November 2018

Redox flow batteries are suitable for the stationary storage of intermittent energy provided by renewable energies. The beneficial design of the redox flow battery enables the storage of energy in liquid electrolytes in different oxidation states outside the actual electrochemical cell. Currently, the active material dissolved in the electrolyte constitutes the main cost factor for redox flow batteries. Using cheaper organic molecules instead, that for example may be obtained by purification of waste products from the pulp and paper industry, could save costs and further increase the economic viability of redox flow batteries. In the search for a suitable molecule that fits this application, the BMEL project FOREST is currently investigating several organic molecules for their stability and performance. The picture shows the measurement setup used for a lab-sized redox flow battery (center). The dissolved active materials – here in the form of an organic electrolyte on the anode and a vanadium (IV) based electrolyte on the cathode side – are transported into the electrochemical cell by pumps. A reference electrode allows for the recording of the working (WE) and counter electrode (CE) potentials during battery cycling and therefore enables to draw conclusions about the performance and degradation behavior of the associated active materials (right). Picture submitted by Dominik Emmel and Jonas Hofmann, RG Dr. Daniel Schröder