TY  - CHAP
U1  - Konferenzveröffentlichung
A1  - Grübl, Daniel
A1  - Bessler, Wolfgang G.
T1  - Electrochemical Pressure Impedance Spectroscopy (EPIS): A Promising Diagnostic Tool for Metal-air Batteries and Fuel Cells
T2  - 68th Annual Meeting of the International Society of Electrochemistry, Providence, USA (09/2017) : Book of Abstracts
N2  - Electrochemical impedance spectroscopy (EIS) is a widely-used diagnostic technique to characterize electrochemical processes. It is based on the dynamic analysis of two electrical observables, that is, current and voltage. Electrochemical cells with gaseous reactants or products (e.g., fuel cells, metal/air cells, electrolyzers) offer an additional observable, that is, the gas pressure. The dynamic coupling of current and/or voltage with gas pressure gives rise to a number of additional impedance definitions, for which we have introduced the term electrochemical pressure impedance spectroscopy (EPIS) [1,2]. EPIS shows a particular sensitivity towards transport processes of gas-phase or dissolved species, in particular, diffusion coefficients and transport pathway lengths. It is as such complementary to standard EIS, which is mainly sensitive towards electrochemical processes. This sensitivity can be exploited for model parameterization and validation. A general analysis of EPIS is presented, which shows the necessity of model-based interpretation of the complex EPIS shapes in the Nyquist plot (cf. Figure). We then present EPIS simulations for two different electrochemical cells: (1) a sodium/oxygen battery cell and (2) a hydrogen/air fuel cell. We use 1D or 2D electrochemical and transport models to simulate current excitation/pressure detection or pressure excitation/voltage detection. The results are compared to first EPIS experimental data available in literature [2,3].
Y1  - 2017
UR  - https://www.ise-online.org/ise-conferences/annmeet/folder/68th_Annual_meeting-BoA.pdf
SP  - 60
S1  - 1
ER  -