This document is a review of redox flow batteries (RFBs), which are gaining attention due to their ability to store large amounts of electrical energy efficiently and cost-effectively. The review focuses on the underlying physical processes, transport phenomena, and kinetic phenomena in RFBs, as well as the most common redox couples. RFBs separate power and energy, allowing for optimization over a broader range of variables and easier storage increases compared to conventional batteries. The review discusses various RFB technologies, including iron/chromium, bromine/polysulfide, all-vanadium, vanadium/bromine, hydrogen-based systems, and hybrid RFBs such as zinc/bromine and soluble lead-acid. It also explores non-aqueous RFBs and other configurations like lithium-air batteries. The kinetics of redox reactions, including the Butler-Volmer model and the distinction between inner-sphere and outer-sphere reactions, are discussed to understand the fundamental principles governing RFB performance. The review aims to provide a comprehensive overview of RFBs, their applications, and future research needs.This document is a review of redox flow batteries (RFBs), which are gaining attention due to their ability to store large amounts of electrical energy efficiently and cost-effectively. The review focuses on the underlying physical processes, transport phenomena, and kinetic phenomena in RFBs, as well as the most common redox couples. RFBs separate power and energy, allowing for optimization over a broader range of variables and easier storage increases compared to conventional batteries. The review discusses various RFB technologies, including iron/chromium, bromine/polysulfide, all-vanadium, vanadium/bromine, hydrogen-based systems, and hybrid RFBs such as zinc/bromine and soluble lead-acid. It also explores non-aqueous RFBs and other configurations like lithium-air batteries. The kinetics of redox reactions, including the Butler-Volmer model and the distinction between inner-sphere and outer-sphere reactions, are discussed to understand the fundamental principles governing RFB performance. The review aims to provide a comprehensive overview of RFBs, their applications, and future research needs.