LAUSR

Abstract This work highlights, for the first time, the important impact of charge redistribution (CR) on the results of galvanostatic charge/discharge (GCD) experiments, as demonstrated with pseudocapacitive manganese oxide films and a transmission line circuit. CR causes the GCD protocol (single- vs. multiple-currents) and electrode history to significantly influence the profile shape and associated figures of merit. Systems that have undergone previous GCD cycling display much shorter charging profiles as CR has already somewhat charged the bulk material in the previous cycles. CR in early GCD cycles can also introduce curvature in the GCD profile. Because of these CR effects, we calculate a full range of the typical GCD-derived figures of merit (capacitance, capacity, energy, coulombic- and energy-efficiencies and Ragone plots) to identify those most strongly impacted by CR and those which are impervious. Generally, the charging data show significant CR-induced variations; the discharging profiles are relatively unaffected by CR. With multiple cycles, the data from the different experimental protocols coalesce. Clearly, researchers must consider CR when designing GCD protocols and evaluating data. Additionally, literature comparisons between GCD data are not possible without an exact description of the experimental protocol and cycle number used to calculate the figures of merit.