Two different charging protocols were applied on the same battery: 5C charge, 30 minutes rest, 3C charge, and 0.2C charge, 30 minutes rest and 3C charge, both followed by a 0.1C memory-erasing discharge, thus only differing in the charge rate during the writing step. Approximately 100 reflections, representing an equal amount of LiFePO4 crystallites, were tracked during the electrochemical protocol with the same methodology applied by van Hulzen . From hereon we refer to one crystallite as one Analyzing the microbeam results provides direct insights into the role of the active particle population in the kinetically induced memory effect under operando conditions. Specifically, under a 0.2C charge rate (writing step), a particle-by-particle lithiation mechanism is observed, with 39% of the particles being charged (full phase transition from LFP to FP) and 27% nucleating the lithium-poor phase without completing the charge (i.e., the coexistence of LFP and FP phases) while the rest remain uncharged (LFP phase). Subsequently, during the 3.0 reading step, the remaining particles (61%) are charged by the imposed current. In contrast, when subjected to a 5.0C rate during the writing step, a more concurrent phase transformation mechanism is observed. In this case, a lower fraction of particles (26%) achieve full charge during this step, while the majority (47%) enter the resting period partially charged, in a phase-separated state. The subsequent 3.0C current can then be sustained by a higher fraction of particles (74%) being either partially charged or uncharged. These findings, summarized graphically in Fig. , underscore the complex relationship between charging rates of the active particle population, shedding light on the dynamics of (de-)lithiation processes within the electrode.