Showing papers on "Supercapacitor published in 2019"

Applications of 2D MXenes in energy conversion and storage systems

Abstract: Transition metal carbides and nitrides (MXenes), a family of two-dimensional (2D) inorganic compounds, are materials composed of a few atomic layers of transition metal carbides, nitrides, or carbonitrides. Ti3C2, the first 2D layered MXene, was isolated in 2011. This material, which is a layered bulk material analogous to graphite, was derived from its 3D phase, Ti3AlC2 MAX. Since then, material scientists have either determined or predicted the stable phases of >200 different MXenes based on combinations of various transition metals such as Ti, Mo, V, Cr, and their alloys with C and N. Extensive experimental and theoretical studies have shown their exciting potential for energy conversion and electrochemical storage. To this end, we comprehensively summarize the current advances in MXene research. We begin by reviewing the structure types and morphologies and their fabrication routes. The review then discusses the mechanical, electrical, optical, and electrochemical properties of MXenes. The focus then turns to their exciting potential in energy storage and conversion. Energy storage applications include electrodes in rechargeable lithium- and sodium-ion batteries, lithium-sulfur batteries, and supercapacitors. In terms of energy conversion, photocatalytic fuel production, such as hydrogen evolution from water splitting, and carbon dioxide reduction are presented. The potential of MXenes for the photocatalytic degradation of organic pollutants in water, such as dye waste, is also addressed, along with their promise as catalysts for ammonium synthesis from nitrogen. Finally, their application potential is summarized.

Review of supercapacitors: Materials and devices

Abstract: Supercapacitors have gained a lot of attention due to their unique features like high power, long cycle life and environment-friendly nature. They act as a link for energy-power difference between a traditional capacitor (having high power) and fuel cells/batteries (having high energy storage). In this perspective, a worldwide research has been reported to address this and rapid progress has been achieved in the advancement of fundamental as well as the applied aspects of supercapacitors. Here, a concise description of technologies and working principles of different materials utilized for supercapacitors has been provided. The main focus has been on materials like carbon-based nanomaterials, metal oxides, conducting polymers and their nanocomposites along with some novel materials like metal-organic frameworks, MXenes, metal nitrides, covalent organic frameworks and black phosphorus. The performance of nanocomposites has been analysed by parameters like energy, capacitance, power, cyclic performance and rate capability. Some of the latest supercapacitors such as electrochromic supercapacitor, battery-supercapacitor hybrid device, electrochemical flow capacitor, alternating current line filtering capacitor, micro-supercapacitor, photo-supercapacitor, thermally chargeable supercapacitor, self-healing supercapacitor, piezoelectric and shape memory supercapacitor have also been discussed. This review covers the up-to-date progress achieved in novel materials for supercapacitor electrodes. The latest fabricated symmetric/asymmetric supercapacitors have also been reported.

A review on recent advances in hybrid supercapacitors: Design, fabrication and applications

Abstract: Hybrid supercapacitors with their improved performance in energy density without altering their power density have been in trend since recent years. The hybrid supercapacitor delivers higher specific capacitance in comparison to the existing electric double layer capacitor (EDLC) and pseudocapacitors. Generally, the asymmetric behavior of hybrid supercapacitors which is the combination of EDLC and pseudocapacitor acts as an enhancer in its respective capacitance values. This asymmetric approach marks a new beginning towards the much-needed pollution free, long lasting and proficient energy-storing performance. Corresponding to their utilization in hybrid electric vehicles and similar sort of power necessity based devices; the research in developing new advanced storage devices finds an enormous and vast future ahead. The most significant factor for the energy efficient applications demands a considerably higher ratio of surface to the volume by incorporation of new materials. This review article gives an overview of recent advances in the development of hybrid supercapacitors, storage mechanism, criteria of formation, components, different electrode and electrolyte materials, electrochemical profile assessment, design fabrication and their applications.

