This project will enable high efficiency conversion of fuels to electricity using a conversion device called a fuel cell. The key components of the fuel cell are the proton conducting electrolyte and the catalysts that facilitate the reaction of oxygen with protons to generate electricity. The project will create advanced electrocatalysts that operate at ~500 degrees Fahrenheit. This temperature is hot enough to accelerate the desired fuel conversion reaction, yet cool enough to slow unwanted material degradation. The research team has previously identified catalyst materials with high activity, but they degrade because they react with the electrolyte in the fuel cell. To address this challenge, the team will utilize ultra-thin barrier layers that are permeable to protons but block the reaction of the catalyst material with the electrolyte. In parallel, they will utilize advanced characterization techniques to reveal the pathway for the reaction of oxygen with protons. This will allow rational design and selection of high activity catalysts. The project will include researchers at various academic levels, and it will support training through internships for high school and undergraduate students, as well as postdoctoral research opportunities for early career professionals. This research aims to design oxygen reduction catalysts suitable for use in solid acid fuel cells. These fuel cells operate at ~ 250 degrees C and incorporate a superprotonic solid acid, cesium dihydrog