Systematic Study of O2 Supply in Li–O2 Batteries with High and Low Doner Number Solvents

Abstract

The Li–O2 battery is a promising technology due to its high theoretical specific energy. However, its practical capacity and cycling performance need further improvement. In this scenario, the influence of the electrolyte and the supply of air/O2 to the device are essential to enhance the performance and build a commercial prototype. This paper presents a study focusing on the influence of oxygen flow and pressure in the gravimetric capacity of Li–O2 batteries using two different electrolytes: dimethyl sulfoxide (DMSO/LiClO4) and tetraethylene glycol dimethyl ether (TEGDME/LiClO4). This study pointed out the negative influence of flow over the capacity when combined in an open cell. Due to electrolyte loss, the life cycle was also deeply affected using the open cell, especially for DMSO. However, DMSO leads to the best performance due to higher ionic conductivity, oxygen diffusivity, and absence of a direct reaction with the lithium anode. Thus, the closed cell reached a maximum discharge capacity of 22537 mAh g–1 with 26 cycles of 1000 mAh g–1 for DMSO and 8764 mAh g–1 with 13 cycles of 1000 mAh g–1 for TEGDME.