Due to their high efficiency, high number of cycles and the independent scalability of power and capacity, flow batteries have the potential to relieve and to decentralise the eletricity grids of the future. Currently, flow batteries based on vanadium are the most widespread. However, this is toxic and expensive due to the limited reserves, which are restricted to only a few countries (Russia, China and South Africa). Iron-based flow batteries are an alternative. Iron is available worldwide in large quantities and has a cost advantage over vanadium. The cooperation project combines the knowledge of six partners from Germany and Korea.
At the Seoul National University of Science and Technology (SNUST), inexpensive organometallic active materials based on iron and zinc or iron and cobalt, corresponding catalysts and aqueous alkaline electrolytes are being developed and tested for the anodic side. On the cathodic side, potassium hexacyanoferrate is used as electrolyte. The development of suitable membranes with chelated metal ions is carried out by the Korea Institute of Science and Technology (KIST). Eisenhuth GmbH develops, produces and tests the bipolar plates. The flow field is being developed jointly with the TU Clausthal. The TU Clausthal is also testing the compatibility and stability of the individual components, investigating the electrochemical kinetics of the electrolyte and testing individual cells. On this basis, stacks of 10 cells are to be developed, produced and tested in Korea by ETIS ltd. The partner Korid Energy ltd. is responsible for expanding the stack to include the periphery for the development of a complete battery system. Initially, prototypes will be produced on a small scale of about 0.2 kW and, after an intermediate step, larger systems with an output of 10 kW.
The aim of the project is to use new materials and economies of scale for larger systems to introduce economical flow batteries to the market as a more environmentally friendly alternative to competitive technologies