Intermetallic interphases in lithium metal and lithium ion batteries

A robust electrode-electrolyte interface is the cornerstone for every battery system, as demonstrated in the meandering history of the development of Li-ion batteries (LIBs). In the thrust to replace the graphite anode with more energetic ones in LIBs, the effectual strategy for stabilizing the original graphite-electrolyte interface becomes obsolete and a new anode-electrolyte interface needs reconfiguration. Unfortunately, this interface has become the Achilles' heel for those anodes, such as Li-metal anode (LMA) and Si-based anode owing to their excessive reductivity, enormous volume change, and so forth. Encouragingly, in the last decade, impressive progress has been made on taming these extremely unstable interfaces and on the solid-state batteries (SSBs) that are reported to be less susceptible to parasitic reactions. One of the distinguished strategies is the application of artificial Li-alloying intermetallic interphases onto the surface of LMA, via the direct introduction of foreign metals to the Li anode or indirect hetero-cations doping in the electrolyte, to regulate the Li deposition/stripping behavior, which has markedly improved the stability of the LMA-electrolyte interface. In parallel, the intermetallic interphases are also witnessed to profoundly enhance the anode-solid electrolyte contact and the corresponding charge transfer kinetics in various SSBs. This review will provide a panoramic overview of the application of the intermetallic interphases at the anode-electrolyte interfaces in the lithium metal batteries (LMBs), SSBs, and also derivative works in the conventional LIBs, which will focus on different concepts, methodologies, and understandings from the encircled studies.