As shown in Equations 7, 16 and 19, to derive the diffusion coefficient, two measurements are required: dE/d√𝑡 during semi-infinite diffusion and the slope of OCP. Therefore, the following text will first compare the two values obtained by the GITT and ICI method. Then, the diffusion coefficients calculated from the two methods will be presented. The data acquired during the current pulses and the rest periods are analyzed by the GITT and ICI methods, respectively, as indicated in Figure . For the GITT, two data selection intervals, 5-40 and 50-150 s, were utilized because they contain the linear region of the E-√𝑡 plot above and below 3.7 V, respectively. An example of each case is plotted in Figure . For the ICI method, the interval was chosen to be 0.2-5 s for the same criteria applied on the data during the rest periods. ) from GITT and ICI, and the Warburg coefficients (σ) multiplied by O8/𝜋 from EIS fittings. This linear relationship of 𝑘 = 𝜎O8/𝜋 has been demonstrated in previous work. 9 Above 3.7 V, the k values determined by ICI and GITT with 5-40 s interval are close to each other, which confirms the theoretical derivation in section 2.2 and is corroborated by the EIS results. The GITT results collected from the 50-150 s interval show higher k values and two local maxima between 3.7 and 4.2 V while the k values from other three analyses fluctuate less and are more consistent with each other. This is expected from the data beyond the time scale of semi-infinite diffusion, as the surface concentration and thus the potential E then becomes linear with t, instead of √𝑡, (Equation ), leading to an overestimation of 𝑑𝐸 𝑑√𝑡 ⁄ .