Silicon-Silicon Oxide Negative Electrode with Density Gradient

The patent applies local quality by creating a density gradient within the primary particle structure, where the surface layer part has lower density than the core part. This local structural differentiation allows the surface to facilitate ion transport and electron conductivity while the core maintains structural stability and stress resistance during cycling, thereby simultaneously improving both cycle characteristics and high-rate discharge capacity.

The patent employs composite materials by combining silicon and silicon oxide in a specific structural arrangement where silicon provides high capacity and silicon oxide provides structural stability. The composite structure is further enhanced by creating a density gradient between the core and surface layers, optimizing both mechanical stability for cycling and electrical properties for high-rate discharge.

The patent applies parameter changes by modifying the density parameter within the primary particle structure, creating a gradient from the core to the surface. This fundamental structural parameter change inherently improves electric conductivity and ion transport without requiring additional carbon coating layers, thereby achieving high-rate discharge capacity while maintaining structural simplicity.

The patent extracts the carbon coating step from the overall structure by achieving the necessary conductivity enhancement through the density gradient structure itself. This eliminates the need for separate carbon surface coverage, simplifying the device structure while maintaining the desired electrical properties for high-rate discharge.