Atomic insights into a family of single transition metal atom-doped MXenes for catalytic conversion of lithium polysulfides in lithium–sulfur batteries

Abstract

Lithium–sulfur (Li–S) batteries are recognized as promising contenders for next-generation energy storage systems. Nevertheless, their electrochemical performance is notably impaired by the lithium polysulfide (Li₂S_n) shuttle effect. In this research, we investigated a series of single-transition-metal-atom-doped MXenes (SM@MXenes) as potential sulfur hosts to promote the efficient conversion of Li₂S_n via theoretical calculations. We analyzed and calculated the adsorption energy, electronic structure, and conversion energy barrier of Li₂S_n on the SM@MXene surface, and pinpointed Sc as an especially promising dopant, for constructing SM@MXenes that exhibit remarkable improvements in sulfur reduction reaction (SRR) kinetics. Moreover, we summarize the fundamental interaction mechanisms between Li₂S_n and host materials by utilizing catalytic volcano plots. This work offers crucial insights into screening functional sulfur hosts with the aim of alleviating the Li₂S_n shuttle effect and advancing high-performance Li–S battery technologies.