The conductivity (sigma) of sulphosalicylic acid and its composites with iron(III) sulphosalicylate (1:4 molar) is measured using impedance spectroscopy and the Hebb-Wagner polarization method. The conductance is found to be purely protonic with typical values of sigma(25 degrees C) = 4.1 x 10(-4) and 3.0 x 10(-4) S cm(-1), respectively. The exchange currents at TiHx H+-solid electrolyte interphase boundaries increase with increasing partial pressure of H-2 in mixtures with argon.