Fracture occurs in silicon-based electrodes due to large volume change during the lithiation/delithiation in lithium-ion batteries. A stable solid electrolyte interphase (SEI) can effectively prevent fractures. However, lithium-ion diffusion inside SEI layer has not been fully understood. In this study, a phase-field model is developed to simulate two-dimensional formation of SEI layer and lithium-ion diffusion inside SEI layer formed on silicon electrode. The details of SEI species are confirmed by XPS experiments reported in the literature. Double-well function is applied to represent the total free energy density considering lithium-ion concentration inside the SEI layer. Simulation results show lithium-ion diffusion coefficients between 298K and 318K are 2.021-2.211(10~(16)) cm~2/s, 7.146-8.038(10~(-13)) cm~2/s, and 1.448-1.585(10~(-15)) cm~2/s for compact, porous, and multilayered SEI layers, respectively. Resistances of the aforementioned SEI layers between 298K and 318K are 1.484-2.609 Ω? cm~2, 4.175-6.372 Ω?cm~2, and 5.171-7.007 Ω?cm~2.
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