Functionalized M2CT2 (M = Ti, V, Cr, Mn; T = O, S, Se) MXenes as anchoring materials for lithium-sulfur batteries

The dissolving of soluble lithium polysulfides (LiPSs) in electrolytes severely hinders the practical applications of Li-S batteries, anchoring material (AM) as a cathode additive restrains the dissolution of LiPSs. The-O/-S/-Se functionalized M2C (M = Ti, V, Cr, Mn) MXenes were comparative studied as AMs by first-principles calculations. We have studied the relationship between the anchoring effect and the valence electrons' number (Ne) of metal elements in MXenes. Oxygen functional group MXene has drawbacks such as too strong interaction or semi-conductor conductivity. However, for sulfur and selenium functional group M2C (M = V, Cr, Mn) MXenes, the moderate interaction of LiPSs and MXenes makes them suitable as AMs. For Ti-based MXene, Ti2CS2 and Ti2CSe2 have better electrical conductivity than Ti2CO2.

Automated summary

This study compares the performance of different functionalized MXenes as anchoring materials using first-principles calculations. The results show that sulfur and selenium functionalized MXenes have moderate interaction with lithium polysulfides, making them suitable as cathode additives.