Easy synthesis of porous graphene nanosheets and their use in supercapacitors

We report the easy synthesis of porous graphene nanosheets (PGNs) using the etching of graphene sheets by MnO2. An electrode made from PGNs exhibits a specific capacitance of 154Fg−1 at 500mVs−1 in 6M KOH compared to a value of 67Fg−1 for graphene nanosheets, and a low capacitance loss of 12% after 5000cycles. Interestingly, PGN electrode material shows an excellent rate capability due to its open layered and mesopore structures that facilitate the efficient access of electrolytes to the electrode material and shorten the ion diffusion pathway through the porous sheets. This approach offers the potential for cost-effective, environmentally friendly and large-scale production of PGNs.