Freeze-drying assisted synthesis of hierarchical porous carbons for high-performance supercapacitors

A novel approach is reported to synthesize carbon foams with designable hierarchical porous structures for energy storage. The obtained carbons have an interconnected macroporous channel structure with narrow mesopores (3-5 nm in diameter) embedded throughout the carbon walls, providing low-resistance pathways for ion transportation to internal carbon surfaces. The obtained carbon electrodes can offer a capacitance up to 270 F g(-1) at a current density of 0.1 A g(-1) and especially an excellent high-rate performance with 222 F g(-1) as the current density increases to 10 A g(-1). Additionally, the electrodes exhibit a long cycling life at a high current density up to 10 A g(-1).