Fig. 4: The electrochemical performance of overall water splitting in an electric-field-assisted AEM cell.

a The schematic illustration of the external electric field enhanced anion exchange membrane cell with 1 M KOH electrolyte flow. The commercial Pt/C (20 wt%) was used as the cathode and the MnO₂ nanowire was the anode. The gate voltage V₂ was applied on the Ti plate (pre-oxidised), with a fluid channel and an oxide layer on the surface to eliminate the leakage current. The cell voltage V₁ was applied to the cathode and anode to drive the water splitting. b The polarisation curves of overall water splitting under different gate voltages. c The plot of chronoamperometry response of electric-field-enhanced AEM cell under different gate voltages (V₂). The cell voltage was set at a constant voltage (V₁ = 2 V). d The bar charts of power density of electrolyser under different gate voltages, the corresponding power of gate consumption and the net increase of power density. The data are from Fig. 4c and Supplementary Fig. 24. The power density is divided by the membrane area. e The plot of long-term cell voltage at constant current density of 100 mA/cm² with 30 V gate voltage.