A flow battery contains two substances that undergo electrochemical reactions in which electrons are transferred from one to the other. When the battery is being charged, the transfer of electrons forces the two substances into a state that's “less energetically favorable” as it stores extra energy. (Think of a ball being. A major advantage of this system design is that where the energy is stored (the tanks) is separated from where the electrochemical reactions occur (the so-called reactor, which. A critical factor in designing flow batteries is the selected chemistry. The two electrolytes can contain different chemicals, but today the. A good way to understand and assess the economic viability of new and emerging energy technologies is using techno-economic modeling. With. The question then becomes: If not vanadium, then what? Researchers worldwide are trying to answer that question, and many are focusing on promising chemistries using materials that are more abundant and.