Redox-Flow Batteries consist of two tanks of electrolyte each connected to half cells separated by an ion membrane. The system gets its name from reduction and oxidation reactions within electrochemical cells that generate a voltage potential and electrical current. These reactions are reversible, with their direction depending on whether the battery is being charged or discharged. The total amount of energy stored is directly related to the amount of electrolyte and can be easily increased. This technology holds incredible potential for grid scale power storage. Most importantly, redox flow batteries can be built from low-cost, safe, and sustainable materials.