where C'(ω) is the real part of the capacitance, Z''(ω) the imaginary part of the impedance, ω the angular frequency (ω=2f, with f as the frequency), |Z(ω)| is the magnitude of the impedance, and m the electrode active mass. All the electrochemical measurements were performed through a multichannel potentiostat/galvanostat (VMP3, Biologic)