Redox Flow and Aqueous Battery Systems
Due to the increasing share of renewable energies, stationary energy storage systems represent a necessary key technology. They are used for intermediate storage to ensure a constant energy supply independent of fluctuating resources, such as wind and sun. The "Redox Flow and Aqueous Battery Systems" group at Helmholtz Institute Münster (HI MS) is dedicated to developing systems that are both ecological and economical. The focus is on redox flow and aqueous battery systems.
Redox Flow Batteries
In contrast to lithium- and lithium-ion batteries, redox-flow batteries are characterised by the fact that their active material, also called "redox species", is present in dissolved form and must be transported between the tank and the reaction cell by mechanical circulation systems. This results in increased demands on both the active materials and the technical design.
The research of the redox flow team combines basic and applied research and focuses on easily accessible and environmentally friendly active materials. For a holistic view of the redox flow battery including the battery cell structure, the group focuses on optimised cell design as well as monitoring, control and regulation technology using customised sensor technology. Among the various approaches, optical sensors are used to monitor the electrolytes. For cell design, modern techniques from 3D printing are used to enable rapid adaptation of the further developed measuring cells to the redox systems under investigation and their hydrodynamics, and to reduce development costs.
Aqueous Battery Systems
Aqueous battery chemistries show great potential for environmentally friendly, sustainable and cost-effective energy storage. To circumvent the low electrochemical stability window of water (1.23 volts), concepts such as water-in-salt electrolytes, for example high salt-in-water concentrations, are applied. The HI MS group’s research focuses on the development of novel, alternative conducting salts with high solubility and strong coordination capacity of water, which also have good compatibility with selected electrodes for good cell performance.
The researchers place a large emphasis on good environmental compatibility and cost-efficient access to the salts. Methods of thermal, electrochemical and spectroscopic analysis are used for characterisation.
Batteries & Supercaps 2021, 4(6), 923-928, DOI: 10.1002/batt.202100018
Journal of Materials Chemistry A 2020, 8, 22280-22291, DOI: 10.1039/D0TA07891C