovskites are promising MIECs and have been applied in many fields, such as O 2 sensors, O 2 permeation membranes and SOFC electrodes.…”