Overall experiment and representative cycles from positive, negative, and switching cycling protocols on cell B2. Conducted with 1 M NaCl (aq) electrolyte, 15 mg electrodes, and 30 mA g -1 current density. Anomalous peaks presumed to be from short-term temperature changes. As opposed to cells A1 and A2, only the electrode not directly exposed to the gas was soaked with electrolyte (the gas-exposed electrode was wetted with a few drops of electrolyte). During the first part of the experiment, where the open circuit voltage was measured, initial pressure increases are observed as the cell thermalizes in the incubator oven. Subsequently, pressure decreases are observed due to chemical adsorption of CO 2 into the supercapacitor cell.