Densifying Solid Electrolytes through Surface Lubrication to Mitigate Shorting of Solid-State Batteries
Mengchen Liu, E. D. Lu, Shen Wang, Shijie Feng, Junwei Gao, Wenlin Yan, Jeong Woo Oh, Min‐Sang Song, Jian Luo, Ping Liu
Abstract
Lithium dendrite penetration has caused internal short-circuits that have limited the life of lithium metal all-solid-state batteries. Defects and pores in dry compacted solid electrolytes promote dendrite growth. This study introduces an organic molecular coating, 1-undecanethiol, that anchors strongly to the surface of Li 6 PS 5 Cl and functions as an adsorbed lubrication layer, thus reducing interparticle friction, facilitating particle rearrangement and densification. Under a compacting pressure of 375 MPa, the 1-undecanethiol coated Li 6 PS 5 Cl achieves a porosity of 1.7%, a substantial reduction from the porosity of 10.9% for Li 6 PS 5 Cl. As a result, Li symmetric cells incorporating the 1-undecanethiol densified Li 6 PS 5 Cl pellet exhibit up to a 4-fold increase in critical current density and demonstrate remarkable 4600 h cycling at a current density of 1 mA cm –2 . Likewise, the Li||LiNi 0.8 Co 0.1 Mn 0.1 O 2 full cell shows a 4-fold increase in cycling current density. This work points to the potential of organic surface engineering to enable long-life solid-state batteries.