The electrical double layer of high surface porous carbon electrode

Soffer, Abraham; Folman, M.

doi:10.1016/s0022-0728(72)80087-1

Cited by 163 publications

(85 citation statements)

References 19 publications

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“…Taken together, the two polarization layers contain an excess of salt ions over the ion concentration in bulk solution, and thus effectively part of the ions in the solution phase is removed. The removal of ions according to this principle from an (aqueous) stream flowing along the electrodes is called capacitive deionization (CDI) or electrosorption desalination [1][2][3][4]. The topic is closely related to research in the field of electric double layer (super-)capacitors .…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic cycle analysis for capacitive deionization

Biesheuvel

2009

Journal of Colloid and Interface Science

148

133

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Section: Introductionmentioning

confidence: 99%

Thermodynamic cycle analysis for capacitive deionization

Biesheuvel

2009

Journal of Colloid and Interface Science

148

133

View full text Add to dashboard Cite

“…4) Inaccessibility of ions to small-diameter micropores, thereby not contributing to the double-layer formation [72]. On the basis of the experimental results, several authors agreed that pores larger than 0.5 nm are electrochemically accessible to aqueous solutions [52,54,[73][74][75]. Lin and coworkers [76] utilized a form of carbon aerogel to estimate that the optimum pore size in aqueous sulfuric acid was 0.8-2 nm.…”

Section: And 23) Studies Proposed By Several Authorsmentioning

confidence: 99%

General Properties of Electrochemical Capacitors

et al. 2013

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“…In this sense, enormous differences in capacitance values can be found depending on the electrolyte used. For carbon materials in neutral solutions, specific capacitance values between 8-12 μF cm -2 have been reported and between 15-20 μF cm -2 in the case of acidic media [12]. Despite that its study is not so frequent, redox reactions in basic media are also possible [13].…”

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confidence: 99%

Long-term cycling of carbon-based supercapacitors in aqueous media

Ruíz

Santamarı́a

Granda

et al. 2009

Electrochimica Acta

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Abstract.-The behaviour of mesophase-derived electrodes on long-duration cycling conditions was studied in 1M sulfuric acid and 6M potassium hydroxide. Variation in the specific capacitance values with the number of cycles shows a good cycling life performance in acidic media but very poor in an alkaline electrolyte. The total loss of capacitance after 7,000 cycles in acidic media is 8 % at 0.6 V and 16 % at 1 V, whereas in the basic electrolyte the reduction in the capacitance values is 72 %, even at a very small operating voltage (0.6 V). This wide range of applications related to their fast energy delivery (e.g. telecommunications systems, maintenance-free traffic lights, uninterruptible power sources, and hybrid electric vehicles among others) [1]. The storage of energy in electrochemical capacitors can arise from either electrostatic charging or from pseudocapacitative chage-discharge [2]. In the first case, electrolyte ions are accumulated at the electrode/electrolyte interface forming the socalled double layer in a similar way as in conventional capacitors. By utilizing high surface area electrodes the amount of charge stored, and consequently the capacitance of the device, is several orders of magnitude higher than that of conventional electrolytic capacitors. In the second case, pseudocapacitance arises from faradaic processes of electroactive species, such as polymeric materials [3], metal oxides [4,5] and certain functionalities at the surface of carbon materials [6,7,8].It is generally believed that pseudocapacitance in carbon materials is largely based on the redox reactions of surface quinoid functionalities, whose reduction requires protons to proceed [9,10]. Nevertheless, some other oxygenated functional groups might be electrochemically active at the working potentials of the acidic solutions, such as some pyrone groups [11,6]. Therefore, and as may be expected, faradic phenomena have a large dependence on the pH of the solution. In this sense, enormous differences in capacitance values can be found depending on the electrolyte used. For carbon materials in neutral solutions, specific capacitance values between 8-12 μF cm -2 have been reported and between 15-20 μF cm -2 in the case of acidic media [12]. Despite that its study is not so frequent, redox reactions in basic media are also possible [13]. In general terms, the presence of the so-called pseudocapacitance has been related in literature to poor cycle life [19] contrary to what occurs in organic media, where only purely charge separation occurs and good cycling stability is typically reported [20]. Investigations in this field are rarely reported, despite that the cyclability of supercapacitors is a property of mayor importance. The present work investigates the effect of the electrolyte (basic or acidic)in the long-term stability of carbon-based supercapacitors. The electro-oxidation of the activated carbon M-AC was carried out in a conventional three-electrode system. Around 100 mg of material was subjected to +0.4 V vs. NHE in a N 2 bu...

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The electrical double layer of high surface porous carbon electrode

Cited by 163 publications

References 19 publications

Thermodynamic cycle analysis for capacitive deionization

Thermodynamic cycle analysis for capacitive deionization

General Properties of Electrochemical Capacitors

Long-term cycling of carbon-based supercapacitors in aqueous media

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