Data for Automated Reaction Prediction of Electrolyte Degradation in Highly Concentrated Electrolytes

High-concentration electrolytes (HCEs) are increasingly investigated for next-generation Li-ion batteries (LIBs) due to their ability to form robust, inorganic-rich solid electrolyte interphases (SEI). While it is established that the SEI composition in HCEs is distinct from dilute electrolytes, the specific anion-mediated reaction networks that drive this transformation remain poorly understood. The complexity of these networks and the transient nature of the radical intermediates involved have precluded the development of a comprehensive mechanistic map of initial SEI formation. Here, the reaction networks governing anion-mediated electrolyte degradation are established using automated reaction discovery and microkinetic modeling (MKM). The study encompasses the decomposition pathways of ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), and acetonitrile (AN) in the presence of reduced anion species derived from LiFSI and LiTFSI. The results reveal a kinetically accessible landscape for solvent decomposition driven by fluoride (F^-) and CF₃ fragments, identifying specific pathways that favor the formation of inorganic LiF and open-ring organic carbonates. Microkinetic modeling further indicates that F^- acts as a reactive driver that is rapidly consumed, shifting the product distribution toward thermodynamically stable fluoro-organic species. These results provide a molecular-level rationalization for the unique SEI chemistries observed in HCEs and suggest that tuning the anion-solvent interaction is a viable pathway for controlling interphase growth.<br>All TSs and IRC pathways generated from the CRNs are openly available on figshare. The TS and IRC trajectories are presented at the 𝜔B97X-D3/def2-TZVPP level of theory. Reaction labels specify the reactants along with the corresponding reaction index and depth.