S3E-CP measurements from 5 -100 mA cm -2 show that the experimental data are fully consistent with the BV equation for a one-step reaction with α = 0.422 and I0 = 4.43 mA cm -2 . LA-GEIS measurements from 1 -10 mA cm -2 also fit the BV equation with α = 0.431 and I0 = 6.11 mA cm -2 , although the experimental data deviates from the BV model at high current densities due to the harmonic distortions. Surprisingly, there is a ~ √2 different in the experimentally measured magnitude of 𝑅 𝑐𝑡 0 , and therefore I0, between direct-current and EIS techniques. This appears to be a physical phenomenon arising from the root-mean-square averaging of the impedance data. Since O-GEIS measurements involve both a DC and EIS component, this empirical difference must be accounted for to obtain an accurate analysis. O-GEIS measurements from 5 -25 mA cm -2 show that the measured 𝑅 𝑐𝑡 ′ versus current data agree reasonably well with the BV equation for a onestep reaction with α = 0.460 and I0 = 5.79 mA cm -2 . However, a two-step BV model assuming α1 = 0.5 and α2 = 3 was shown to fit the data much more closely and allowed for deconvolution of the resistance for each reaction step based on the assumed α values. Overall, the S3E-CP, LA-GEIS, and O-GEIS measurements are all quantitatively consistent with a two-step charge-transfer reaction for LCO with transfer coefficients of α1 = 0.5 and α2 = 3. It is proposed that the reaction step with α = 3 could be attributed to Li + (de)solvation at the SEI/electrolyte interface, while the reaction step with α = 0.5 could plausibly be attributed to either electron-transfer or Li + conduction through the SEI, but not to both. To the best of our knowledge, there are no existing theories in the literature which would quantitatively predict an α value for the (de)solvation or SEI conduction reactions in LIBs.