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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
Optimized anion exchange membranes for vanadium redox flow batteries.
Dongyang Chen1, Michael A Hickner, Ertan Agar
1Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
ACS Applied Materials & Interfaces
|June 27, 2013
Summary
Researchers developed new quaternary ammonium functionalized Radel (QA-Radel) membranes for vanadium redox flow batteries (VRFBs). Optimizing ion exchange capacity (IEC) is key, with a 2.0 mequiv g(-1) IEC showing the best balance for VRFB performance.
Area of Science:
- Materials Science
- Electrochemistry
- Energy Storage
Background:
- Vanadium redox flow batteries (VRFBs) are promising for large-scale energy storage.
- Developing efficient and durable membranes is crucial for VRFB performance.
- Anion exchange membranes (AEMs) offer potential advantages over traditional cation exchange membranes.
Purpose of the Study:
- To synthesize and evaluate quaternary ammonium functionalized Radel (QA-Radel) membranes with varying ion exchange capacities (IECs) for VRFB applications.
- To understand the relationship between membrane properties (ionic conductivity, vanadium permeability) and VRFB performance.
- To identify an optimal QA-Radel membrane composition for enhanced VRFB efficiency and longevity.
Main Methods:
- Synthesis of QA-Radel membranes with IECs ranging from 1.7 to 2.4 mequiv g(-1).
- Characterization of membrane transport properties, including ionic conductivity and vanadium (VO2+) permeability.
- Evaluation of membrane performance in single-cell VRFB tests, measuring Coulombic efficiency, voltage efficiency, energy efficiency, and capacity fade during cycling.
Main Results:
- Increasing IEC of QA-Radel membranes enhanced ionic conductivity and VO2+ permeability.
- The 1.7 mequiv g(-1) IEC membrane exhibited the highest Coulombic efficiency and best capacity retention.
- The 2.0 mequiv g(-1) IEC QA-Radel membrane achieved the best balance of properties, yielding a maximum power density of 218 mW cm(-2).
Conclusions:
- Membrane material parameters, specifically IEC, must be carefully optimized for maximum VRFB cell performance.
- QA-Radel membranes show potential for VRFB applications, with the 2.0 mequiv g(-1) IEC offering a promising balance of conductivity and low vanadium crossover.
- Further research into membrane optimization can lead to improved VRFB energy storage systems.
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