Using Hemoglobin as a Performance Enhancer in Rechargeable Lithium–Oxygen Batteries

Abstract

We demonstrate here that hemoglobin, a biological oxygen binder/transporter, can be used as a performance-enhancing additive in nonaqueous lithium–oxygen batteries. In a fashion similar to the way hemoglobin binds and transports oxygen in the human blood, it can bind and transport oxygen in the electrolyte solution in a conventional lithium–oxygen battery. Binding and transport of oxygen into the soluble electrolyte phase enhance the efficiency of oxygen reduction reactions (ORRs) occurring at the air cathode by preventing the accumulation of solid insulating discharge products at the cathode site. We observe stable galvanostatic cycling, high specific capacity, and low polarization in the cell in the presence of hemoglobin. Electrochemical impedance spectroscopy indicates low interfacial resistance even after several rounds of galvanostatic charge–discharge cycles. We thus propose the use of oxygen-binding natural biomolecules as possible redox mediators for energy-harvesting systems utilizing oxygen electrochemistry in the future.