Large area few-layer graphene with scalable preparation from waste biomass for high-performance supercapacitor

Carbonaceous materials with high surface area and a sheet-like structure promote fast ion-transport kinetics, making them an ideal choice to be used in supercapacitors. Few-layer graphene (FLG)-like nanosheets with abundance of micro as well as mesopores are achieved via mechanical exfoliation method from an agricultural waste biomass: peanut shell (PS). A well-known elementary method of probe-sonication, for the achievement of FLG sheets from renewable sources, is introduced in this study for the very first time. The Peanut shell-derived FLG (PS-FLG) possesses remarkably high specific surface area (2070 m(2) g(−1)) with a sufficiently large pore volume of 1.33 cm(3) g(−1). For the fabrication of a binder-free supercapacitor, the PS-FLG-based electrodes exhibited a high specific capacity of 186 F g(−1) without the use of any binder in 1 M H(2)SO(4) as supporting electrolyte. The highest energy density of 58.125 W h Kg(−1) and highest power density of 37.5 W Kg(−1) was achieved by the material. Surprisingly, the working potential increased to 2.5 V in an organic electrolyte leading to an obvious increase in the energy density to 68 W h Kg(−1). Solid-state-supercapacitor was fabricated with this material for the possible use of low-cost, high energy promising energy storage device.