The stack capacitances of all tested stacks derived from CV and EIS are in good agreement with each other. At intermediate frequencies, Warburg diffusion resistances (Rdiff) are observed for the stacks having values of 0.19, 0.46, 1.23 and 1.29 Ω, respectively. In the high frequency region, the stacks exhibit small semi-circles. The charge-transfer resistance Rct calculated from the semicircles varies from 0.20 to 1.31 Ω, indicating the presence of some pseudocapacitive charge- transfer processes on the electrode surface. Contact resistance between interfaces within the stacks may also make a contribution to Rct. As expected, the solution, charge transfer and diffusion resistance tend to increase with the number of electrode pairs in the stack, with minor deviations. Rsol and Rdiff are somewhat larger than expected for the 8-cell stack, and Rct is somewhat smaller than expected for the 4-cell stack, for reasons not being clear. Overall, the EIS analysis confirms the expected, capacitive behavior of the stack. To determine the performance of the stacks for supercapacitive swing adsorption, they were charged and discharged at a constant current of 50 mA to the final voltage (2V, 4V, 8V, and 12V, respectively). A 10-minute potential holding step was added after 1V, and 0V were reached, respectively. The holding steps were added to allow the adsorption and desorption to complete. Concurrently, a continuous stream of 15%CO2/85% N2 was flown through the module. Figure shows the CO2 concentration changes (in blue) of the effluent gas, and the GCD voltage profiles (charging in red and discharging in black) as a function of time. Reversible adsorption was observed during the charging, and the subsequent potential holding step. Desorption of CO2 took place during the discharge process, and the subsequent potential holding step at 0V. For each cycle, the CO2 concentration first decreased to 12-13% during charging, and then returned to the original value (~15%) at the end of the 10 min holding step after charging. Upon discharge, the CO2 concentration increased to 17-18% due to desorption, and then returned to 15%. The CO2 concentration potentiostatic charging holding charging discharging holding discharging achievement of higher gas purity is currently prevented by the relatively slow gas adsorption rate. The elimination of this limitation will be subject to future research.