During a pulse, lithium ion-electron pairs (de)intercalate into the solid active material or electrolyte bath, driven by a current or voltage hold. This large perturbation over short timescales offers signifcant insight into the electrochemical dynamics . Since ion diffusion timescales in the electrolyte and solid are much longer than the reaction timescales, the latter are most discernable immediately after the pulse is applied. Even at shorter timescales, double layer relaxation tends to dominate , so the experimental choice of measurement times must be tailored to avoid this effect.