LA-GEIS is inherently stationary at relatively high frequencies (> 1 Hz), since large concentration or resistance changes do not have time to accumulate, and no net capacity change occurs due to the measurement. DC measurements (e.g., chronopotentiometry) are inherently nonstationary: the cell voltage changes continuously during the measurement, due to the sloping OCV profile of LCO, as well as the resistance growth arising from concentration polarization of both the AM and electrolyte. However, stationary conditions for chronopotentiometry measurements can be easily approximated with a pseudo-steady-state extrapolation (S3E) approach . This is because DC measurements allow rapid data acquisition times (e.g., < 1 ms), so large amount of voltage versus capacity data can be collected before the resistance growth becomes severe, even at extreme current densities. A simple linear extrapolation of the voltage versus capacity data to a capacity of zero can give a remarkably accurate approximation of steady-state conditions (Fig. ).