Gas evolution in activated carbon/propylene carbonate based double-layer capacitors

Hahn, Matthias; Würsig, Andreas; Gallay, R.; Novák, Petr; Kötz, R.

doi:10.1016/j.elecom.2005.06.015

Cited by 129 publications

(84 citation statements)

References 7 publications

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“…5, which is capable of separately collecting gases from the positive and negative compartments. 81 The analysis revealed CO2 and CO from the positrode, while H2, and other gases, like propylene, CO2, ethylene and CO, were found on the negatrode after a float-test applied at cell voltages above 3.0 V. 81,82 Many efforts have been focused on the implementation of novel solvents with wider operating voltage ranges. In 2011, new electrolytes based on linear sulfones were reported, showing that ethyl isopropyl sulfone (EiPS)-based electrolytes have high voltage durability of 3.7 V with high cycling stability.…”

Section: Supercapacitorsmentioning

confidence: 99%

Electrolytes for electrochemical energy storage

Xia

et al. 2017

Mater. Chem. Front.

225

116

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A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription.For more information, please contact eprints@nottingham.ac.uk Journal NameThis journal is © The Royal Society of Chemistry 20xxJ. Name., 2013, 00, 1-3 | 1 Electrolyte is a key component of electrochemical energy storage (EES) devices and its properties greatly affect the energy capacity, rate performance, cyclability and safety of all EES devices. This article offers a critical review of recent progresses and challenges in electrolyte research and development particularly for supercapacitors and supercapatteries, recharegable batteries (such as lithium-ion and sodium-ion batteries), and redox flow batteries (including fuel cells in a broad sense). The review will focus on liquid electrolytes, particularly aqueous and organic electrolytes, ionic liquids and molten salts. Influences of electrolyte properties on the performances of different EES devices are discussed in detail.

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Section: Supercapacitorsmentioning

confidence: 99%

Electrolytes for electrochemical energy storage

Xia

et al. 2017

Mater. Chem. Front.

225

116

View full text Add to dashboard Cite

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“…13 Ageing processes include mainly side-reactions that lead to electrolyte depletion, electrode pore blocking, and internal cell pressure increase because of volatile side-products. Studies of electrochemically induced gas evolution and associated cell pressure build-up have already provided important insights into degradation mechanisms of activated carbon-based EDLCs, operating in either aqueous [12][13][14][15] or non-aqueous [16][17][18] electrolytes. Several approaches, such as Tafel plot based estimations, 15 gas chromatography 14 and cell pressure characterization, 12,13 were previously employed to probe the origin of gas evolution in EDLCs.…”

Section: Introductionmentioning

confidence: 99%

“…[20][21][22][23][24][25][26][27] To the best of our knowledge, OEMS dedicated to EDLCs has only been reported once, but for a non-aqueous electrolyte system. 18 The aim of the present study is to identify potential onsets and govern mechanisms of performance limiting side-reactions in a high-voltage aqueous EDLC by performing a comprehensive in situ analysis of gas evolving side-reactions.…”

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confidence: 99%

Ageing phenomena in high-voltage aqueous supercapacitors investigated by in situ gas analysis

Fic

Frckowiak

et al. 2016

Energy Environ. Sci.

221

173

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a High-voltage aqueous electrolyte based supercapacitors (U 4 1.23 V) attract significant attention for next-generation high power, low cost and environmentally friendly energy storage applications. Cell ageing is however markedly pronounced at elevated voltages and results in accelerated overall performance fade and increased safety concerns. Online electrochemical mass spectrometry, combined with cell pressure analysis, is for the first time shown to provide a powerful means for in situ investigation of degradation mechanisms in aqueous electrolyte/carbon based supercapacitors. The activated carbon electrodes possess high specific surface area and oxygen-based surface functionalities (mainly phenol, lactone and anhydride groups), which are oxidized already at a cell voltage of 0.6 V to provoke the evolution of minor amounts of CO and CO 2 . Noticeable water decomposition starts at a high voltage of 1.6 V with the evolution of H 2 on the negative electrode and carbon corrosion on the positive electrode with the generation of predominantly CO. In this paper we also report that short-term cycling leads to partly reversible gas evolution/consumption side-reactions giving negligible capacitance.On the other hand, long-term cycling causes irreversible side-reactions, deteriorates the electrochemical performance, and increases the internal pressure of the cell. Repeated cycling (U o 2 V) is confirmed as a more harmful technique for the electrode integrity compared to the voltage holding in a floating test.In situ gas analysis is shown to provide valuable insights into the electrochemical cell ageing aspects, such as the nature and potential onsets of side-reactions, hence paving the way for fundamental understanding and mitigating the performance and safety loss of high-energy aqueous supercapacitors. Broader contextGlobal energy consumption and environmental concerns steadily increase with the growth of the world's population and the technical development of our society. Future sustainability is largely dependent upon the widespread implementation of renewable energy generation and storage. Supercapacitors constitute a crucial part in the effective energy storage and delivery, e.g. in electric vehicles (start-stop systems) and wind mills (balancing the energy provided to the grid), because of their exceptional power capability and long cycle life. Supercapacitors with high surface area carbon electrodes operating in aqueous electrolytes offer high power rates, low cost, safe and environmental benign devices, but at moderate energy densities. Significant energy enhancement can be achieved by applying higher operating cell voltages (U 4 1.23 V) when using sulphate-based electrolytes. However, for practical implementations a fundamental understanding of their premature ageing as well as related safety issues are required. In the present work, state-of-the-art in situ gas analysis is shown to deliver valuable insights into the governing mechanisms behind the ageing of these devices. Assignment of safe operating voltage ...

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“…Hahn et al [28] have shown for the first time the gas evolution in a double-layer capacitor cell employing activated carbon electrodes and an electrolyte solution of 1 M (C 2 H 5 ) 4 NBF 4 salt in a PC solvent. The gas has been monitored by means of online mass spectrometry differential electrochemical mass spectrometry (DEMS).…”

Section: Physical Origin Of Agingmentioning

confidence: 99%