In Situ Organoselenization for Ultrastable Li-Se Batteries.

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• The shuttle effect of lithium polyselenides (Li2Sen) is a major obstacle for practical lithium-selenium (Li-Se) batteries.
• Existing methods to confine Li2Sen have limitations in fundamentally resolving this issue.

Purpose of the Study:

• To develop a novel strategy for stabilizing Li-Se batteries by eliminating Li2Sen formation.
• To enhance the electrochemical performance and cycle life of Li-Se batteries.

Main Methods:

• In situ conversion of inorganic selenium to organic forms via nucleophilic reaction between Li2Sen and 2-benzothiazole diethyldithiocarbamate (BTZA).
• Grafting selenium atoms onto an organic framework to form organic diselenides upon charging.
• Concurrent production and conversion of lithium benzothiazole sulfide (BTSLi) to 2,2'-dibenzothiazole disulfide (BTDS) for capacity compensation.

Main Results:

• Elimination of Li2Sen formation through organoselenium product generation.
• Organoselenium products exhibit high discharge voltages and improved lithium-ion transport.
• Demonstrated excellent stability with 92.87% capacity retention after 1300 cycles at 2 C.
• Stable operation of a 0.6 Ah pouch cell for 30 cycles at 0.1 C.

Conclusions:

• The in situ organification strategy effectively suppresses the shuttle effect in Li-Se batteries.
• The developed method enhances energy density, reaction kinetics, and long-term cycling stability.
• This approach offers a promising pathway for developing highly stable and practical Li-Se batteries.