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![Schematic sketches of the energy storage mechanism of supercapacitors. a Principle and structure of one-single-cell electron double layer capacitor (EDLC) or pseudocapacitor. b The schematic sketch of the formation of electron double layer (EDL) at the interface between solid electrode and liquid electrolyte. c The schematic sketch of pseudocapacitor electrode/electrolyte interface, which shows the formation of EDL and fast ion redox reaction. Reprinted with permission from Ref [37]. Copyright@Elsevier](publication/299594023/figure/fig1/AS:960333141266498@1605972671871/Schematic-sketches-of-the-energy-storage-mechanism-of-supercapacitors-a-Principle-and.gif)
Schematic sketches of the energy storage mechanism of supercapacitors. a Principle and structure of one-single-cell electron double layer capacitor (EDLC) or pseudocapacitor. b The schematic sketch of the formation of electron double layer (EDL) at the interface between solid electrode and liquid electrolyte. c The schematic sketch of pseudocapacitor electrode/electrolyte interface, which shows the formation of EDL and fast ion redox reaction. Reprinted with permission from Ref [37]. Copyright@Elsevier
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This review article investigates the hot topics by presenting the latest advances on graphene-based nanostructures for supercapacitors. In literature, many scientists have studied the nanomaterials and combination of conducting polymers in supercapacitor (SC) devices. The main aim of this review article is to present the higher capacitance, and hig...
Citations
... Supercapacitors can be classified into three groups based on their charge and discharge mechanisms [114]. Supercapacitors can be made from different materials based on Figure 3 shows an illustration of a region plot, which contrasts the overall performance of several energy storage technologies by graphing specific energy against specific power. ...
... Supercapacitors can be classified into three groups based on their charge and discharge mechanisms [114]. Supercapacitors can be made from different materials based on the type of energy storage required and the application of the capacitance range. ...
The rising demand for energy storage systems with high power density, rapid charge/ discharge capabilities, and long cycle life has pushed extensive research into advanced materials for supercapacitor applications. There are several materials under investigation, and among these materials, conductive polymer composites have emerged as promising candidates due to their unique combination of electrical conductivity, flexibility, and facile synthesis. This review provides a comprehensive analysis of recent advancements in the development and application of conductive polymer composites for supercapacitor applications. The review begins with an overview of the fundamental principles governing electrical conductivity mechanism, applications of conductive polymers and the specific requirements for materials employed for these devices. Subsequently, it delves into the properties of conductive polymers and the challenges associated with their implementation for supercapacitors, highlighting the limitations of pristine conductive polymers and the strategies employed to overcome these drawbacks through composite formation. In this review, conductive polymer composites and their applications on supercapacitors are explored, and their advantages and disadvantages are discussed. Finally, the electromechanical properties of each conductive polymer composite are elaborated.
... Supercapacitors can be classified into three groups based on their charge and discharge mechanisms [114]. Supercapacitors can be made from different materials based on Figure 3 shows an illustration of a region plot, which contrasts the overall performance of several energy storage technologies by graphing specific energy against specific power. ...
... Supercapacitors can be classified into three groups based on their charge and discharge mechanisms [114]. Supercapacitors can be made from different materials based on the type of energy storage required and the application of the capacitance range. ...
... Hybrid word in its name implies that it is a combination of EDLC and pseudocapacitive materials as shown in Fig. 3(c). EDLC electrode materials are activated carbon (AC), carbon nanotubes (CNT), graphene and pseudocapacitive electrode materials are conducting polymer [52] and metal-oxides. Hybrid supercapacitor is constructed by using conducting polymer as positive electrode known as anode and activated carbon as negative electrode known as cathode. ...
Energy storage plays crucial role to complete global and economical requirements of human beings. Supercapacitor act as promising candidate for energy storage applications due to its astonishing properties like - high power density, remarkable crystallinity, large porosity, elongated life-cycle, exceptional chemical & thermal stability, framework diversity and high specific surface area. The current review article embraces the history along with the difference of supercapacitors with fuel cells, capacitors, and batteries and detailed explanation of fabrication of supercapacitors i.e. proper selection of electrode and electrolyte material, separator and current collector. As a supercapacitor electrode material, several carbon-based materials, metal-oxides, and metal-organic frameworks have been briefly mentioned here. The current review article also discusses the supercapacitor components and various types of electrolytes. Electrochemical characterization techniques such as Cyclic Voltammetry (CV), Galvanostatic Charge Discharge (GCD) and Electrochemical Impedance Spectroscopy (EIS) are also briefly discussed here. Furthermore, this article outlines the current issues as well as potential solutions for upcoming time period.
... Hybrid word in its name implies that it is a combination of EDLC and pseudocapacitive materials as shown in Fig. 3(c). EDLC electrode materials are activated carbon (AC), carbon nanotubes (CNT), graphene and pseudocapacitive electrode materials are conducting polymer [52] and metal-oxides. Hybrid supercapacitor is constructed by using conducting polymer as positive electrode known as anode and activated carbon as negative electrode known as cathode. ...
