ES (Ethylene Sulfite, >99.0%) as Battery Electrolyte Additive, 10-50 g/bottle, CBEAES

Ethylene Sulfite (ES)—systematically named 1,3,2-dioxathiolane 2-oxide—is a cyclic sulfur-containing organic ester widely used as a film-forming SEI/CEI additive and PC-co-solvent suppressor in non-aqueous electrolytes for lithium-ion, lithium-metal, and sodium-ion batteries. 

Sacrificial Reduction & Sulfur-Rich Inorganic SEI: Ethylene Sulfite possesses a higher reduction potential (~ 1.2 V to1.4 V vs. Li/Li+) than cyclic carbonates like ethylene carbonate (EC) or propylene carbonate (PC). During initial formation, ES preferentially reduces at the anode surface, cleavage of the C–O and S–O bonds yields an inorganic-rich Solid Electrolyte Interphase (SEI) dominated by inorganic sulfur species (such as lithium sulfite, Li2SO3, and lithium sulfide, Li2S) alongside alkyl sulfites (CH2OSO2Li2).

Inhibition of Graphite Exfoliation in PC-Rich Formulations: Standard Propylene Carbonate (PC) causes destructive graphite exfoliation due to co-intercalation of solvated Li+ or Na+ ions. Adding a small quantity of ES forms a dense, passivating SEI on graphite prior to PC reduction, suppressing co-intercalation and enabling PC-based electrolytes to cycle stably on graphite anodes at sub-zero temperatures.

Cathode Interphase Passivation (CEI): ES also participates in oxidative passivation at cathode surfaces above 4.2 V vs. Li/Li+. The resulting Cathode Electrolyte Interphase (CEI) mitigates transition-metal leaching Ni^(3+)/Ni^(4+), Mn^(3+) and reduces oxygen release from high-nickel layered oxides or high-manganese cathodes.

Lower Interfacial Charge-Transfer Impedance: The inorganic sulfur species (Li2SO3 / Li2S) formed within the SEI exhibit significantly higher ionic conductivity for Li+ or Na+ cations compared to standard organic alkyl carbonate reduction products (ROCO2Li). This reduces charge-transfer resistance and improves low-temperature rate performance.

Part Number	CBEAES (C-BEA-ES)
CAS	3741-38-6
Chemical Formula	C2H4O3S
Appearance	Colorless Liquid
Purity	>99.0%
Molecular Weight	108.12 g/mol
Density	1.433 g/mL at 25 °C
Boiling Point	159.1 °C (lit.)
Package Size	10 g, 20 g, and 50 g/bottle

Notes: Please store the EC solution in the dry place (glovebox is the best)

References: 

1. W. Yao, et al. Vinyl ethylene sulfite as a new additive in propylene carbonate-based electrolyte for lithium ion batteries, Energy Environ. Sci. (2009) 2 (10): 1102–1108.
2. F. Ren, et al. Comprehensive Understanding of Reduction Mechanisms of Ethylene Sulfite in EC-Based Lithium-Ion Batteries, J. Phys. Chem. C (2019) 123 (10): 5871–5880.