Temperature Dependence of the Oxygen Reduction Mechanism in Nonaqueous Li-O2 Batteries

Abstract

The temperature dependence of the oxygen reduction mechanism in nonaqueous Li-O2 batteries is investigated within the temperature range of -20 to 40 °C. The discharge capacity of the Li-O2 battery first decreases from 7492 mAh g-1 at 40 °C to 2930 mAh g-1 at 0 °C and then increases sharply with a further decrease in temperature and reaches a very high capacity of 17 716 mAh g-1 at -20 °C at 0.1 mA cm-2. The lifetime of superoxide intermediates and the solution pathway were found to play a dominant role in the discharge of the Li-O2 battery in the temperature range of -20 to 0 °C, but the electrochemical kinetics of oxygen reduction and the surface pathway dominate the discharge behavior of the Li-O2 batteries between 0 and 40 °C. This work will broaden the fundamental understanding of the oxygen reduction process in the Li-O2 battery, especially at different temperatures.