Ultrahigh surface area biomass derived 3D hierarchical porous carbon nanosheet electrodes for high energy density supercapacitors

A simple one step activation method is used to achieve an ultra-high specific surface area of 2943 m(2) g(-1), and abundant pore volume of 1.83 cm(3) g(-1) with a rational micro/meso/macro pore size distributed activated carbon nanosheets from Prosopis Juliflora wood carbon waste blocks. A superior electrochemical performance has been achieved with a specific capacitance of 588 F g(-1) at 0.5 A g(-1) with an excellent stability (retention 92.5% after 6000 cycles) in 6 M KOH electrolyte for a three-electrode approach. The assembled symmetric supercapacitor device outperformed in a neutral aqueous electrolyte compared to an alkaline electrolyte, such as with a gravimetric capacitance of 403 and 426 F g(-1) and superior energy density of 32.9 W h kg(-1) (at 172.7 W kg(-1)) and 56.7 W h kg(-1) (at 248.8 W kg(-1)), and a large electrochemical window of 0-1.4 V in 6 M KOH and 0-2 V in 1 M Na2SO4 electrolyte, respectively. The electrochemical performance has been enhanced by the degree of graphitization, surface functional groups, surface area and pore structure/volume. This work provides a trustworthy approach to produce higher energy density devices from renewable biomass carbon wastes for various energy storage applications. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

An ultra-high specific surface area and abundant pore volume activated carbon nanosheets were prepared from Prosopis Juliflora wood carbon waste blocks, showing excellent electrochemical performance and superior energy density for energy storage applications. The enhancement of electrochemical performance is attributed to graphitization, surface functional groups, surface area, and pore structure/volume.