A Universal Quasi-Atom Interaction Model and Application in Designing Single-Atom Catalysts for Alkali-Metal Chalcogenide Batteries.

Abstract

A deep understanding of reactant adsorption behaviors is crucial for unraveling structure-activity relationships and identifying simple descriptors for the kinetics of multi-electron redox reactions, such as the sulfur redox process in Li-S batteries (LSBs). Recently, the "10-electron rule" for evaluating the adsorption strength of single atoms (Eads) has been established for free-atom-like single-atom alloys (SAAs). However, our density-functional theory calculations show that this rule is unfeasible for single-atom catalysts (SACs) with metal centers covalently coordinated by nonmetal atoms. Herein, we proposed a new 18-electron rule for covalent SACs by establishing the quasi-atom interaction model (Q-AIM), which interprets the U-type behavior of Eads(S) dominated by antibonding-orbital filling. Additional calculations demonstrate that Eads(S) can serve as an efficient descriptor of the kinetics of sulfur redox involving multiatom polysulfides. Then, guided by the efficient predictor and Q-AIM, we employed machine learning to screen ∼800,000 candidate SACs. Ultimately, we obtained over 400 and 8000 promising SACs for sulfur evolution and sulfur reduction, respectively. Furthermore, Eads(S) can be extended to predict the catalytic performance of SACs in Li/Na/K-S/Se batteries. This work not only simplifies complex multi-electron processes to single-atom adsorption energy but also establishes a link between occupied electronic states and the catalytic performance of SACs.