Electrochemical properties and chemical stabilities of (NH4)(2)SO4/TiO2 composites at intermediate temperatures

摘要

A proton-conductive electrolyte of (NH4)(2)SO4/TiO2 composite was synthesized, and its proton conductivity and chemical stability at intermediate temperatures were investigated. In the composite, partial decomposition of (NH4)(2)SO4 Occurred at around 250 degrees C, and the resulting materials showed high proton conductivity. The highest conductivity achieved was 15 and 35 mS cm(-1) under dry and wet atmospheres at 250 degrees C, respectively. The temperature dependences of the conductivity were almost reversible in any conditions investigated, and the composite was relatively stable. Under a hydrogen atmosphere, however, the reduction of (NH4)(2)SO4 phase occurred and the formation of H2S was observed. (c) 2005 Elsevier B.V All rights reserved.