Ionic transport kinetics and enhanced energy storage in the electrode/poly(N-vinyl imidazole) interface for...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Controlling ionic transport at electrode/electrolyte interfaces is crucial for micro-scale energy storage.
• Nanostructured solid polymer electrolytes (SPEs) offer potential for advanced device design.

Purpose of the Study:

• To investigate ionic transport and electrical double layer capacitance (EDLC) in a planar micro-supercapacitor (MSC) device.
• To optimize MSC performance by controlling the thickness of a nanostructured poly(N-vinyl imidazole) (PVI) with potassium hydroxide (KOH) electrolyte.

Main Methods:

• Fabrication of planar MSCs using ITO/PVI-KOH/ITO architecture.
• Investigation of adsorption/desorption kinetics at the ITO/PVI-KOH interface.
• Systematic electrochemical characterization of MSCs with varying electrolyte thickness.

Main Results:

• Volumetric capacitance and retention varied significantly with PVI-KOH layer thickness at the nanoscale.
• A five-series-cell MSC achieved a 5.0 V operating voltage.
• Maximum volumetric energy and power densities were 0.056 mW h cm⁻³ and 6.89 mW cm⁻³, respectively.

Conclusions:

• Hydrated PVI facilitates charge migration and ion separation at electrode/electrolyte interfaces.
• The study confirms the role of electromotive force in separating cations and anions.
• Nanostructured SPEs are promising for high-performance micro-supercapacitors.