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@INPROCEEDINGS{Dao:1022606,
      author       = {Dao, Tuan Anh and Kadyk, Thomas and Finkenwirth, Olav and
                      Eikerling, Michael},
      title        = {{I}nvestigation of localized hydrogen starvation in {PEMFC}
                      with dynamic electrochemical impedance spectroscopy},
      reportid     = {FZJ-2024-01572},
      year         = {2023},
      abstract     = {Hydrogen fuel utilization is one of the significant factors
                      for the commercialization of PEMFC in automotive
                      applications. Too low fuel utilisation decreases the driving
                      range and fuel economy. However, too high utilization might
                      lead to localized hydrogen starvation, which significantly
                      reduces the lifetime and performance of the fuel cell system
                      [1]. Hence, advanced diagnostics are needed to detect
                      hydrogen starvation early and during operation [2].In this
                      paper, a commercial MEA is tested under low hydrogen
                      stoichiometry to simulate the spatial anode starvation
                      condition. A newly developed electrochemical impedance
                      spectroscopy (EIS) setup, which could measure up to 1000
                      impedance values in 1 second, is run in parallel for online
                      characterization. The single cell stack is equipped with a
                      current distribution measurement plate to confirm the
                      starvation condition by the presence of a current deficit
                      area in the anode outlet (Fig. 1). In addition, a novel
                      localized CO stripping method is employed to validate the
                      degradation on the cathode catalyst layer by measuring the
                      localized distribution of the electrochemical active surface
                      area (dECSA).This study shows that EIS spectra are
                      non-sensitive towards hydrogen stoichiometry in the range of
                      sufficient hydrogen supply, 𝜆𝜆>1. However, when
                      stoichiometry drops close to 𝜆𝜆≈1 and the localized
                      anode starvation starts to occur, the EIS spectra broaden
                      remarkably, even though the cell performance does not yet
                      indicate starvation. Furthermore, the EIS curves exhibit an
                      oscillation in the middle and high-frequency range in both
                      phase and magnitude when the cell is in the localized anode
                      starvation condition (Fig. 2). The oscillation becomes more
                      apparent when the starvation area is bigger. Meanwhile, the
                      low-frequency regime exhibits inductive behavior, becoming
                      more dominant with a more substantial effect of localized
                      starvation. The dynamic current density measurement observes
                      the hydrogen concentration oscillation in the anode outlet
                      area. The localized CO Stripping reveals a significant drop
                      of the dECSA on the cathode side in the same location,
                      indicating cathode carbon corrosion under localized anode
                      starvation conditions (Fig. 3).This work is a first step
                      towards an onboard diagnosis method, which could detect the
                      presence of localized anode starvation conditions early and
                      take control measures to prevent degradation.References:[1]
                      H. Chen et al., Energy Convers. Manag.182, 282-298
                      (2019).[2] Z. Tang et al. J. Power Sources 468, 228361
                      (2020).},
      month         = {Sep},
      date          = {2023-09-03},
      organization  = {74th Annual Meeting of the
                       International Society of
                       Electrochemistry, Lyon (France), 3 Sep
                       2023 - 8 Sep 2023},
      subtyp        = {After Call},
      cin          = {IEK-13},
      cid          = {I:(DE-Juel1)IEK-13-20190226},
      pnm          = {1231 - Electrochemistry for Hydrogen (POF4-123)},
      pid          = {G:(DE-HGF)POF4-1231},
      typ          = {PUB:(DE-HGF)6},
      doi          = {10.34734/FZJ-2024-01572},
      url          = {https://juser.fz-juelich.de/record/1022606},
}