Universal-Descriptors-Guided Design of Single Atom Catalysts toward Oxidation of Li2S in Lithium–Sulfur Batteries

Abstract

The sulfur redox kinetics critically matters to superior lithium–sulfur (Li–S) batteries, for which single atom catalysts (SACs) take effect on promoting Li2S redox process and mitigating the shuttle behavior of lithium polysulfide (LiPs). However, conventional trial-and-error strategy significantly slows down the development of SACs in Li–S batteries. Here, the Li2S oxidation processes over MN4@G catalysts are fully explored and energy barrier of Li2S decomposition (Eb) is identified to correlate strongly with three parameters of energy difference between initial and final states of Li2S decomposition, reaction energy of Li2S oxidation and Li-S bond strength. These three parameters can serve as efficient descriptors by which two excellent SACs of MoN4@G and WN4@G are screened which give rise to Eb values of 0.58 and 0.55 eV, respectively, outperforming other analogues in adsorbing LiPs and accelerating the redox kinetics of Li2S. This method can be extended to a wider range of SACs by coupling MN4 moiety with heterostructures and heteroatoms beyond N where WN4@G/TiS2 heterointerface is predicted to exhibit enhanced catalytic performance for Li2S decomposition with Eb of 0.40 eV. This work will help accelerate the process of designing a wider range of efficient catalysts in Li–S batteries and even beyond, e.g. alkali-ion-Chalcogen batteries.