Electrochemical capacitors operating in aqueous electrolyte with volumetric characteristics improved by sustainable templating of electrode materials

Abstract Soft- and salt-templating methods have been combined to obtain highly microporous carbon materials with mesopores in the narrow pore size range. Phenolic resin was used as a carbon source, and rubidium and caesium chloride were used as salt-templates, giving a well-developed microporosity with a high specific surface area, whereas a sacrificial triblock polymer Pluronic F-127 (soft-template) induced the mesopores of essential importance for fast access of the electrode surface area for the electrolytic solution. The combination of a high specific surface area (up to 2556 m2 g−1) with a suitable pore size (0.77–0.88 nm) resulted in an excellent performance of the electrochemical capacitor. High specific energies of 16.7 Wh∙kg−1 at 300 W kg−1 of specific power have been achieved for a CsCl-T-based high-voltage (1.5 V) device with a 0.5 mol⋅L−1 Li2SO4 electrolytic solution. The improved rate handling was allowed to maintain 10 Wh⋅kg−1 of specific energy at 4 kW kg−1 of specific power. In contrast to the other carbons with well-developed porosities, the material density obtained allowed our device to reach competitive, remarkably higher volumetric characteristics.