Multiscale Theoretical Screening of Vinylene Carbonate Derivatives as Electrolyte Additives for Lithium-Ion Batteries: Implications for Interfacial Film Formation

Abstract

With the increasing demand for high–energy-density lithium-ion batteries, elevating the operating voltage has been widely regarded as an effective strategy to enhance energy density, yet conventional carbonate-based electrolytes still suffer from intrinsic limitations under high-voltage conditions. In this work, a series of vinylene carbonate (VC) derivatives were designed by introducing alkyl chains of different lengths with mono- and disubstitution at the ester sites, and the C═C bond was shifted from the ring to the terminal position of the side chain to form an alkenyl chain structure for investigating the effect of double-bond location. Multiscale theoretical simulations, including quantum chemical calculations and molecular dynamics, were performed to systematically study these derivatives. Quantum chemical calculations reveal that variations in the position of the C═C bond lead to different alkyl or alkenyl substitution patterns. Meanwhile, the introduction of mono- or disubstitution together with side chains with different methylene unit numbers regulates the electronic structure of the molecules through inductive effects, σ–π hyperconjugation, and π conjugation. Extension of the alkyl chain or disubstitution generally enhances electron-donating effects, resulting in increased HOMO levels and reduced oxidation potentials; however, this influence weakens when long alkyl chains are far from the conjugation center. Meanwhile, relocating the C═C bond to the terminal position of the side chain disrupts the π-conjugation within the ring, reduces electron delocalization, and concentrates electron density on the carbonyl oxygen, thereby strengthening its coordination with Li+. Molecular dynamics simulations indicate that the electronic effects and steric hindrance of substituents cooperatively regulate Li+ solvation structures. Long-chain or disubstituted molecules tend to promote the formation of contact ion pairs due to increased steric volume, whereas smaller or weakly coordinating molecules favor higher fractions of free Li+, thereby enhancing ionic mobility and conductivity. Comprehensive screening identifies DVEC as the most promising anode film-forming additive, benefiting from its relatively high reduction potential, moderate dipole moment, and suitable Li+ binding ability, which enable preferential reduction and stable ion transport. This study provides theoretical insights for the rational design of carbonate electrolyte additives for high-voltage lithium-ion batteries.