Ceramic proton conductor

Dr. Hui has worked on various projects, including chemical sensors, solid oxide fuel cells, magnetic materials, gas separation membranes, nanostruc-tured materials, thin film fabrication, and protective coatings for metals. He has more than 80 research publications, one worldwide patent, and one U.S. patent (pending). He is currently leading and involved in several projects for the development of metal-supported solid oxide fuel cells (SOFCs), ceramic nanomaterials as catalyst supports for high-temperature PEM fuel cells, protective ceramic coatings on metallic substrates, ceramic electrode materials for batteries, and ceramic proton conductors. Dr. Hui is also an active member of the Electrochemical Society and the American Ceramic Society. 

Gupta, V. K, Lin, Y. S. Ceramic proton conductors. In SammeUs, A. F, Mundschau, M. V, editors, Nonporous inorganic membranes. Weinheim Germany Wiley-VCH . 2006. pp. 49-76. 

M. F. Bell and M. Sayer, The Development of Ceramic Proton Conductors, Report No. OSU 81-00440, Queen s University, Kingston, Ontario, Canada, 1983. 

The above-described situation displays the fact that there is a temperature gap in the availability of electrolytes between ca. 200 °C and 650 °C. Today, major research efforts are carried out to extend the range of aqueous and OH conduction to temperatures beyond 100 °C, for technological reasons (heat rejectiOTi in cars, CO tolerance of platinum-based catalysts). On the other hand, oxide materials are developed with improved 02 conductivity al temperatures lower than the operation temperatures of standard SOFCs. Also ceramic proton conductors [11] and protonconducting salts like CsHS04 [12] are considered as electrolytes for this temperature regime. 

The major problem with ceramic proton conductors is that those that exhibit high proton conductivity, such as the ones we have exemplified so far, are rather basic in nature because Sr and Ba are main components. They are thus vulnerable to destructive reaction with acidic gases such as CO2 or SO2/SO3, especially at moderate temperatures, and may also react with water at moderate and low temperatures to form hydroxides. 

NASA (National Aeronautics and Space Administration) has also pursued ceramic proton conductors as part of their SOFC program by fabricating and characterizing thin BaCeOs-based [71] and other proton-conducting ceramic films. 

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