Possible applications of high temperature proton conductors (HTPCs)

Abstract

First, the applications for HTPCs as suggested by Iwahara et al. are critically reviewed. In a second step the criteria for the application of HTPCs in SOFCs are outlined. 4 prominent HTPCs (doped Ba and Sr cerates, doped Ba and Sr zirconates and the mixed perovskite Ba3Ca1.18Nb1.82O9-δ) are critically examined for use as electrolytes in SOFCs. Generally, the following materials parameters are desirable: deviation from exact oxygen stoichiometry δ≈0.05; enthalpy of solution of water -ΔHs≥1.5 eV; effective activation energy for proton transport EHeff <=0.55 eV and proton transfer number tH≈1. Third, the following applications are discussed: a) Introduction of hydrogen into a vacuum system; b) hydrogen charging of metals; c) a variable standard hydrogen leak; and d) a hydrogen partial pressure detector. Fourth, possible applications of HTPCs in tritium technology are presented. These compounds are potentially quite useful in glove-box atmosphere treatment, isotope separation, oxidation and reduction procedures and immobilization of tritium.