The oxygen reduction reaction (ORR) is one of the most important electrochemical reactions in energy conversion and storage technologies, such as fuel cells and metal–air batteries.

The need for reducing the solid oxide fuel cell (SOFC) operating temperature below 600 °C is imposed by cost reduction, which is essential for widespread SOFC use, but might also disclose new applications. To this aim, high-temperature proton-conducting (HTPC) oxides have gained widespread interest as electrolyte materials alternative to oxygen-ion conductors. This Progress Report describes recent developments in electrolyte, anode, and cathode materials for protonic SOFCs, addressing the issue of chemical stability, processability, and good power performance below 600 °C. Different fabrication methods are reported for anode-supported SOFCs, obtained using state-of-the-art, chemically stable proton-conducting electrolyte films. Recent findings show significant improvements in the power density output of cells based on doped barium zirconate electrolytes, pointing out towards the feasibility of the next generation of protonic SOFCs, including a good potential for the development of miniaturized SOFCs as portable power supplies.

Energy crisis and environmental problems caused by the conventional combustion of fossil fuels boost the development of renewable and sustainable energies. H2 is regarded as a clean fuel for many applications and it also serves as an energy carrier for many renewable energy sources, such as solar and wind power. Among all the technologies for H2 production, steam electrolysis by solid oxide electrolysis cells (SOECs) has attracted much attention due to its high efficiency and low environmental impact, provided that the needed electrical power is generated from renewable sources. However, the deployment of SOECs based on conventional oxygen-ion conductors is limited by several issues, such as high operating temperature, hydrogen purification from water, and electrode stability. To avoid these problems, proton-conducting oxides are proposed as electrolyte materials for SOECs. This review paper provides a broad overview of the research progresses made for proton-conducting SOECs, summarizing the past work and finding the problems for the development of proton-conducting SOECs, as well as pointing out potential development directions.

No abstract

Over the past years the performance of electrochromic smart windows with the promising potential for significant energy savings has been progressively improved; however, the electrochromic windows have not yet to come into use at scale mainly because the electrochromic materials suffer from some significant drawbacks such as low coloration efficiency, slow switching time, bad durability and poor functionality. Herein, we fabricate the optically modulated electrochromic smart devices through sequential deposition of the crown-type polyoxometalates, KLiHPWO·92HO (PW), and WO nanowires. Unlike most reported electrochromic smart devices, the resulting PW and WO nanocomposites allow active and selective manipulation of the transmittance of near-infrared (750-1360 nm) and visible light (400-750 nm) by varying the applied potential. Furthermore, thanks to the stable nature of both PW and WO and precise structural control over the nanocomposites, the prepared electrochromic smart devices exhibit high efficiency, quick response and excellent stability.

No abstract

No abstract

A new composite cathode material made of La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 À d (LSCF), a mixed oxygen-ion/ electron conductor, and BaZr 0.5 Pr 0.3 Y 0.2 O 3 À d (BZPY30), a mixed proton/electron conductor, is here developed for application in intermediate temperature solid oxide fuel cells (IT-SOFCs) based on proton conducting electrolytes. The wet chemical synthesis route allows sub-micrometre particle powders to be obtained, resulting in a highly porous microstructure. The developed composite cathode shows improved performance compared to the reported cathodes working in protonic SOFCs, achieving a total area specific resistance (ASR) in wet O 2 of 0.011, 0.089, and 0.6 U cm 2 at 700, 600, and 500 C, respectively. Electrochemical impedance spectroscopy measurements indicate that several processes contribute to the overall cathode resistance. Performing area specific resistance measurements at different p O 2 values allows the correlation of the various semicircles observed in the LSCF-BZPY30 impedance plots to different cathode reaction processes, i.e. water formation, oxygen surface dissociation, and diffusion. Fuel cell tests confirm the good performance of the LSCF-BZPY30 cathode for proton conducting oxide electrolytes.