This chapter presents a redox flow batteries review that has been investigated and developed over the past few decades. Redox flow batteries (RFBs) can be used as stationary energy storage systems from small to large scale. Flow batteries are interesting energy storage devices that can be designed flexibly due to the possibility of decoupling of power and energy. The design process allows a battery to evolve as the user needs change. Unfortunately, conventional batteries do not provide such a possibility. Therefore, flow batteries can be used as high energy and high power energy storage devices which could work together with grid-connected renewable energy sources (RES). The main aspects of this chapter correspond to the characterization of redox flow electrodes and electrolytes chemistries. Usually, carbon materials can be used to construct electrode materials of RFBs. Carbon materials are characterized by relatively high electrical conductivity, chemical resistance, and stability in a wide electrochemical window. This review provides a summary of current research and development of RFBs technology including cell design, electrode improvements, separators, and electrolytes.