Charging voltage, double-layer capacitance

Increase of the electronic state density in the carbon pore walls with the voltage. Hahn et al. [52] have measured double-layer capacitance and electronic conductance of an activated carbon electrode in an aprotic electrolyte solution, 1 mol/dm3 (C2H5)4NBF4 in acetonitrile. Both quantities show a similar dependency on the electrode potential with distinct minima near the potential of zero charge. This correlation suggests that the capacitance, like the conductance, is governed substantially by the electronic properties of the solid, rather than by the ionic properties of the solution in the interface of the double layer. 

Progress in the accuracy of micromachined products by EMM started with the introduction of high-frequency ultrashort voltage pulses [8,9]. Thus, dissolution of metal is confined to the resolution of machining limited by the charging time constant, r = ps Ca h, of the double layer. Electrolyte resistance along with electrical double-layer capacitance constitutes an equivalent circuit as shown in Fig. 3.5. 

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