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

Abstract

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 m2 g−1) with a sufficiently large pore volume of 1.33 cm3 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 H2SO4 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.

The synthesis and performance analysis of various biomass‐based carbon materials for electric double‐layer capacitors: A review

“…For example, by pre‐carbonization at 900°C and then activation, the prepared CAs have an SSA of 997 m 2 /g, while by pre‐carbonization at 500°C and then activation, the SSA of the prepared CAs is increased by 47% to 1468 m 2 /g . In addition, high temperature can promote the etching of activating agent, improving not only the graphitic degrees but also the SSA and pore structure of carbon materials as mentioned earlier …”

“…Besides, this process could also reduce the corrosion of equipment by strong alkali, which was of great significance to the activation process of biomass. Purkait et al synthesized a sheet‐like graphene with peanut shell using traditionally heating subsequent elementary method of probe‐sonication. They found the as‐prepared samples possessed remarkably high SSA (2070 m 2 /g), a sufficiently large pore volume of 1.33 cm 3 /g with abundance of micro as well as mesopores.…”

“…They found the as‐prepared samples possessed remarkably high SSA (2070 m 2 /g), a sufficiently large pore volume of 1.33 cm 3 /g with abundance of micro as well as mesopores. Porous carbon with abundant mesoporous and high surface‐to‐volume ratio facilitates both sufficient charge storage (high energy density) and fast charge transfer (high power density) . In other words, a certain amount of graphite structure in carbon materials is necessary for the high power and energy density in EDLCs.…”

“…Porous carbon with abundant mesoporous and high surface-to-volume ratio facilitates both sufficient charge storage (high energy density) and fast charge transfer (high power density). 81 In other words, a certain amount of graphite structure in carbon materials is necessary for the high power and energy density in EDLCs. The great increase of total pore volume would lead to the reduction of the density, which has an adverse effect on the volumetric performances as the electrode material for EDLCs.…”

Excellent Compatibility of the Gravimetric and Areal Capacitances of an Electric‐Double‐Layer Capacitor Configured with S‐Doped Activated Carbon

“…Most of the research so far focused on improving the gravimetric capacitance and ignored the areal capacitance. The areal capacitances of most EDLCs previously reported are low (<0.8 F cm −2 ) because of the limited loading mass (<4 mg cm −2 ) . The actual size of a EDLC depends on the areal capacitance.…”