Hello, A new project on the LCRC cluster has been requested. Please forward the information on to the LCRC Allocation sub-committee. Applicant's name: Rajesh Ahluwalia Applicant's institution: ANL Applicant's division: NE Project Name: PEMFC-Microstructure Project title: Nano-scale Characterization and Electrochemical Transport in Electrodes of Polymer Electrolyte Fuel Cells Associated funding: DOE-EERE-FCTO Other Systems: Limited availability on NE cluster Eddy: 48 nodes, 8 cores/node, 768 GB memory Limited availability on NE cluster Eddy2: 8 nodes, 32 cores/node, 1028 GB memory Limited availability on TRACC clusters Zephyr and Phoenix Science: Resolve detailed electrode microstructure at nanometer (nm) length scale in terms of spatial and size distributions of catalyst, carbon, ionomer, primary pores and secondary pores Conduct multiphase simulations of electrochemical kinetic and transport processes on the nanoscale microstructure Develop foundational understanding of the relationship between electrode performance and its microstructure Project description: We are developing a new approach to quantitatively characterize the detailed cathode electrode microstructure from nm to μm length scales by combining data from different experimental techniques: nano-scale X-ray computed tomography (X-CT) in phase contrast mode at APS 26-ID-C and 32-ID-C beam lines for secondary pores and solids (~20 nm resolution); X-CT in absorption contrast mode for carbon and ionomer distribution within the solid phase (~20 nm resolution); transmission electron microscopy (TEM) and X-ray scattering in ultra-small angle (USAXS) to small-angle (SAXS) regions at APS 9-ID-C for primary carbon and catalyst particle size distributions (~1 nm resolution); and BET and mercury intrusion porosimetry (MIP) for primary pore size distribution. We have developed a stochastic percolation algorithm in MATLAB to incorporate the experimental data from the above characterization techniques with different length scales in one geometric representation (hybrid microstructure) with the required resolution determined by the technique with the highest resolution. We have run COMSOL and STAR-CCM+ simulations on the hybrid microstructure to determine anisotropic oxygen transport and proton conductivity on extracted sample volumes. Because of limited computer resources, the simulations have been limited to 1 um x 1 um x 1 um domain, discretized in 64 million (64M) nodes for 2.5 nm length scale resolution. We have started to develop pore scale microscopic models in MATLAB and C-language for liquid water transport in the hybrid microstructure. We have been successful in developing algorithms for the dynamic invasion model (DIM) and obtaining initial illustrative results on coarse grids. Meaningful results will require access to full parallel computing on a supercomputer. Proposed Work on LCRC 1. Expand hybrid microstructure model to combine information from phase contrast and absorption contrast • Refine ionomer structure, ionomer film thickness, and ionomer segregation • Validate results with TEM data 2. Conduct pore-scale DIM simulations on full thickness of electrodes • 1 um x 1 um x 10 um domain, discretized using 640M nodes for 2.5 nm resolution and 10B nodes for 1 nm resolution • Extract transport properties for use in macroscopic model 3. Extend DIM to water transport in diffusion media (DM) • Conduct liquid water transport in cathodes attached to macro porous layer (MPL) with gas diffusion layer (GDL) • Extract transport properties for use in macroscopic model • Validate results with nano and micro X-CT data 4. Combine DIM with pore-scale oxygen/water vapor transport in electrode pores and ionomer 5. Create foundational understanding of electrochemistry and transport processes by conducting simulations of oxygen reduction reaction on catalyst particles combined with gas and liquid transport in hybrid microstructure Project Team Members: Rajesh K Ahluwalia (NE), Cankur F Cetinbas (NE), J-K Peng (NE), Xiaohua Wang (NE), Dennis. D. Papadias (NE) On-going Experiments: Nano-XCT studies of electrode microstructure at APS; USAXS and SAXS studies of inks and electrodes at APS; TEM studies of cathodes at ORNL Industry partnership: Project URL: http://www.fcpad.org Requested allocation: 400000 Q1: 100000 Q2: 100000 Q3: 100000 Q4: 100000 Justification: Storage requirements: 1 TB The requester has used undetermined amount hours of their initial startup project. In addition to approving an initial amount, please specify a Category and Subcategory for this project. For a list of the current selection of approved categories, please see: https://wiki.lcrc.anl.gov/wiki/Processes/Categories Once the Allocation committee has approved the project, please go to the Project Management page to create it: https://accounts.lcrc.anl.gov/projects.php Thank You, The LCRC Accounts System