Fig. 3. Investigations on the CO₂RR performance of the SC-BPMEA using catholyte thicknesses of 250, 125, 65, and 16 μm.

All the results are collected at 35 °C with a CO₂ flow rate of 10 sccm cm⁻² (normalized by the geometric area of the cathode), a catholyte of 0.5 M K₂SO₄, and an anolyte of 0.1 M KHCO₃. a The dependence of cell voltages on current density. b Distribution of voltage losses measured in the SC-BPMEA with 65 μm thick catholyte operating at 200 mA cm⁻² (cell voltage = 3.82 V). The breakdown of the voltage is explained in SI7 of the Supplementary Information. The dependence of the CO₂RR gas products FE on the current density for the SC-BPMEAs with the catholyte thickness of 250 (c), 125 (d), and 65 μm (e). The FE result for 16 μm is shown in Supplementary Fig. 12. The error bars represent the standard deviation of three measurements.