The effect of the SEI layer on the electrochemical impedance in the graphite/ Li[Ni0.5Mn0.3Co0.2]O2 lithium-ion full cells

•The additive effects on the middle-frequency semi-circle (charge transfer resistance).•The growth of inner and outer SEI layers have different effects on resistance and Warburg.•The middle-frequency resistance grows more at low potentials.•The activation energy increases more in the initial cycles than in later cycles.•The charge transfer resistance may depend on the frequency factor in the Arrhenius equation.