Flow batteries are a type of rechargeable battery that store energy in liquid electrolytes. These electrolytes are contained in separate tanks, allowing for easy scaling of energy capacity by simply increasing the size of the tanks. This design makes flow batteries particularly suitable for large-scale energy storage applications, such as integrating renewable energy sources like solar power and wind energy into the grid. The two main types of flow batteries are vanadium redox and zinc-bromine batteries. They offer advantages like long cycle life and the ability to discharge energy over extended periods. Flow batteries are increasingly being explored for use in smart grids and energy management systems due to their flexibility and efficiency.