If λ is chosen too low, artificial peaks can be created, but if λ is chosen too high, merging of distinct peaks can mask individual processes resulting in a loss of information in the DRT transformation. This is demonstrated in Figures S3A, S3C for the choice of various regularization parameters λ. This is why the sum of square residuals (SSR) is used as an indicator of sufficiently low λ, when the residual between measured and DRT-reconstructed EIS data no longer decreases. In the present case, this leads to the selection of the λ value of 10 -3 . The procedure is demonstrated for an exemplary impedance spectrum, its DRT transformation, the comparison of measured and reconstructed EIS from DRT, and the related SSR for various regularization parameters in Fig. . The impact of different λ values on the resulting DRT curves, as well as the impact of a shape factor (0.38 chosen in this study), is further demonstrated in Fig. . Further, more detailed information on the choice of the regularization parameter has been the topic of previous works. Generally, the obtained DRT profiles obtain six to seven signals, each corresponding to individual processes in the electrochemical system occurring at different time scales (as indicated by the frequency). Based on the general assumptions about impedance analysis of electrochemical intercalation reactions, we first assign the DRT signals to certain subprocesses a priori and confirm this assignment subsequently by experimental modifications of the electrochemical system.