Asymmetric electrochemical capacitors—Stretching the limits of aqueous electrolytes

Long, Jeffrey W.; Bélanger, Daniel; Brousse, Thierry; Sugimoto, Wataru; Sassin, Megan B.; Crosnier, Olivier

doi:10.1557/mrs.2011.137

Cited by 380 publications

(269 citation statements)

References 105 publications

(38 reference statements)

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“…In addition, in the case of AC, negatively charged surface groups that improve hydrophilicity also raise the OCP in aqueous electrolytes to above 0.3 V versus SHE, which is too high for a useful anode with a CuHCF cathode 22,23 . One benefit of using AC as an anode in aqueous electrolytes is its suppression of H 2 evolution at low potentials 24 , but its low capacity, steep discharge profile and high OCP limit its practicality.…”

Section: Resultsmentioning

confidence: 99%

A high-rate and long cycle life aqueous electrolyte battery for grid-scale energy storage

et al. 2012

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new types of energy storage are needed in conjunction with the deployment of solar, wind and other volatile renewable energy sources and their integration with the electric grid. no existing energy storage technology can economically provide the power, cycle life and energy efficiency needed to respond to the costly short-term transients that arise from renewables and other aspects of grid operation. Here we demonstrate a new type of safe, fast, inexpensive, long-life aqueous electrolyte battery, which relies on the insertion of potassium ions into a copper hexacyanoferrate cathode and a novel activated carbon/polypyrrole hybrid anode. The cathode reacts rapidly with very little hysteresis. The hybrid anode uses an electrochemically active additive to tune its potential. This high-rate, high-efficiency cell has a 95% round-trip energy efficiency when cycled at a 5C rate, and a 79% energy efficiency at 50C. It also has zero-capacity loss after 1,000 deep-discharge cycles.

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Section: Resultsmentioning

confidence: 99%

A high-rate and long cycle life aqueous electrolyte battery for grid-scale energy storage

et al. 2012

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“…Electrochemical capacitors (ECs) also known as supercapacitors represent an emerging class of energy-storage devices and are suitable for such application due to their high power density and excellent cycle life [1,2]. They are differentiated from their storage counterparts by their ability to store charge at electrochemical interfaces which gives rise to effective capacitance orders of magnitude higher than those obtained by storing charge in an electric field applied across a conventional dielectric material [3]. ECs have the ability to release the stored energy over timescales of a few seconds and exhibit excellent cycle life (thousands of cycles) which represents an advantage over batteries [3].…”

Section: Introductionmentioning

confidence: 99%

“…They are differentiated from their storage counterparts by their ability to store charge at electrochemical interfaces which gives rise to effective capacitance orders of magnitude higher than those obtained by storing charge in an electric field applied across a conventional dielectric material [3]. ECs have the ability to release the stored energy over timescales of a few seconds and exhibit excellent cycle life (thousands of cycles) which represents an advantage over batteries [3]. The design of asymmetric supercapacitors (ASCs) has been shown to be an effective method for the integration of different capacitive or pseudocapacitive electrode materials with appropriate or different potential windows in the same electrolyte, extending the operating potential window which improves the energy density of the supercapacitors and hence, providing an effective power source with high energy density which is crucial for many applications [3,4].…”

Section: Introductionmentioning

confidence: 99%

Asymmetric supercapacitor based on nanostructured graphene foam/polyvinyl alcohol/formaldehyde and activated carbon electrodes

Bello

Barzegar

Momodu

et al. 2015

Journal of Power Sources

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We present the electrochemical results of highly porous and interconnected carbon material by activation of graphene foam/polyvinyl alcohol-formaldehyde composite material designated as GF/PVA-F. Asymmetric supercapacitor devices were fabricated using the activated material (GF/PVA-F) and activated carbon (AC) as the positive and negative electrodes respectively. The device exhibited a maximum energy density of 42 mWh cm -2 , a power density of 0.5 W cm -2 and 98% retention of its initial capacitance after 2000 cycles in an extended cell potential window of 1.8 V in 1 M Na 2 SO 4 aqueous electrolyte. This work shows the great potential of this material for high performance energy storage application.

