Role of the Lithium Salt in the Performance of Lithium-Oxygen Batteries: A Comparative Study

In this paper we report a comparative study of the electrochemical properties of a lithium-oxygen cell using a tetraethylene glycol dimethyl ether (TEGDME)-based electrolyte solution with four different lithium salts, namely, lithium-bis-(trifluormethanesulfonyl)-imide, LiN(SO2CF3)(2), lithium trifluoromethanesulfonate, LiCF3SO3, lithium perchlorate, LiClO4, and lithium hexafluorophosphate, LiPF6. This study evidences the role of the electrolyte salt in affecting the cell polarization as a reflection of its specific properties in terms of lithium transference number and interface resistance. LiCF3SO3 is finally identified as the best choice for assuring low cell polarization.