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CuO-based cathodes partially discharged using high-density current have been studied by analytical electron spectroscopies with the aim of elucidating the cell-discharge mechanism with particular reference to the formation of an LixCuO intercalation phase. The most interesting spectroscopic data of involved Cu species are reported and discussed. The disappearance of CuII at the cathode surface just at the beginning of the cell discharge and the formation of CuO and/or CuI were observed. The calculated modified Auger parameter values allowed characterization of CuI and CuO and distinction to be made between them when both were present. The presence of CuI has been rationalized on the base of an after-discharge solid-state reaction between electrochemically produced metallic copper and the underlying CuO. These results, together with the inhomogeneous depth profile of Li species concentration, seem to exclude the hypothesis of the formation of a genuine intercalation phase. At the same time an alternative explanation based on a ‘porous electrode’ model is suggested for the electroanalytical data reported by other authors and interpreted in terms of the formation of an intercalation phase.

Polybithiophene (pbT) thin films have been electrochemically deposited on n-TiO2 prepared by electrochemical oxidation of titanium. The rectifying behaviour of this novel inorganic semiconductor/conducting polymer interface is demonstrated by cyclic voltammetry experiments, interpreted in the framework of Gerischer's theory on ‘semiconductor/redox-electrolyte’ interfaces treated as Schottky barriers. Moreover, experimental evidence of a photovoltaic effect is given by a photoelectrochemical investigation carried out by illuminating the pbT layer with photons of appropriate frequency.