Fabrication and enhanced supercapacitive performance of graphene/nano-carbide derived carbon composites

• Introduction of nano-CDC can effectively impede the stacking of graphene sheets.
• Graphene/nano-CDC composites own higher SSA and developed pore structure.
• Graphene/nano-CDC composites exhibit excellent supercapacitive performance.

Introducing carbon nanotube (CNT) or carbon black (CB) among graphene sheets has been demonstrated an effective strategy to impede the restacking of graphene sheets and eventually enhances the supercapacitive performance. However, due to their relatively low specific surface area (SSA) and undeveloped pores, the introduced CNT or CB itself has limited contribution to the electrochemical performance. To address the problem, we have synthesized a graphene/nanometer-sized carbide-derived carbon (graphene/nano-CDC) composite. Benefiting from the introduction of the porous nano-CDC, the graphene/nano-CDC composite behaves higher SSA and developed pore structure, and thus superior supercapacitive performance. The specific capacitance of the graphene/nano-CDC composite can reach 195 F g−1 at a scan rate of 5 mV s−1, a 179% increase compared with RGO (only 70 F g−1). Most interestingly, even at the scan rate of 5000 mV s−1, its cyclic voltammogram curves can still keep a relatively typical rectangle shape and the capacitance retention can maintain 67% (130 F g−1), approximately 5 times higher than those of the RGO (13%, 9 F g−1). In addition, the specific capacitance of the graphene/nano-CDC composite is quite stable over the entire cycle numbers, and has no significant degradation even after 10,000 cycles.