Three-dimensional hierarchical porous carbon foams for supercapacitors

摘要

A method of fabricating porous carbon foam includes mixing equal masses of SiO₂ particle dispersion with a chitosan solution, dropwise adding a glutaraldehyde aqueous solution into the mixture and solidifying it in air forming a room temperature hydrogel, lyophilizing the hydrogel to form a sponge-like SiO₂-embedded aerogel, carbonizing in a furnace the aerogel to form a SiO₂-embedded carbon foam, soaking the embedded carbon foam in NaOH to dissolve the SiO₂ particles to form a carbon foam having carbon sheets with sub-micron cavities, immersing the carbon sheets in de-ionized water to remove any NaOH residuals followed by drying, placing the carbon foam in KOH solution followed by drying, annealing in nitrogen atmosphere the dried carbon foam to synthesize a carbon foam with a multi-dimensional porous system, immersing the synthesized carbon foam in de-ionized water to prevent self-burning in air, and rinsing the carbon foam in HCl and water, then oven drying.