Influence of the Lithium Cation Desolvation Process at the Electrolyte/Electrode Interface on the Performance of Lithium Batteries

Abstract

The article considers the effect of the solvate environment of the lithium cation in various aprotic solvents.The redox reactions of electrodes made from a polymeric condensation product of triquinoyl with 1,2,4,5-tetraaminobenzene are studied. A 1 M LiPF6 solution was used as an electrolyte, in either ethylene carbonate/dimethyl carbonate (EC/DMC) or tetraglyme. Based on the electrochemical studies and quantum chemical modeling, it was shown that the desolvation of lithium cations in the tetraglyme-based electrolyte makes it possible to obtain a capacity close to the theoretical one (up to 546 mAh g−1) and only 125 mAh g−1 for the EC/DMC electrolyte. This decrease is due to the fact that the lithium cation adds to the functional groups of the organic material with two dimethyl carbonate molecules, as well as the PF6− anion.