Dense Silicon-Carbon Anode Aggregates for Volume Expansion Control

The silicon-based active material particles are embedded within a carbon material matrix to form aggregates. The carbon material acts as a container or host structure that accommodates the active material particles, providing mechanical support and constraining volume expansion during lithium deintercalation. This nested structure allows the high-capacity silicon material to be utilized while the carbon framework maintains structural integrity and prevents pulverization, thereby improving cycle stability without sacrificing energy density.

The aggregate structure exhibits local quality differentiation where the internal active material particles maintain their high-capacity silicon-based composition for energy density, while the external carbon material framework provides mechanical strength and volume constraint for cycle stability. This spatial differentiation of material properties allows simultaneous optimization of both energy density and cycle stability, as each region performs its specialized function without compromising the other.

The carbon material is pre-mixed with the silicon-based active material particles before aggregate formation, creating a precursor mixture that naturally forms densified aggregates during the sintering or drying process. This preliminary mixing action ensures uniform distribution of carbon material around active material particles, which facilitates subsequent densification without requiring complex post-processing steps. The pre-established configuration enables structural stability to be achieved through relatively simple manufacturing processes.