Unveiling d-orbital antibonding state regulation and charge transfer mechanism for anchoring and catalytic performance of TM-TaS2 in lithium-sulfur batteries

Lithium-sulfur batteries (LSBs) hold great promise for next-generation high-energy storage due to their high theoretical energy density and low cost. However, the inherent mechanism of the “shuttle effect” caused by soluble polysulfides and the slow kinetics of sulfur conversion reactions are still unclear, greatly hindering their application. Hence, a synergistic computational strategy integrating density functional theory (DFT) with machine learning (ML) to systematically investigate transition metal-doped TaS 2 as a cathode host material for LSBs, revealing the “dispersion-rebalance” charge transfer mechanism at the interface of TM-TaS 2 and polysulfide. Among the screened materials, Zr-TaS 2 and Cr-TaS 2 demonstrate moderate anchoring capacity, excellent sulfur reduction reaction catalytic performance, and low Li 2 S decomposition energy barriers (0.509 eV and 0.403 eV, respectively). Further ML analysis reveals that the combined attribution analysis of Sparsifying Operator (SISSO) and SHapley Additive exPlanations (SHAP) demonstrates that the adsorption energy of Li 2 S is primarily modulated by atomic size and the d -band center, while the free energy barrier of the rate-determining step is jointly governed by the number of d -orbital electrons and the d -band center. The results of descriptor construction and feature contribution analysis from both methods mutually verify each other, elucidating the differential regulation mechanism of d -orbital antibonding state occupancy on anchoring performance and catalytic activity. This also provides a data-driven research strategy for the design of high-performance cathode materials for LSBs.