Seed Layer Formation on Carbon Electrodes to Control LiO Discharge Products for Practical Li-O Batteries with High Energy Density and Reversibility.

The high theoretical energy densities of lithium-air batteries (LAB) make this technology an attractive energy storage system for future mobility applications. LiO growth process on the cathode relies on the surrounding chemical environment of electrolytes. Low conductivity and strong reactivity of LiO discharge products can cause overpotential and induce side reactions in LABs, respectively, eventually leading to poor cyclability. The capacity and reversibility of LABs are highly susceptible to the morphology of the LiO discharge products. Here, we identify for the first time that a seed layer formed by the combination of a cathode and an electrolyte determines the morphology of LiO discharge products. This seed layer led to its high reversibility with a large areal capacity (up to 10 mAh/cm). Excellent OER (oxygen evolution reaction) was achieved by the formation of a favorable interface between the carbon electrode and electrolyte, minimizing the decomposition of the electrolyte. These remarkable improvements in LAB performance demonstrate critical progress toward advancing LAB into practical uses, which would exploit good reversibility of LABs in pouch-type cell arrangements with 1.34 Ah.