In the present work, Zeolitic Imidazolate Framework-8 (ZIF-8) was prepared at room temperature using a simple solvothermal method. X-ray diffraction revealed the formation of a cubic phase with I − 43 m space group. Scanning Electron Microscopy and High Resolution Transmission Electron Microscopy analysis showed the hexagonal-type morphology of as prepared pure ZIF-8. Brunauer–Emmett–Teller analysis, confirmed the formation of a narrow mesopores having surface area (877 m2/g) and average pore diameter (1.16 nm). The prepared ZIF-8 as electrode material investigated in aqueous (i.e. 2 M LiOH, 6 M KOH, and 6 M NaOH) and redox additive electrolytes RAE1 and RAE2 (i.e. 0.35 M [K4(Fe (CN)6)].3H2O in 6 M NaOH and 0.17 M [K4(Fe (CN)6)].3H2O in 1 M Na2SO4) for electrochemical analysis. The fabricated pristine ZIF-8 shows battery-type redox behavior in the three-electrode system in presence of redox additive electrolyte (RAE) and ultrahigh specific capacity (637.5 C/g) is obtained in RAE1 at a current density of 10 A/g. Furthermore, this electrode could maintain about 75% of its initial capacitance at 20 A/g after 1500 repeated charge-discharge cycles. In addition, an asymmetric supercapacitor (ASSC) device was constructed with graphene nanoplatelets (GNPs) as a negative electrode and pure ZIF-8 as a positive electrode. In the presence of RAE1, the fabricated device offers a significant energy density E of 36.91 Wh/kg at a power density P of 4429.08 W/kg in a wide voltage window range (0.0–1.9 V). The ASSC device retains 87% of its capacitance after 3200 galvanostatic charge-discharge cycles. Moreover, two asymmetric devices are joined in series to light up red and green LEDs for a practical utility.
... Further increase of the storage capabilities, and possibly also improved handling of graphene, by forming composites with ICPs has been suggested; some examples have been presented in [76,[150][151][152][153][154][155][156]. Along with its composites, 3D-graphene has been highlighted in [157]; self-assembled 3D graphene macrostructures have been examined for supercapacitor application in [158]. ...
... Metal-organic frameworks (MOFs) and their composites have been considered as active masses in supercapacitor electrodes [239][240][241][242]; combined with ICPs, the obtained composites were examined for various electrochemical applications [243]. The poor electronic conductivity of MOFs was noticed as a major hindrance to their use in a supercapacitor electrode; forming composites [156,[244][245][246], including ICPs, is an obvious solution [77,242]. Only a few experimental observations focused on material science aspects were recorded. ...
Intrinsically conducting polymers ICPs can be combined with further electrochemically active materials into composites for use as active masses in supercapacitor electrodes. Typical examples are inspected with particular attention to the various roles played by the constituents of the composites and to conceivable synergistic effects. Stability of composite electrode materials, as an essential property for practical application, is addressed, taking into account the observed causes and effects of materials degradation.
... The charging of conducting polymers takes place all over the material, whereas only surface is involved for plain carbon electrodes. For the redox reaction, the ions from the electrolyte transfer into the polymer and out of it which results in an improved capacitance and also exhibits reduced cyclability [158]. Polyaniline (PANI) is one of the examples of this type of polymer which has undergone many studies. ...
For hybrid electric vehicles, supercapacitors are an attractive technology which, when used in conjunction with the batteries as a hybrid system, could solve the shortcomings of the battery. Supercapacitors would allow hybrid electric vehicles to achieve high efficiency and better power control. Supercapacitors possess very good power density. Besides this, their charge-discharge cycling stability and comparatively reasonable cost make them an incredible energy-storing device. The manufacturing strategy and the major parts like electrodes, current collector, binder, separator, and electrolyte define the performance of a supercapacitor. Among these, electrode materials play an important role when it comes to the performance of supercapacitors. They resolve the charge storage in the device and thus decide the capacitance. Porous carbon, conductive polymers, metal hydroxide, and metal oxides, which are some of the usual materials used for the electrodes in the supercapacitors, have some limits when it comes to energy density and stability. Major research in supercapacitors has focused on the design of stable, highly efficient electrodes with low cost. In this review, the most recent electrode materials used in supercapacitors are discussed. The challenges, current progress, and future development of supercapacitors are discussed as well. This study clearly shows that the performance of supercapacitors has increased considerably over the years and this has made them a promising alternative in the energy sector.
... Conducting polymers allow charging to take place throughout the material. Throughout the redox reaction, ions are exchanged between polymer backbone and electrolyte (Ates, 2016). Polyaniline is one of conducting polymers which has been tested as an electrode material for supercapacitors in combination with different materials like carbon nanotubes and graphene nanosheets. ...
