Indexed on: 02 Jun '18Published on: 02 Jun '18Published in: ACS Applied Materials & Interfaces
Supercapacitors combine the advantages of electrochemical storage technologies like high energy density batteries and high power density capacitors. At 5-10 Wh Kg-1,1 the energy densities of current supercapacitors are still significantly lower than energy densities of lead acid (20-35 Wh Kg-1),1-2 Ni-metal hydride (40-100 Wh Kg-1)1 and Li-ion (120-170 Wh Kg-1)3 batteries. Recently, graphene based supercapacitors have shown energy density of 40-80 Wh/kg.1 However, their performance is mainly limited due to the reversible agglomeration and restacking of individual graphene layers caused by π-π interactions. The restacking of graphene layers leads to significant decrease of ion-accessible surface area and the low capacitance of graphene based supercapacitors. Here, we introduce a microstructure substrate based method to produce fully delaminated and stable interconnected graphene structure using flash reduction of GO in a few seconds. With this structure, we achieve the highest amount of volumetric capacitance obtained so far by any type of pure carbon based material. The affordable and scalable production method is capable of producing electrodes with energy density of 0.37 Wh cm-3 and power density of 416.6 W cm-3. This electrode maintained more than 91 % of its initial capacitance after 5000 cycles. Moreover, combining with ionic liquid, this solvent free graphene electrode material is highly promising for on-chip electronics, micro supercapacitors as well as high power applications.