Reductive Decomposition Mechanism of Prop-1-ene-1,3-sultone in the Formation of a Solid–Electrolyte Interphase on the Anode of a Lithium-Ion Battery

A novel electrolyte additive, prop-1-ene-1,3-sultone (PES), has recently attracted great attention due to its formation of effective solid–electrolyte interphase (SEI) films and remarkable cell performance in lithium-ion batteries. Herein, the reductive decomposition of PES is investigated through density functional calculations combined with a self-consistent reaction field method, in which the bulk solvent effect is accounted for by the geometry optimization and transition-state search. We examine three ring-opening pathways, namely, O–C, S–C, and S–O bond-breaking processes. Our calculations reveal that the Li⁺ ion plays a pivotal role in the reductive decomposition of PES. While the most kinetically favored processthe S–O bond breakingis effectively blocked via the formation of an intermediate structure, namely, the Li⁺-participated seven-membered ring, the other decomposition processes via O–C and S–C bond breaking lead to stable decomposition products. The constituents of SEI observed in previous experimental studies, such as RSO₃Li and ROSO₂Li, can be reasonably understood as the decomposition products resulting from O–C and S–C bond breaking, respectively.