Previous research works on solid oxide fuel cells (SOFCs) have mainly focused on the large length scale phenomena, such as physical and chemical transport phenomena at macroscale. A new approach is proposed in this work, which combines concepts from all-atom (AA) modeling with coarse-graining (CG) molecular dynamics (MD) method to reveal the replacement mechanism of Yttria-Stabilized Zirconia (YSZ) and establish the nanostructures of a NiO-based anode and an YSZ-based electrolyte. Lattice constants of NiO and YSZ are obtained by special measurements. Nanocrystalline structures of anode and electrolyte material structures under disparate conditions are generated via Atomistic Simulation Environment (ASE). By combining this technique with the local lattice constants, the effect of temperature on crystal formation and the influence of sintering conditions on the volume shrinkage are predicted. The combined AA-CG-MD method is validated and subsequently applied to an equilibrated anode and electrolyte nanostructures with a box length of 50 nm. The resulting nanostructures of the materials show good agreement with the distributions from experiments based on Transmission/Scanning Electron Microscopy (TEM/SEM) techniques, and provide insight into atom/pore distribution and the volume shrinkage at a length scale which is expanded into atomistic/molecular dynamics simulation to capture the best materials’ performance and the balance of oxygen-ion conductivity and material stability.
The Roles of Classical Molecular Dynamics Simulation in Solid Oxide Fuel Cells