Biomass-derived porous carbon materials with different dimensions for supercapacitor electrodes: a review

Abstract: The exploration of renewable, cost-effective, and environmentally friendly electrode materials with high adsorption, fast ion/electron transport, and tunable surface chemistry is urgently needed for the development of next-generation biocompatible energy-storage devices. In recent years, biomass-derived carbon electrode materials for energy storage have attracted significant attention because of their widespread availability, renewable nature, and low cost. More importantly, their inherent uniform and precise biological structures can be utilized as templates for fabricating electrode materials with controlled and well-defined geometries. Meanwhile, the basic elements of biomass are carbon, sulfur, nitrogen, and phosphorus. The special naturally ordered hierarchical structures as well as abundant surface properties of biomass-derived carbon materials are compatible with electrochemical reaction processes such as ion transfer and diffusion. To date, a series of novel porous carbon materials with different dimensions have been prepared by various methods using biomass as the raw material, which is an important field in the fabrication of supercapacitor electrode materials. Herein, we summarized recently reported biomass-derived carbon materials with one-dimensional, two-dimensional, and three-dimensional structures and their applications as carbon-based electrode materials for supercapacitors. Finally, the current challenges and future perspectives of the carbon-based electrode materials with respect to the supercapacitor's performance were closely highlighted.

Current progress achieved in novel materials for supercapacitor electrodes: mini review

Abstract: Supercapacitors are highly attractive for a large number of emerging mobile devices for addressing energy storage and harvesting issues. This mini review presents a summary of recent developments in supercapacitor research and technology, including all kinds of supercapacitor design techniques using various electrode materials and production methods. It also covers the current progress achieved in novel materials for supercapacitor electrodes. The latest produced EDLC/hybrid/pseudo-supercapacitors have also been described. In particular, metal oxides, specifically ZnO, used as electrode materials are in focus here. Eventually, future developments, prospects, and challenges in supercapacitor research have been elaborated on.

Metal-organic framework-derived materials for electrochemical energy applications

Abstract: As emerging crystalline porous organic-inorganic hybrid materials, metal-organic frameworks (MOFs) have been widely used as sacrificial precursors for the synthesis of carbon materials, metal/metal compounds, and their composites with tunable and controllable nanostructures and chemical compositions for electrochemical energy applications. Herein, recent progress of MOF-derived nanomaterials for various electrochemical energy storage and conversion applications including Li-ion batteries, Li-S batteries, Na-ion batteries, supercapacitors, water splitting, and oxygen reduction reaction is reviewed. Structural and compositional design of MOF-derived nanomaterials is systematically summarized, which may hopefully offer inspirations and guidances for future development of MOF-derived nanomaterials for more efficient and more durable electrochemical energy applications.

Influences from solvents on charge storage in titanium carbide MXenes

Abstract: Pseudocapacitive energy storage in supercapacitor electrodes differs significantly from the electrical double-layer mechanism of porous carbon materials, which requires a change from conventional thinking when choosing appropriate electrolytes. Here we show how simply changing the solvent of an electrolyte system can drastically influence the pseudocapacitive charge storage of the two-dimensional titanium carbide, Ti3C2 (a representative member of the MXene family). Measurements of the charge stored by Ti3C2 in lithium-containing electrolytes with nitrile-, carbonate- and sulfoxide-based solvents show that the use of a carbonate solvent doubles the charge stored by Ti3C2 when compared with the other solvent systems. We find that the chemical nature of the electrolyte solvent has a profound effect on the arrangement of molecules/ions in Ti3C2, which correlates directly to the total charge being stored. Having nearly completely desolvated lithium ions in Ti3C2 for the carbonate-based electrolyte leads to high volumetric capacitance at high charge–discharge rates, demonstrating the importance of considering all aspects of an electrochemical system during development.

