| Period: |
01.11.2024 - 31.05.2027 |
|---|---|
| Partner: | Forschungsinstitut für Edelmetalle und Metallchemie |
| Funding: |
Bundesministerium für Wirtschaft und Energie (BMWE) Förderkennzeichen: 011F23477N |
| Project Manager: | Dr. Claudia Weidlich |
| Division: | Chemische Technik |
| Team: | Angewandte Elektrochemie |
Redox flow batteries (RFBs) represent a robust and cost-effective energy storage technology that will be capable of compensating for fluctuations in electricity generation in the future. Due to their inherently low self-discharge and the independent scalability of power and capacity, RFBs are particularly well suited for this role as large-scale electrochemical energy storage systems.
The vanadium-based RFBs commercialized to date are still limited in their application due to their relatively low energy density of 25–50 Wh/L and significant self-discharge caused by vanadium crossover between the half-cells.
Within the scope of this project, new electrolytes for redox flow batteries are therefore to be developed that exhibit a substantially improved energy density while also maintaining low self-discharge. For this purpose, special molybdenum- and tungsten-based polyoxometalates (POMs) will be employed, as they are capable of storing a very large number of electrons.
Owing to the high solubility and the exceptional electron-storage capability of 18 electrons per molecular unit of [P₂Mo₁₈O₆₂]⁶⁻, the energy density is expected to increase by at least a factor of five. Other polyoxometalates, such as [PMo₁₂O₄₀]³⁻ and [H₂W₁₂O₄₀]⁶⁻, can also accommodate a large number of electrons and will likewise be investigated as novel negative electrolytes.
A bromide-based electrolyte will be used in the positive half-cell, which also offers a very high energy density.
In addition, the size of the POM clusters and their anionic structure ensure that no crossover into the positive half-cell occurs during operation, thereby preventing self-discharge. The high stability of these inorganic molecules is also expected to enable a very long service life for the RFB. Furthermore, the recyclability of the electrolytes at the end of their lifetime will be investigated.
To characterize the electrolytes, in situ measurements will also be carried out using reference electrodes and UV/Vis spectroscopy.
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