Dresden 2011 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 19: Poster: Interfaces and Thin Films
CPP 19.13: Poster
Dienstag, 15. März 2011, 18:00–20:00, P2
Impedance Spectroscopy Simulation of Solid Electrolytes — •Manuel Landstorfer1,2, Stefan Funken1, and Timo Jacob2 — 1Institut für Numerische Mathematik, Universität Ulm, Helmholtzstr. 18 — 2Institut für Elektrochemie, Universität Ulm, Albert-Einstein-Allee 47
Solid electrolytes are promising functional materials for a wide range of applications, e.g. lithium ion batteries, solid oxide fuel cells, sensors or electrochromic devices. One of the main characterization methods of electrolytes is the impedance spectroscopy, in which the cell response to AC conditions is monitored. Besides the classical simulations of impedance spectroscopy, in which the electrolyte is modeled as a RC network, more fundamental studies in terms of transport equations can be performed.
We describe ion transport in a solid electrolyte via an extended Poisson–Nernst–Planck system, which takes into account the finite amount of ion sites. Boundary conditions for the impedance spectroscopy simulations are derived, which incorporate the capacitance of the electrode/electrolyte intermediate layer. It resolves space- and time-dependent the charge region within the solid electrolyte. Using a finite element method (FEM) and Newton’s methods to solve the nonlinear partial differential equation system, we present numerical results for various frequencies allowing us to evaluate the system’s response in impedance spectroscopy measurements. The AC frequency of purely capacitative behaviour, i.e. no double layer formation, is determined by our numerical studies.