Review of zinc dendrite formation in zinc bromine redox flow battery

The zinc bromine redox flow battery (ZBFB) is a promising battery technology because of its potentially lower cost, higher efficiency, and relatively long life-time. However, for large-scale applications the formation of zinc dendrites in ZBFB is of a major concern. Details on formation, characterization, and state-of-the-art of preventing zinc dendrites are presented here and analyzed both from a micro and macro perspective. Generally, the zinc dendrite formation includes an initiation and a growth stage. The overpotential is the determining factor for the initiation of dendrites, while the initiation time and the deposition morphology of further growth are largely related to the localized current density. The dominant strategies for preventing dendritic growth include reducing the concentration gradient of ions, eliminating the nonuniform localized current density, and changing the nuclear potential of zinc ions. Improving the electrolyte and electrode performance as well as managing the physical properties of the battery would be of great importance for these purposes. Several promising ideas to solve the zinc dendrite issue are proposed such as covering 3D porous electrodes with a zinc oxide film or employing a self-healing electrostatic shield mechanism.