DOI: 10.1615/ICHMT.2015.IntSympAdvComputHeatTransf
ISBN Print: 978-1-56700-429-8
ISSN: 2578-5486
PORE-SCALE TRANSPORT RESOLVED MODEL FOR LI-AIR BATTERIES
Краткое описание
Li-air battery, with its usable energy density close to 1,700Wh/kg, has captured worldwide attention as a promising battery solution for electric vehicles. However, current Li-air technology suffers from low round-trip efficiency and rate capacity. The electrode microstructure plays an integral role in the performance of the non-aqueous Li-air battery. In this work, a pore-scale transport resolved model of the non-aqueous Li-air battery has been developed that is capable of simulating the species/charge transport and reaction kinetics at the distinct phases of liquid electrolyte, solid electrode, and lithium peroxide. This pore-scale approach is in contrast to the more common volume-averaged model, which considers the domain as a homogenous medium of uniform porosity. Utilizing a pore-scale approach requires no simplification or assumptions regarding the electrode morphology, and has enabled the detailed studies into the effects of the precise electrode microstructure. A model for the thickness-dependent Li2O2 conductivity is developed based on inputs from the density functional theory (DFT) calculations and is incorporated into the pore-scale model to simulate the galvanostatic discharge of a nanostructured Li-air cell and validated by experiments. Good agreement is reached between the model and experiment, including the sudden drop in cell voltage at the end of discharge, which can not be recovered with the use of a constant Li2O2 conductivity. A critical insulation thickness of 12.6nm for the Li2O2 buildup on the electrode surface is identified, above which the electrode becomes insulating.