Indirect Modulation of Cu Atoms Supported on Black Phosphorus for Fast Kinetic Li–S Batteries: A Theoretical Study

Designing catalysts to facilitate sulfur species conversion has been widely recognized as a promising strategy to achieve fast kinetic Li–S batteries. Herein, we employ density functional theory to investigate the performance of Cu single-atom catalysts supported on black phosphorus (Cu@BP). Despite exhibiting high stability, Cu@BP demonstrates comparable or even inferior discharge activity compared to pure BP when Cu atoms directly interact with sulfur species. Only when Cu atoms are located at the opposite side of the BP monolayer (CuO@BP), indirectly modulating the conversion of sulfur species, would the discharge activity be boosted. Specifically, CuO@BP displays a small free energy change of the rate-determining step (−0.04 or −0.03 eV) during discharge and a low decomposition barrier of *Li2S (0.56 eV) during charge. The underlying mechanism behind this indirect modulation of Cu atoms is adequately examined through electronic structure analysis. This work highlights CuO@BP as a promising candidate for Li–S batteries and encourages deeper exploration of catalyst design in achieving improved battery performance.