Emulsions that store oxygen for fast ORR kinetics and multifunctional robotic and mobility systems

Abstract

Human circulatory systems store large concentrations of oxygen and provide it continuously and simultaneously to trillions of cells without the need for each cell to access the surrounding environment. Inspired by biological circulatory systems, we envision future robotic systems with multifunctional, fully integrated, air-rechargeable energy delivery and storage. We present an aqueous air catholyte emulsion (ACE) with high oxygen solubility that can derive energy entirely from dissolved oxygen. With only 20% silicone oil by volume, ACEs can store twice as much dissolved oxygen (15 mg/L) as pure KOH samples, remain stable for several months, and show superior oxygen reduction reaction kinetics compared to KOH. Zinc-air flow cells with fully submerged electrodes can achieve 4.6 mW/cm² at 5.6 mA/cm². A multifunctional actuator flow cell configuration employs an ACE as both a hydraulic actuator and an energy storage fluid, demonstrating the feasibility of ACEs as multifunctional, flexible power sources for soft robotic systems.