Self-Association Propensity of Three Organic Battery Solvents Probed by Infrared Spectroscopy
Year: 2026
Type: preprint
Abstract: Cyclic organic carbonates possess high dipole moments, and are extensively used as electrolyte solvents in lithium-ion batteries due to their high dielectric constants, low toxicity, and low flammability. However, intermolecular associations may reduce the availability of solvent molecules for effective coordination with lithium ions, an essential attribute of the battery solvents. Therefore, a preferred carbonate should have lower tendency to undergo selfassociation, where C-H…O-type hydrogen bonding also plays a significant role. In this work, the self-association behavior of propylene carbonate (PC), methoxy propylene carbonate (MPC), and vinyl ethylene carbonate (VEC) was investigated using concentration-dependent Fourier transform infrared (FTIR) spectroscopy in CCl4 solutions at room temperature. Particular attention was given to the νC=O stretching region, where progressive broadening and the emergence of lower-wavenumber bands with increasing concentration indicate the formation of intermolecularly associated species. Experimental band deconvolution, combined with density functional theory calculations at the B3LYP-D3/6-311++G(d,p) level using an IEFPCM CCl4 solvent model, enabled assignments of the observed features to monomeric, dimeric, and trimeric species. The calculated structures reveal antiparallel orientations of the carbonyl groups in the dimers, stabilized by intermolecular C–H… O hydrogen bonding, while the trimers are predominantly stabilized by similar interactions. Among the three carbonates, PC exhibits the strongest tendency toward self-association, followed by MPC and VEC. The comparatively weaker self-association of VEC suggests a greater availability of free solvent molecules for lithium-ion solvation, indicating its potential advantage over PC and MPC as an electrolyte solvent.
Source: ChemRxiv
Authors: Anwesha Datta, Tapas Chakraborty
Institution: Indian Association for the Cultivation of Science
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7211925560