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

Lim, Y.S. and Lai, Chin Wei and Hamid, Sharifah Bee Abd (2017) Porous 3D carbon decorated Fe3O4 nanocomposite electrode for highly symmetrical supercapacitor performance. RSC Advances, 7 (37). pp. 23030-23040. ISSN 2046-2069

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Official URL: http://dx.doi.org/10.1039/c7ra00572e

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.

Item Type: Article
Uncontrolled Keywords: Capacitance; Carbon; Carbonaceous adsorbents; Carbonization; Chemical activation; Electrodes; Electrolytes; Nanocomposites; Nanoparticles; Nanostructures; Shells (structures); Supercapacitor
Subjects: Q Science > QD Chemistry
Divisions: Nanotechnology & Catalysis Research Centre
Depositing User: Ms. Juhaida Abd Rahim
Date Deposited: 10 Aug 2017 08:02
Last Modified: 19 Oct 2018 04:06
URI: http://eprints.um.edu.my/id/eprint/17668

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