Metal oxide-based supercapacitors: progress and prospectives

Abstract: Distinguished by particular physical and chemical properties, metal oxide materials have been a focus of research and exploitation for applications in energy storage devices. Used as supercapacitor electrode materials, metal oxides have certified attractive performances for fabricating various supercapacitor devices in a broad voltage window. In comparison with single metal oxides, bimetallic oxide materials are highly desired for overcoming the constraint of the poor electric conductivity of single metal oxide materials, achieving a high capacitance and raising the energy density at this capacitor-level power. Herein, we investigate the principal elements affecting the properties of bimetallic oxide electrodes to reveal the relevant energy storage mechanisms. Thus, the influences of the chemical constitution, structural features, electroconductivity, oxygen vacancies and various electrolytes in the electrochemical behavior are discussed. Moreover, the progress, development and improvement of multifarious devices are emphasized systematically, covering from an asymmetric to hybrid configuration, and from aqueous to non-aqueous systems. Ultimately, some obstinate and unsettled issues are summarized as well as a prospective direction has been given on the future of metal oxide-based supercapacitors.

Construction of CoO/Co-Cu-S Hierarchical Tubular Heterostructures for Hybrid Supercapacitors.

Abstract: Hierarchical hollow structures for electrode materials of supercapacitors could enlarge the surface area, accelerate the transport of ions and electrons, and accommodate volume expansion during cycling. Besides, construction of heterostructures would enhance the internal electric fields to regulate the electronic structures. All these features of hierarchical hollow heterostructures are beneficial for promoting the electrochemical properties and stability of electrode materials for high-performance supercapacitors. Herein, CoO/Co-Cu-S hierarchical tubular heterostructures (HTHSs) composed of nanoneedles are prepared by an efficient multi-step approach. The optimized sample exhibits a high specific capacity of 320 mAh g-1 (2300 F g-1 ) at 2.0 A g-1 and outstanding cycling stability with 96.5 % of the initial capacity retained after 5000 cycles at 10 A g-1 . Moreover, an all-solid-state hybrid supercapacitor (HSC) constructed with the CoO/Co-Cu-S and actived carbon shows a stable and high energy density of 90.7 Wh kg-1 at a power density of 800 W kg-1 .

Boosting Zn-Ion Energy Storage Capability of Hierarchically Porous Carbon by Promoting Chemical Adsorption.

Abstract: The construction of advanced Zn-ion hybrid supercapacitors (ZHSCs) with high energy density is promising but still challenging, especially at high current densities. In this work, a high-energy and ultrastable aqueous ZHSC is demonstrated by introducing N dopants into a hierarchically porous carbon cathode for the purpose of enhancing its chemical adsorption of Zn ions. Experimental results and theoretical simulations reveal that N doping not only significantly facilitates the chemical adsorption process of Zn ions, but also greatly increases its conductivity, surface wettability, and active sites. Consequently, the as-fabricated aqueous ZHSC based on this N-doped porous carbon cathode displays an exceptionally high energy density of 107.3 Wh kg-1 at a high current density of 4.2 A g-1 , a superb power density of 24.9 kW kg-1 , and an ultralong-term lifespan (99.7% retention after 20 000 cycles), substantially superior to state-of-the-art ZHSCs. Particularly, such a cathode also leads to a quasi-solid-state device with satisfactory energy storage performance, delivering a remarkable energy density of 91.8 Wh kg-1 . The boosted energy storage strategy by tuning the chemical adsorption capability is also applicable to other carbon materials.

Ultrathin NiCo-MOF Nanosheets for High-Performance Supercapacitor Electrodes

Abstract: Metal–organic frameworks (MOFs) have attracted intensive attention for high-performance supercapacitors owing to their large specific surface area and tunable pore structure. Herein, ultrathin NiCo-MOF nanosheets are fabricated by a facile ultrasonication at room temperature and employed as a supercapacitor electrode material. The unique nanosheet-like structure of NiCo-MOF provides more electroactive sites and a shorter pathway for electron transfer and electrolyte diffusion, resulting in excellent electrochemical performance with a high specific capacitance of 1202.1 F g–1 at 1 A g–1. In addition, an asymmetric supercapacitor of NiCo-MOF//activated carbon was assembled in 2 M KOH electrolyte. It delivers an energy density of 49.4 W h kg–1 at a power density of 562.5 W h kg–1 in a voltage window of 1.5 V. The results demonstrate a new method to fabricate ultrathin MOF nanosheets for high-performance supercapacitor electrode materials.

