Stochastic simulation model for the 3D morphology of composite materials in Li–ion batteries

Thiedmann, Ralf; Stenzel, Ole; Spettl, Aaron; Shearing, Paul R.; Harris, Stephen J.; Brandon, Nigel P.; Schmidt, Volker

doi:10.1016/j.commatsci.2011.06.031

Cited by 53 publications

(50 citation statements)

References 19 publications

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“…The generated models, which are due to the randomness of the real structures, are not exactly the same geometric structure but are fitted by choosing parameters so that the characteristic properties of the material are realistically represented. 48 Stochastic modeling allows for a random distribution of objects within the generated structures and includes the macroscopic homogeneity present in the actual structures. 49 The details of the composition of the simulated electrode microstructures used in this study is provided in Table I, which includes the specific surface area, volume fraction of active material, volume fraction of electrolyte, and the mean particle radius.…”

Section: Methodsmentioning

confidence: 99%

Influence of Microstructure on Impedance Response in Intercalation Electrodes

Cho

Chen

Mukherjee

2015

J. Electrochem. Soc.

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The active particle morphology and microstructure affect the impedance behavior of intercalation electrodes due to the underlying charge transport, active material/electrolyte interfacial surface area, and solid-phase diffusion in lithium-ion batteries (LIB). In order to capture the impact of the electrode microstructural variability on the impedance response, an integrated electrochemical impedance predictive analysis is presented. In the analysis, stochastically reconstructed 3-D microstructures of representative LIB electrodes are considered with variations in the active material morphology and particle size distribution. With the properties evaluated from the virtual 3-D microstructures, the corresponding impedance response is predicted. The concept of electrochemical Sauter mean diameter (ESMD) has been introduced to investigate the effect of active particle morphology, such as particle agglomeration. This integrated analysis is envisioned to offer a virtual impedance response probing framework to elucidate the influence of electrode microstructural variability and underlying electrochemical and transport interactions. Lithium-ion batteries (LIBs), due to their favorable energy density and power capability, are considered as the candidate of choice for vehicle electrification. [1][2][3][4] To further improve the cell performance, different efforts have been undertaken to study the microstructural characteristics, including electrode thickness, 5 porosity, 6 particle size, 7 conductive additives 8 and composition. 9 Particularly, the influence of electrode microstructure on charge (i.e. electron and ion) transport, and solid-phase diffusion is critical, which ultimately affects the cell performance.One of the powerful methods for analyzing the electrochemical and transport behavior in porous electrodes is the electrochemical impedance spectroscopy (EIS), which measures the response of a small perturbation of potential or current.10-17 By investigating the impedance response, the charge transport resistance, including electron transport in the solid phase, ionic transport in the electrolyte, solid-state diffusion in the active material, and the intercalation process, can be quantified.14,18-26 Meyers et al. proposed a mathematical model to capture the impedance behavior of a spherical active particle dependent on the physical properties related to the faradaic and nonfaradaic impedance.14 The model also included the effect of particle size distribution on the impedance response.The impedance response of intercalation electrodes, which is sensitive to the interfacial processes, the surface morphology, and the charge transport, has been described mathematically by the fundamental physical approach for various electrochemical systems.14,27-39The effect of various properties, such as electrical and ionic conductivity, and layer thickness, have been investigated by Levi and Aurbach. 28 Besides the electrode properties (e.g. electrical conductivity, ionic conductivity, and layer thickness), the electrode microst...

