The effect of various electrolyte cations on electrochemical performance of polypyrrole/RGO based supercapacitors

Abstract

In this work, polypyrrole/graphene doped by p-toluenesulfonic is prepared as an active material for supercapacitors, and its capacitance performance is investigated in various aqueous electrolytes including HCl, LiCl, NaCl, and KCl with a concentration of 3 M, respectively. A rising trend of capacitance is observed according to the cationic mobility (Li(+) < Na(+) < K(+) < H(+)), which is due to its effect on the ionic conductivity, efficient ion/charge diffusion/exchange and relaxation time. On the other hand, long-term cycling stability is in the following order: KCl < NaCl < LiCl < HCl, corresponding to the decreasing tendency of cation size (K(+) > Na(+) > Li(+) > H(+)). The reason can be attributed to the fact that the insertion/de-insertion of large size cation brings a significant doping level decrease and an over-oxidation increase during the charging-discharging cycles. Hence, we not only obtain good capacitance performance (280.3 F g(-1) at 5 mV s(-1)), superior rate capability (225.8 F g(-1) at 500 mV s(-1)) and high cycling stability (92.0% capacitance retention after 10,000 cycles at 1 A g(-1)) by employing 3 M HCl as an electrolyte, but also reveal that the electrolyte cations have a significant effect on the supercapacitors' electrochemical performance.

Cauliflower‐shaped ternary nanocomposites with enhanced power and energy density for supercapacitors

“…For nanocomposite C5 (1:2:0), the peaks obtained are similar to the peaks observed for pure PPY indicating that PPY nanoparticles are formed in the composite. The prominent peaks observed are 1521 cm −1 (C—C stretching), 1294 cm −1 (C—N stretching), 1129 cm −1 (benzenoid‐NH + ‐quinoid stretching), 1029 cm −1 (C—H in‐plane deformation), and 869 cm −1 (C—H/N—H) out‐of‐plane bending …”

“…The prominent peaks observed are 1521 cm −1 (C-C stretching), 1294 cm −1 (C-N stretching), 1129 cm −1 (benzenoid-NH +quinoid stretching), 1029 cm −1 (C-H in-plane deformation), and 869 cm −1 (C-H/N-H) out-of-plane bending. [29][30][31] Raman analysis was done to study the structural properties of CPs, defects in the rGO, and structural changes of their nanocomposites. 28,29 Figure 5A,B shows the Raman spectra for GO, rGO, PANI, and PPY.…”

Study on Combined Optical and Electrochemical Analysis Using Indium‐tin‐oxide‐coated Optical Fiber Sensor

“…The electrolyte concentration has a significant influence on the mass transport of the analyte according to the Nerst‐Planck equation. Additionally, the cationic mobility influence the ionic conductivity, efficient ion/charge diffusion/exchange and relaxation time .…”

A pH‐Tailored Anodic Deposition of Hydrous RuO2 for Supercapacitors

“…Obviously, all CV curves keep a well rectangle‐like shape (even when operated at 200 mV s ‐1 ) and all GCD curves present a symmetric‐triangular shape, both indicating a good rate behavior for ideal capacitors . And all GCD curves are linear without any obvious ohm‐drop (i.e., IR ‐drop), representing a high reversibility of typical capacitors . The specific capacitance C s based on the discharging curve of GCD results at different rates is calculated by equation …”