Voltage dependence of carbon-based supercapacitors for pseudocapacitance quantification

Abstract

Abstract.-In order to understand the participation of electrical double layer and pseudocapacitance to the overall behavior of supercapacitors, a new approach to the analysis of the electrochemical data is proposed. Both the variation of the specific capacitance values and the dependence of these values with the operating voltage window (varying from 0-0.2 V to 0-1 V) were evaluated and used to quantify the contribution arising from each mechanism of energy storage to the total capacitance of the system. The suitability of the methodology here proposed was tested in various carbon materials (multiwalled carbon nanotubes, a carbon aerogel and two activated carbons), different both in nature and physicochemical characteristics. For all of the carbons studied, the capacitance with an exclusive faradic and non -faradic origin was quantified. Whereas some of the carbons studied showed a behavior close to an ideal Electrical Double Layer Capacitor (EDLC) with virtually no pseudocapacitance contribution (case of the carbon nanotubes), others presented up to a 40 % of pseudocapacitance contribution (case of KOH -activated carbon).

Ionic liquid-based polymer gel electrolytes for symmetrical solid-state electrical double layer capacitor operated at different operating voltages

“…The cell was able to store 80, 75, 70 and 64 F g À1 at 0.8, 1.0, 1.6 and 2.0 V, respectively, at the second cycle. According to Ruiz and colleagues [56], CV is inadequate to quantitatively isolate the contributions of double layer and pseudocapacitance in carbon based EDLC. Thus, galvanostatic charge-discharge (GCD) curves in Fig.…”

Investigation of double-layer and pseudocapacitance of surface-modified ionic liquid-functionalized graphene oxide

“…As expected, limited double-layer charging is observed on the bare Pt electrode, indicating that the pseudocapacitive behavior observed on IFGO is a property of the hybrid material. already in previous reports [50,51]. Ruiz and co-workers did develop an empirical model in an attempt to decouple double-layer and pseudocapacitive contributions in carbon-based supercapacitor electrodes [51], but the general applicability of that method to our system is questionable.…”

“…already in previous reports [50,51]. Ruiz and co-workers did develop an empirical model in an attempt to decouple double-layer and pseudocapacitive contributions in carbon-based supercapacitor electrodes [51], but the general applicability of that method to our system is questionable. In our case, the double-layer formation is voltagedependent, as evidenced by the cyclic voltammograms of the unmodified GO and IFGO electrodes, likely a result of the microporous structure of the GO and IFGO composite sheets.…”

Enhanced energy density of carbon-based supercapacitors using Cerium (III) sulphate as inorganic redox electrolyte

“…3B and 3D it can be inferred that the operating cell voltage could be extended to at least 1.5 V. When the applied cell voltage is 1.0 V, the negative electrode is working at around 0.2 V versus the reference electrode (Fig. 3D), but it is well known that this activated carbon can work at much more negative potentials without provoking the hydrogen evolution reaction [17,36]. Consequently, it can be predicted that, if the operating cell voltage is increased, the positive electrode will remain within the potential of the Ce 3+ /Ce 4+ reactions, while the negative electrode will shift to more negative potentials.…”