Nitrogen-doped carbon nanosheets derived from GO for enhancement of supercapacitor performance

Graphene oxide (GO) is widely used in supercapacitors due to its high electrical conductivity, rich functional groups and large specific surface area. However, GO is susceptible to van der Waals forces, resulting in stacking between the sheets and affecting its properties. Herein, GO is modified with porous carbon layers (rGONS) derived from ionic liquid to inhibit stacking between the layers and to facilitate ion conduction. In this process, ionic liquid and tetraethyl orthosilicate are used as carbon precursor and pore-forming agent, respectively. The prepared rGONS has large specific surface area, abundant pores and high nitrogen doping content. When used as an electrode in a supercapacitor, compared with GO and nitrogen-doped GO, composite structure significantly improves the capacitance value in supercapacitor with specific capacitance of 199.5 F g-1 at the current density of 0.5 A g-1, and good cyclic stability of 94.4 %, indicating its good application prospect in electrochemical energy storage.