The Correlation Between Surface Chemistry, Surface Morphology, and Cycling Efficiency of Lithium Electrodes in a Few Polar Aprotic Systems

Abstract

Lithium electrodes in a few selected polar aprotic electrolyte systems were investigated using electrochemical techniques in conjunction with surface‐sensitive Fourier transform infrared spectroscopy and scanning electron microscopy. The solvents used were γ‐butyrolactone (BL), propylene carbonate (PC), and tetrahydrofuran (THF), and the salts included and . Cycling efficiency of lithium electrodes was correlated to their surface chemistry and morphology in the various solvent systems. The effects of both water and oxygen contamination were rigorously studied. It was found that the presence of oxygen in solutions considerably increased the cycling efficiency of the lithium electrode. This effect correlates well with the influence of the presence of oxygen on the surface morphology of lithium electrodes in solutions. The presence of water increases cycling efficiency of Li electrodes in PC, and decreases cycling efficiency of Li electrodes in ethers. These results are discussed in light of the surface chemistry of lithium electrodes in the various solvent systems.