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The structure and properties of PEDOT synthesized by template-free solution method.

Zhao Q, Jamal R, Zhang L, Wang M, Abdiryim T - Nanoscale Res Lett (2014)

Bottom Line: In this study, a simple one-step template-free solution method was developed for the preparation of poly(3,4-ethylenedioxythiophene) (PEDOTs) with different morphologies by adjusting various ratios of oxidant (FeCl3·6H2O) to monomer (3,4-ethylenedioxythiophene (EDOT)).The morphological analysis showed that PEDOT prepared from an oxidant/monomer ratio of 3:1 displayed a special coral-like morphology, and the branches of 'coral' would adjoin or grow together with increasing content of oxidant in the reaction medium; consequently, the morphology of PEDOT changed from coral to sheets (at an oxidant/monomer ratio of 9:1).The electrochemical analysis proved that the PEDOT prepared from an oxidant/monomer ratio of 3:1 had the lowest resistance and the highest specific capacitances (174 F/g) at a current density of 1 A/g with a capacity retention rate of 74% over 1,500 cycles, which indicated that the PEDOT with a coral-like morphology could be applied as a promising electrode material for supercapacitors.

View Article: PubMed Central - HTML - PubMed

Affiliation: Key Laboratory of Petroleum and Gas Fine Chemicals, Educational Ministry of China, School of Chemistry and Chemical Engineering, Xinjiang University, Urumqi 830046, People's Republic of China ; Key Laboratory of Functional Polymers, Xinjiang University, Urumqi 830046, People's Republic of China.

ABSTRACT
In this study, a simple one-step template-free solution method was developed for the preparation of poly(3,4-ethylenedioxythiophene) (PEDOTs) with different morphologies by adjusting various ratios of oxidant (FeCl3·6H2O) to monomer (3,4-ethylenedioxythiophene (EDOT)). The results from structural analysis showed that the structure of PEDOT was strongly affected by the oxidant/monomer ratio, and the polymerization degree, conjugation length, doping level, and crystallinity of PEDOT decreased with increasing of the oxidant/monomer ratio. The morphological analysis showed that PEDOT prepared from an oxidant/monomer ratio of 3:1 displayed a special coral-like morphology, and the branches of 'coral' would adjoin or grow together with increasing content of oxidant in the reaction medium; consequently, the morphology of PEDOT changed from coral to sheets (at an oxidant/monomer ratio of 9:1). The electrochemical analysis proved that the PEDOT prepared from an oxidant/monomer ratio of 3:1 had the lowest resistance and the highest specific capacitances (174 F/g) at a current density of 1 A/g with a capacity retention rate of 74% over 1,500 cycles, which indicated that the PEDOT with a coral-like morphology could be applied as a promising electrode material for supercapacitors.

No MeSH data available.


EIS spectra of PEDOT (3:1), PEDOT (6:1), and PEDOT (9:1) at 5 mV. Frequency range =0.01 Hz to 100 KHz.
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Figure 7: EIS spectra of PEDOT (3:1), PEDOT (6:1), and PEDOT (9:1) at 5 mV. Frequency range =0.01 Hz to 100 KHz.

Mentions: Nyquist plots of PEDOTs at 5 mV over the frequency range of 0.01 Hz to 100 KHz are given in Figure 7. It can be seen that EIS plots contain three well-separated patterns. Firstly, the high-frequency intercept of the semicircle with the real axis can be used to evaluate the value of internal resistance, which included the resistance of the electrolyte solution, the intrinsic resistance of the active material, and the contact resistance at the interface active material/current collector[41,42]. The values of solution resistance (Rs) obtained from Figure 7 are 0.68 Ω (PEDOT (3:1)), 0.80 Ω (PEDOT (6:1)), and 0.96 Ω (PEDOT (9:1)), respectively. It is clear that the internal resistance of PEDOT (3:1) is relatively lower among PEDOTs. The radius of the semicircle represents the charge transfer resistance (Rct) as can be seen from Figure 7. The charge transfer resistance (Rct) is 0.14 Ω (PEDOT (3:1)), 0.15 Ω (PEDOT (6:1)), and 0.16 Ω (PEDOT (9:1)), respectively. The small semicircle might be due to the diffusion effect of the electrolyte in the electrodes. Secondly, in the middle-frequency regime, an extremely small 45° inclination can be seen (Warburg response) which arises as a result of distributed capacitance/impedance in a porous material. Thirdly, at low frequencies, the vertical line indicates the pure capacitive behavior (Rp); the more vertical curve suggests the better capacitive behavior of the supercapacitor[43]. It can be seen that the inclined line with a slope is closer to 90° for the PEDOT (3:1), which was a characteristic feature of pure capacitive behavior[44]. All the results also further illustrate that PEDOT (3:1) shows lower resistances and a better capacitive behavior.


