Issue 10, 2019

Free-standing supercapacitors from Kraft lignin nanofibers with remarkable volumetric energy density

Abstract

We have discovered a very simple method to address the challenge associated with the low volumetric energy density of free-standing carbon nanofiber electrodes for supercapacitors by electrospinning Kraft lignin in the presence of an oxidizing salt (NaNO3) and subsequent carbonization in a reducing atmosphere. The presence of the oxidative salt decreases the diameter of the resulting carbon nanofibers doubling their packing density from 0.51 to 1.03 mg cm−2 and hence doubling the volumetric energy density. At the same time, the oxidative NaNO3 salt eletrospun and carbonized together with lignin dissolved in NaOH acts as a template to increase the microporosity, thus contributing to a good gravimetric energy density. By simply adjusting the process parameters (amount of oxidizing/reducing agent), the gravimetric and volumetric energy density of the resulting lignin free-standing carbon nanofiber electrodes can be carefully tailored to fit specific power to energy demands. The areal capacitance increased from 147 mF cm−2 in the absence of NaNO3 to 350 mF cm−2 with NaNO3 translating into a volumetric energy density increase from 949 μW h cm−3 without NaNO3 to 2245 μW h cm−3 with NaNO3. Meanwhile, the gravimetric capacitance also increased from 151 F g−1 without to 192 F g−1 with NaNO3.

Graphical abstract: Free-standing supercapacitors from Kraft lignin nanofibers with remarkable volumetric energy density

Supplementary files

Article information

Article type
Edge Article
Submitted
05 nóv. 2018
Accepted
12 jan. 2019
First published
14 jan. 2019
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2019,10, 2980-2988

Free-standing supercapacitors from Kraft lignin nanofibers with remarkable volumetric energy density

P. Schlee, S. Herou, R. Jervis, P. R. Shearing, D. J. L. Brett, D. Baker, O. Hosseinaei, P. Tomani, M. M. Murshed, Y. Li, M. J. Mostazo-López, D. Cazorla-Amorós, A. B. Jorge Sobrido and M. Titirici, Chem. Sci., 2019, 10, 2980 DOI: 10.1039/C8SC04936J

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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