Silicon-Sulfur Anode Composition for Fast-Charging Li-Ion Cells

The patent applies local quality by creating a non-uniform distribution of sulfur within the graphite particles. Sulfur is concentrated at specific locations (surface or internal regions) rather than uniformly distributed, allowing localized control over expansion behavior. This localized sulfur presence restrains silicon expansion in specific zones while maintaining high silicon content for capacity, thus resolving the contradiction between capacity improvement and cycle performance deterioration.

The patent changes the chemical composition parameters by introducing sulfur at controlled concentrations (0.01-5 wt%) and adjusting the Si/S ratio (0.1-10). By modifying these compositional parameters, the patent achieves a balance where sulfur's restraining effect on silicon expansion is optimized to maintain cycle performance while preserving the high capacity benefits of silicon.

The patent optimizes the sulfur content parameter within a specific range (0.01-5 wt%) and controls the Si/S ratio (0.1-10) to achieve the desired balance. By precisely adjusting these parameters, the patent ensures sufficient sulfur is present to restrain silicon expansion and improve cycle performance, while avoiding excessive sulfur that would cause harmful reactions with the electrolyte and deteriorate storage performance.

The patent applies partial action by using a controlled, limited amount of sulfur rather than excessive sulfur content. This partial incorporation of sulfur (at optimized concentrations) provides just enough restraining effect on silicon expansion to improve cycle performance, while avoiding the excessive sulfur that would lead to harmful side reactions with the electrolyte solution and poor storage performance.