@article{26184,
  keywords = {Model, Nucleation, Temperature, Performance, Water, Growth, Catalyst layer, Cold-start, PEFC, Porous media},
  author = {Thomas J Dursch and Monica A Ciontea and Clayton J Radke and Adam Z Weber},
  title = {Isothermal Ice Crystallization Kinetics in the Gas-Diffusion Layer of a Proton-Exchange-Membrane Fuel Cell},
  abstract = {<p>Nucleation and growth of ice in the fibrous gas-diffusion layer (GDL) of a proton-exchange membrane fuel cell (PEMFC) are investigated using isothermal differential scanning calorimetry (DSC). Isothermal crystallization rates and pseudo-steady-state nucleation rates are obtained as a function of subcooling from heat-flow and induction-time measurements. Kinetics of ice nucleation and growth are studied at two polytetrafluoroethylene (PTFE) loadings (0 and 10 wt %) in a commercial GDL for temperatures between 240 and 273 K. A nonlinear ice-crystallization rate expression is developed using Johnson-Mehl-Avrami-Kolmogorov (JMAK) theory, in which the heat-transfer-limited growth rate is determined from the moving-boundary. Stefan problem. Induction times follow a Poisson distribution and increase upon addition of PTFE, indicating that nucleation occurs more slowly on a hydrophobic fiber than on a hydrophilic fiber. The determined nucleation rates and induction times follow. expected trends from classical nucleation theory. A validated rate expression is now available for predicting ice-crystallization kinetics in GDLs.</p>},
  year = {2012},
  journal = {Langmuir},
  volume = {28},
  pages = {1222 - 1234},
  month = {01/2012},
  issn = {0743-7463},
  doi = {10.1021/la2033737},
}