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Park et al. Energy Mater 2023;3:300005 https://dx.doi.org/10.20517/energymater.2022.65 Page 9 of 13

Figure 7. Schematic summary of the Li metal battery focusing on its advantages, dendritic Li growth, artificial SEI layers and solid
electrolytes.

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(RH = 50%), the Li-ion conductivity of the pristine Li PS Cl was 0.23 × 10 S cm while the zeolite
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embedded Li PS Cl was 0.39 × 10 S cm . The decrease in ionic conductivity was reduced in the zeolite-
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embedded Li PS Cl because the continuous contact between H O and Li PS Cl was significantly reduced,
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since porous zeolite nanoparticles adsorb H S and H O effectively in their porous structure.
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PERSPECTIVE AND OUTLOOK
Enormous research and development efforts have been focused on batteries since they are the energy
storage devices of many electronic devices and have become ubiquitous in our daily lives. Ultimately,
consumers are demanding electronic devices with high-capacity and lightweight batteries. To meet these
requirements, it is necessary to construct batteries using Li metal as the anode, which has advantages such as
high theoretical capacity and energy density and low oxidation potential. To commercialize these attractive
Li metal batteries, however, it is necessary to suppress the inevitable growth of Li dendrites. Dendritic Li
growth is intensified by localized Li-ion flux through cracks in the SEI. This repeated Li growth creates
isolated "dead Li", which dramatically reduces the capacity of the battery. In this mini review, we have
summarized the SEI layer, which affects the dendritic Li growth, and focused on electrolyte additives in
terms of ionic conductivity, mechanical strength and solid electrolytes as a solution to suppress dendritic Li
growth, as summarized in Figure 7. To suppress the growth of Li dendrites, the primary key points are
achieving increased ionic conductivity of the SEI layer and improved mechanical stability, which is an
inherent property of the SEI. In particular, to utilize Li metal as an anode, it is essential to research additives,
which generate SEI components, such as Li N and Li S. These obtain higher ionic conductivity than other
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SEI components. In addition to these SEI components, an accurate understanding of bilayers and new
research insights into additives compatible with each layer are required.

From the mechanical perspective, the use of solid electrolytes is an essential technique to overcome these
technical issues. Solid electrolytes can inhibit dendritic Li growth with their robust mechanical strength.
However, they have crucial drawbacks, such as low ionic conductivity, compared to liquid electrolytes and
contact loss problems with active materials. Argyrodite-type solid electrolytes are emerging as a solution
with high ionic conductivity. Note that argyrodite solid electrolytes spontaneously react with moisture in