Supercapacitive Behavior of Two Glucose-Derived Microporous Carbons: Direct Pyrolysis versus Hydrothermal Carbonization

The physical and chemical characteristics of activated carbons produced from glucose and hydrothermally carbonized glucose are compared for the first time, as well as their performance as electrodes in supercapacitors with aqueous electrolyte (H2SO4). Both KOH-activated carbons exhibit similar textural properties, with Brunauer-Emmett-Teller surface areas of approximate to 1400-1500 m(2)g(-1) and a pore volume of approximate to 0.70 cm(3)g(-1), with the pore size distribution centered in the micropore range. When tested as supercapacitor electrodes, the activated carbon produced from hydrothermally carbonized glucose exhibits a superior rate capability, owing to lower equivalent distributed resistance (being able to work at an ultrahigh discharge current of 90 Ag-1), as well as higher specific capacitance (approximate to 240 Fg(-1) vs. approximate to 220 Fg(-1) for the glucose-derived activated carbon at 0.1 Ag-1). Both supercapacitors have excellent robustness, even for a large cell voltage of 1.2 V in 1m H2SO4.