Role of Cations in Ionic Liquid-Based Polymer Composite Electrolyte Organic Supercapacitors

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Solid-state supercapacitors with ionic liquid-based polymer composite electrolytes (IL-b-PCEs) are promising for energy storage.
• The impact of different cation species on IL-b-PCE performance needs further investigation.

Purpose of the Study:

• To analyze the influence of 1-ethyl-3-methylimidazolium (EMIM+), 1-butyl-3-methylimidazolium (BMIM+), and proton (H+) cations on PVA-based IL-b-PCEs.
• To correlate cation properties with physicochemical characteristics and charge storage behavior.

Main Methods:

• Fourier-transform infrared (FTIR) spectroscopy to analyze hydrogen bonding.
• Electrochemical analysis to determine specific capacitance and equivalent series resistance.

Main Results:

• Proton (H+)-based electrolytes (HCl/PVA) showed the highest specific capacitance (12.67 F/g) and lowest resistance (7.7 Ω).
• Imidazolium cations (BMIM+ and EMIM+) resulted in reduced hydrogen bonding, lower capacitance, and higher resistance due to their larger size and steric effects.
• FTIR indicated shifts in O-H stretching bands, confirming reduced hydrogen bonding with bulkier cations.

Conclusions:

• Cation selection critically impacts the electrochemical performance of IL-based solid-state supercapacitors.
• Proton (H+) electrolytes are superior for high-performance energy storage applications due to enhanced ion mobility.
• Findings provide valuable insights for designing advanced energy storage systems.