Characterization of Reaction Products on the Surface of Li/Air Battery Electrodes

Recently, the Li/air batteries have received a lot of attention as an alternative of lithium ion batteries (LIB), since they provide higher energy density than LIB. The Li/air batteries are composed of air electrode, separator, electrolyte, and anode electrode. Among them air electrode plays a key role because the capacity and cycle life of the Li/air batteries are highly dependent on the air electrode. Therefore many studies have focused on the development of air electrode with enhanced electrochemical performances. During the discharge, lithium ions and oxygen dissolved in electrolyte have a reaction on the surface of air electrode and forms reaction products like Li₂O₂. Interestingly, it has been reported that the morphology of the reaction products can affect the electrochemical property of the Li/air cell such as cyclic performance and overpotential [1, 2]. Our study gives importance to characterize the morphology of reaction products. To achieve the image of morphologies on the surface of air electrode, we have composed the air electrode on the nickel grid for TEM and manufactured cell. After test of cell using the grid, we could take the TEM images of reaction products. In addition, it is observed that morphologies have difference according to several conditions like the presence of a catalyst or the rate of discharge/charge. It is expected that observation of morphologies in our approach could signpost for development of enhanced air electrode for Li/air batteries.

Reference

[1] Y. Shao-Horn, B. M. Gallant, R. R. Mitchell, D. G. Kwabi, J. Zhou, L.Zuin, C. V. Thompson, J.Phys. Chem. C 2012, 116, 20800-20805

[2] Y. shao-Horn, B. M. Gallant, D. G. Kwabi, R. R. Mitchell, J. Zhou, C. V. Thompson, Energy Environ. Sci. DOI: 10.1039/c3ee40998h