Multidopant Induced Entropy Effect on TiS₂/TiSe₂-Based Layered Anode and Formation of Electrode–Electrolyte Interphase

Van der Waals (vdW) heterostructures (HSs) have attracted intense interest worldwide as they offer several routes to design materials with novel features and wide-ranging applications. Unfortunately, vdW HSs are currently restricted to a small number of stackable layers due to the weak vdW forces holding adjacent layers together. In this article, computational studies of a bulk vdW material consisting of alternating TiS₂ and TiSe₂ (TSS) vertically arranged layers are reported as a potential candidate for anode applications. Density functional theory (DFT) calculations and ab-initio molecular dynamics (AIMD) simulations are used to explore the effect of close-to-high entropy on several electrochemically relevant properties of the bulk HS (TSS-HS) by substituting Mo₅₊ and Al₃₊ at the transition metal site (Ti₄₊). Additionally, solvation shell formation at the electrode-electrolyte interphase (EEI) is studied using AIMD to determine Li-coordination. Based on the properties computed using DFT and AIMD, ‘entropy-induced’ TSS-HS (TSS-EI) might possess improved electrochemical performance over standard TSS-HS. Factors that can improve the performance of TSS-EI are 1) less structural deformation, 2) strong bonding (metal-sulphur), 3) better electron mobility, 4) wider operational voltage window, and 5) faster Li-ion diffusion. Observations suggest that ‘entropy’ can be an effective strategy to design new anode materials for Li-ion batteries.