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

Due to its high energy density, largely exceeding that of conventional lithium-ion batteries,[1–2] the Li/O₂ battery is presently considered as a very promising energy storage system. However, the practical development of this battery is still hindered by several issues, such as: 1) the limited cycle number, affecting its life; 2) the high charge–discharge polarization, resulting in low energy efficiency, and 3) the occurrence of side processes due to moisture and carbon dioxide contamination that preventing its use in open air.

The choice of solvent and of electrolyte salt is expected to play a key role in influencing the cell behavior. To further investigate this important aspect, in this work we have examined the response of a Li/O₂ cell using a tetraethylene glycol dimethyl ether electrolyte solutions, with four different salts, that is, LiPF₆, LiClO₄, LiCF₃SO₃, LiN(SO₂CF₃)₂. This comparative study demonstrates that LiCF₃SO₃ salt is the best choice for assuring low cell polarization [3].

[1] B. Scrosati, J. Hassoun, Y.-K. Sun, Energy Environ. Sci. 2011, 4, 3287 –3295.

[2] G. Girishkumar, B. McCloskey, A. C. Luntz, S. Swanson, W. Wilcke, J. Phys. Chem. Lett. 2010, 1, 2193– 2203.

[3] Giuseppe Antonio Elia, Jin-Bum Park, Yang-Kook Sun, Bruno Scrosati, Jusef Hassoun, ChemElectroChem, DOI: 10.1002/celc.201300160.