Long-cycling organic flow batteries enabled by electronic-spatial synergistic modulation

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Aqueous organic redox flow batteries (AORFBs) are promising for grid-scale energy storage.
• Key limitations include poor stability and solubility of active materials.
• Developing robust and soluble organic molecules is crucial for AORFB advancement.

Purpose of the Study:

• To enhance the aqueous dissolution and electrochemical robustness of organic redox-active species.
• To design and synthesize novel 4-aminophenol (PAP)-based molecules with improved properties.
• To investigate the structure-property relationships governing stability and solubility.

Main Methods:

• Electronic-spatial synergistic modulation strategy.
• Synthesis of 1-(4-(4-hydroxyphenyl)piperazin-1-yl)ethan-1-one (AHPP) via piperazine ring and acetyl group incorporation.
• In situ spectroscopic and electrochemical analysis.
• Computational modeling.
• Life cycle assessment.

Main Results:

• AHPP exhibits enhanced solubility (1.9 molar) and electrochemical stability.
• An all-organic flow battery using AHPP achieved 95.7% capacity retention over 5000 cycles.
• Stable operation was observed across a wide temperature range.
• Elucidation of redox chemistry and link between intermediate stability and functional groups.

Conclusions:

• The synergistic modulation strategy effectively enhances both solubility and stability of organic active materials.
• AHPP demonstrates significant potential for practical, long-term grid-scale energy storage.
• Life cycle assessment indicates a favorable environmental footprint for AHPP-based batteries.