Surface Modification of Sulfonated Poly(phenylene oxide) Membrane for Vanadium Redox Flow Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Sulfonated poly(phenylene) oxide (sPPO) is a common polymer electrolyte membrane material.
• Vanadium redox flow batteries (VRFBs) require durable and cost-effective membranes for efficient energy storage.
• Existing sPPO membranes can suffer from poor chemical durability in VRFB operating conditions.

Purpose of the Study:

• To develop a low-cost, highly durable polymer electrolyte membrane for VRFBs.
• To enhance the chemical stability of sPPO membranes using a polydopamine (PDA) coating.
• To evaluate the performance of the PDA-coated sPPO membrane in VRFB applications.

Main Methods:

• Coating sPPO membranes with a dopamine hydrochloride solution to form a PDA layer.
• Characterization of the PDA coating using Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray spectroscopy (EDX).
• Assessment of proton conductivity and chemical stability through VO²⁺ reducibility tests.

Main Results:

• SEM and EDX confirmed the successful deposition of a PDA coating on the sPPO membrane.
• The PDA-coated sPPO membrane exhibited decreased proton conductivity due to increased resistance.
• Significant improvement in chemical stability was observed, with enhanced resistance to VO²⁺ in VRFB conditions.

Conclusions:

• The PDA coating effectively enhances the chemical durability of sPPO membranes for VRFBs.
• Despite reduced proton conductivity, the improved stability makes PDA-coated sPPO a promising candidate for long-term VRFB operation.
• This cost-effective membrane offers a viable solution for advancing VRFB technology.