Protonic conductivity of novel composite superionic conductors

The compound of composition Ti(H2L)4·10H3L·6H2O (H3L=H3[(COO)OC6H3(SO3)]) is synthesized. Its conductivity measured using impedance spectroscopy is amounts to 4.8×10−5 S cm−1 at 25°C. The electronic conductivity is negligibly small, so the transfer number of proton (tH+) is close to 1. This compound (named ‘Ti-composite’) is stable in a humid atmosphere up to 90% relative humidity. In the humidity range from 30 to 80% its conductivity increases linearly, but at higher values of humidity (>90%) the conductivity grows sharply. An exchange current (io) of the TiHx/Ti-composite interface describing the speed of the reaction 2H++2e−⇔H2, is 17 μA cm−2 at 25°C.