Numerical Modeling on The Delamination-Induced Capacity Degradation of Silicon Anode
Numerical Modeling on The Delamination-Induced Capacity Degradation of Silicon Anode
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Silicon is a promising candidate for the negative electrode in lithium-ion battery. However, silicon-based electrodes experience large volume changes during the lithiation-delithiation process, which may lead to their failure and hinder their application. Delamination of the silicon layer from the current collector substrate is one of the critical failure modes; its effects on the performance degradation of Si anode need to be better understood. In this study, a multi-physics based finite element model is established to investigate the impact of Si layer delamination, where an artificial insulating interface is introduced to simulate the delamination phenomenon. It is found that delamination could result in a large amount of residual lithium within Si phase at the end of the delithiation process, leading to the capacity degradation of the Si anode. Furthermore, depth of delamination, Si layer thickness and charging/discharging C-rate are three critical influencing factors for the performances of the Si anode. With the increase of depth of delamination and Si layer thickness, the remaining useful capacity of the Si anode will gradually reduce. In addition, under high C-rate operating conditions, the capacity loss of the anode will be largely exaggerated by the presence of the delamination.
Silicon is a promising candidate for the negative electrode in lithium-ion battery. However, silicon-based electrodes experience large volume changes during the lithiation-delithiation process, which may lead to their failure and hinder their application. Delamination of the silicon layer from the current collector substrate is one of the critical failure modes; its effects on the performance degradation of Si anode need to be better understood. In this study, a multi-physics based finite element model is established to investigate the impact of Si layer delamination, where an artificial insulating interface is introduced to simulate the delamination phenomenon. It is found that delamination could result in a large amount of residual lithium within Si phase at the end of the delithiation process, leading to the capacity degradation of the Si anode. Furthermore, depth of delamination, Si layer thickness and charging/discharging C-rate are three critical influencing factors for the performances of the Si anode. With the increase of depth of delamination and Si layer thickness, the remaining useful capacity of the Si anode will gradually reduce. In addition, under high C-rate operating conditions, the capacity loss of the anode will be largely exaggerated by the presence of the delamination.
Published 1 paper as the 2nd author on Journal of Energy Storage
Schematic of the Si anode-based LIB. An insulating gap is manually introduced to represent the delamination of Si layer from metal current collector.
Discharging curves of the Si anode-based LIB with and without delamination. Inset illustrates the current density profile in the Si phase with the length of delamination d = 10 μm.
(a) Lithium concentration and (b) lithium diffusive flux in the Si anode with and without delamination at 2700 s simulation time.
(a) Discharging curves of the LIBs with different depths of delamination; Si layer thickness and discharging C-rate are 500 nm and 1C, respectively. (b) Lithium concentration along the Si anode with various depths of delamination at the simulation time of 2700 s.
(a) Discharging curves of the LIBs with different Si layer thickness; depth of delamination and C-rate are 10 μm and 1C, respectively. (b) Lithium concentration as a function of discharging time with different Si layer thickness.
(a) Discharging curves of the LIBs with a 10 μm long delamination and 500 nm thick Si layer under different C-rates. (b) Lithium concentration along the Si thin film under different C-rates.
Discharging curves of the LIBs with different depths of delamination and C-rate.
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