As shown here in Fig. , and in previous gas-diffusion layer modelling work, we can see however that the maximum current densities are much higher in the case of a gas-diffusion layer as a result of the reduced CO2 diffusion distance; here all electrolytes are capable of sustaining current densities over the proposed 200 mA/cm 2 minimum. This agrees well with experimental literature where current densities substantially higher than 200 mA/cm 2 have been reported, including the first report using gas-diffusion layers for CO2 reduction from Cook et al. in 1990. In recent work by Dinh et al., for example, current densities of 1 A/cm 2 were reached in 1 M KOH at 1 atm with an overall CO2 reduction selectivity over 90%. While these current densities might not be desired economically due to the corresponding increase in cell potential required, it indicates that substantial CO2 reduction reaction rates are possible even if the CO2 partial pressure is reduced. This is important for future largescale devices (>100 cm 2 catalyst areas) where CO2 partial pressure will decrease as it is converted in the device. It is also worth noting that the proposed 200 mA/cm 2 minimum current density is defined primarily for two-electron reduction products. For multi-carbon products requiring more electrons per CO2 molecule converted, this current density limit must be higher to have the same molecular yield per unit area.