Microwave-assisted synthesis of metal oxide/hydroxide composite electrodes for high power supercapacitors – A review
TL;DR: In this article, the performance data of metal oxide thin film electrodes by microwave-assisted as an inexpensive, quick and versatile technique is presented for supercapacitor performance data, and metal oxide films will continue to play a major role in supercapACitor technology and are expected to considerably increase the capabilities of these devices in near future.
About: This article is published in Journal of Power Sources.The article was published on 2014-10-01. It has received 355 citations till now. The article focuses on the topics: Supercapacitor & Nickel oxide.
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TL;DR: The latest progress in supercapacitors in charge storage mechanisms, electrode materials, electrolyte materials, systems, characterization methods, and applications are reviewed and the newly developed charge storage mechanism for intercalative pseudocapacitive behaviour is clarified for comparison.
Abstract: Electrochemical capacitors (i.e. supercapacitors) include electrochemical double-layer capacitors that depend on the charge storage of ion adsorption and pseudo-capacitors that are based on charge storage involving fast surface redox reactions. The energy storage capacities of supercapacitors are several orders of magnitude higher than those of conventional dielectric capacitors, but are much lower than those of secondary batteries. They typically have high power density, long cyclic stability and high safety, and thus can be considered as an alternative or complement to rechargeable batteries in applications that require high power delivery or fast energy harvesting. This article reviews the latest progress in supercapacitors in charge storage mechanisms, electrode materials, electrolyte materials, systems, characterization methods, and applications. In particular, the newly developed charge storage mechanism for intercalative pseudocapacitive behaviour, which bridges the gap between battery behaviour and conventional pseudocapacitive behaviour, is also clarified for comparison. Finally, the prospects and challenges associated with supercapacitors in practical applications are also discussed.
2,698 citations
01 Nov 2000
TL;DR: In this paper, the authors compared the power density characteristics of ultracapacitors and batteries with respect to the same charge/discharge efficiency, and showed that the battery can achieve energy densities of 10 Wh/kg or higher with a power density of 1.2 kW/kg.
Abstract: The science and technology of ultracapacitors are reviewed for a number of electrode materials, including carbon, mixed metal oxides, and conducting polymers. More work has been done using microporous carbons than with the other materials and most of the commercially available devices use carbon electrodes and an organic electrolytes. The energy density of these devices is 3¯5 Wh/kg with a power density of 300¯500 W/kg for high efficiency (90¯95%) charge/discharges. Projections of future developments using carbon indicate that energy densities of 10 Wh/kg or higher are likely with power densities of 1¯2 kW/kg. A key problem in the fabrication of these advanced devices is the bonding of the thin electrodes to a current collector such the contact resistance is less than 0.1 cm2. Special attention is given in the paper to comparing the power density characteristics of ultracapacitors and batteries. The comparisons should be made at the same charge/discharge efficiency.
2,437 citations
TL;DR: In this article, the authors demonstrate why it is inappropriate to describe nickel oxide or hydroxide and cobalt oxide/hydroxide as pseudocapacitive electrode materials, and demonstrate the difference between these two classes of materials.
Abstract: There are an increasing number of studies regarding active electrode materials that undergo faradaic reactions but are used for electrochemical capacitor applications. Unfortunately, some of these materials are described as “pseudocapacitive” materials despite the fact that their electrochemical signature (e.g., cyclic voltammogram and charge/discharge curve) is analogous to that of a “battery” material, as commonly observed for Ni(OH)2 and cobalt oxides in KOH electrolyte. Conversely, true pseudocapacitive electrode materials such as MnO2 display electrochemical behavior typical of that observed for a capacitive carbon electrode. The difference between these two classes of materials will be explained, and we demonstrate why it is inappropriate to describe nickel oxide or hydroxide and cobalt oxide/hydroxide as pseudocapacitive electrode materials. © The Author(s) 2015. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives 4.0 License (CC BY-NC-ND, http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reuse, distribution, and reproduction in any medium, provided the original work is not changed in any way and is properly cited. For permission for commercial reuse, please email: oa@electrochem.org. [DOI: 10.1149/2.0201505jes] All rights reserved.
1,957 citations
TL;DR: Improved capacitance performance was successfully realized for the ASC (Co3O4//carbon), better than those of the SSCs based on nanoporous carbon and nanoporous Co3O 4 materials (i.e., carbon//carbon and Co3o4//Co3 O4).
Abstract: Nanoporous carbon and nanoporous cobalt oxide (Co3O4) materials have been selectively prepared from a single metal–organic framework (MOF) (zeolitic imidazolate framework, ZIF-67) by optimizing the annealing conditions. The resulting ZIF-derived carbon possesses highly graphitic walls and a high specific surface area of 350 m2·g–1, while the resulting ZIF-derived nanoporous Co3O4 possesses a high specific surface area of 148 m2·g–1 with much less carbon content (1.7 at%). When nanoporous carbon and nanoporous Co3O4 were tested as electrode materials for supercapacitor application, they showed high capacitance values (272 and 504 F·g–1, respectively, at a scan rate of 5 mV·s–1). To further demonstrate the advantages of our ZIF-derived nanoporous materials, symmetric (SSCs) and asymmetric supercapacitors (ASCs) were also fabricated using nanoporous carbon and nanoporous Co3O4 electrodes. Improved capacitance performance was successfully realized for the ASC (Co3O4//carbon), better than those of the SSCs bas...
