@article{ToetzkeGaiselmannOsenbergetal.2016,
  author    = {T{\"o}tzke, Christian and Gaiselmann, G. and Osenberg, M. and Arlt, T. and Mark{\"o}tter, H. and Hilger, A. and Kupsch, Andreas and M{\"u}ller, B. R. and Schmidt, V. and Lehnert, W. and Manke, Ingo},
  title     = {Influence of hydrophobic treatment on the structure of compressed gas diffusion layers},
  series = {Journal of power sources : the international journal on the science and technology of electrochemical energy systems},
  volume    = {324},
  journal   = {Journal of power sources : the international journal on the science and technology of electrochemical energy systems},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0378-7753},
  doi       = {10.1016/j.jpowsour.2016.05.118},
  pages     = {625 -- 636},
  year      = {2016},
  abstract  = {Carbon fiber based felt materials are widely used as gas diffusion layer (GDL) in fuel cells. Their transport properties can be adjusted by adding hydrophobic agents such as polytetrafluoroethylene (PTFE). We present a synchrotron X-ray tomographic study on the felt material Freudenberg H2315 with different PIPE finishing. In this study, we analyze changes in microstructure and shape of GDLs at increasing degree of compression which are related to their specific PTFE load. A dedicated compression device mimicking the channel-land pattern of the flowfield is used to reproduce the inhomogeneous compression found in a fuel cell. Transport relevant geometrical parameters such as porosity, pore size distribution and geometric tortuosity are calculated and consequences for media transport discussed. PTFE finishing results in a marked change of shape of compressed GDLs: surface is smoothed and the invasion of GDL fibers into the flow field channel strongly mitigated. Furthermore, the PTFE impacts the microstructure of the compressed GDL. The number of available wide transport paths is significantly increased as compared to the untreated material. These changes improve the transport capacity liquid water through the GDL and promote the discharge of liquid water droplets from the cell. (C) 2016 Elsevier B.V. All rights reserved.},
  language  = {en}
}
@article{FazeliHinebaughFishmanetal.2016,
  author    = {Fazeli, Mohammadreza and Hinebaugh, James and Fishman, Zachary and T{\"o}tzke, Christian and Lehnert, Werner and Manke, Ingo and Bazylak, Aimy},
  title     = {Pore network modeling to explore the effects of compression on multiphase transport in polymer electrolyte membrane fuel cell gas diffusion layers},
  series = {Journal of power sources : the international journal on the science and technology of electrochemical energy systems},
  volume    = {335},
  journal   = {Journal of power sources : the international journal on the science and technology of electrochemical energy systems},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0378-7753},
  doi       = {10.1016/j.jpowsour.2016.10.039},
  pages     = {162 -- 171},
  year      = {2016},
  abstract  = {Understanding how compression affects the distribution of liquid water and gaseous oxygen in the polymer electrolyte membrane fuel cell gas diffusion layer (GDL) is vital for informing the design of improved porous materials for effective water management strategies. Pore networks extracted from synchrotron-based micro-computed tomography images of compressed GDLs were employed to simulate liquid water transport in GDL materials over a range of compression pressures. The oxygen transport resistance was predicted for each sample under dry and partially saturated conditions. A favorable GDL compression value for a preferred liquid water distribution and oxygen diffusion was found for Toray TGP-H-090 (10\%), yet an optimum compression value was not recognized for SGL Sigracet 25BC. SGL Sigracet 25BC exhibited lower transport resistance values compared to Toray TGP-H-090, and this is attributed to the additional diffusion pathways provided by the microporous layer (MPL), an effect that is particularly significant under partially saturated conditions. (C) 2016 Elsevier B.V. All rights reserved.},
  language  = {en}
}