Dynamic 1T-2H Mixed-Phase MoS2 Enables High-Performance Li-Organosulfide Battery

Small. 2022 Jan;18(1):e2105071. doi: 10.1002/smll.202105071. Epub 2021 Nov 5.

Abstract

Achieving high energy density and long cycle life in realistic batteries is still an unmet need, which has triggered research into the discoveries of new electrode materials as well as new storage mechanisms. As a kind of new cathode materials for rechargeable lithium batteries, organosulfide compounds R-Sn -R (n = 3-6) based on conversion chemistries of SS bonds have many advantages and promising prospects; however, poor electric/ionic conductivity and sluggish redox kinetics is a major hinder for their applications. Here an organic-inorganic hybrid cathode by introducing 1T MoS2 grown on reduced graphene oxide to hybridize with phenyl tetrasulfide (Ph-S4 -Ph, theoretical specific capacity 570 mAh g-1 ), enhancing the battery performance is reported. This includes the improved charge transfer, stable long cycles, and close-to-practical energy density in coin cells and pouch cells, which also show high mass loadings and contents, and low electrolyte dependence. Furthermore, the dynamic 1T-2H mixed-phase during the charge/discharge is revealed to be critical for the improved performance. This study proves the hybrid nanomaterials as a promising solution to address the challenges facing lithium-organosulfide batteries.

Keywords: 1T MoS 2; cycle life; lithium batteries; organosulfide cathodes; phase transition.