Superior Polymeric Lithicones for Extremely Long-Life Lithium Metal Anodes

Lithium (Li) metal has been highly regarded as an ultimate anode 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). However, Li metal has been hindered from commercialization, due to its high reactivity and dendritic growth. To this end, uncountable efforts have been invested to address these issues and they can be categorized into two main strategies: (i) architecting Li anodes and (ii) Li interface engineering. In the past decade, atomic layer deposition (ALD) has emerged as a new technique for engineering battery interfaces, featuring inorganic coating materials.^1-3 Following ALD, molecular layer deposition (MLD) recently has been employed to develop polymeric coatings for lithium-ion batteries and beyond.⁴ Owing to their same operational principle and similar working mechanisms, ALD and MLD share some unrivaled capacities, such as enabling extremely uniform and conformal coatings, atomic/molecular preciseness, low deposition temperature, and so on.^4-5 Using MLD, in a recent study we developed three new lithium-containing polymers, lithicones.⁶ Among them, we found that LiGL (GL = glycerol) is particularly superior, showing high ion conductivity and flexibility. As a consequence, the LiGL-coated Li metal anodes could achieve extremely long-life cyclability (over 15,000 cycles) without having any sign of failure at 5 mA/cm² and 1 mAh/cm². We found that the LiGL coating could protect the Li metal from corrosion, significanlty mitigate electrolyte decomposition and formation of solid electrolyte interphase, and therefore dramatically extend the lifetime of Li||Li symmetric cells. Thus, this work paves a new avenue for developing safety-reliable high-performance lithium metal anodes.<br/><br/>References:<br/>1. Meng, X.; Yang, X. Q.; Sun, X. L., Emerging applications of atomic layer deposition for lithium-ion battery studies. Adv. Mater. 2012, 24 (27), 3589-3615.<br/>2. Meng, X., Atomic layer deposition of solid-state electrolytes for next-generation lithium-ion batteries and beyond: Opportunities and challenges. Energy Storage Materials 2020, 30, 296-328.<br/>3. Meng, X., Atomic-scale surface modifications and novel electrode designs for high-performance sodium-ion batteries via atomic layer deposition. J. Mater. Chem. A 2017, 5, 10127-10149.<br/>4. Meng, X., An overview of molecular layer deposition for organic and organic-inorganic hybrid materials: Mechanisms, growth characteristics, and promising applications. J. Mater. Chem. A 2017, 5 (35), 18326-18378.<br/>5. Sun, Q.; Lau, K. C.; Geng, D.; Meng, X., Atomic and molecular layer deposition for superior lithium-sulfur batteries: Strategies, performance, and mechanisms. Batteries Supercaps 2018, 1 (2), 41-68.<br/>6. Meng, X.; Lau, K. C.; Zhou, H.; Ghosh, S. K.; Benamara, M.; Zou, M., Molecular Layer Deposition of Crosslinked Polymeric Lithicone for Superior Lithium Metal Anodes. Energy Material Advances 2021, 2021, 9786201.