2D Micro-Structure Resolved Model for Silicon Anode in Li-Ion Battery
Miao Wang (Michigan State University), Xinran Xiao (Michigan State University)
Lithium ion batteries: When Chemistry meets Mechanics
Tue 4:20 - 5:40
Salomon 003
High capacity anode materials such as silicon experience large volumetric changes during charge/discharge cycling in battery cells. Large cyclic deformation often leads to particle fracture, mechanical failure and delamination at particle-binder, particle-current collector interface, which results in pulverization and capacity fading. In our work, a 2D microstructure resolved full-cell model has been developed using COMSOL Multiphysics to investigate the kinetics of Li transport and electrochemical reactions, stress accumulation and structural deformation (W. Wu et al., Battery Congress 2013.). This model is further adopted for high capacity anode material, silicon. Based on previous studies, silicon experiences huge mechanical properties change during lithiation/delithiation, such as elastic moduli decrease with increasing lithium concentration (V. A. Sethuraman et al., Electrochemistry Communications 2010, vol. 12, no. 11, pp. 1614–1617), partial molar volume changes (K. Zhao et al., Nano Lett. 2011, vol. 11, no. 7, pp. 2962–2967) and Poisson’s ratio variation under different lithium concentration (V. B. Shenoy et al., Journal of Power Sources 2010, vol. 195, no. 19, pp. 6825–6830). Moreover, lithiated silicon may yield and deform plastically. Its yield strength and plastic modulus vary with lithium concentration. These behaviors are considered in the 2D microstructure resolved half-cell model. This model allows the observations of anisotropic morphologies and stress distributions in silicon anode as that observed in real-time experiments. In turn, we may also observe how the electrochemistry reactions and lithium distributions are affected by this huge volume change.