New materials for organic redox flow batteries Scientists in Russia have designed a whole series of new compounds that could serve as catholytes and anolytes in organic redox flow batteries. The materials promise to open up new pathways for further research, and overcome some of the challenges for organic redox flow batteries in commercial, large-scale energy storage projects. Thanks to the potential size of the market for electric vehicles, battery research in recent years has tended to focus on innovations in lithium-ion and other related chemistries that promise to serve this market. For the large-scale energy storage that is increasingly required to balance the intermittency of wind and solar energy, however, redox-flow batteries present an attractive opportunity. The batteries are inherently scalable, and avoid many of the issues with long-term performance, safety, and material availability associated with lithium-ion batteries. Many of the early commercial projects for redox flow batteries (RFBs) rely on vanadium, which comes with some toxicity concerns. There is, however, a long list of materials worth investigating as flow battery components, including abundant organic materials. Among other issues, organic redox flow batteries are held back by low specific capacity. Finding new materials (and combinations of materials) with better characteristics is the simplest way to overcome this challenge, and has been the focus for a group of scientists led by Russian’s Skolkovo Institute of Science and Technology (Skoltech). “We are working with organic redox-active materials solubilized in organic solvents (non-aqueous organic RFBs),” says Skoltech Ph.D. student Elena Romadina. “The main advantages for non-aqueous organic RFB are high cell voltage (up to 5V, versus around 1.6 V for water-based systems), a huge variety of organic redox-active molecules which could be applied, and potential operability at low temperatures, without any concern for freezing below 0 degrees C,” she stated Romadina is the lead author of two new papers exploring new organic materials for RFBs, published in the Journal of Materials Chemistry A and in Chemical Communications. The first evaluated a series of seven promising catholyte materials, and the second describes the synthesis of a phenazine-based anolyte material.