Effects of Pore Size Distribution on the Discharge Characteristics of Li-Air Batteries with Organic Electrolyte

摘要

The effects of the pore size distribution on the discharge characteristics of Li-air batteries with organic electrolyte are investigated. The theory of concentrated solutions is used to solve the transport equations in the electrolyte, which include oxygen diffusion, anion and cation drift and diffusion, reaction product deposition in the cathode, and Butler-Volmer kinetics. It is shown that the pore size distribution has a significant effect on the specific area in the cathode, specific capacity, and discharge characteristics of the battery: the specific area, the specific capacity and the voltage drop decrease when the standard deviation of the pore radius increases; the specific capacity increases when the average value of the pore radius increases. In addition, we found that the specific capacity of lithium-air batteries does not depend monotonically on the resistivity of the discharge product. The finite resistivity of the deposit layer has a positive effect on the performance of the battery by slightly increasing the specific capacity at low values of the resistivity. When the resistivity of the deposit layer becomes too high the specific capacity of the battery decreases abruptly with the resistivity because of the large voltage drop across the deposit layer.