Researchers develop new system for high-energy-density, long-life, multi-electron transfer bromine-based flow batteries. Credit: DICP Bromine-based flow batteries store energy using a chemical reaction between bromide ions and elemental bromine. This chemistry is attractive because bromine is widely available, has a high electrochemical potential, and dissolves well in liquid electrolytes. The downside appears during charging, when large amounts of bromine are produced. This reactive material