The structure and properties of PEDOT synthesized by template-free solution method.

Zhao Q, Jamal R, Zhang L, Wang M, Abdiryim T - Nanoscale Res Lett (2014)

EIS spectra of PEDOT (3:1), PEDOT (6:1), and PEDOT (9:1) at 5 mV. Frequency range =0.01 Hz to 100 KHz.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4196207&req=5

Figure 7: EIS spectra of PEDOT (3:1), PEDOT (6:1), and PEDOT (9:1) at 5 mV. Frequency range =0.01 Hz to 100 KHz.
Mentions: Nyquist plots of PEDOTs at 5 mV over the frequency range of 0.01 Hz to 100 KHz are given in Figure 7. It can be seen that EIS plots contain three well-separated patterns. Firstly, the high-frequency intercept of the semicircle with the real axis can be used to evaluate the value of internal resistance, which included the resistance of the electrolyte solution, the intrinsic resistance of the active material, and the contact resistance at the interface active material/current collector[41,42]. The values of solution resistance (Rs) obtained from Figure 7 are 0.68 Ω (PEDOT (3:1)), 0.80 Ω (PEDOT (6:1)), and 0.96 Ω (PEDOT (9:1)), respectively. It is clear that the internal resistance of PEDOT (3:1) is relatively lower among PEDOTs. The radius of the semicircle represents the charge transfer resistance (Rct) as can be seen from Figure 7. The charge transfer resistance (Rct) is 0.14 Ω (PEDOT (3:1)), 0.15 Ω (PEDOT (6:1)), and 0.16 Ω (PEDOT (9:1)), respectively. The small semicircle might be due to the diffusion effect of the electrolyte in the electrodes. Secondly, in the middle-frequency regime, an extremely small 45° inclination can be seen (Warburg response) which arises as a result of distributed capacitance/impedance in a porous material. Thirdly, at low frequencies, the vertical line indicates the pure capacitive behavior (Rp); the more vertical curve suggests the better capacitive behavior of the supercapacitor[43]. It can be seen that the inclined line with a slope is closer to 90° for the PEDOT (3:1), which was a characteristic feature of pure capacitive behavior[44]. All the results also further illustrate that PEDOT (3:1) shows lower resistances and a better capacitive behavior.

Bottom Line: In this study, a simple one-step template-free solution method was developed for the preparation of poly(3,4-ethylenedioxythiophene) (PEDOTs) with different morphologies by adjusting various ratios of oxidant (FeCl3·6H2O) to monomer (3,4-ethylenedioxythiophene (EDOT)).The morphological analysis showed that PEDOT prepared from an oxidant/monomer ratio of 3:1 displayed a special coral-like morphology, and the branches of 'coral' would adjoin or grow together with increasing content of oxidant in the reaction medium; consequently, the morphology of PEDOT changed from coral to sheets (at an oxidant/monomer ratio of 9:1).The electrochemical analysis proved that the PEDOT prepared from an oxidant/monomer ratio of 3:1 had the lowest resistance and the highest specific capacitances (174 F/g) at a current density of 1 A/g with a capacity retention rate of 74% over 1,500 cycles, which indicated that the PEDOT with a coral-like morphology could be applied as a promising electrode material for supercapacitors.

View Article: PubMed Central - HTML - PubMed

Affiliation: Key Laboratory of Petroleum and Gas Fine Chemicals, Educational Ministry of China, School of Chemistry and Chemical Engineering, Xinjiang University, Urumqi 830046, People's Republic of China ; Key Laboratory of Functional Polymers, Xinjiang University, Urumqi 830046, People's Republic of China.

ABSTRACT
In this study, a simple one-step template-free solution method was developed for the preparation of poly(3,4-ethylenedioxythiophene) (PEDOTs) with different morphologies by adjusting various ratios of oxidant (FeCl3·6H2O) to monomer (3,4-ethylenedioxythiophene (EDOT)). The results from structural analysis showed that the structure of PEDOT was strongly affected by the oxidant/monomer ratio, and the polymerization degree, conjugation length, doping level, and crystallinity of PEDOT decreased with increasing of the oxidant/monomer ratio. The morphological analysis showed that PEDOT prepared from an oxidant/monomer ratio of 3:1 displayed a special coral-like morphology, and the branches of 'coral' would adjoin or grow together with increasing content of oxidant in the reaction medium; consequently, the morphology of PEDOT changed from coral to sheets (at an oxidant/monomer ratio of 9:1). The electrochemical analysis proved that the PEDOT prepared from an oxidant/monomer ratio of 3:1 had the lowest resistance and the highest specific capacitances (174 F/g) at a current density of 1 A/g with a capacity retention rate of 74% over 1,500 cycles, which indicated that the PEDOT with a coral-like morphology could be applied as a promising electrode material for supercapacitors.

No MeSH data available.