ABSTRACT
The Li+ ion mobility through the porous cathode is a critical aspect in the development of commercial Li-air batteries. The bulk transport properties of lithium salts in organic solvents are not reliable parameters for the design of this type of battery since confinement could significantly modify the transport properties, especially when pore diameters are below 10 nm. In this work, we studied the effect of the carbon mesostructure and surface charge on the diffusion of LiTf and LiTFSI salts dissolved in diglyme, typical electrolytes for lithium-air batteries. Interdiffusion coefficients of the salts were determined using a conductimetric method. NMR spectroscopy and relaxometry were used to explore the effect of the carbon structure and the surface charge density on the interaction between the electrolytes and the pore wall. We showed that carbon micro/mesoporous structure plays a critical role in the transport properties of the electrolyte, producing a decrease of up to 2-3 orders of magnitude in the salt interdiffusion coefficients when going from bulk solutions to pores below 4 nm in diameter. It was observed that for pores 25 nm in diameter, the reduction in the diffusion coefficient can be mainly ascribed to the porosity of the sample, giving tortuosity factors around 1. However, for smaller pore sizes (1-10 nm diameter) bigger tortuosity coefficients were observed and were related to strong ion-pore wall interactions. Moreover, it was noticed that the ratio between the diffusion coefficients of the two studied salts dissolved in diglyme, is different in bulk and under confinement, demonstrating that the interactions of the ions with the charged pore wall probably compete with the cation-anion interactions, affecting salt association under confinement.
ABSTRACT
Se comenta un trabajo experimental donde la ligadura de la arteria mesentérica superior en un grupo de 12 perros, fue seguida de la administración de oxígeno por vía digestiva y en otro grupo no. Los dos lotes fueron sometidos a controles de ácido láctico y gases sanguíneos. Los resultados logrados convalidan la posibilidad de utilizar este procedimiento en el tratamiento de la isquemia intestinal aguda y llaman la atención sobre el valor que podría tener el ácido láctico para el diagnóstico precoz (AU)
Subject(s)
Dogs , Animals , Blood Gas Analysis , Ligation , Mesenteric Vascular Occlusion/surgery , Oxygen/blood , Thrombosis/diagnosisABSTRACT
Se comenta un trabajo experimental donde la ligadura de la arteria mesentérica superior en un grupo de 12 perros, fue seguida de la administración de oxígeno por vía digestiva y en otro grupo no. Los dos lotes fueron sometidos a controles de ácido láctico y gases sanguíneos. Los resultados logrados convalidan la posibilidad de utilizar este procedimiento en el tratamiento de la isquemia intestinal aguda y llaman la atención sobre el valor que podría tener el ácido láctico para el diagnóstico precoz