Facile synthesis of ternary graphene nanocomposites with doped metal oxide and conductive polymers as electrode materials for high performance supercapacitors

Saira Ishaq,Farah Kanwal,Mahmoud Moussa,Muhammad Saleem,Muhammad Ehsan,Truc Ngo Van,Dusan Losic

doi:10.1038/s41598-019-41939-y

Saira Ishaq, Farah Kanwal + Show 5 more

Open Access

https://doi.org/10.1038/s41598-019-41939-y

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Abstract

Supercapacitors (SCs) due to their high energy density, fast charge storage and energy transfer, long charge discharge curves and low costs are very attractive for designing new generation of energy storage devices. In this work we present a simple and scalable synthetic approach to engineer ternary composite as electrode material based on combination of graphene with doped metal oxides (iron oxide) and conductive polymer (polypyrrole) with aims to achieve supercapacitors with very high gravimetric and areal capacitances. In the first step a binary composite with graphene mixed with doped iron oxide (rGO/MeFe2O4) (Me = Mn, Ni) was synthesized using new single step process with NaOH acting as a coprecipitation and GO reducing agent. This rGO/MnFe2O4 composite electrode showed gravimetric capacitance of 147 Fg−1 and areal capacitance of 232 mFcm−2 at scan rate of 5 mVs−1. In the final step a conductive polypyrrole was included to prepare a ternary composite graphene/metal doped iron oxide/polypyrrole (rGO/MnFe2O4/Ppy) electrode. Ternary composite electrode showed significantly improved gravimetric capacitance and areal capacitance of 232 Fg−1 and 395 mFcm−2 respectively indicating synergistic impact of Ppy additives. The method is promising to fabricate advanced electrode materials for high performing supercapacitors combining graphene, doped iron oxide and conductive polymers.

Highlights

Energy consumption is continuously increasing throughout the world with 575 quadrillion British thermal units (BTU) in 2015 that is expected to rise up to 736 quadrillion BTU in 20401
Scalable and environmentally sustainable method for preparation ternary composite electrodes for supercapacitors applications consisting of reduced graphene oxide (rGO), mixed metal doped Iron oxide and conductive Ppy is presented
Compared with previous results this is the highest value among all synthesized rGO/MeFe2O4 electrodes reported in literature

Summary

Introduction

Energy consumption is continuously increasing throughout the world with 575 quadrillion British thermal units (BTU) in 2015 that is expected to rise up to 736 quadrillion BTU in 20401. Metal oxides and conducting polymers can deliver much higher energy densities through Faradic reactions with low cyclic stability and power density compared to EDL based supercapacitors. The first combination with of metal ferrites and graphene is demonstrated by Wang et al, who fabricated copper ferrite attached on graphene electrodes for supercapacitors showing an outstanding gravimetric capacitance 576.6 Fg−1 at current density of 1 Ag−1 measured by three electrodes system[20]. Biswas et al, synthesized graphene/polypyrrole composite material displaying gravimetric capacitance of 165 Fg−1 at current density of 1 Ag−1 measured by two electrodes system while using 1 M NaCl aqueous solution as electrolyte[23]. Parl et al, used graphite/polypyrrole composite for supercapacitor electrodes showing gravimetric capacitance of 400 Fg−1 measured by three electrodes system[24]

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