Symmetric supercapacitors based on porous 3D interconnected carbon framework

• Three dimensional synthesis of graphene foam (GF) using CVD.
• Microwave treatment of GF with PVA to produce three dimensional hydrogel.
• KOH activation of the hydrogel to produce porous carbons.
• Symmetric supercapacitor based on the porous carbon exhibit good electrochemical performance.

The construction and design of novel porous carbons for electric double-layer capacitors (EDLCs) application to meet the increasing demand and supply of energy is eminent. This is important because the pore volume (PV)/micropore volume (MV) in the porous network architecture of the carbon is mostly responsible for the ion traps in energy storage. Three dimensional carbon materials based on graphene materials with relatively high specific surface area (SSA) represents a promising material candidate for EDLCs applications. In this work, we synthesized highly porous carbon from graphene foam (GF) and polyvinyl alcohol PVA as a sacrificial template, and investigate their performance as electrodes for EDLCs applications. The as-produced carbons present a fairly large surface area (502 m2 g−1), and a highly porous interconnected framework with mesopore walls and micropore texture which are suitable as electrode for energy storage. As electrode material in a symmetric configuration the activated graphene foam (AGF) showed a specific capacitance of 65 F g−1, energy density of 12 Wh kg−1, power density of 0.4 kW kg−1, good rate performance and excellent long term stability in 1 M Na2SO4 aqueous with no capacitance loss after 3000 cycles.