Santoni, F. Della Pietra, M. Pumiglia, D. Munoz, C. Boigues McPhail, S. J. Cigolotti, V. Nam, S. W. Kang, M. G. Yoon, S. P. 2024-01-19T21:30:45Z 2024-01-19T21:30:45Z 2021-09-05 2018-11-20 0013-4686 https://pubs.kist.re.kr/handle/201004/120672 This work has the difficult task to deeply study the electrochemical processes that occur inside a 100 cm(2) of Molten Carbonate Fuel Cells (MCFC) impedance spectra using the high resolution of Distribution of Relaxation Time (DRT) method. Using this method, it is possible to shed light on the different physicochemical processes occurring within these cells, identifying the characteristic relaxation times by means of an appropriate experimental campaign where temperature and gas compositions in anode and cathode were varied one at a time. The quality of the recorded spectra was verified by Kramers-Kronig relation before applying DRT calculations. In this work, five distinct and separated peaks with different time constants ranging from 0.01 to 500 Hz were identified and associated with physiochemical processes of the cell. Three peaks at high frequency represent the charge transfer processes in anode and cathode active sites. The other two, located at low frequency, are associated with the gas diffusion in the electrodes and to the gas conversion process. This study represents the first application of the DRT approach to this technology allowing to understand the physicochemical origin of the individual polarization processes controlling the cell performance and the degradation. The analysis of degradation processes using the DRT method and the physiochemical processes identification presented in this paper will be shown in part II of this work. (c) 2018 Elsevier Ltd. All rights reserved. English PERGAMON-ELSEVIER SCIENCE LTD ELECTROCHEMICAL IMPEDANCE SPECTRA PERFORMANCE ASSESSMENT CATHODE DISSOLUTION HYDROGEN OXIDATION IMMITTANCE DATA AC-IMPEDANCE GAS CAPTURE ANODES MCFC Accurate in-operando study of molten carbonate fuel cell degradation processes -part I: Physiochemical processes individuation Article 10.1016/j.electacta.2018.08.100 1 ELECTROCHIMICA ACTA, v.291, pp.343 - 352 ELECTROCHIMICA ACTA 291 343 352 scie scopus 000447646800039 2-s2.0-85054729072 Electrochemistry Electrochemistry Article ELECTROCHEMICAL IMPEDANCE SPECTRA PERFORMANCE ASSESSMENT CATHODE DISSOLUTION HYDROGEN OXIDATION IMMITTANCE DATA AC-IMPEDANCE GAS CAPTURE ANODES MCFC Distribution of relaxation time Molten carbonate fuel cell Polarization losses Deconvolution of impedance spectra Degradation processes