Graphene-Coated Silicon-Graphite Anode for Stable High-Capacity Batteries

The patent applies nested structure by placing alloy-based active material particles inside a porous hollow sphere. The inner particle contains the high-capacity alloy material (e.g., silicon, tin) while the outer porous hollow sphere provides structural support and accommodation space for volume expansion. This nested configuration allows the inner particle to expand and contract during charging-discharging cycles without causing pulverization or detachment, thus maintaining both high capacity and good cycle performance.

The patent creates a composite structure combining alloy-based active material with porous hollow sphere material (such as carbonaceous materials, metal oxides, or conductive polymers). This composite design leverages the high capacity of alloy materials while the porous hollow sphere provides mechanical strength and structural stability. The composite structure prevents pulverization and detachment by distributing stress during volume changes, resolving the contradiction between capacity and reliability.

The nested structure places active material particles inside porous hollow spheres, allowing high proportion of active material while the hollow sphere walls provide mechanical strength. The active material can occupy most of the internal volume of the hollow sphere, maximizing capacity, while the sphere's structural integrity maintains mechanical strength even at high active material loading.

The patent applies local quality by having different regions with different functions: the inner active material region provides high capacity while the outer porous hollow sphere region provides mechanical strength and structural support. This spatial differentiation of properties allows the electrode to simultaneously achieve high capacity and adequate mechanical strength.

The porous hollow sphere itself acts as a composite material that provides both structural support (replacing traditional binders) and conductive pathways (replacing or supplementing conductive additives). The sphere's porous structure and material composition (e.g., conductive polymers, metal oxides, or carbonaceous materials) simultaneously provide mechanical integrity and electrical conductivity, reducing the need for separate binder and conductive material components.

The porous hollow sphere serves multiple functions simultaneously: it provides structural support to prevent collapse, maintains conductive pathways to prevent blocking, and accommodates volume changes during cycling. This multi-functionality reduces the need for separate binder and conductive material components, thereby increasing the proportion of active material and improving capacity while maintaining electrode stability.