Impedance Inhomogeneity in SiO/Gr Composite Anode

Silicon/carbon (Si/C) composite anode materials have emerged as promising candidates for high-energy-density lithium-ion batteries (LIBs), boasting advantages such as high capacity, cost-effectiveness, and abundance. However, the integration of Si-based materials into conventional graphite anodes introduces heterogeneous interactions between electrochemical and mechanical behaviors, owing to substantial volume changes and chemical potential variations. One significant consequence of these interactions is the impedance inhomogeneity, which adversely affects the discharging capacity of Si-based LIBs. In an effort to comprehensively understand this phenomenon and its underlying mechanisms, an electrochemo-mechanical-coupled model is established, incorporating detailed particle geometries on the anode side. The model is employed to investigate polarization components and their evolution during the charging/discharging process. Various influencing factors, such as SiO weight percentage (wt%), electrode thickness, and SiO distributions (both in terms of distribution uniformity and direction), are systematically discussed. In this study, an efficient computational approach is offered to analyze battery polarizations, deepening the understanding of the inhomogeneous evolution of these polarizations in Si/C composite anodes. Ultimately, these insights guide the design of anodes for next-generation high-energy-density LIBs.