Conversion of SeS2 to Organoselenosulfides Enables High-Performance Rechargeable Lithium Batteries

Selenium sulfide (SeS2) having the characteristics of sulfur (S) and selenium (Se) has higher conductivity than S and higher theoretical specific capacity than Se, being a promising cathode material for rechargeable batteries. However, the inherent shuttle effect of SeS2 restricts its further development. Herein, we introduce the reaction of diphenyl disulfide (DPDS) and SeS2 in different molar ratios (2:1, 1:1, and 1:2) to form various organoselenosulfides, which not only provide more lithiation sites than DPDS but also alleviate the shuttle effect of SeS2. The formed products are analyzed by mass spectrometry and density functional theory calculations. The lithium cell with a DPDS/SeS2 ratio of 1:1 delivers a specific capacity of 397.7 mA h g(-1) in the first cycle and retains 67.4% of the capacity over 600 cycles at a current density of 0.3 mA cm(-2) . In addition, it shows steady rate capability. This study demonstrates that the conversion of SeS2 to organoselenosulfides provides a promising strategy to overcome the intrinsic issues of SeS2 as the cathode material for rechargeable lithium batteries.

Automated summary

Selenium sulfide (SeS2) exhibits high conductivity and theoretical specific capacity, but its shuttle effect limits its further application. The formation of organoselenosulfides through the reaction with diphenyl disulfide (DPDS) provides more lithiation sites and alleviates the shuttle effect. The resulting DPDS/SeS2 ratio of 1:1 shows excellent cycling stability and rate capability in lithium batteries.