849 citations
TL;DR: Nonthermal plasma technology has recently appeared as an extremely promising alternative for the synthesis and surface modification of nanomaterials for electrochemical devices including electrocatalysts for fuel cells, water splitting, metal-air batteries, and electrode materials for batteries and supercapacitors, etc.
Abstract: Renewable energy technology has been considered as a "MUST" option to lower the use of fossil fuels for industry and daily life. Designing critical and sophisticated materials is of great importance in order to realize high-performance energy technology. Typically, efficient synthesis and soft surface modification of nanomaterials are important for energy technology. Therefore, there are increasing demands on the rational design of efficient electrocatalysts or electrode materials, which are the key for scalable and practical electrochemical energy devices. Nevertheless, the development of versatile and cheap strategies is one of the main challenges to achieve the aforementioned goals. Accordingly, plasma technology has recently appeared as an extremely promising alternative for the synthesis and surface modification of nanomaterials for electrochemical devices. Here, the recent progress on the development of nonthermal plasma technology is highlighted for the synthesis and surface modification of advanced electrode materials for renewable energy technology including electrocatalysts for fuel cells, water splitting, metal-air batteries, and electrode materials for batteries and supercapacitors, etc.
425 citations
References
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TL;DR: Researchers must find a sustainable way of providing the power their modern lifestyles demand to ensure the continued existence of clean energy sources.
Abstract: Researchers must find a sustainable way of providing the power our modern lifestyles demand.
15,980 citations
TL;DR: This work has shown that combination of pseudo-capacitive nanomaterials, including oxides, nitrides and polymers, with the latest generation of nanostructured lithium electrodes has brought the energy density of electrochemical capacitors closer to that of batteries.
Abstract: Electrochemical capacitors, also called supercapacitors, store energy using either ion adsorption (electrochemical double layer capacitors) or fast surface redox reactions (pseudo-capacitors). They can complement or replace batteries in electrical energy storage and harvesting applications, when high power delivery or uptake is needed. A notable improvement in performance has been achieved through recent advances in understanding charge storage mechanisms and the development of advanced nanostructured materials. The discovery that ion desolvation occurs in pores smaller than the solvated ions has led to higher capacitance for electrochemical double layer capacitors using carbon electrodes with subnanometre pores, and opened the door to designing high-energy density devices using a variety of electrolytes. Combination of pseudo-capacitive nanomaterials, including oxides, nitrides and polymers, with the latest generation of nanostructured lithium electrodes has brought the energy density of electrochemical capacitors closer to that of batteries. The use of carbon nanotubes has further advanced micro-electrochemical capacitors, enabling flexible and adaptable devices to be made. Mathematical modelling and simulation will be the key to success in designing tomorrow's high-energy and high-power devices.
14,213 citations
TL;DR: The battery systems reviewed here include sodium-sulfur batteries that are commercially available for grid applications, redox-flow batteries that offer low cost, and lithium-ion batteries whose development for commercial electronics and electric vehicles is being applied to grid storage.
Abstract: The increasing interest in energy storage for the grid can be attributed to multiple factors, including the capital costs of managing peak demands, the investments needed for grid reliability, and the integration of renewable energy sources. Although existing energy storage is dominated by pumped hydroelectric, there is the recognition that battery systems can offer a number of high-value opportunities, provided that lower costs can be obtained. The battery systems reviewed here include sodium-sulfur batteries that are commercially available for grid applications, redox-flow batteries that offer low cost, and lithium-ion batteries whose development for commercial electronics and electric vehicles is being applied to grid storage.
11,144 citations
TL;DR: Two important future research directions are indicated and summarized, based on results published in the literature: the development of composite and nanostructured ES materials to overcome the major challenge posed by the low energy density.
Abstract: In this critical review, metal oxides-based materials for electrochemical supercapacitor (ES) electrodes are reviewed in detail together with a brief review of carbon materials and conducting polymers. Their advantages, disadvantages, and performance in ES electrodes are discussed through extensive analysis of the literature, and new trends in material development are also reviewed. Two important future research directions are indicated and summarized, based on results published in the literature: the development of composite and nanostructured ES materials to overcome the major challenge posed by the low energy density of ES (476 references).
7,642 citations
TL;DR: Electrochemical capacitors enable rapid storage and efficient delivery of electrical energy in heavy-duty applications and are being enabled by electrochemical capacitor technology.
Abstract: Rapid storage and efficient delivery of electrical energy in heavy-duty applications are being enabled by electrochemical capacitors.
4,177 citations