Ion Transport in Laser-Induced Graphene Cation-Exchange Membrane Hybrids

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Ion-exchange membranes are crucial in various applications.
• Hybridizing membranes with laser-induced graphene (LIG) offers potential functional surface effects.
• Understanding electrical property changes in LIG-modified membranes is essential.

Purpose of the Study:

• To investigate the electrical properties of ion-exchange membranes modified with laser-induced graphene (LIG).
• To establish electrochemical impedance spectroscopy (EIS) as a method for characterizing LIG-modified membranes.
• To correlate membrane electrical properties with ion transport selectivity.

Main Methods:

• Electrochemical impedance spectroscopy (EIS) was employed to study LIG-modified ion-exchange polymeric membranes.
• EIS spectra were fitted to an electrochemical equivalent circuit to determine conductivity and capacitance.
• Transport selectivity of counterions was quantified using membrane conductivities derived from EIS.

Main Results:

• The conductivity and effective capacitance of sulfonated poly(ether sulfone) membranes were determined.
• A direct correlation was found between total ohmic resistance and polymer thickness.
• The contribution of the LIG layer to the ohmic resistance was negligible.

Conclusions:

• Electrochemical impedance spectroscopy (EIS) is a rapid, low-cost, and noninvasive method for probing LIG modification on membranes.
• Membrane electrical properties, particularly resistance, are primarily influenced by polymer thickness, not the conductive LIG layer.
• EIS measurements can inform the transport selectivity of modified ion-exchange membranes.