Issue 34, 2019, Issue in Progress

Rapid microwave activation of waste palm into hierarchical porous carbons for supercapacitors using biochars from different carbonization temperatures as catalysts

Abstract

A rapid, simple and cost-effective approach to prepare hierarchical porous carbons (PCs) for supercapacitors is reported by microwave activation of abundant and low-cost waste palm, biochar (BC) and KOH. BCs from waste palm at different carbonization temperatures (300–700 °C), as catalysts and microwave receptors, were used here for the first time to facilitate the conversion of waste palm into hierarchical PCs. As a result, the high-graphitization PC obtained at a BC carbonization temperature of 300 °C (PC-300) possessed a high surface area (1755 m2 g−1), a high pore volume (0.942 cm3 g−1) and a moderate mesoporosity (37.79%). Besides their high-graphitization and hierarchical porous structure, the oxygen doping in PC-300 can also promote the rapid transport of electrolyte ions. The symmetric supercapacitor based on the PC-300 even in PVA/LiCl gel electrolyte exhibited a high specific capacitance of 164.8 F g−1 at a current density of 0.5 A g−1 and retained a specific capacitance of 121.3 F g−1 at 10 A g−1, demonstrating a superior rate capacity of 73.6%. Additionally, the PC-300 supercapacitor delivered a high energy density of 14.6 W h kg−1 at a power density of 398.9 W kg−1 and maintained an energy density of 10.8 W h kg−1 at a high power density of 8016.5 W kg−1, as well as an excellent cycling stability after 2000 cycles with a capacitance retention of 92.06%.

Graphical abstract: Rapid microwave activation of waste palm into hierarchical porous carbons for supercapacitors using biochars from different carbonization temperatures as catalysts

Supplementary files

Article information

Article type
Paper
Submitted
24 Apr 2019
Accepted
13 Jun 2019
First published
20 Jun 2019
This article is Open Access
Creative Commons BY license

RSC Adv., 2019,9, 19441-19449

Rapid microwave activation of waste palm into hierarchical porous carbons for supercapacitors using biochars from different carbonization temperatures as catalysts

C. Liu, W. Chen, M. Li, S. Hong, W. Li, M. Pan, Q. Wu and C. Mei, RSC Adv., 2019, 9, 19441 DOI: 10.1039/C9RA03031J

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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