The root causes of the drop in capacity at high rates can be elucidated through examination of the voltage profiles at each rate (Figure ). At C/3, both charge and discharge profiles exhibited the expected dual plateaus, with minimal polarisation, and thus high capacity was achieved. As the rate was increased, an evolution toward a more sloped profile shape was observed, associated in part with heterogeneity in the LMFP cathode, while polarisation increase significantly. At 5 C and 10 C, it is clear from the slope at 2.5 V that the cells are not completely discharged upon reaching the lower cutoff, and therefore an arbitrary lower cutoff may have provided increased capacity. Also at higher rates, it is evident that a greater proportion of the charge cycle completed during the CV step (as opposed to the CC phase), suggested a significant impact of this step on observed capacity.