Effect of the Agglomerate Geometry on the Effective Electrical Conductivity of a Porous Electrode

Abstract

The study of the microstructure of random heterogeneous materials, related to an electrochemical device, is relevant because their effective macroscopic properties, e.g., electrical or proton conductivity, are a function of their effective transport coefficients (ETC). The magnitude of ETC depends on the distribution and properties of the material phase. In this work, an algorithm is developed to generate stochastic two-phase (binary) image configurations with multiple geometries and polydispersed particle sizes. The recognizable geometry in the images is represented by the white phase dispersed and characterized by statistical descriptors (two-point and line-path correlation functions). Percolation is obtained for the geometries by identifying an infinite cluster to guarantee the connection between the edges of the microstructures. Finally, the finite volume method is used to determine the ETC. Agglomerate phase results show that the geometry with the highest local current distribution is the triangular geometry. In the matrix phase, the most significant results are obtained by circular geometry, while the lowest is obtained by the 3-sided polygon. The proposed methodology allows to establish criteria based on percolation and surface fraction to assure effective electrical conduction according to their geometric distribution; results provide an insight for the microstructure development with high projection to be used to improve the electrode of a Membrane Electrode Assembly (MEA).

Evaluation of the morphology and chelating agent excess in the design of luminescent metalorganic framework of europium thenoyltrifluoroacetone

“…There is a correlation between the coordination geometry and the dimensionality: size 1 Divisio ´n de Ciencias Ba ´sicas e Ingenierı ´a, Universidad Auto ´noma Metropolitana-Azcapotzalco, Col. Reynosa-Tamaulipas, Me ´xico or hardness of the metal center and electronic configuration affect the resulting topology of MOF. 2,3 Over the last years, MOFs have emerged as a new promising porous material in the areas of gas sorption and separation, 4 as platform for immobilizing molecular catalysts on conductive substrates, [5][6][7][8] water treatment, 9 storage, 10 antibacterial and antobiofilm 10 and light emitting diodes (LEDs). 11 Rare earth doped materials are very useful nowadays, because the characteristics that provide the lanthanides to the material can confer new applications as optoelectronics devices, fiber amplifiers, solid state laser, 12 solar cells, 13 and luminescence.…”

Microstructural Analysis of Effective Electrode Conductivity in Molten Salt, Na-ZnCl2 Batteries

“…The transport properties of porous electrodes have been widely studied in several contexts, [23][24][25] and the relation between their microstructural properties and their effective conductivity is an essential factor for many practical applications, 23,26,27 and it has been of interest in Li-ion batteries recently. 28,29 This is even more important when the electrode is a composite of multiple materials sharing the available space, constraining each other's connectivity and location.…”