Protonic conductivity of novel composite superionic conductors

The compound of composition Ti(H2L)(4). 10H(3)L . 6H(2)O (H3L = H-3[(COO)OC 6H3(SO3)]) is synthesized. Its conductivity measured using impedance spectr oscopy is amounts to 4.8 x 10(-5) S cm(-1) at 25 degreesC. The electronic c onductivity is negligibly small, so the transfer number of proton (t(H)(+)) is close to 1. This compound (named 'Ti-composite') is stable in a humid a tmosphere up to 90% relative humidity. In the humidity range from 30 to 80% its conductivity increases linearly, but at higher Values of humidity (> 9 0%) the conductivity grows sharply. An exchange current (i(o)) of the TiHx/ Ti-composite interface describing the speed of the reaction 2H(+) + 2e(-) d ouble left right arrow H-2, is 17 muA cm(-2) at 25 degreesC. (C) 2000 Elsev ier Science B.V. All rights reserved.