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Silicon anodes in lithium-ion batteries are a promising next-generation battery technology offering ten times higher theoretical capacity than commercial graphite anodes. However, substantial volume changes (around 300%) associated with silicon anodes pose a significant challenge to the cycle life of these batteries. To understand the effect of the interaction between lithiation (diffusion) and mechanics (volume expansion, stress generation) on cycle life, a theoretical chemo-mechanical model of an isolated deforming silicon anode nanospherical particle is proposed in this study. Existing models, designed for low-capacity electrode materials, ignore the effect of deforming volume in the model formulation. Deforming volume, critical for high-capacity electrodes like silicon, is accounted for in the proposed model. Galvanostatic and potentiostatic operating conditions are considered. Simulations of the model help explain the importance of smaller particle sizes in observed longer cycle lives of silicon anodes. These enable mathematically accurate calibration of the partial molar volume of the material and determination of the developed mechanical stresses. Simulations of the proposed model help us optimize design parameters like particle size, particle thickness, and the charge rate/ applied voltage for elastic operation to ensure longer cycle lives of these batteries. Figure 1
Joshi et al. (Fri,) studied this question.