Numerical study on TPB density and percolation properties of microstructure reconstruction of nickel/yttria stabilized zirconia cermet anode based on discrete element method
Numerical study on TPB density and percolation properties of microstructure reconstruction of nickel/yttria stabilized zirconia cermet anode based on discrete element method
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DOI：
10.1016/j.ijhydene.2022.06.132
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Xinxin Zhang
中科院分区：
文献类型：
--
作者：
Yunhao Wei;Cheng Bao;Zeyi Jiang;Xinxin Zhang
Microstructure is essential for electrochemistry and transport in Ni/YSZ cermet anodes. Targeting the complexity and irregularity of porous networks, the percolation theory is widely used to model electrode microstructures in representative element (RE) scale based on an ideal prototype of particle units. With the pros of simplicity and generality, however, the idealized particle model deviates somehow the true state of particle clusters. Modeling connections between a lot of particles, the discrete element method (DEM) provides a more realistic state, meanwhile brings high computation cost. This paper provides a combined approach which starts from a DEM-based model for compaction and evolution between particle arrays, then analyzes the statistical properties, e.g. density of triple phase boundary (TPB) and percolations of particles. With consideration of multiple-particle overlaps, the DEM-fitted relationship of percolation probability vs. coordination number presents a smaller percolation threshold and a slower growing rate before reaching a full percolation, compared with some published formulae based on the percolation theory. Simulations at different temperatures are employed to study the effects of sintering. This work has significance of understanding the evolution and optimization of the electrode microstructure, not limited to Ni/YSZ system, and is helpful for more accurate solid oxide fuel cell modeling. • A DEM-based microstructure reconstruction method for Ni/YSZ cermet anode. • More real compaction and evolution in particle array scale than in RE scale. • Modified formula for percolation probability compared to the percolation theory. • Comparison of TPB density and percolation probability before and after sintering. • Sikensitive analysis of microstructural parameters correlated to TPB density.