Review of carbon-based electrode materials for supercapacitor energy storage

Abstract: In today’s nanoscale regime, energy storage is becoming the primary focus for majority of the world’s and scientific community power. Supercapacitor exhibiting high power density has emerged out as the most promising potential for facilitating the major developments in energy storage. In recent years, the advent of different organic and inorganic nanostructured materials like nano carbons, metal oxides, nanosheets of graphene, and conducting polymers has enabled high-performance-fabricated devices. A review of different carbon-based materials used in the fabrication of electrodes for electrochemical capacitors is presented in this paper. Along with materials used, a brief overview of different types of supercapacitors depending on charge storage mechanism is also been discussed. Materials summary including applications have been provided through the exhaustive analysis of the literature. Keeping nano-architecture electrodes in view, a summary of different technologies considering the integration of metal oxide into carbon nanofibers, carbon fiber papers, graphene/reduced graphene oxide, and SWCNTs/MWCNTS has been presented in this work. The specific capacitance in the range of 40–300 F/g had been reported in the literature for the EDLC (electric double-layer capacitors) supercapacitors. In contrast to this, carbon nanomaterials-based metal-oxides supercapacitors (CNMO-SC) have emerged as the new promising candidate which possess large specific capacitance (> 100 F/g), high energy density, and cost effectiveness. Hence, a review of certain types of carbon nanomaterials has also been reported here.

3D Printing of Freestanding MXene Architectures for Current-Collector-Free Supercapacitors.

Abstract: Additive manufacturing (AM) technologies appear as a paradigm for scalable manufacture of electrochemical energy storage (EES) devices, where complex 3D architectures are typically required but are hard to achieve using conventional techniques. The combination of these technologies and innovative material formulations that maximize surface area accessibility and ion transport within electrodes while minimizing space are of growing interest. Herein, aqueous inks composed of atomically thin (1-3 nm) 2D Ti3 C2 Tx with large lateral size of about 8 µm possessing ideal viscoelastic properties are formulated for extrusion-based 3D printing of freestanding, high specific surface area architectures to determine the viability of manufacturing energy storage devices. The 3D-printed device achieves a high areal capacitance of 2.1 F cm-2 at 1.7 mA cm-2 and a gravimetric capacitance of 242.5 F g-1 at 0.2 A g-1 with a retention of above 90% capacitance for 10 000 cycles. It also exhibits a high energy density of 0.0244 mWh cm-2 and a power density of 0.64 mW cm-2 at 4.3 mA cm-2 . It is anticipated that the sustainable printing and design approach developed in this work can be applied to fabricate high-performance bespoke multiscale and multidimensional architectures of functional and structural materials for integrated devices in various applications.

Multivalent metal ion hybrid capacitors: a review with a focus on zinc-ion hybrid capacitors

Abstract: Multivalent metal ion hybrid capacitors have been developed as novel electrochemical energy storage systems in recent years. They combine the advantages of multivalent metal ion batteries (e.g., zinc-ion batteries, magnesium-ion batteries, and aluminum-ion batteries) with those of supercapacitors, and are characterized by good rate capability, high energy density, high power output and ultralong cycle life. Herein, after a brief introduction to supercapacitors and multivalent metal ion batteries, we reviewed the recent progress in research on multivalent metal ion hybrid capacitors, with a focus on zinc-ion hybrid capacitors, from the perspectives of design concept, configuration, electrochemical behavior and energy storage mechanism. An outlook of the future research regarding multivalent metal ion hybrid capacitors was also presented. This review will be beneficial for researchers around the world to have a better understanding of multivalent metal ion hybrid capacitors and develop novel electrochemical energy storage systems to meet the demands of rapidly developing electric vehicles and wearable/portable electronic products.

Nanowires for Electrochemical Energy Storage.

