Electrochemical Energy Storage with an Aqueous Zinc–Quinone Chemistry Enabled by a Mediator-Ion Solid Electrolyte

Quinone series of organics are promising electrode materials for the development of low-cost, sustainable, environmentally benign electrochemical energy storage technologies. However, the redox potential of quinones is sensitively dependent on the acidity and alkalinity of aqueous solutions. This study demonstrates a high-voltage aqueous zinc–quinone battery with an alkaline anode electrolyte (anolyte) and an acidic cathode electrolyte (catholyte), which are separated by a sodium mediator-ion solid electrolyte membrane. The redox chemistries of the acidic quinone cathode and the alkaline Zn anode are ionically linked by the shuttling of sodium mediator ions through the solid electrolyte.