Carbon Capture with High Mass Loading Supercapacitor Electrodes from Biomass Waste.

Supercapacitive Swing Adsorption (SSA) is a carbon capture technique that achieves selective, and reversible CO₂ adsorption through capacitive charge and discharge of activated carbon electrodes in aqueous electrolytes. We report SSA with garlic roots-derived activated carbon achieving a record adsorption capacity of 312 mmol/kg at a low energy consumption of 72 kJ/mol and high mass loadings (>30 mg/cm²) at 1 V. 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. Up to a voltage of 1.4 V there is only minor increase in energy consumption, and a sorption capacity of 524 mmol/kg at an energy consumption of 130 kJ/mol 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.