and a light mass density of 0.53 g cm −3 , is considered as the "Holy Grail" anode to realize a breakthrough for above limitation. [3] When Li metal anode (LMA) is used as a substitute for graphite anode and equipped with traditional cathodes (e.g., LiCoO 2 ), the energy density of batteries can be enhanced from ≈260 Wh kg −1 to ≈500 Wh kg −1 . [4] Given the dramatically improved theoretical energy density, advanced Li metal batteries (LMBs), such as Li-oxygen (Li-O 2 ) (≈3505 Wh kg −1 ) and Li-sulfur (Li-S) (≈2600 Wh kg −1 ) batteries, are in the spotlight. [5][6][7][8][9][10] So far, practical gravimetric energy densities of Li-lithium transition-metal oxide (Li-LMO), Li-S, and Li-O 2 batteries can achieve ≈440 Wh kg −1 , ≈650 Wh kg −1 and ≈950 Wh kg −1 , respectively, surpassing that of commercialized LIBs.Notably, the Li-O 2 batteries owning a high volumetric energy density (≈1100 Wh L −1 ) is on a par with petrol (≈1200 Wh L −1 ) (Figure 1a). [11] Since 2010s, chasing higher energy density boosts the rapid development of LMAs (Figure 1b) and exponentially increasing scientific researches (Figure 1c).Nevertheless, the practical implementation of LMAs is confronted with some intrinsic obstructions. Li metal with low electrochemical potential is highly reactive with organic components of electrolyte, leading to the generation of side products and formation of heterogeneous and unstable solid electrolyte interphase (SEI) on LMAs surface. [16][17][18][19] In heterogeneous SEI, formed "hotspots", namely the bulges on the surface of Li metal which own higher surface exchange current density and local temperature compared with other flat region, are harnessed to induce faster conduction of partial Li ions and drastically enhance the deposition of Li ions, which is the critical factor of Li dendrites forming. [20] Besides, the poor robustness of SEI may trigger the continuously alternating processes of destruction and reconstruction, vastly consuming the fresh Li and electrolyte. [21,22] Furthermore, the large volume change of LMAs during the continuous Li plating/stripping is detrimental due to the formation of "dead" Li and porous Li. [23,24] These uncontrollable processes are pernicious to Li cycling efficiency and electrochemical performance of LMBs. Some valid strategies have been proposed, including electrolyte engineering, [25][26][27] Li metal hosts, [28][29][30] protective layers (PLs), [31][32][33][34][35] and so forth.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/smtd.202201177.