Soluble Lead Redox Flow Batteries: Status and Challenges

Abstract Soluble lead redox flow battery (SLRFB) is an emergent energy storage technology appropriate for integrating solar and wind energy into the primary grid. It is an allied technology of conventional lead‐acid batteries. This appraisal compares lead‐acid batteries and SLRFB apropos their general characteristics. SLRFBs can overcome the inadequate cycle‐life of Lead‐Acid batteries as the electrodes of SLRFB do not participate in the reaction, which helps extending its durability. However, SLRFB has challenges of dendrite formation, oxygen evolution reaction, passivation of PbO 2 and shunt current. These problems need to be resolved before SLRFBs can be projected for large‐scale energy storage applications. In this technical update, we have reviewed the recent studies pertinent to dendrite formation, mechanism of the lead electrode, and reversibility of the PbO 2 electrode in the state‐of‐art of SLRFB along with progress in advances while developing a 12 V – 250 Wh 8‐cell SLRFB stack.