Issue 37, 2017, Issue in Progress

Porous 3D carbon decorated Fe3O4 nanocomposite electrode for highly symmetrical supercapacitor performance

Abstract

In the present study, a hierarchical nanostructure of Fe3O4-porous hydrochar (p-Fe/HC) core shell nanocomposite was readily synthesized via a facile hydrothermal carbonization route followed by a KOH activation. In our new invention, hydrothermally formed core–shell nanoparticles underwent KOH activation to create micro- and mesopores forming porous hydrochar outer-shell on Fe3O4 nanoparticles core for improving capacitance performance. These porous structures eventually could act as potential electrolyte-accessible pathways which led to the contribution of pseudocapacitance connecting from the core (reaction at Fe3O4/electrolyte interface). Based on our electrochemical capacitive performance evaluation, p-Fe/HC nanocomposite electrode which comprised of 5 wt% Fe3O4 nanoparticles (±45 nm) could reach the specific capacitance of 259.3 F g−1 with a superior wide potential window of 1.8 V in 1 mol L−1 Na2SO4 aqueous electrolyte. By comparing KOH activation of pristine porous hydrochar and p-Fe/HC, an exceptionally high specific surface area (1712.8 m2 g−1) with bimodal type pores size distribution was observed. In addition, p-Fe/HC displayed a maximum energy density of 29.2 W h kg−1 at a power density of 1.2 kW kg−1, which is about 26% higher energy density than that of pristine porous hydrochar. In this manner, the synthesized porous hydrochar outer-shell could provide additional electrochemical stability to Fe3O4 core, preventing volume change at high current loading as well as conductive coating to enhance pseudocapacitance performance. Consequently, a symmetrical nanocomposite cell was successfully designed, with high capacitance retention of 95.1% after 5000 cycles.

Graphical abstract: Porous 3D carbon decorated Fe3O4 nanocomposite electrode for highly symmetrical supercapacitor performance

Supplementary files

Article information

Article type
Paper
Submitted
14 Jan 2017
Accepted
15 Apr 2017
First published
26 Apr 2017
This article is Open Access
Creative Commons BY license

RSC Adv., 2017,7, 23030-23040

Porous 3D carbon decorated Fe3O4 nanocomposite electrode for highly symmetrical supercapacitor performance

Y. S. Lim, C. W. Lai and S. B. Abd Hamid, RSC Adv., 2017, 7, 23030 DOI: 10.1039/C7RA00572E

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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