Tin Fluoride-Carbon Composite Anode for Sodium Batteries

The patent employs a composite anode material consisting of tin fluoride particles dispersed in a carbonaceous matrix. This composite structure combines the high capacity of tin fluoride with the stability and conductivity of carbon, resolving the contradiction between achieving high cycle life and maintaining manufacturing simplicity. The carbonaceous material serves as both a structural framework and a conductive network, enabling straightforward manufacturing while delivering superior electrochemical performance.

The patent applies local quality by creating a heterogeneous structure where tin fluoride particles are distributed within the carbonaceous matrix. Different regions of the anode material serve different functions: tin fluoride provides high capacity sites for sodium ion insertion, while the carbon matrix provides structural integrity and electrical conductivity. This localized functional distribution achieves high reliability without complicating the overall manufacturing process.

The patent creates a composite material where tin fluoride particles are embedded in a carbonaceous matrix. The carbon component provides excellent electrical conductivity and structural stability, while tin fluoride contributes high charge/discharge capacity through reversible sodium ion insertion. This composite approach resolves the contradiction by combining materials with complementary properties.

The carbonaceous material acts as an intermediary between tin fluoride particles and the electrolyte, facilitating electron transport and maintaining electrical conductivity. The carbon matrix serves as a conductive network that connects tin fluoride particles to the current collector, enabling efficient charge transfer while allowing tin fluoride to maintain its high capacity characteristics.

The patent creates a hierarchical structure where tin fluoride particles of optimized size are distributed within the carbon matrix. This local optimization ensures that high-capacity regions (tin fluoride) are surrounded by high-conductivity regions (carbon), enabling fast electron and ion transport. The local quality approach allows the material to deliver high capacity at various rates by maintaining efficient transport pathways throughout the structure.

The composite structure combines tin fluoride's high capacity with carbon's superior rate performance. The carbon matrix provides rapid electron transport pathways and maintains structural integrity during fast charging/discharging cycles, while tin fluoride particles provide the high capacity mechanism. This synergistic combination resolves the contradiction between capacity and rate performance.