Structure and electrochemical performance of highly nanoporous carbons from benzoate–metal complexes by a template carbonization method for supercapacitor application

A series of highly nanoporous carbons have been prepared by converting benzoate–metal complexes, including zinc benzoate, magnesium benzoate and aluminium benzoate through a template carbonization process. The carbonization temperature plays a pivotal role in determining the carbon structures as well as the resultant electrochemical behaviors in supercapacitors. The carbon–Zn-900 sample derived from zinc benzoate complex has a high specific surface area (1466.4 m2 g–1), large pore volume (2.54 cm3 g–1) and hierarchical pore size distribution. It can also deliver a large specific capacitance of 314.1 F g−1 at a current density of 0.5 A g−1, together with a large energy density of 67.2 Wh kg−1 when measured in a three-electrode system using 6 mol L−1 KOH as electrolyte. Besides, the carbon–Zn-900 sample has been tested in a two-electrode system using [EMIm]BF4/AN as electrolyte at different operation temperatures of 25/50/80 °C.