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Jorge García-Cañadas

Publications and source records attributed to Jorge García-Cañadas.

3 recordsLinked to original sources
PubMed2006

Correlation between volume change and cell voltage variation with composition for lithium intercalated amorphous films.

Interactions between the intercalant and the host have been studied in homogeneous amorphous Li(x)WO3 prepared by electron beam evaporation, using electrochemical experiments with films of different thickness (100-400 nm). We have related the intercalation thermodynamics, described previously by us [Solid State Ionics 2005, 176, 1701] with other models that take into account film volume dilatation along the intercalation. A distinct behavior of cell voltage variation with composition and volume change is observed for the thinnest (100 nm) films: cell voltage follows ideal insertion thermodynamics and no deformation was detected using profilometry techniques. In contrast, thicker films exhibited both volume changes and, correspondingly, cell voltage departs from ideality due to contributions to the chemical potential arising from elastic distortions of the host matrix.

Letter↗
PubMed2004

Effects of the Gaussian energy dispersion on the statistics of polarons and bipolarons in conducting polymers.

We discuss the interpretation of usually broad oxidation peaks observed in electronically conducting polymers, in terms of the statistical distributions functions of polarons and bipolarons. The analysis is based on examining the chemical capacitance, that relates the change of concentration to a modification of the chemical potential of a given species, for different statistical models. We first review the standard models for single energy species that provide a nernstian dependence, and the limitations of these models are discussed. A new model that assumes a Gaussian distribution of energies related to molecular geometry fluctuations is suggested, and this model shows excellent agreement with the results of electrochemical oxidation of polypyrrole in quasiequilibrium conditions. From a fit of the data, it is found that the density of conjugated chain segments in polypyrrole, Ns approximately 10(21) cm(-3), shows a Gaussian distribution of half width sigma approximately 170 meV, tentatively attributed to bipolaron formation energies.

Journal Article↗