Elucidation and Comparison of the Effect of LiTFSI and LiNO3 Salts on Discharge Chemistry in Nonaqueous Li–O2 Batteries

The role of lithium salts in determining the discharge capacity of Li–O2 batteries has been highlighted in several recent studies; however, questions pertaining to their effect on the cathode surface and in the solution phase still remain unanswered. We conducted galvanostatic discharge experiments with different compositions of a binary mixture of 1 M of LiNO3 and LiTFSI in tetraglyme (TEGDME) as the electrolyte and analyzed the discharge products using techniques such as FT-IR, Raman spectroscopy, and SEM. It was observed that there is a nonlinear correlation between the electrolyte composition and the first discharge capacity, with the highest discharge capacity achieved with the electrolyte composition as 0.75 M LiNO3 and 0.25 M LiTFSI. The ID/IG values obtained from Raman spectroscopy, which represent the degree of order in the carbon cathode surface, were found to be correlated to the measured capacity. Our results indicate that at concentrations of LiNO3 higher than 0.75 M in the electrolyte, nitro...