The experimental Nyquist plots for both formulations present mainly a typical electrical blocking behavior with a slope of 45° from the real axis and constant real impedance in the high-frequency and low-frequency regions, respectively (see Figure and). The Nyquist plots for the Si15% electrodes coincide between the pristine, calendered 10% electrodes. The Rion is slightly higher for the 20% electrode (see Figure ). In contrast, the Rion value for the electrode calendered at 30% is the highest, as observed for the Si8%/Gr83% formulation with 29% -30% porosities.