Temperature-Resolved Crystal Structure of Ethylene Carbonate

Ethylene carbonate (EC) is an organic solvent of the class of carbonate esters, which is used in state-of-the-art Li-ion batteries as part of the electrolyte mixture, being primarily responsible for the formation of a solid electrolyte interface. Thermal analysis showed that the sample’s melting point is 309 K. The crystal structure of EC is investigated using powder diffraction in a temperature range from 3 K up to its melting point, using neutron- and synchrotron-based radiation. Over the whole temperature range, the sample shows single-phase behavior with the space group being C2/c (No. 15), and given the detailed temperature dependence of the structural evolution, thermodynamic and mechanical properties of solid EC are studied. The local structure in both solid and liquid states was additionally investigated by total scattering diffraction and analysis of the pair distribution function. The results obtained are discussed in line with those of molecular dynamics simulations.