Flow Batteries

Renewable energy sources including wind and solar require reliable electrical energy storage systems because of their intermittent nature. Electrochemical energy storage devices such as batteries, fuel cells and flow batteries, and electrochemical capacitors are among the leading energy storage systems because of their scalability, versatility, and ability to provide the energy densities needed for large-scale electrical energy storage. Redox flow batteries consist of two separate electrolytes, one storing the electroactive materials for the negative electrode reactions and the other for the positive electrode reactions. An ion-selective membrane is often used to prevent mixing or crossover of the electroactive species, which can result in the chemical short-circuit. Only the common counter ion carrier is allowed to cross the membrane.