Ohmic drop of Prussian-blue/graphite plus epoxy electrodes

Ohmic drop effects on the voltammogram shape of the Prussian-blue reversibl e arrow Everitt's salt system have been studied by considering the electroa ctive film model. As the uncompensated resistance varies: the experimental characteristic curve parameters also varies. A dependence of the voltammogr ams with the graphite proportion was found related with the ohmic drop due to the composite electrodes. The optimal graphite proportion to obtain a go od faradaic-to-charge current ratio was 62% in weight which coincides with the second percolation threshold. The ohmic overpotential, which relates th e ohmic drop with the electrochemical magnitudes, is also minimum at this p roportion. (C) 1999 Elsevier Science Ltd. All rights reserved.