VAFLOW: Using metallic residues for energy storage

Vanadium from industrial by-products stores energy for business and private households

Refineries as a residue source

Vanadium-containing residues accumulate in various industries, e.g. in refineries.

Metallic residues

Residues serve as raw materials for efficient energy storage.

Redox flow battery

The developed electrolytes are tested in the battery laboratory of Fraunhofer UMSICHT.

Project aims

Efficient energy storage systems require economically strategic raw materials. The aim of the VAFLOW joint project is to pyro- and hydrometallurgically process industrial vanadium-containing residues and by-products to make a quality-assured vanadium electrolyte. This electrolyte is to be used in redox flow battery storage to reduce the dependence on imports of one of the key components of this storage technology and to further increase competitiveness.


The strong expansion of renewable energies is already causing demand for energy storage systems to increase. Their production, in turn, depends on raw materials such as vanadium, which could not previously be substituted. Although domestic industrial residues also have a relevant vanadium content, most of the raw material is currently imported. The joint project VAFLOW is, therefore, investigating and developing new ways of using vanadium-containing residues from domestic industry. In doing so, the researchers are particularly considering residual materials that have not yet been the focus of attention for vanadium recovery and electrolyte production.

Linking of the energy transition and raw materials shift

The VAFLOW joint project is developing processing methods for vanadium-containing residual materials for use in redox flow battery storage systems. Industrial raw materials will thus ideally not only be used much more efficiently. The extracted recyclable materials will also be converted as electrolytes into a concrete application for the energy transition. In this way, the joint project addresses the energy transition and raw materials shift in equal measure. The project team is pursuing an interdisciplinary approach for the targeted screening of various industries in which the relevant residual substances are produced, the analysis of these substances, and the development of new business models.


The joint project VAFLOW covers the entire value creation chain: Using material flow and process analyses, residual materials containing vanadium are first identified and characterized in various branches of industry and a catalog of requirements is drawn up for use in redox flow battery storage and metallurgical processing. The residual materials are then hydro- and pyrometallurgically processed in laboratory processes. The researchers then apply the most promising processes on a pilot-plant scale and provide vanadium electrolytes for long-term and cycle tests in a test laboratory. Recovery strategies and business models for vanadium recovery are also developed – especially from sources in which vanadium is only present in low concentrations as an accompanying element. In addition, the project team analyses and evaluates the process chain from an economic and ecological point of view.

Project partners

  • Nickelhütte Aue GmbH
  • TU Bergakademie Freiberg – Institut für NE-Metallurgie und Reinststoffe
  • CMS Green Energy GmbH
  • Assoziierte Partner aus der Erdöl- und Chemieindustrie

Funding information

Federal Ministry of Education and Research


Duration: May 2016 to April 2019