Related Experiment Video
Updated: Jun 25, 2025
09:49
A Protocol for Electrochemical Evaluations and State of Charge Diagnostics of a Symmetric Organic Redox Flow Battery
Published on: February 13, 2017
10.5K
Aqueous Redox Flow Cells Utilizing Verdazyl Cations enabled by Polybenzimidazole Membranes
Simon Kunz1,2, Trung Tuyen Bui2, Dominik Emmel3
1Institute of Physical Chemistry and Center for Materials Research, Justus Liebig University Giessen, Heinrich-Buff-Ring 17, 35392, Giessen, Germany.
Chemsuschem
|May 21, 2024
Summary
This study explores verdazyl cations in aqueous redox flow batteries (RFBs). Polybenzimidazole (PBI) membranes show superior stability and performance compared to Nafion, enabling efficient energy storage.
Area of Science:
- Electrochemistry and Energy Storage
- Materials Science for Batteries
Background:
- Non-aqueous organic redox flow batteries (RFBs) using verdazyl radicals are promising for energy storage.
- Verdazyl cations in acidic aqueous electrolytes and their membrane interactions remain underexplored.
Purpose of the Study:
- To investigate the interactions between 1,3,5-triphenylverdazyl cation and commercial Nafion 211 and polybenzimidazole (PBI) membranes.
- To enhance the performance of aqueous RFBs utilizing verdazyl cations.
Main Methods:
- Systematic investigation of 1,3,5-triphenylverdazyl cation interactions with Nafion 211, mPBI, and OPBI membranes.
- Evaluation of membrane pre-treatments with KOH and H3PO4.
- Lab-scale symmetrical RFB cell tests to assess capacity retention and I-V curves.
Main Results:
- Nafion 211 exhibited significant absorption of the verdazylium cation, leading to conductivity loss.
- mPBI and OPBI membranes demonstrated chemical stability and negligible absorption of the verdazylium cation.
- KOH pre-treatment of PBI membranes enhanced ionic conductivity and reduced cation absorption/permeation.
Conclusions:
- Polybenzimidazole (PBI) based membranes offer superior cycling stability for aqueous RFBs with 1,3,5-triphenylverdazyl cations compared to Nafion 211.
- Low-cost PBI membranes with verdazyl cations in acidic electrolytes achieve high cycling stability (2% d⁻¹ capacity fading), outperforming non-aqueous systems.
Keywords:
energy storagemembranesorganic electrolytespolybenzimidazoleredox flow batteryverdazyl radicalMore Related Videos
Related Concept Videos
02:47Voltaic/Galvanic Cells
57.1K
Spontaneous Chemical Reactions
Spontaneous redox reactions occur abundantly in nature. The chemical reaction occurring in a disposable AA battery powering our remote controls is one such example of a spontaneous redox reaction. Another example is the immersion of coiled copper wire into an aqueous silver nitrate solution. The reaction shows a gradual, visually impressive color change from colorless to bright blue and the formation of a grey precipitate on the copper wire. In this experiment,...
Spontaneous redox reactions occur abundantly in nature. The chemical reaction occurring in a disposable AA battery powering our remote controls is one such example of a spontaneous redox reaction. Another example is the immersion of coiled copper wire into an aqueous silver nitrate solution. The reaction shows a gradual, visually impressive color change from colorless to bright blue and the formation of a grey precipitate on the copper wire. In this experiment,...
57.1K
03:00Electrolysis
26.3K
In a galvanic cell, the electrical work is done by a redox system on its surroundings as electrons produced by the spontaneous redox reactions are transferred through an external circuit. Alternatively, an external circuit does work on a redox system by imposing a voltage sufficient to drive an otherwise nonspontaneous reaction in a process known as electrolysis. For instance, recharging a battery involves the use of an external power source to drive the spontaneous (discharge) cell reaction in...
26.3K
01:15Potentiometry: Membrane Electrodes
564
Membrane electrodes, also known as p-ion electrodes, use membranes that selectively interact with free analyte ions, generating a potential difference across the membrane. The resulting membrane potential, known as the asymmetry potential, is not zero even when analyte concentrations on both sides of the membrane are equal. The membrane's response is typically not selective to a single analyte but proportional to the concentration of all ions in the sample solution capable of interacting at...
564
01:10Voltammetric Techniques: Cyclic Voltammetry
445
Cyclic voltammetry (CV) is an electrochemical technique used to investigate the redox properties of a chemical species. It involves measuring the current response of an electrochemical cell as a function of the applied potential. The setup for cyclic voltammetry typically consists of a working electrode, a reference electrode, and a counter electrode—all immersed in an electrolyte solution. The working electrode is where the redox reaction of interest occurs, while the reference electrode...
445