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Hierarchical porous carbon materials obtained by Cu–Al double hydroxide templates with high gravimetric and volumetric capacitance

The hard-template method belongs to an effective route for preparing porous carbon materials with ideal hierarchical pores. In this work, a kind of hierarchical porous carbon (HPC) with high gravimetric and volumetric capacitance is fabricated by the use of Al–Cu double hydroxides (Al–Cu DHs) as hard templates and polyethylene glycol-200 as carbon precursors. It is found that the Al/Cu molar ratio has a profound influence on the morphology and composition of Al–Cu DHs and the obtained hierarchical porous architecture of HPCs owing to the template and catalyst functions of both Cu and Al2O3. For Al/Cu molar ratios of 5:1 and 7:1, the prepared HPC-05 and HPC-07 display a large specific surface area and appropriate hierarchical porous architecture. They can be used as the electrode materials of supercapacitors without any activation. The HPC-05 exhibits gravimetric capacitance (296.9 F g−1) and high volumetric capacitance (183.3 F cm−3). Moreover, the capacitance retention is 105% in 1 M Na2SO4 electrolyte with an ultrahigh gravimetric energy density of 16.32 W h kg−1 and a volumetric energy density of 10.09 W h l−1. This paper provides a tunable double-hydroxide-template way to construct HPC materials with high gravimetric and volume capacitance.