Thin-film intercalating electrodes provide the simplest configuration and a robust approach to study the solid-state diffusion phenomena . In this work, we have combined the thin-film configuration with the next-generation cobalt-free LNMO cathode material to revisit solid-state diffusion impedance, a long-lasting puzzle of LIBs. Thin-film LNMO electrodes were prepared and comprehensively characterized by various surface and electrochemical techniques. The basic electrochemical characteristics of the electrode are presented in the CV and the galvanostatic cycling results shown in Supplementary Materials (Figure ). More comprehensive discussion of these results have been reported in our previous work . In this work, we focus mainly on its EIS data, particularly on the diffusion impedance at the low frequency range.