Oriented and Interlinked Porous Carbon Nanosheets with an Extraordinary Capacitive Performance

Abstract

Highly porous carbon nanosheets that are oriented and interlinked are prepared by a one-step KOH activation of polymerized glucose spheres (pGSs) that are hydrothermally derived from glucose at 180 °C yet without carbonization. This is totally unexpected because a spherical microporous carbon is produced by a normally employed two-step process that includes a precarbonization and a successive KOH activation. In our one-step activation, the melt of potassium species directed the formation of oriented carbon nanosheets; the oxygen constituents in the pGSs are critical for the morphological evolution from sphere to sheet. The carbon nanosheets have a large surface area (2633 m2 g–1) and a high pore volume (1.86 cm3 g–1). The oriented structure and hierarchical porosity impose advantages for mass transfer and ion accommodation and give rise to an ultrahigh rate performance (184 F g–1 at 100 A g–1) of the carbon nanosheets in supercapacitors in comparison with the case of microporous carbon spheres (56 F g–1 at 100 A g–1).