Vanadium-Redox-Flow-Batteries

Vanadium Redox Flow Batteries (VRFB) are promising devices for energy storage especially with respect to short time stationary demand. Nonetheless, side reactions, Vanadium species cross over through the membrane and volume change over several cycles are challenges that yet need to be overcome.

A critical element of the VRFB is the ionomeric membrane. To achieve high chemical stability, these materials are fluorinated to a high degree. To form the unique water network in between the commonly crystalline backbone sulfonyl-groups are introduced. Depending on the degree of hydratisation the sulfonyl side chains form inverse micelle structures giving rise to water channels inside the otherwise hydrophobic membrane.

In a collaborative effort together with the Beuermann group (technical chemistry) and Turek/Kunz group (chemical engineering) the Fittschen groups studies gradients of Vanadium species in novel membrane materials and common Nafion separators.