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Section: Methodsmentioning

confidence: 99%

Influence of Microstructure on Impedance Response in Intercalation Electrodes

Cho

Chen

Mukherjee

2015

J. Electrochem. Soc.

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“…In the present paper, we have used a uniform kernel with the size of one voxel for the solar cell data since it turns out that in this case, it works most efficient. This means that for any location s ∈ C, the value D(s) is proportional to the number of accepted centers which are located in a certain (infinitesimal) neighborhood of s ∈ C. However, note that for another application of our stochastic algorithm to represent 3D image data of electrodes used in Li-ion batteries by unions of overlapping spheres (Thiedmann et al (2010)), a Gaussian kernel with bandwidth of 1.5 voxel sizes worked best.…”

Section: Intensity Mapmentioning

confidence: 99%

“…For instance, another application of this algorithm is considered in Thiedmann et al (2010), where the microstructure of porous materials in electrodes of lithium-ion batteries is analyzed and modeled on the basis of its representation by unions of overlapping spheres. However, we emphasize that in Thiedmann et al (2010) a stochastic point-process model is developed for materials in Li-ion batteries, which uses the representation by unions of overlapping spheres just as a starting point. But, Thiedmann et al (2010) does not focus on the representation algorithm itself.…”

Section: Introductionmentioning

confidence: 99%

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A Multiscale Approach to the Representation of 3d Images, With Application to Polymer Solar Cells

Thiedmann¹,

Hassfeld²,

Stenzel³

et al. 2011

Image Anal Stereol

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A multiscale approach to the description of geometrically complex 3D image data is proposed which distinguishes between morphological features on a 'macro-scale' and a 'micro-scale'. Since our method is mainly tailored to nanostructures observed in composite materials consisting of two different phases, an appropriate binarization of grayscale images is required first. Then, a morphological smoothing is applied to extract the structural information from binarized image data on the 'macro-scale'. A stochastic algorithm is developed for the morphologically smoothed images whose goal is to find a suitable representation of the macro-scale structure by unions of overlapping spheres. Such representations can be interpreted as marked point patterns. They lead to an enormous reduction of data and allow the application of well-known tools from point-process theory for their analysis and structural modeling. All those voxels which have been 'misspecified' by the morphological smoothing and subsequent representation by unions of overlapping spheres are interpreted as 'micro-scale' structure. The exemplary data sets considered in this paper are 3D grayscale images of photoactive layers in hybrid solar cells gained by electron tomography. These composite materials consist of two phases: a polymer phase and a zinc oxide phase. The macro-scale structure of the latter is represented by unions of overlapping spheres.

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“…However, the 2D model and the assumed microstructure do not represent the real complex morphology of LIB electrodes. The realistic three dimensional (3D) microstructure of LIB electrodes is required to perform this study [9].…”

Section: Introductionmentioning

confidence: 99%

Geometric Characteristics of Three Dimensional Reconstructed Anode Electrodes of Lithium Ion Batteries

et al. 2014

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Abstract:The realistic three dimensional (3D) microstructure of lithium ion battery (LIB) electrode plays a key role in studying the effects of inhomogeneous microstructures on the performance of LIBs. However, the complexity of realistic microstructures imposes a significant computational cost on numerical simulation of large size samples. In this work, we used tomographic data obtained for a commercial LIB graphite electrode to evaluate the geometric characteristics of the reconstructed electrode microstructure. Based on the analysis of geometric properties, such as porosity, specific surface area, tortuosity, and pore size distribution, a representative volume element (RVE) that retains the geometric characteristics of the electrode material was obtained for further numerical studies. In this work, X-ray micro-computed tomography (CT) with 0.56 μm resolution was employed to capture the inhomogeneous porous microstructures of LIB anode electrodes. The Sigmoid transform function was employed to convert the initial raw tomographic images to binary images. Moreover, geometric characteristics of an anode electrode after 2400 cycles at the charge/discharge rate of 1 C were compared with those of a new anode electrode to investigate morphological change of the electrode. In general, the cycled electrode shows larger porosity, smaller tortuosity, and similar specific surface area compared to the new electrode. OPEN ACCESSEnergies 2014, 7 2559

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Stochastic simulation model for the 3D morphology of composite materials in Li–ion batteries

Cited by 53 publications

References 19 publications

Influence of Microstructure on Impedance Response in Intercalation Electrodes

Influence of Microstructure on Impedance Response in Intercalation Electrodes

A Multiscale Approach to the Representation of 3d Images, With Application to Polymer Solar Cells

Geometric Characteristics of Three Dimensional Reconstructed Anode Electrodes of Lithium Ion Batteries

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