Enhanced high-current capacitive behavior of graphene/CoAl-layered double hydroxide composites as electrode material for supercapacitors

摘要

Graphene nanosheets (GNS)/CoAI-layered double hydroxide (CoAl-LDH) composite with a laminated structure is fabricated by a simple refluxing method. It is found that CoAl-LDH lamellar crystallites gradually self-assemble on the graphene oxide (GO) which is reduced to GNS during the refluxing procedure in the presence of urea. The GNS/CoAl-LDH composite has a higher specific surface area (23.4 m~2 g~(-1)) and superior electrochemical performance. As electrode material for supercapacitors, the composite shows a maximum specific capacitance of 711.5 Fg~(-1) at low current density of 1 Ag~(-1).and it remains 516.8Fg~(-1) when the current density increase to 10Ag~(-1). Furthermore, the capacitance keeps at least about 81% (compare with 64% for that of pure LDH) after 2000 cycles at 10Ag~(-1) indicating the composite has excellent high-current capacitive behavior.