By using a set of advanced techniques such as the broad band dielectric spectroscopy, X-Ray and FIB-SEM computed tomography, it will be described which factor(s) (material properties, engineering parameters) mainly influence the rate discharging behavior of NMC- or LFP-based composite electrodes. This fundamental understanding will be rationalized to disclose ultra-high surface capacities electrodes (more than 10 mAh / cm²) with reasonable rate performance.