Accurately Constitute Robust Interfaces for High-Performance High-Energy Lithium Metal Batteries

Abstract

High-energy lithium metal batteries (LMBs) have been receiving an ever-increasing interest. Among them, coupling lithium metal (Li) with nickel-rich LiNixMnyCozO2 (NMCs, x ≥ 0.6, x + y + z = 1) is promising, for Li anodes enable an extremely high capacity (3860 mAh g−1) and the lowest redox potential (−3.04 V vs. standard hydrogen electrode) while NMCs can achieve a much higher capacity of 200 mAh g-1 and lower cost than those of LiCoO2. However, the resultant Li||NMC cells have been hindered from commercialization, due to a series of challenges related to the interface stability of both Li anodes and NMC cathodes. Specifically, Li anodes suffer from Li dendritic growth and the formation of solid electrolyte interphase (SEI), while NMC cathodes have been harassed by the formation of cathode electrolyte interphase (CEI), and other interface-related issues including transition metal dissolution, oxygen release, cracking, and so on. To tackle these issues, recently, two sister techniques, atomic and molecular layer deposition (ALD and MLD), have emerged and exhibited tremendous capabilities to accurately constitute robust interfaces for accomplishing high-performance Li||NMC LMBs. They can uniquely develop uniform and conformal films as surface coatings of LMBs in a precisely controllable mode at the atomic/molecular level while proceeding film deposition at low temperatures (e.g., ≤ 250 oC). In this Feature Article, we highlight our latest research progress in developing novel surface coatings via ALD and MLD for Li||NMC LMBs and discuss our outcomes in pursuing their high performance.