Abstract: Nanomaterials provide many desirable properties for electrochemical energy storage devices due to their nanoscale size effect, which could be significantly different from bulk or micron-sized materials. Particularly, confined dimensions play important roles in determining the properties of nanomaterials, such as the kinetics of ion diffusion, the magnitude of strain/stress, and the utilization of active materials. Nanowires, as one of the representative one-dimensional nanomaterials, have great capability for realizing a variety of applications in the fields of energy storage since they could maintain electron transport along the long axis and have a confinement effect across the diameter. In this review, we give a systematic overview of the state-of-the-art research progress on nanowires for electrochemical energy storage, from rational design and synthesis, in situ structural characterizations, to several important applications in energy storage including lithium-ion batteries, lithium-sulfur batteries, sodium-ion batteries, and supercapacitors. The problems and limitations in electrochemical energy storage and the advantages in utilizing nanowires to address the issues and improve the device performance are pointed out. At the end, we also discuss the challenges and demonstrate the prospective for the future development of advanced nanowire-based energy storage devices.

Assembling 2D MXenes into Highly Stable Pseudocapacitive Electrodes with High Power and Energy Densities.

Abstract: Electrochemical capacitors (ECs) that store charge based on the pseudocapacitive mechanism combine high energy densities with high power densities and rate capabilities. 2D transition metal carbides (MXenes) have been recently introduced as high-rate pseudocapacitive materials with ultrahigh areal and volumetric capacitances. So far, 20 different MXene compositions have been synthesized and many more are theoretically predicted. However, since most MXenes are chemically unstable in their 2D forms, to date only one MXene composition, Ti3 C2 Tx , has shown stable pseudocapacitive charge storage. Here, a cation-driven assembly process is demonstrated to fabricate highly stable and flexible multilayered films of V2 CTx and Ti2 CTx MXenes from their chemically unstable delaminated single-layer flakes. The electrochemical performance of electrodes fabricated using assembled V2 CTx flakes surpasses Ti3 C2 Tx in various aqueous electrolytes. These electrodes show specific capacitances as high as 1315 F cm-3 and retain ≈77% of their initial capacitance after one million charge/discharge cycles, an unprecedented performance for pseudocapacitive materials. This work opens a new venue for future development of high-performance supercapacitor electrodes using a variety of 2D materials as building blocks.

A low-cost “water-in-salt” electrolyte for a 2.3 V high-rate carbon-based supercapacitor

Abstract: Aqueous electrolytes have shown extraordinary promise for safe electrochemical energy storage devices, but their widespread use is severely limited by the narrow electrochemical stability window (ESW). Here we demonstrate the great feasibility of using a superconcentrated sodium perchlorate aqueous solution as a low-cost “water-in-salt” electrolyte to construct a high-performance carbon-based supercapacitor (SC). The attractive features of this electrolyte including wide ESW and excellent conductivity enable the model SC to fully work at 2.3 volts with superior rate capability and outstanding cycling stability. This SC exhibits a comparable energy density, a higher power density and a much lower price compared to commercial non-aqueous SCs working at 2.7 volts, representing significant progress toward practical applications.

Metal-organic frameworks for energy storage devices: Batteries and supercapacitors

Abstract: The rise of metal-organic frameworks (MOFs) that are distinctive class of porous materials has attained enormous consideration during the last decades owing to their controllable structures, high surface areas and tunable pore sizes. The applications of MOFs range from the traditional gas separation and storage, drug delivery, sensors and catalysis to the emerging field of energy storage devices, such as high energy density rechargeable batteries and supercapacitors. Metal-organic frameworks are excellent candidates for electrode materials in electrochemical energy storage devices due to their irreplaceable morphology, appropriate functional linkers, high specific surface area and metal sites. Herein, a brief review is carried out on recent development in the utilization of metal-organic framework based materials for rechargeable batteries and supercapacitors, which would be the prevailing guidance to the materials design and optimization for battery community and electrochemical energy storage applications.