Energy storage accompanied by high power density is an overshadowing issue of 21st century. In this regard supercapacitor promises a bright future as it can be charged and discharged less than 1 s. The potential applications of these supercapacitors are spread over all industries such as electric vehicles, braking systems and quick start/stop systems. This article reviews that necessity of supercapacitors, followed by fundamentals and classification. In addition, various potential materials are discussed for fabrication of electrodes. This study also sheds light on future prospects and applications of supercapacitor.
... Among these conductive polymers, carbazol-based polymers are often complementary parts of the active electrode material in capacitors. That is, when an electric field is applied ions are transfer in and out of the polymer backbone from the electrolyte over the course of the redox process [165]. This process occurs due to excellent attributes of hole transport, relatively high specific capacity, excellent atmospheric stability, in addition to their physical and electronic properties, such as surface morphology, thickness, electrical conductivity, internal resistance, and durability, which directly affect the performance of super capacitors [166]. ...
Polycarbazole and its derivatives have been extensively used for the last three decades, although the interest in these materials briefly decreased. However, the increasing demand for conductive polymers for several applications such as light emitting diodes (OLEDs), capacitators or memory devices, among others, has renewed the interest in carbazole-based materials. In this review, the synthetic routes used for the development of carbazole-based polymers have been summarized, reviewing the main synthetic methodologies, namely chemical and electrochemical polymerization. In addition, the applications reported in the last decade for carbazole derivatives are analysed. The emergence of flexible and wearable electronic devices as a part of the internet of the things could be an important driving force to renew the interest on carbazole-based materials, being conductive polymers capable to respond adequately to requirement of these devices.
... Briefly, hollow structures can provide the extra potential for compositional and structural modification to design a functional material for desired applications. Therefore, there has been a growing research interest towards the fabrication of carbonaceous hollow spheres for their applications in a fuel cell, capacitors, and lithium-ion batteries [9][10][11]. Apart from all the recent developments, we think that there is still a substantial space for enhancement in the production of "carbon precursors and carbon microspheres." ...
Herein, hollow nitrogen-doped carbon microspheres (HNCMs) have been synthesized with controlled shell thickness and high surface area by pyrolysis of polydopamine-coated polystyrene (PS@PDA) core-shell microspheres. A polystyrene (PS) core was removed from the core-shell structures by pyrolysis at 500 °C under N2 atmosphere. Charge transfers, redox transformations (caused by N–H/catechol groups of the polydopamine (PDA)), and pyrolysis (introduce the nitrogen atoms along with a high degree of graphitization) may be attributed to the increase in the electrochemical and electrocatalytic performances. Our resulting material exhibited the improved electrochemical behavior towards supercapacitors with the maximum specific capacitance of 261.6 F g−1 at a scan rate of 2 mV s−1. It also showed moderate electrocatalytic properties via a 4-electron pathway mechanism (with high onset potential of 0.919 V vs. RHE at 1600 rpm) during oxygen reduction reaction. Importantly, the synergistic effect of heat treatment and a suitable concentration of PDA enhance the electrochemical performances of HNCMs.
Graphical abstract
... These reactions are in addition to the EDLC, and can significantly increase the capacitance and energy density of the SC. The downside to using pseudocapacitance lies in the [30][31][32][33][34][35][36][37][38][39][40] fact that it introduces chemical reactions to the process, which means that the charge/discharge rate is slower, and the cyclability is lowered. This is because the rate of pseudocapacitance is restricted by chemical reaction kinetics, and there will be inevitable depletion of the electrolyte, as well as volume change. ...
... Unlike plain carbon electrodes, which only involve their surface, conducting polymer charging takes place throughout the bulk of the material. Ions transfer into and out of the polymer backbone from the electrolyte over the course of the redox process [36]. This process results in a combination of increased capacitance and lower cyclability as a result of the reactions taking place and changing the volume of the cell. ...
... Journal of EnergyStorage 20 (2018) [30][31][32][33][34][35][36][37][38][39][40] ...
Supercapacitors (SCs) have shown great promise as a possible solution to the increasing world demand for efficient energy storage. Two types of mechanisms for SCs exist (double-layer and pseudocapacitive), and each type utilizes a wide variety of materials. In this review, a detailed overview of the mechanisms employed by SCs is provided in the introduction, and many studies are compared in order to determine which materials produce electrodes with high capacitance and cyclability in SCs, and to summarize and gauge the state of such research. The types of materials looked at include graphene and graphene nanocomposites, activated carbons from renewable materials, conducting polymers, and transition metal dichalcogenides. Additionally, different methods of activation that are meant to increase specific capacitance are examined.
Among the dozens of materials found in the literature during this study, the ones that exhibited the highest specific capacitances are rGO/PANI (Reduced Graphene Oxide/Polyaniline), and PANI-NFS/GF (Polyaniline Nanofiber Sponge Filled Graphene Foam) demonstrated impressive performances. These materials all exceeded the current expectations of SCs by remarkable amounts, and more research into similar materials is highly encouraged.
As more fundamental studies carried out for understanding the mechanisms of SCs, energy density and specific capacitance values continue to improve. Production of SCs from renewable materials encourage optimism for environmentally friendly options soon becoming feasible for use on larger scales.
