Graphene a promising electrode material for supercapacitors-A review (original) (raw)
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Advances in graphene-based supercapacitor electrodes
Energy Reports, 2020
Graphene-based materials are widely explored as the active electrode materials for energy storage and conversion devices, especially supercapacitors (SCs). Their high electrochemically active surface area, hierarchical porous structure, excellent compressibility, and high mechanical stability, as well as excellent conductivity, are the critical merits for providing robust and facilitative channels for charge transport. Various studies have explored many possible ways to utilize the maximum potential of graphene-based SC electrodes, and graphene research is booming, given its exceptional charge storage properties. This review focuses on the class-specific electrode materials for different types of SCs, followed by the classification and critical review of graphene-based electrodes reported in the past five years. The current challenges in the field have also been discussed with a focus on promising pathways for future research.
Strategies for Development of High-Performance Graphene-Based Supercapacitor
Current Graphene Science, 2020
The development of high-performance supercapacitors requires efforts in materials design and nanotechnology to provide more efficient electrodes with higher electrochemical window, capacitance, energy and power density. In terms of candidates for electrodes, the high surface area of graphene (2630 m2g-1) makes this carbon derivative a widely explored building block for supercapacitor electrodes. Herein, it is presented a review about the state-of-art in surface modification of graphene derivatives with the aim of avoiding restacking processes in nanosheets. It allows that Faradaic and non-Faradaic mechanisms can be synergically explored to reach not only superior results in power density but in energy density, a typical drawback in supercapacitors (by comparison with conventional batteries), introducing graphene-based supercapacitors as promising candidates for energy storage devices.
Batteries are misery in the design ofappliances and exertions. Substantial, incompetent and venomous, batteries are frequently the obligingissue in the design of appliances. Form factor is habituallyprejudiced by battery size and location. Nowadays, graphene can be used as a frivolous, supple supercapacitor to power equipment. Graphene materialize as a super substantial and as existence allied with several studies from translucentshielding coatings to electronics. With astonishingassets, itpotentials to transfigurenumerousparts and supercapacitorslooks to be one of them, because of its greatoutward area. In this paper, the methodologies to fabricate supercapacitor via graphene-Carbon nanotubes (CNT)-transition metal oxide has been discussed. The performance of the proposed model also has been investigated.
Electrochimica Acta, 2019
Graphene is considered to be a promising candidate as electrode materials for supercapacitor due to its unique structure and excellent electrochemical properties. Nevertheless, the extremely low bulk packing density of graphene hinders its application. Here, a novel strategy for preparing high density graphene flakes (HDGF) for high-performance supercapacitors is reported. HDGF is simply prepared by shredding thermally reduced graphene oxide film into small pieces. High packing density, as well as fast electron and ion transportation have been achieved simultaneously by breaking the continuity of graphene film, while keeping its dense structure. The as-prepared HDGF exhibits high gravimetric capacitance (237 F g-1) and volumetric capacitance (261 F cm-3) simultaneously, as well as excellent cycling stability with 98% of its initial capacitance after 10,000 cycles. Moreover, the symmetrical supercapacitor using HDGF as the electrode materials can obtain volumetric capacitances of up to 16 Wh L-1 at a power density of 88 W L-1 in the aqueous system. This strategy provides a new way to design high volumetric capacitance supercapacitors for energy storage applications in the future.
Graphene for batteries, supercapacitors and beyond
Since its discovery a decade ago, dozens of potential uses for graphene have been proposed, from faster computer chips and flexible touchscreens to hyper-efficient solar cells and desalination membranes. One exciting property that has sparked significant interest is its ability to store electrical charge. A single sheet of graphene sufficient in size to cover an entire American football field would weigh just a fraction of a gram. This huge surface area associated with this small amount of graphene can be squeezed inside an AA battery, enabling the design of new energy-storage devices with the ability to store massive amounts of charge. In this Review, we discuss the inherent properties of graphene and what it has to offer for energy storage. Much of the Review covers the synthesis and assembly of graphene into macrostructures that exploit the unique features of individual graphene sheets to build new materials for various applications. Particular attention is paid to the processing of graphene into electrodes, which is an essential step in the production of devices. Graphene can be useful by itself, but it is also promising — as we discuss — for composites with superior performance compared with existing materials. Currently, graphene is the most studied material for charge storage and the results from many laboratories confirm its potential to change today's energy-storage landscape. Specifically, graphene could present several new features for energy-storage devices, such as smaller capacitors, completely flexible and even rollable energy-storage devices, transparent batteries, and high-capacity and fast-charging devices. These and other features are explored in this Review. Despite notable progress, the future of graphene in the energy-storage market is uncertain because of several challenges. We discuss and propose solutions to these challenges and also briefly discuss the potential of other emerging 2D materials for energy-storage applications. Graphene for energy storage The fundamental properties of graphene make it promising for a multitude of applications. In particular, graphene has attracted great interest for supercapacitors because of its extraordinarily high surface area of up to 2,630 m 2 g −1. Recently, the intrinsic capacitance of single-layer graphene was reported to be ~21 μF cm −2 ; this value sets the upper limit for electric double-layer (EDL) capac-itance for all carbon-based materials 1. Thus, supercapac-itors based on graphene could, in principle, achieve an EDL capacitance as high as ~550 F g −1 if the entire surface area can be fully utilized. However, to understand the limits of graphene in supercapacitors, it is important to know the energy density of a fully packaged cell and not just the capacitance of the active material. In addition to the capacitance of graphene, the maximum energy density of graphene-based supercapacitors depends on several other parameters, such as the thickness and density of the graphene film and other cell components, including the current collector and the separator, the nature and density of the electrolyte, the operating voltage window of the cell and the packaging efficiency. As illustrated in FIG. 1, when using a standard current collector, separator and acetonitrile-based electrolyte, the two key parameters that control the energy density of graphene supercapacitors are the density of the graphene film and the voltage of the cell. For an electrochemical cell using 200-μm-thick graphene electrodes with a density of 1.5 g cm −3 and an operating voltage of 4 V, the maximum theoretical energy density is ~169 Wh kg −1 Abstract | Graphene has recently enabled the dramatic improvement of portable electronics and electric vehicles by providing better means for storing electricity. In this Review, we discuss the current status of graphene in energy storage and highlight ongoing research activities, with specific emphasis placed on the processing of graphene into electrodes, which is an essential step in the production of devices. We calculate the maximum energy density of graphene supercapacitors and outline ways for future improvements. We also discuss the synthesis and assembly of graphene into macrostructures, ranging from 0D quantum dots, 1D wires, 2D sheets and 3D frameworks, to potentially 4D self-folding materials that allow the design of batteries and supercapacitors with many new features that do not exist in current technology. NATURE REVIEWS | MATERIALS ADVANCE ONLINE PUBLICATION | 1 REVIEWS © 2 0 1 6 M a c m i l l a n P u b l i s h e r s L i m i t e d. A l l r i g h t s r e s e r v e d .
Nanoarchitectured graphene-based supercapacitors for next-generation energy-storage applications
Chemistry (Weinheim an der Bergstrasse, Germany), 2014
Tremendous development in the field of portable electronics and hybrid electric vehicles has led to urgent and increasing demand in the field of high-energy storage devices. In recent years, many research efforts have been made for the development of more efficient energy-storage devices such as supercapacitors, batteries, and fuel cells. In particular, supercapacitors have great potential to meet the demands of both high energy density and power density in many advanced technologies. For the last half decade, graphene has attracted intense research interest for electrical double-layer capacitor (EDLC) applications. The unique electronic, thermal, mechanical, and chemical characteristics of graphene, along with the intrinsic benefits of a carbon material, make it a promising candidate for supercapacitor applications. This Review focuses on recent research developments in graphene-based supercapacitors, including doped graphene, activated graphene, graphene/metal oxide composites, gr...
Graphene for supercapacitor applications anqiju
Graphene has attracted extensive interest in the field of supercapacitor research due to its 2D structure which grants it exceptional properties such as superior electrical conductivity and mechanical properties as well as an extensive surface area better than that of carbon nanotubes (CNTs). Furthermore, unlike other carbon materials, graphene is particularly optimal for supercapacitor applications as its surface area does not vary with pore size distribution and grants electrolyte access to both its surfaces. This article aims to review the advances in recent research and development of the use of graphene for supercapacitor use. The focus would mainly be on the areas of graphene synthesis, graphene modification, graphene-nanoporous carbon composites, graphene-polymer composites and graphenemetal oxides and their potential use in both asymmetric and symmetric supercapacitors. Lastly, the article aims to identify optimal testing methods for electrode performance and choice of electrolytes. It will then stress the increasing need to standardise electrode testing to ensure that test results are as relevant to real life applications as possible.
Crystals, 2020
In this research, a facile and cost-effective method of graphene synthesis by the modified carburization process and its applications for supercapacitor electrodes is reported. In this simple approach, carbon was diffused into nickel foam and naturally cooled to obtain carbon precipitation for the in situ growth of graphene by decarburization. Phase-structure and surface-morphology analysis revealed the presence of a highly reduced structure of the graphene layer. Furthermore, the large-intensity D, substantial G, and 2D bands in Raman spectra were attributed to disordered multilayer graphene. The three-electrode systems were used to measure electrochemical efficiency. The electrode sample exhibited enhanced current density of 0.6 A/g, electrode energy of 1.0008 Wh/kg, and power density of 180 W/kg, showing significant electrochemical performance for supercapacitor electrode applications.
Few layers Graphene nanosheets were synthesized by large quantity via modified Hummer's method chemical oxidation route involving graphite oxidation and thermal reduction. Few layer thermally reduced graphene were characterized by powder XRD crystalline materials. SEM and High resolution TEM (HR-TEM) observations show that graphene nanosheets were produced with sizes in the range of 20 to 30 nm. The order and disorder quality of graphene nanosheets were characterized by Raman spectroscopy. The electrochemical characterization was used in few layer TR-GNS for cyclic Voltammetry. The maximum specific capacitance (Csp) was observed 57 F/g at scan rate 50 mV/s. The large scale synthesis of few layer thermal reduction graphene was effective as using in increasing the gravimetric specific capacitance for the supercapacitor electrodes.