Method to Determine the In-Plane Tortuosity of Porous Electrodes

Abstract

The tortuosity of a porous electrode is one of the critical parameters that governs the effective transport properties such as effective conductivity and effective diffusivity of ions in the electrolyte phase. While there exist several methods to determine the through-plane tortuosity for lithium-ion battery electrodes, methods to determine in-plane tortuosity are scarcely explored. In this paper, we present a method that restricts ion transport to only the in-plane direction, which facilitates the determination of transport properties in the in-plane direction. The here proposed cell design is analyzed using a blocking condition transmission line model to measure the in-plane tortuosity, followed by validation experiments to establish its validity and robustness. The measurement of the in-plane tortuosity may act as an indispensable tool for the design, characterization, and modeling of 3-dimensional battery architectures (e.g., laser structured electrodes) and help to estimate the distribution of various properties in the through-plane direction such as porosity, tortuosity, binder content, etc.

3D Quantification of Microstructural Properties of LiNi0.5Mn0.3Co0.2O2 High‐Energy Density Electrodes by X‐Ray Holographic Nano‐Tomography

“…It has been demonstrated by tomography‐based approach as well as experimental measurements (for the case of MCMB AM) to increase with either the non‐spherical AM particles or the calendaring process. [ 59–62 ] A minor tortuosity anisotropy (τ through−plane > τ in−plane ) is reported for NMC electrodes in refs. [ 61,62 ] via simulations using 3D microstructures with numerically‐generated CBD.…”

Tortuosity Modulation toward High‐Energy and High‐Power Lithium Metal Batteries

“…[21,44] For example, high porosity of ≈48% would reduce the tortuosity from ≈5.95 (porosity, ≈28.5%) to 2.3 for a randomly assembled porous electrode. [26,45] Such low tortuosity modulation principle can be further extended to the cathodes and SCEs of LMBs to promote the fast transport of lithium ions in the whole battery, theoretically giving rise to high-energy and high-power LMBs.…”

“…The randomly assembled cathodes generate high-tortuous and discontinuous conductive pathways for ions and electrons, resulting in low-rate capabilities. [24,26] In addition, Figure 6. a) Schematic of fabricating the ZnO-coated carbonized wood/lithium hybrid anode.…”

“…[22] Numerous experimental and computational results have demonstrated that shortening the conductive pathways of lithium ions (i.e., reducing the tortuosity of electrodes) would greatly accelerate ion transport in the porous electrodes, thus largely improving the rate capabilities of electrodes and the power densities of LIBs. [21,[23][24][25][26] In this regard, various materials with 3D porous structures have been employed to shorten the distance of ion transport pathways. [27][28][29] In comparison, in a LMB system with a bare lithium anode, although the kinetic processes in the cathode part are similar to that of LIBs, the conductive pathways of lithium ions in the lithium anode are totally blocked, since the redox reaction of Li + /Li only occurs at limited lithium/electrolyte interfaces, usually resulting in very low-rate capabilities (<1 mA cm −2 ) and low power densities.…”

Functionality of Dual‐Phase Lithium Storage in a Porous Carbon Host for Lithium‐Metal Anode

“…The TBA‐containing electrolyte allows for an ideal polarization behavior, i.e., no faradaic charge‐transfer reaction across the solid/liquid interface. [ 45,46 ] When TBA ions are used in the measurement, only the double‐layer charging occurs on the pore surface and thus, the impedance behavior can be modeled by the de Levie's transmission line (TL) (Figure S2, Supporting Information), showing phase angles (θ) of 45° in the high‐frequency range (i.e., ion migration in the internal pores) and 90° in the low‐frequency range (i.e., ion accumulation at the bottom of the pores). [ 45 ]…”