Novel Polymeric Lithicone Coatings for Addressing the Issues of Lithium Anodes
Authors: Meng Xiangbo , Velasquez Kevin , Shao Aiying 
Published: December 2024

Lithium metal batteries (LMBs) enable much higher energy densities than that of state-of-the-art lithium-ion batteries (LIBs), ascribed to their adoption of lithium metal (Li) as anodes. Li anodes have been highly regarded as one of the ultimate anodes for high-energy rechargeable batteries, ascribed to its extremely high capacity (3860 mAh/g) and the lowest negative electrochemical potential (-3.04 V versus the standard hydrogen electrode). Unfortunately, Li anodes have been hindered from commercialization so far, due to its high reactivity and dendritic growth. To address these issues, uncountable efforts have been invested for developing electrolyte additives, solid electrolytes, three-dimensional architectured Li anodes, and robust interfaces.

Recently, we have developed a series of novel polymeric lithicone coatings using molecular layer deposition (MLD), such as LiGL (GL = glycerol) 1 and LiTEA (TEA = triethanolamine) 2. These polymeric lithicones exhibited excellent protection effects over Li anodes and helped them achieve extremely long cyclability in Li||Li symmetric cells. Furthermore, these polymeric coatings also demonstrated their exceptional effectiveness in improving the performance of Li||NMC full cells. The underlying mechanisms lie in that these polymeric coatings are desirable in their properties, including excellent ionic conductivity (~ 1 mS/cm at room temperature) and good flexibility. All these indicate that MLD is powerful for interface engineering of Li anodes. Particularly, MLD has several unique capabilities and emerged a new technique of interface engineering of rechargeable batteries in the past decade.3-7 Specifically, MLD can accurately tune battery interfaces at the molecular level, proceed at low process temperature (≤ 150 oC), deposit films conformally and uniformly, and enable a large variety of coating choices. All these empower MLD a powerful tool for addressing the issues of LMBs.

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