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 Litparticipated 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.