Transport properties of lithium salts in carbon confined glymes in relation to lithium-ari batteries

E. FUENTES QUESADA; I. ANGARITA; M. FACTOROVICH; S. MALDONADO OCHOA; F. VACA CHAVEZ; R. H. ACOSTA; E. DE LA LLAVE; M. P. LONGINOTTI; H. R. CORTI

Buenos Aires

Simposio; 8th Symposium on hydrogen, fuell cells and advanced batteries; 2022

In this work, we studied the effect of confinement and surface charge in the transport properties of LiTf and LiTFSI salts in diglyme solutions. We showed that carbon mi-cro/mesoporous structure plays a critical role on the transport properties of the electrolyte, producing a de-crease up to 3 orders of magnitude on the salt diffusion coefficient when it goes from bulk to a pore with a diameter of 1 nm. It was observed that for pores with 10 and 25 nm diameters the reduction in the diffusion coefficient can be ascribed to the porosity of the sample, being the tortuosity approximately close to one. However, for smaller pore sizes (1-4 nm diameter) bigger tortuosity values can be related to high ion-pore wall interactions.We want to highlight that based on our findings, in order to have an efficient carbon material as electrode for lithi-um-air batteries, special care should be taken to the carbon micro/mesostructure architecture, as it has a critical influ-ence in electrolyte transport behavior. The knowledge of the diffusivity of Li+ ions in mesoporous carbon is also rele-vant to improve the predictions of LABs performance using multiscale modeling [10], which currently use bulk-solvent diffusion coefficients as input parameters. In these work, we demonstrated that the relationship observed between the diffusion coefficients of two salts (LiTf and LiTFSI), dis-solved in diglyme, are different in bulk and under confine-ment, demostrating that the interactions of the ions with the pore wall probably compete with the interactions cati-on-anion