Organic Redox Targeting Flow Battery Utilizing a Hydrophilic Polymer and Its In-Operando Characterization via...

Area of Science:

• Electrochemistry
• Polymer Science
• Energy Storage

Background:

• Aqueous organic redox targeting flow batteries (RTFBs) offer potential for grid-scale energy storage.
• Developing stable and efficient redox target materials is crucial for RTFB performance.

Purpose of the Study:

• To synthesize and characterize a novel hydrophilic, water-insoluble polymer, poly(2,2,6,6-tetramethylpiperdinyloxy-4-yl-methacrylamide) (PTMAm), as a redox target material.
• To evaluate the performance of PTMAm in combination with TEMPOAmide in an RTFB.
• To introduce in-operando state-of-charge (SOC) monitoring for redox targets and a new metric, "redox targetivity".

Main Methods:

• Synthesis and processing of PTMAm into granules with conductive agents and alginate binder.
• Electrochemical characterization of the PTMAm/TEMPOAmide system.
• Flow battery testing and in-operando electrolyte SOC monitoring.
• Development and application of the "redox targetivity" figure of merit.

Main Results:

• PTMAm was successfully processed into a hydrophilic, water-insoluble redox target material.
• The PTMAm/TEMPOAmide combination demonstrated electrochemical activity suitable for RTFBs.
• In-operando SOC monitoring of the redox target was achieved for the first time, providing cycling insights.
• The proposed "redox targetivity" metric offers a new tool for optimizing RTFB components and operation.

Conclusions:

• PTMAm is a promising redox target material for aqueous organic RTFBs.
• In-operando SOC monitoring and the "redox targetivity" metric advance the understanding and design of RTFBs.
• This work facilitates the optimization of materials, cell designs, and operational parameters for future RTFB development.