Universal-Descriptors-Guided Design of Single Atom Catalysts toward Oxidation of Li2 S in Lithium-Sulfur Batteries.

The sulfur redox kinetics critically matters to superior lithium-sulfur (Li-S) batteries, for which single atom catalysts (SACs) take effect on promoting Li2 S 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 Li2 S oxidation processes over MN4 @G catalysts are fully explored and energy barrier of Li2 S decomposition (Eb ) is identified to correlate strongly with three parameters of energy difference between initial and final states of Li2 S decomposition, reaction energy of Li2 S 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 Li2 S. 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 Li2 S 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.