context: The Mg/Ti dual dopants also enhance the surface stability even upon deep electrochemical delithiation. Here we found that ex situ soft XAS surface analysis may provide misleading results if the charged electrodes are not handled properly. In principle, Ni should experience oxidation during charging and reduction during discharging. However, due to the cathode–electrolyte parasitic reaction, the surface nickel oxidation state at various charge/discharge states were lower than that of the bulk (Fig. S9†). Another phenomenon that we constantly observe is that the Ni oxidation states for the charged samples were lower than that at the pristine state in both the TEY and FY modes (Fig. S9†), which is counterintuitive. We believe that this might be due to the thermodynamically unstable Ni4+ continually reacting with the electrolyte during the cell teardown and subsequent sample handling. Thus, eliminating the cell resting time and removing the residual electrolyte are critical for maintaining the true Ni oxidation states for soft XAS analysis. We found that the best practice is to dissemble the cell and rinse the electrode immediately after the cell has reached the designated state of charge. This practice is particularly important for the charged electrodes. Here we rinsed the cycled electrode in an Ar filled glove box immediately after the cells were charged to 4.4 V vs. Li/Li+. The LiNiO2 delivered a higher charge capacity at this upper cutoff voltage than the Mg/Ti–LiNiO2 (Fig. S10†). If the surface was stable at the charged state, the Ni oxidation state at the surface should not exhibit significant difference in these two electrodes, because the charge capacity only differed by 22 mA h g−1 (i.e., the Ni oxidation state differed by 0.08). However, we found drastic differences between these electrodes, as explained below. The Ni L3-right/left peak ratios were averaged from three electrodes at the charged state. A significantly higher L3-right/left peak ratio in both FY and TEY modes was found in the Mg/Ti–LiNiO2 sample than that in the LiNiO2 sample (Fig. 4d), indicating enhanced surface stability of the Mg/Ti–LiNiO2 sample in the charged state. Moreover, the low L3-right/left peak ratio in the FY mode of the LiNiO2 electrodes also suggests that the surface reaction induced Ni reduction extended to the deep subsurface. The direct comparison between NMC622 and NMC811 (Fig. S11†) further supports that a higher nickel content results in more surface instability, which can potentially complicate the state of charge assessment using the surface sensitive soft XAS technique. As more studies have made use of the soft XAS technique for analyzing the surface chemistry of battery materials, our results clearly demonstrate that caution is needed when interpreting the data. Although the synchrotron characterization is not highly accessible, other surface-sensitive characterization methods, e.g., XPS, IR, Raman, TEM, ToF-SIMS, also encounter the similar challenges when preparing/handling samples. To improve the data representativeness, the effective error analysis, based on repeated measurements, is recommended.