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Stoeckli, Fritz

Nom
Stoeckli, Fritz
Affiliation principale
Fonction
Professeur.e émérite
Email
fritz.stoeckli@unine.ch
Identifiants
https://libra.unine.ch/handle/123456789/471

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  • Publication
    Accès libre
    Performance of mesoporous carbons derived from poly(vinyl alcohol) in electrochemical capacitors
    (2008)
    Fernández, J. A.
    ;
    Morishita, T.
    ;
    Toyoda, M.
    ;
    Inagaki, M.
    ;
    Stoeckli, Fritz 
    ;
    Centeno, Teresa A.
    The present work shows that mesoporous materials obtained by the carbonization of mixtures of poly(vinyl alcohol) with magnesium citrate are very promising candidates for electrodes in supercapacitors. Their high performance arises essentially from a double-layer mechanism through the extent of the total surface area and one obtains at low current density (1 mA cm−2) values as high as 180 F g−1 in aqueous 2 M H2SO4 electrolyte and around 100 F g−1 in 1 M (C2H5)4NBF4 in acetonitrile. Moreover, in most cases the specific capacitance is reduced only by 15% at 100 mA cm−2, as opposed to many other types of carbons which display much higher reductions.

    This study suggests that these novel carbons could be potentially more advantageous as electrodes in electrochemical capacitors than templated mesoporous carbons.
  • Publication
    Accès libre
    Correlation between capacitances of porous carbons in acidic and aprotic EDLC electrolytes
    (2007)
    Centeno, Teresa A.
    ;
    Hahn, M.
    ;
    Fernández, J. A.
    ;
    Kötz, R.
    ;
    Stoeckli, Fritz 
    A study based on a total of 41 nanoporous carbons shows that there exists a good correlation between the limiting gravimetric capacitances Co at low current densities j (1 mA cm −2 ) measured in aprotic (1 M (C2H5)4NBF4 in acetonitrile) and in acidic (2 M aqueous H2SO4) electrolytes. The comparison of the surface-related capacitances (F m −2 ) of well characterized samples with the amount of thermodesorbed CO suggests a strong contribution of CO generating surface groups to charge storage in the acidic electrolyte, but a negligible contribution in the aprotic medium. It also appears that the decrease of the capacitance with current density is similar in both electrolytes. This confirms that the average micropore width and the CO2 generating surface groups are the main factors which limit the ionic mobility in both electrolytes.