High-Voltage Supercapacitive Swing Adsorption of Carbon Dioxide.

Supercapacitive swing adsorption (SSA) with garlic roots-derived activated carbon achieves a record adsorption capacity of 312 mmol kg-1 at a low energy consumption of 72 kJ mol-1 and high mass loadings (>30 mg cm-2 ) at 1.0 V for 85%N2 /15%CO2 mixtures. The activated carbons are inexpensively prepared in a one-step process using potassium carbonate, and air as activators. The adsorption capacity further increases with increasing voltage. At a voltage of 1.4 V, a sorption capacity of 524 mmol kg-1 at an energy consumption of 130 kJ mol-1 can be achieved. The volumetric sorption capacity is also enhanced and reaches values of 85.7 mol m-3 at 1.0 V, and 126 mol m-3 at 1.4 V. Cycle stability for at least 130 h is demonstrated.