Descriptor-driven solvent screening for rational electrolyte design in high-voltage Li-ion batteries

The instability of the electrode-electrolyte interface (EEI) at high voltages remains a major obstacle to developing high-energy-density lithium-ion batteries (LIBs). Solvent selection critically influences solvation structure and EEI formation, which ultimately determine cycling stability. However, a systematic framework for rationally designing solvents for high-voltage applications is still lacking. Herein, we propose a descriptor-driven strategy for solvent selection and electrolyte formulation by integrating solvent solvation energy, surface adsorption strength, and the highest occupied molecular orbital level as key descriptors. These descriptors synergistically regulate solvent behavior across the entire interfacial evolution: enabling Li + solvation, co-migration into the inner Helmholtz plane, strong surface passivation, and controlled decomposition to build a robust LiF-rich cathode-electrolyte interphase. Screening fluorinated solvents identifies 3,3,3-trifluoropropylene carbonate (TFPC) as an optimal primary solvent. A TFPC-based electrolyte suppresses LiCoO 2 (LCO) structural degradation and electrolyte oxidation at 4.6 V (vs. Li/Li + ), enabling a 3.5 Ah LCO||graphite pouch cell to retain 80.4% capacity after 450 cycles at 1 C. This work establishes a descriptor-guided solvent design framework, highlights the feasibility of high-voltage LIBs based on the commercial salt, and provides new insights into EEI stabilization mechanisms for high-energy-density battery systems. The behavior of solvent molecules at the inner Helmholtz plane (IHP) critically determines the formation and stability of the cathode-electrolyte interphase (CEI). A descriptor-driven solvent screening strategy is presented to synergistically regulate the entire interfacial evolution process, encompassing Li ion solvation, migration toward the IHP, surface passivation, and controlled decomposition. This approach facilitates a robust F-rich CEI, demonstrating how molecular-level solvent design fundamentally links to high-voltage interfacial stabilization. Download: Download high-res image (217KB) Download: Download full-size image