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 Na2SO4electrolyte with an ultrahigh gravimetric energy density of 16.32 W h kg-1and 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.