Unveiling the (de)lithiation heterogeneity of SiO/Graphite composite anodes in a 150 Ah high-energy-density Li-ion prismatic cell

Silicon monoxide (SiO)-graphite (Gr) composite anodes are considered as an ideal choice for next-generation lithium-ion batteries. However, the (de)lithiation heterogeneity within composite electrodes and the effect of SiO incorporation on batteries are not studied clearly. To get a deep insight, an extended pseudo-2-dimension (P2D) model based on a 150 Ah high-energy-density (HED) Li-ion prismatic cell with SiO/Gr blended anode and Ni-rich ternary cathode couple is established. The effect of SiO content, the interaction between SiO and graphite particles, and the inhomogeneity through the whole electrode are all investigated at a multiscale of material-electrode-battery. We find that SiO particles are preferential lithiation and lagging de-lithiation in the SiO/Gr blended anodes at the SOC range of 0∼0.91. Unlike the SiO particles, the big SOC inconsistency in graphite particles across the electrode thickness direction cannot be eliminated by Li+ redistribution during the relaxation process, when particles with different SOCs (such as 0.65–0.95) have the same equilibrium potential. Therefore, the potential plateaus of graphite are the main obstacle to its high-rate charging performance. Incorporating SiO particles is beneficial to the high-rate and low-temperature charging performance to a certain extent, owing to its relatively higher equilibrium potential and preferential lithiation behaviour.