Surface and Diffusion Charge Contribution Studies of Human Hair-Derived Heteroatom-Doped Porous Carbon Electrodes for Supercapacitors

Abstract

Owing to the high specific surface area and adjustable pore size distribution, biowaste-derived activated carbon (AC) has lately aroused the interest of researchers in supercapacitor applications. Herein, we employ human hair-derived heteroatomdoped porous AC for supercapacitor applications. Electrochemical assessment of the as-synthesized material is examined in three distinct electrolytes, viz., basic (6 M KOH), neutral (1 M Na 2 SO 4 ), and acidic (1 M H 2 SO 4 ), and shows superior performance in 1 M H 2 SO 4 implying its perfect compatibility in an acidic electrolyte. This finding is corroborated via surface and diffusion charge contribution analysis of the AC sample in different electrolytes. Comparing with 6 M KOH (37.5%) and 1 M Na 2 SO 4 (67.5%), superior diffusion charge contribution is observed in the case of 1 M H 2 SO 4 (79%) electrolyte at 20 mV/s that helps to achieve the highest specific capacitance of 274.5 F/g at 1 A/g. Moreover, the as-fabricated all-solid-state symmetric supercapacitor device delivered a remarkable energy density of 47.4 W h/kg at a power output of 1642.8 W/kg, as well as a long cycle life of 87% after 10 000 charge/discharge cycles. As a consequence, this astonishing finding paves the way for the use of various biowastes for a variety of applications for energy storage.

Chemically Oxidized Carbon Paper as a Free‐Standing Electrode for Supercapacitor: An Insight into Surface and Diffusion Contribution

“…A combination of essentially two types of contributions, namely surface and diffusion contributions, determines a material‘s specific capacitance. The contribution from each of these activities to the specific capacitance may be determined because they each have a unique connection to the scan rate (v), which can be expressed in the form of equations (3) and 4: [45,46,47] $$$\vcenter{\openup.5em\halign{$\displaystyle{#}$\cr {\rm I}={\rm a}v{^{{\rm b}}}\hfill\cr}}$$$ $$$\vcenter{\openup.5em\halign{$\displaystyle{#}$\cr {\rm log}({\rm I})={\rm b}\ {\rm log}(v)+{\rm log}\ {\rm a}\hfill\cr}}$$$ …”

“…A combination of essentially two types of contributions, namely surface and diffusion contributions, determines a material's specific capacitance. The contribution from each of these activities to the specific capacitance may be determined because they each have a unique connection to the scan rate (v), which can be expressed in the form of equations ( 3) and ( 4): [45,46,47] I ¼ av b…”

Human Hair-Derived Porous Activated Carbon as an Efficient Matrix for Conductive Polypyrrole for Hybrid Supercapacitors

“…HHAC was synthesized using hydrothermal carbonization followed by the KOH activation route as per the protocol published elsewhere . For the preparation of the HHAC/PPy composite material, an in situ chemical oxidation polymerization strategy, was followed.…”

“…HHAC was synthesized using hydrothermal carbonization followed by the KOH activation route as per the protocol published elsewhere. 17 For the preparation of the HHAC/PPy composite material, an in situ chemical oxidation polymerization strategy, was followed. In brief, 50 mg of HHAC was dispersed in 50 mL of DI water, while in another beaker, 2.5 g of APS was dissolved in 50 mL of DI water.…”

Zeolitic Imidazole Framework Derived Cobalt Phosphide/Carbon Composite and Waste Paper Derived Porous Carbon for High‐Performance Supercapattery

“…Further, the CV scan is used to calculate the surface and diffusion charge contribution in the material based on the fact that current from the surface contribution varies directly proportional to the scan rate whereas the current from the diffusion varies with the square root of the scan rate. [32,33] For, Surface controlled current :…”