Exploring supercapacitance of solvothermally synthesized N-rGO sheet: role of N-doping and the insight mechanism

Yadav, A and Kumar, R and Sahoo, B (2021) Exploring supercapacitance of solvothermally synthesized N-rGO sheet: role of N-doping and the insight mechanism. In: Physical Chemistry Chemical Physics, 24 (2). pp. 1059-1071.

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Abstract

We demonstrate the method of achieving excellent supercapacitance in nitrogen-doped reduced graphene oxide (N-rGO) sheets by controlling the amount of N-content through the use of different ratios of GO and urea during solvothermal synthesis. Here, urea plays a dual role in reducing GO and simultaneously doping nitrogen into the GO flakes forming exfoliated N-rGO sheets. The nitrogen content in N-rGO samples rises with an increase in the amounts of urea and saturates at a value of ∼14% for the GO : urea ratios beyond 1 : 8. The obtained N-rGO sheets with ∼ 5% N-content (obtained for GO : urea ratio of 1 : 3) were demonstrated as excellent supercapacitor materials. Using a 3-electrode setup, the maximum specific capacitance obtained for this sample was 514 F g−1 at a current density of 0.5 A g−1 (mass normalized current). The insights into the origin of this excellent supercapacitive behavior are explained through our results on optimum N-content, the relative amount of different N-environments, defects/disorders, and the degree of reduction of GO. Importantly, a proper stacking of rGO sheets with moderate N-content (∼5–6%) and a moderate amount of defects is the key to achieve high specific-capacitance. Furthermore, our 2-electrode device demonstrates the excellence of our samples with a Csp of 237 F g−1, a power density of 225 W kg−1, and an energy density of 6.7 W h kg−1 at 0.5 A g−1, exhibiting a high cyclic constancy with high capacitive retention of ∼ 82% even after 8000 cycles. Hence, our work provides a way to control the properties of N-rGO in achieving excellent supercapacitive performance.

Item Type:	Journal Article
Publication:	Physical Chemistry Chemical Physics
Publisher:	Royal Society of Chemistry
Additional Information:	The copyright for this article belongs to the Owner Societies, Royal Society of Chemistry.
Keywords:	Capacitance; Defects; Doping (additives); Graphene; Metabolism, Dual role; N content; N-Doping; Nitrogen content; Nitrogen-doped; Oxide samples; Reduced graphene oxides; Solvothermal synthesis; Solvothermally; Synthesised, Urea
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	01 Jul 2022 06:25
Last Modified:	01 Jul 2022 06:25
URI:	https://eprints.iisc.ac.in/id/eprint/74069

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