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Updated: Jun 24, 2025
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A Protocol for Electrochemical Evaluations and State of Charge Diagnostics of a Symmetric Organic Redox Flow Battery
Published on: February 13, 2017
10.5K
A Universal Coulombic Efficiency Compensation Strategy for Zinc-Based Flow Batteries
Shiqiang Huang1, Mengxiao Li1, Yuxi Song1
1Department of Materials Science and Engineering, National University of Singapore, Singapore, 117576, Singapore.
Advanced Materials (Deerfield Beach, Fla.)
|June 13, 2024
Summary
Alkaline zinc-iron flow batteries (AZIFBs) achieve improved cycling by using oxygen evolution reaction (OER) to compensate for coulombic efficiency (CE) loss. This strategy enhances battery longevity and stability for energy storage applications.
Area of Science:
- Electrochemistry
- Materials Science
- Energy Storage
Background:
- Alkaline zinc-iron flow batteries (AZIFBs) offer safe, low-cost energy storage.
- Irreversible anodic parasitic reactions degrade AZIFB coulombic efficiency (CE) and cycling performance.
- Unbalanced catholyte/anolyte charge states and pH fluctuations are key issues.
Purpose of the Study:
- To develop a universal CE compensation strategy for AZIFBs.
- To address coulombic efficiency loss and improve cycling stability.
- To mitigate parasitic reactions and pH imbalances.
Main Methods:
- A CE compensation strategy utilizing the oxygen evolution reaction (OER) on the cathodic side was implemented.
- OER was achieved electrochemically on the electrode or via a redox-mediated process in an external reactor.
- The strategy consumes excess hydroxide ions (OH-) during cycling to counteract parasitic reactions.
Main Results:
- The strategy effectively equalized catholyte/anolyte charge states and counteracted pH fluctuations.
- Accumulation of [Fe(CN)6]3- and [Zn(OH)4]2- was mitigated.
- AZIFBs exhibited exceptional cycling stability with a capacity fading rate of 0.0128%/day over 600 cycles at 80% SOC.
Conclusions:
- The OER-centered CE compensation strategy significantly enhances AZIFB cycling performance.
- This approach offers a viable solution for coulombic efficiency loss in AZIFBs.
- The strategy is potentially applicable to other battery technologies suffering from water/oxygen-induced parasitic reactions.
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