Electrochemical solid electrolyte sensors based on Yttria Stabilised Zirconia (YSZ) with mixed potential electrodes are suited for in-situ measurements of low concentrations of combustibles like hydrogen, carbon monoxide or hydrocarbons and also nitrogen oxides. The parameters sensitivity, selectivity and long-term stability of these sensors are correlated mainly with the performance of the electrode material. This work is directed on the investigation of newly developed conductive polymer composite materials (CPC) based on polyaniline (PANI). These materials have been characterised with respect to their morphology, thermal stability, catalytic activity and electrochemical behaviour on solid electrolytes in gases containing hydrogen, ethene and propene. For the first time it could be demonstrated, that CPC, consisting of PANI and different metal oxides or metal salts can be used at high temperature measurement up to temperatures of 450 degrees C because of improved thermal properties. (C) 2012 Elsevier B.V. All rights reserved.