Its chemical formula is C₃H₄O₃ (structural formula: C₂H₄OCO₂), a five-membered cyclic structure) and CAS number is 96-49-1. EC features high polarity, excellent thermal stability, low volatility, and strong solvency for lithium salts, making it a core raw material for lithium-ion battery electrolytes and a versatile green solvent in chemical synthesis.

Key Applications

Lithium-ion Battery Electrolyte (Core Use): EC is an indispensable component of electrolytes for lithium-ion batteries. It has a high dielectric constant (ε = 90 at 25 °C), which enables efficient dissociation of lithium salts (e.g., LiPF₆, LiBF₄) into conductive ions. When mixed with low-viscosity co-solvents (e.g., DMC, ethyl methyl carbonate (EMC)), it improves electrolyte conductivity, thermal stability, and cycle performance of batteries. Widely used in consumer electronics, electric vehicles, and energy storage systems.

Chemical Synthesis Intermediate: Serves as a green methylating agent and carboxylating agent, replacing toxic reagents such as dimethyl sulfate and phosgene. It is used in the synthesis of pharmaceuticals, pesticides, and fine chemicals, including anti-inflammatory drugs, herbicides, and polycarbonate oligomers.

Industrial Solvent & Plasticizer: As a high-boiling-point, low-VOC solvent, EC is used in coatings, inks, and adhesives, improving the solubility of resins and pigments and reducing environmental pollution. It also acts as a plasticizer for cellulose acetate and polyvinyl chloride (PVC), enhancing the flexibility and processability of polymer materials.

Gas Separation Solvent: Excellent solubility for polar acidic gases (e.g., CO₂, H₂S) makes EC an ideal solvent for natural gas purification and flue gas treatment. It selectively absorbs acidic impurities, improving gas quality and reducing greenhouse gas emissions.

Other Uses: Applied as a humectant in cosmetics and personal care products; used as a cross-linking agent in the production of polyurethanes; and serves as a heat transfer fluid in high-temperature industrial systems.