Fig. 3: DAE module performance at 25 °C unless specified.

a J–V curves for modules using various porous substrate with different pore sizes. b Effect of temperature and foam thickness on J-V performance. c The experimental steady state concentration of sulfuric acid at J = 15.0 mA cm⁻² (red) VS equilibrium concentration \({{{{{{\rm{C}}}}}}}_{{{{{{{\rm{H}}}}}}}_{2}{{{{{{\rm{SO}}}}}}}_{4}}^{\ast }\) (black) under different R.H. Error bars represent standard deviation, n = 3 independent replicates. The inset shows the effect of current density on steady state concentration under 80% R.H. where \({{{{{{\rm{C}}}}}}}_{{{{{{{\rm{H}}}}}}}_{2}{{{{{{\rm{SO}}}}}}}_{4}}^{\ast }\) = 26.8 wt% (red dashed line). d The effect of electrolyte concentration on J–V performance. e Example recording of cell voltage (black symbol), H₂SO₄ concentration (red symbol),\({{{{{{\rm{C}}}}}}}_{{{{{{{\rm{H}}}}}}}_{2}{{{{{{\rm{SO}}}}}}}_{4}}^{\ast }\) = 47.7 wt% (red dashed line), Faradaic efficiency (blue symbol) for DAE modules at constant current density of 15.0 mA cm⁻² for 288 h at 40% R.H. f Current density collected under different voltage for 288 h at 40% R.H. Figures 3c to 3f were operated with G1 sintered glass foam and 1.5 cm gap between the two electrodes. Source data are provided as a Source Data file.