Water in Redox Active Ionic Liquid (WIL) Electrolytes for Energy Storage

Large-scale and efficient utilization of renewable energy (e.g. solar and wind) can significantly address the burgeoning energy demand of modern society, and simultaneously mitigate the resource limitation and environmental problems of fossil fuels. With the technological merits of decoupled energy and power, high current and power performance, and non-flammable and low cost aqueous supporting electrolytes, aqueous redox flow batteries (ARFBs) are highly attractive for scalable and dispatchable storage (up to MW/MWh) of renewable but intermittent solar and wind energy. ARFBs employ two redox couples in liquid forms as charge storage materials for energy conversion between electrical energy and chemical energy. The cathode and anode liquid electrolytes, called catholyte and anolyte respectively, are stored in two separate reservoirs and pumped through electrode surface of an independent electrochemical cell where electrochemical reactions take place for the energy conversion. However, traditional aqueous inorganic redox batteries (AIRFBs) such as the state-of-the-art vanadium AIRFBs are difficult to implement for wide-spread energy storage applications due to a number of technical challenges including high capital costs. Here we propose to develop novel charge storage electrolytes called water in redox active ionic liquid electrolytes to address the existing challenges of AORFBs. The success of the propose will open a new regime to develop high voltage, high energy density, and sustainable AORFBs for scalable and dispatchable energy storage.