One-Electron Mechanism in a Gel–Polymer Electrolyte Li–O2 Battery

Abstract

Development of better energy storage media is vital in the adoption of renewable energy technologies, and lithium–air (O2) batteries have spurred great interest. However, current Li–O2 batteries are plagued by unwanted side reactions, flammable electrolytes, and slow kinetics attributed to the 2 mol e–/mol O2 peroxide chemistry. In this work, we show that a gel polymer electrolyte consisting of a polymer, ionic liquid, and salt can control the oxygen reduction chemistry in a Li–O2 cell (switching from a 2 e– to a 1 e– superoxide chemistry), support the formation of ionic liquid–superoxide complexes, and reduce the number of reactive species present in the cell. A one electron process could allow for newer energy-dense Li–O2 batteries with faster kinetics and higher energy efficiencies typical of superoxide-dominant Na–O2 and K–O2 batteries.