Cathode for metal-sulfur batteries, manufacturing method thereof, and metal-sulfur battery comprising the same

Binder-free, high-pressure molded freestanding metal-sulfur cathode with segregated sulfur and graphene regions

This technology optimizes sulfur utilization, electrical conductivity, and ion transport pathways in metal-sulfur battery cathodes by physically segregating sulfur-rich regions from carbon-rich regions, such as graphene.

Conventional lithium-sulfur batteries suffer from low electrical conductivity, poor sulfur utilization, polysulfide dissolution into the electrolyte, and limited low-temperature performance. Furthermore, traditional slurry casting processes require binders, which reduce specific capacity and complicate manufacturing.

This technology creates a binder-free, freestanding cathode film by mechanically mixing graphene with sulfur-containing materials like S8 or Li2S, then compressing them at 750–1100 MPa. During compression, Li2S undergoes a phase transition from cubic to orthorhombic, while the addition of ammonium nitrate (NH4NO3) to the electrolyte improves low-temperature performance and sulfur efficiency. Ideal for drones, urban air mobility, and cold-climate portable power, this binder-free approach increases energy density by reducing weight.

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Key Features:

• Graphene-dense regions filling areas outside of sulfur-dense regions without impregnation
• Sulfur-dense regions, segregated from graphene-dense regions, composed of S8, Li2S, sulfur polymers, or mixtures thereof
• Freestanding cathode active material layer containing 60 to 90 wt% sulfur-containing material with the remainder being graphene
• Step of forming a freestanding film by placing a mixture of graphene and sulfur-containing material into a mold and compressing at 750 to 1100 MPa

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