Investigation of the carbon electrode changes during lithium oxygen cell operation in a tetraglyme-based electrolyte

In this paper we investigate in details the changes occurring in the lithium-oxygen cell during operation in a tetraglyme-base electrolyte, in terms of electrochemical behavior and of carbon electrode morphology. The study evidences a decrease of the cell polarization and impedance during cycling associated with a morphological change of the carbon electrode, as demonstrated by SEM images. We attribute the change of the electrode morphology to the already known carbon oxidation process, here resulting in an increased porosity favoring the reversible electrochemical process. The results here reported shed light on important aspects to be considered in order to better understand the complex behavior of the lithium-oxygen battery.