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“…Using both Faradaic and nonFaradaic processes to store charge, hybrid capacitors can achieve energy and power densities greater than EDLCs without sacrificing the cycling stability and affordability that have so far limited the success of pseudocapacitors (4). Several combinations of materials, such as RuO 2 (5), Co 3 O 4 (6), NiO (7), V 2 O 5 (8), Ni(OH) 2 (9), and MnO 2 (10), have been studied for preparing hybrid supercapacitors.…”

mentioning

confidence: 99%

Engineering three-dimensional hybrid supercapacitors and microsupercapacitors for high-performance integrated energy storage

El‐Kady

Ihns

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

506

321

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Supercapacitors now play an important role in the progress of hybrid and electric vehicles, consumer electronics, and military and space applications. There is a growing demand in developing hybrid supercapacitor systems to overcome the energy density limitations of the current generation of carbon-based supercapacitors. Here, we demonstrate 3D high-performance hybrid supercapacitors and microsupercapacitors based on graphene and MnO 2 by rationally designing the electrode microstructure and combining active materials with electrolytes that operate at high voltages. This results in hybrid electrodes with ultrahigh volumetric capacitance of over 1,100 F/cm 3 . This corresponds to a specific capacitance of the constituent MnO 2 of 1,145 F/g, which is close to the theoretical value of 1,380 F/g. The energy density of the full device varies between 22 and 42 Wh/l depending on the device configuration, which is superior to those of commercially available double-layer supercapacitors, pseudocapacitors, lithium-ion capacitors, and hybrid supercapacitors tested under the same conditions and is comparable to that of lead acid batteries. These hybrid supercapacitors use aqueous electrolytes and are assembled in air without the need for expensive "dry rooms" required for building today's supercapacitors. Furthermore, we demonstrate a simple technique for the fabrication of supercapacitor arrays for high-voltage applications. These arrays can be integrated with solar cells for efficient energy harvesting and storage systems.A s a result of the rapidly growing energy needs of modern life, the development of high-performance energy storage devices has gained significant attention. Supercapacitors are promising energy storage devices with properties intermediate between those of batteries and traditional capacitors, but they are being improved more rapidly than either (1). Over the past couple of decades, supercapacitors have become key components of everyday products by replacing batteries and capacitors in an increasing number of applications. Their high power density and excellent low-temperature performance have made them the technology of choice for backup power, cold starting, flash cameras, regenerative braking, and hybrid electric vehicles (2, 3). The future growth of this technology depends on further improvements in energy density, power density, calendar and cycle life, and production cost.According to their charge storage mechanism, supercapacitors are classified as either electric double-layer capacitors (EDLCs) or pseudocapacitors (2). In EDLCs, charge is stored through rapid adsorption-desorption of electrolyte ions on high-surfacearea carbon materials, whereas pseudocapacitors store charge via fast and reversible Faradaic reactions near the surface of metal oxides or conducting polymers. The majority of supercapacitors currently available in the market are symmetric EDLCs featuring activated carbon electrodes and organic electrolytes that provide cell voltages as high as 2.7 V. Although these EDLCs exhibit high...

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Asymmetric electrochemical capacitors—Stretching the limits of aqueous electrolytes

Abstract: Abstract

Cited by 380 publications

References 105 publications

A high-rate and long cycle life aqueous electrolyte battery for grid-scale energy storage

A high-rate and long cycle life aqueous electrolyte battery for grid-scale energy storage

Asymmetric supercapacitor based on nanostructured graphene foam/polyvinyl alcohol/formaldehyde and activated carbon electrodes

Engineering three-dimensional hybrid supercapacitors and microsupercapacitors for high-performance integrated energy storage

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