A Mechanistic and Quantitative Understanding of the Interactions between SiO and Graphite Particles

摘要

SiO, comprised of silicon and silicon dioxides (SiO_2), is one of the mostcommercially promising anode materials to mix with current widely usedgraphite for the high energy density lithium-ion batteries (LIBs). One of themajor bottlenecks for SiO/Graphite (SiO/Gr) composite anode is the cyclabilitydue to considerable stress and strain (deformation) caused within and amongthe composite particles. However, a sophisticated and quantitative understandingof the highly electrochemical–mechanical coupling behaviors is stilllacking. Herein, an electro–chemo–mechanical model with a detailed geometricdescription to quantitatively reveal the underlying governing mechanismsof SiO/Gr composite anodes using the half-cell configuration is establishedand validated. Results show that an 8–10 wt.% of SiO is an optimal choiceregarding capacity delivery and minimizing Li plating under 1C constant currentcharging condition. Positioning SiO particles near the separator and reducingthe sizes of SiO particles are also demonstrated to be beneficial for electrochemicalperformance with trivial influence on mechanical mismatch. Thisstudy highlights a promising multiphysics model for the design and evaluationof next-generation batteries and unlocks the mechanistic and quantitativeunderstanding of the interactions among composite particles in electrodes.