Studies on Soluble Lead Redox Flow Battery

Abstract

Redox flow batteries (RFBs) offer an opportunity to make renewable energy storage more affordable and could accelerate prospects for utility-scale development of solar/wind energy storage. RFBs can be almost instantly recharged by replacing the liquid electrolyte. RFBs can be cycled more often and can lend themselves to 100% depth-of-discharge with no negative effects on performance unlike lead-acid and lithium-ion batteries with depths-of-discharge of 60 and 80%, respectively. RFBs can also last for decades (up to 25 years) before being replaced, making them promising for large utility applications, microgrids and off-grid projects. In particular, soluble lead redox flow batteries (SLRFBs) present several advantages over competing flow battery systems. SLRFBs make use of variable oxidation states of lead. In its simplest form, Pb2+_ions are dissolved in a less toxic and cost-effective aqueous methanesulfonic acid medium as electrolyte that flows through the cells without expensive separators. There are, of course, challenges to surmount such as those related to phase changes at both the positive and negative electrodes. The studies in this thesis are primarily directed to propel SLRFBs from laboratory scale to a functional system by addressing key issues of scaling-up materials, fabrication and engineering.