The effects of microstructural parameters on the electrochemical properties of LSM-LSCF composite cathode by the particle-based discrete element method

Abstract

In this paper, the particle packing-based discrete element method is applied to study the correlations between the microstructural parameters and electrochemical performances of LSM-LSCF composite electrodes. Firstly, through the verification of domain size independence and the comparison with the percolation theory, the computational domain size and effectiveness of the particle packing are determined. Then, the changes of the electrochemical reaction sites in the composite electrode with the LSM volume fraction under two different ratios of particle radius are investigated, including the LSM-LSCF-pore three-phase boundaries (TPBs) per electrode volume, TPBs per electrolyte surface, and percolated LSCF-pore double phase boundaries (DPBs). The distribution characteristics of the LSM-LSCF-pore TPBs within and outside the threshold volume fraction zone at different particle size ratio cases are obtained. When the particles are of equal radius, the formation of both percolated e−, O2−, and O2 transport paths is in the LSM volume fraction range of 0 to 0.7, due to the electronic conducting path is fully connected. The distribution characteristics of the LSCF-pore DPBs within the electrode in the percolation area and outside the percolation area are obtained respectively. This work is of great significance for the follow-up study of the physical and electrochemical processes within porous composite electrodes based on large-scale complex morphology.