Flow batteries are rechargeable energy storage systems that do their job by storing energy in contained liquid chemicals divided by a membrane layer. Once the battery has been filled by drawing electrons away from a positively-charged liquid mixture into a negatively-charged fluid, an electric current is created when the battery is turned on and the electron movement goes in the opposite direction from the negative to the positive solution. The resultant cell voltage generated by this electron shift is typically in the region of 2 volts. Researchers at Harvard University have now come up with a new way to create these alkaline flow batteries making use of a modified natural vitamin, known as vitamin B2. Initially, the researchers replaced the metal ions that normally reside within the products of acidic electrolytes, with organic compounds called quinones. This was followed by a research study where they created a quinone able to operate in alkaline fluids by replacing the original bromine additive with ferrocyanide, a common anti-caking substance used in kitchen salt. This work eventually led to the hunt for a much more environmentally-friendly quinone, before the researchers realised that the natural vitamin B2 could be used as a substitute. Making use of molecules such as vitamin B2 opened up a new world of similar natural molecules for the group to explore, with the goal of creating a high-performing, long-lasting, organic-based flow battery. Like vitamin B2, many of these molecular derivatives are non-toxic and are able to be manufactured inexpensively, so the scientists hope that their use could one day facilitate large, ineffective power storage from renewable sources such as wind and solar.