Prediction of Effective Properties of Porous Carbon Electrodes from a Parametric 3D Random Morphological Model
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Pore structures have a major impact on the transport and electrical properties of electrochemical devices, such as batteries and electric double-layer capacitors (EDLCs). In this work we are concerned with the prediction of the electrical conductivity, ion diffusivity and volumetric capacitance of EDLC electrodes, manufactured from hierarchically porous carbons. To investigate the dependence of the effective properties on the pore structures, we use a structurally resolved parametric model of a random medium. Our approach starts from 3D FIB-SEM imaging, combined with automatic segmentation. Then, a random set model is fitted to the segmented structures and the effective transport properties are predicted using full field simulations by iterations of FFT on 3D pore space images and calculations based on the geometric properties of the structure model. A parameter study of the model is used to investigate the sensitivity of the effective conductivity and diffusivity to changes in the model parameters. Finally, we investigate the volumetric capacitance of the EDLC electrodes with a geometric model, make a comparison with experimental measurements and do a parameter study to suggest improved microstructures.
KeywordsPorous electrodes Double-layer capacitor FIB-SEM nanotomography Stochastic modeling
This work was partly funded by the German Federal Ministry of Education and Research, Project AMiNa (03MS603D).
- Balach, J., Miguel, F., Soldera, F., Acevedo, D., Mücklich, F., Barbero, C.: A direct and quantitative image of the internal nanostructure of nonordered porous monolithic carbon using fib nanotomography. J. Microsc. (2012)Google Scholar
- Bazant, M.Z., Thornton, K., Ajdari, A.: Diffuse-charge dynamics in electrochemical systems. Phys. Rev. E 70(021), 506 (2004)Google Scholar
- Conway, B.: Electrochemical Supercapacitors: Scientific Fundamentals and Technological Applications. Springer, US (2013)Google Scholar
- de Levie, R.: On porous electrodes in electrolyte solutions: I. Capacitance effects. Electrochim. Acta 8(10), 751–780 (1963)Google Scholar
- Jeulin, D., Moreaud, M.: Multi-scale simulation of random spheres aggregates-application to nanocomposites. In: 9th European Congress on Stereology and Image Analysis, Zakopane, Poland, vol. 1, pp 341–348 (2005)Google Scholar
- Jeulin, D.: Random structures in physics. In: Bilodeau, M., Meyer, F., Schmitt, M. (eds.) Space, Structure and Randomness. Lecture Notes in Statistics, vol. 183, pp. 183–219. Springer, New York (2005)Google Scholar
- Matheron, G.: Random Sets and Integral Geometry. Wiley series in probability and mathematical statistics, Probability and mathematical statistics. Wiley, London (1975)Google Scholar
- Matheron, G.: Elements pour une théorie des milieux poreux. Masson, Paris (1967)Google Scholar
- Papanicolau, G., Bensoussan, A., Lions, J.: Asymptotic Analysis for Periodic Structures, Studies in Mathematics and its Applications. Elsevier Science, Amsterdam (1978)Google Scholar
- Sánchez-Palencia, E.: Non-homogeneous Media and Vibration Theory, Lecture Notes in Physics. Springer, London (1980)Google Scholar
- Serra, J.: Image Analysis and Mathematical Morphology. Academic Press, London (1982)Google Scholar