Uniform High Ionic Conducting Lithium Sulfide Protection Layer for Stable Lithium Metal Anode

• Published in: Advanced energy materials 2019-06, Vol.9 (22), p.n/a
• Main Authors: Chen, Hao, Pei, Allen, Lin, Dingchang, Xie, Jin, Yang, Ankun, Xu, Jinwei, Lin, Kaixiang, Wang, Jiangyan, Wang, Hansen, Shi, Feifei, Boyle, David, Cui, Yi
• Format: Article
• Language: English
• Subjects: Anode effect; Anodic protection; artificial SEI; compositional homogeneity; Cycles; Dendritic structure; high ionic conductivity; High temperature; Ion currents; Lithium; Lithium batteries; lithium metal batteries
• ISSN: 1614-6832; 1614-6840
• DOI: 10.1002/aenm.201900858

Artificial solid‐electrolyte interphase (SEI) is one of the key approaches in addressing the low reversibility and dendritic growth problems of lithium metal anode, yet its current effect is still insufficient due to insufficient stability. Here, a new principle of “simultaneous high ionic conductivity and homogeneity” is proposed for stabilizing SEI and lithium metal anodes. Fabricated by a facile, environmentally friendly, and low‐cost lithium solid‐sulfur vapor reaction at elevated temperature, a designed lithium sulfide protective layer successfully maintains its protection function during cycling, which is confirmed by both simulations and experiments. Stable dendrite‐free cycling of lithium metal anode is realized even at a high areal capacity of 5 mAh cm−2, and prototype Li–Li4Ti5O12 cell with limited lithium also achieves 900 stable cycles. These findings give new insight into the ideal SEI composition and structure and provide new design strategies for stable lithium metal batteries. A “simultaneous homogeneous and high ionic conductivity” principle is developed to suppress dendrite growth and stabilize the lithium metal anode through a gas phase reaction toward a uniform lithium sulfide (Li2S) protective layer.