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Thermochemically activated carbon as an electrode material for supercapacitors.

Ostafiychuk BK, Budzulyak IM, Rachiy BI, Vashchynsky VM, Mandzyuk VI, Lisovsky RP, Shyyko LO - Nanoscale Res Lett (2015)

Bottom Line: The results of electrochemical studies of nanoporous carbon as electrode material for electrochemical capacitors (EC) are presented in this work.It is established that there is an optimal ratio of 1:1 between content of KOH and carbon material at chemical activation, while the maximum specific capacity of NCM is 180 F/g.An equivalent electrical circuit, which allows modeling of the impedance spectra in the frequency range of 10(-2) to 10(5) Hz, is proposed, and a physical interpretation of each element of the electrical circuit is presented.

View Article: PubMed Central - PubMed

Affiliation: Vasyl Stefanyk PreCarpathian National University, 57 Shevchenko Str., Ivano-Frankivsk, 76018 Ukraine.

ABSTRACT
The results of electrochemical studies of nanoporous carbon as electrode material for electrochemical capacitors (EC) are presented in this work. Nanoporous carbon material (NCM) was obtained from the raw materials of plant origin by carbonization and subsequent activation in potassium hydroxide. It is established that there is an optimal ratio of 1:1 between content of KOH and carbon material at chemical activation, while the maximum specific capacity of NCM is 180 F/g. An equivalent electrical circuit, which allows modeling of the impedance spectra in the frequency range of 10(-2) to 10(5) Hz, is proposed, and a physical interpretation of each element of the electrical circuit is presented.

No MeSH data available.


Cyclic voltammograms of the NCM taken at different scan rates. (а)s = 1 mV/s. (b)s = 5 mV/s. C31 —□—, C32 —●—, C33 —Δ—, C34 —○—.
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Fig4: Cyclic voltammograms of the NCM taken at different scan rates. (а)s = 1 mV/s. (b)s = 5 mV/s. C31 —□—, C32 —●—, C33 —Δ—, C34 —○—.

Mentions: Figure 4 shows the cyclic voltammograms for the NCM in 30% aqueous KOH at the linear scanning electrode potential of 1 and 5 mV/s. When scan rate is s = 1 mV/s, the curves have a symmetrical, almost rectangular shape with no obvious redox peaks, indicating the dominance of the electrostatic electric charge accumulation processes at the interface electrode/electrolyte [11]. A small peak at the potentials of 0.85 … 1 V is due to the release of oxygen dissolved in the electrolyte and adsorbed by the surface of the active material [12]. Comparing the cyclic voltammograms at the scan rate of 5 mV/s, it can be noted that all the samples in the positive potential range have a slight peak. Given that in this region the capacity of the material is provided mostly by negative electrolyte ions (OH− groups), we can conclude that there is a possible intercalation process of these groups into the pores of the electrode material. Using these cyclic voltammograms, we calculated the values of the specific capacity of the samples at the scan rate of 1 mV/s (Table 2).Figure 4


Thermochemically activated carbon as an electrode material for supercapacitors.

Ostafiychuk BK, Budzulyak IM, Rachiy BI, Vashchynsky VM, Mandzyuk VI, Lisovsky RP, Shyyko LO - Nanoscale Res Lett (2015)

Cyclic voltammograms of the NCM taken at different scan rates. (а)s = 1 mV/s. (b)s = 5 mV/s. C31 —□—, C32 —●—, C33 —Δ—, C34 —○—.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4385132&req=5

Fig4: Cyclic voltammograms of the NCM taken at different scan rates. (а)s = 1 mV/s. (b)s = 5 mV/s. C31 —□—, C32 —●—, C33 —Δ—, C34 —○—.
Mentions: Figure 4 shows the cyclic voltammograms for the NCM in 30% aqueous KOH at the linear scanning electrode potential of 1 and 5 mV/s. When scan rate is s = 1 mV/s, the curves have a symmetrical, almost rectangular shape with no obvious redox peaks, indicating the dominance of the electrostatic electric charge accumulation processes at the interface electrode/electrolyte [11]. A small peak at the potentials of 0.85 … 1 V is due to the release of oxygen dissolved in the electrolyte and adsorbed by the surface of the active material [12]. Comparing the cyclic voltammograms at the scan rate of 5 mV/s, it can be noted that all the samples in the positive potential range have a slight peak. Given that in this region the capacity of the material is provided mostly by negative electrolyte ions (OH− groups), we can conclude that there is a possible intercalation process of these groups into the pores of the electrode material. Using these cyclic voltammograms, we calculated the values of the specific capacity of the samples at the scan rate of 1 mV/s (Table 2).Figure 4

Bottom Line: The results of electrochemical studies of nanoporous carbon as electrode material for electrochemical capacitors (EC) are presented in this work.It is established that there is an optimal ratio of 1:1 between content of KOH and carbon material at chemical activation, while the maximum specific capacity of NCM is 180 F/g.An equivalent electrical circuit, which allows modeling of the impedance spectra in the frequency range of 10(-2) to 10(5) Hz, is proposed, and a physical interpretation of each element of the electrical circuit is presented.

View Article: PubMed Central - PubMed

Affiliation: Vasyl Stefanyk PreCarpathian National University, 57 Shevchenko Str., Ivano-Frankivsk, 76018 Ukraine.

ABSTRACT
The results of electrochemical studies of nanoporous carbon as electrode material for electrochemical capacitors (EC) are presented in this work. Nanoporous carbon material (NCM) was obtained from the raw materials of plant origin by carbonization and subsequent activation in potassium hydroxide. It is established that there is an optimal ratio of 1:1 between content of KOH and carbon material at chemical activation, while the maximum specific capacity of NCM is 180 F/g. An equivalent electrical circuit, which allows modeling of the impedance spectra in the frequency range of 10(-2) to 10(5) Hz, is proposed, and a physical interpretation of each element of the electrical circuit is presented.

No MeSH data available.