Graphene Nanoplatelets with Selectively Functionalized Edges as Electrode Material for Electrochemical Energy Storage

Abstract

In recent years, graphene-based materials have been in the forefront as electrode material for electrochemical energy generation and storage. Despite this prevalent interest, synthesis procedures have not attained three important efficiency requirements, that is, cost, energy, and eco-friendliness. In this regard, in the present work, graphene nanoplatelets with selectively functionalized edges (XGnPs) are prepared through a simple, eco-friendly and efficient method, which involves ball milling of graphite in the presence of hydrogen (H2), bromine (Br2), and iodine (I2). The resultant HGnP, BrGnP, and IGnP reveal significant exfoliation of graphite layers, as evidenced by high BET surface area of 414, 595, and 772 m(2) g(-1), respectively, in addition to incorporation of H, Br, and I along with other oxygen-containing functional groups at the graphitic edges. The BrGnP and IGnP are also found to contain 4.12 and 2.20 at % of Br and I, respectively in the graphene framework. When tested as supercapacitor electrode, all XGnPs show excellent electrochemical performance in terms of specific capacitance and durability at high current density and long-term operation. Among XGnPs, IGnP delivers superior performance of 172 F g(-1) at 1 A g(-1) compared with 150 F g(-1) for BrGnP and 75 F g(-1) for HGnP because the large surface area and high surface functionality in the IGnP give rise to the outstanding capacitive performance. Moreover, all XGnPs show excellent retention of capacitance at high current density of 10 A g(-1) and for long-term operation up to 1000 charge-discharge cycles.

FACILE FUNCTIONALIZATION OF sp2 CARBON ALLOTROPES WITH A BIOBASED JANUS MOLECULE

“…Functionalization of graphene layers is a hot research topic. [31][32][33][34][35][36][37] The use of exfoliated graphene oxide platelets allowed stable and fine dispersions in natural rubber (NR) latex and interconnected graphene networks in the nano-composites. 38,39 Relevant efforts have been dedicated to the functionalization of carbon black, both in the academic and industrial worlds.…”

Facile and sustainable functionalization of graphene layers with pyrrole compounds

“…The polymeric nature of graphene layer with the six atoms aromatic ring as the repeating unit is responsible for such exceptional properties. Hence, main objectives of graphene synthesis [8][9][10][11][12] and functionalization [8,[13][14][15][16][17][18][19][20][21][22][23] are to obtain and preserve such structure.…”

Chlorine-doped reduced graphene oxide nanosheets as an efficient and stable electrode for supercapacitor in acidic medium

“…Carbon based materials have received much attention in recent years due to their unique structural stability, polarizability, excellent electrical conductivity, high surface area, low cost and versatile forms of existence such as fibers, powders, sheets, tubes and etc [12,13] .…”

“…Although, as a result of ingesting expensive precursor, energy and time, development of simple low-cost approaches for synthesis of graphene-based materials is still a foremost challenge in research area . According to these parameters, eco-friendly or environmental benignity and facile synthesis process, graphene and graphene derivatives have studied as excellent materials for supercapacitor [12,17].…”

“…However, the agglomeration due to intensive p-p interaction is dramatically reduces the surface area, resulting in a lower capacitance [23]. Yu et.al [12] have reported the synthesis of X-doped graphene (X= I, Br, ) through a method, which involves ball milling of graphite in the presence of hydrogen (H 2 ), bromine (Br 2 ) and iodine (I 2 ) and tested as supercapacitor electrode. All the X-doped graphene show excellent electrochemical performance in terms of specific and long term stability.…”