Lithium-Metal Batteries: From Fundamental Research to Industrialization.

Lithium-metal batteries (LMBs) are representative of post-lithium-ion batteries with the great promise of increasing the energy density drastically by utilizing the low operating voltage and high specific capacity of metallic lithium. LMBs currently stand at a point of transition at which the accumulation of knowledge from fundamental research is being translated into large-scale commercialization. This review summarizes the available strategies for addressing the intrinsic shortcomings of LMBs, such as the suppression of dendritic growth and parasitic reactions from the material to the electrode to the cell level. The discussion pertaining to the cell level includes efforts and concerns relating to scaling up established knowledge and expertise with the view of commercialization. This review intends to encourage researchers in both fundamental research institutions and industry to make a synergistic effort and share their views comprehensively to ensure that LMB technology continues to evolve in harmony to become a mature technology.

Seed Layer Formation on Carbon Electrodes to Control Li2O2 Discharge Products for Practical Li-O2 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. Li2O2 growth process on the cathode relies on the surrounding chemical environment of electrolytes. Low conductivity and strong reactivity of Li2O2 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 Li2O2 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 Li2O2 discharge products. This seed layer led to its high reversibility with a large areal capacity (up to 10 mAh/cm2). 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.