Lithium Silicates as an Artificial SEI for Rechargeable Lithium Metal Batteries

Abstract

The major motivation of replacing lithium-ion batteries with lithium metal batteries is to obtain higher energy density by adopting the metallic lithium anode (3860 mAh g-1, theoretically), which means they can store more energy in the same volume or weight. One of the main challenges of rechargeable lithium metal batteries is the formation of lithium dendrites during the charging process.1 Lithium dendrites are tiny needle-like structures that can grow from the surface of the lithium metal electrode and penetrate the separator, causing battery short-circuiting. This can lead to safety issues, including the potential for fire or explosion. Another challenge is the formation of solid-electrolyte interface (SEI) on the surface of the lithium metal electrode, which can reduce the battery's efficiency and cycle life.2 The SEI layer can also lead to the formation of inactive lithium and increase the risk of dendrite growth.In the present work, various lithium silicates have been synthesized to be implemented as the artificial SEI layer via a facile dry coating method.3,4 The lithium silicate coating acts as a protective barrier that prevents direct contact between the lithium metal and the electrolyte, which may cause undesirable side reactions and reduce the efficiency and lifespan of the battery.4 The lithium silicate-based artificial SEI layer improves the stability and efficiency of lithium metal batteries by reducing unwanted surface reactions, improving ion transport kinetics, and protecting the lithium metal anode from mechanical deformation and unstable SEI formation during extended cycling. This laminated lithium anode structure could be an effective design for the future development of long-cycle-life lithium metal batteries. F. Wu et al., Energy Storage Materials, 15, 148–170 (2018).X.-B. Cheng et al., Adv. Sci., 3, 1500213 (2016).A. Bhat, P. Sireesha, Y. Chen, and Y. Su, ChemElectroChem, 9 (2022) https://onlinelibrary.wiley.com/doi/10.1002/celc.202200772.Y.-S. Su, K.-C. Hsiao, P. Sireesha, and J.-Y. Huang, Batteries, 8, 2 (2022). Figure 1