Cathode for All-Solid-State Lithium-Sulfur Batteries, All-Solid-State Lithium-Sulfur Battery Including the Same, and Manufacturing Method Thereof

High-Adhesion All-Solid-State Lithium-Sulfur Cathode Formed via Interfacial Intermediate Compounds Using Polar Solvent Wet Mixing

This technology involves wet-mixing a sulfur composite—created by impregnating sulfur into a conductive carbon carrier coated with transition metal sulfides—with a sulfide-based solid electrolyte using a polar solvent with a polarity index of 3–5 (e.g., isopropyl acetate). This forms a polysulfido-intermediate compound (P-IC) at the interface, maximizing contact area and interfacial bonding strength between particles.

Conventional dry mixing or the use of non-polar solvents often results in poor uniformity between sulfur and the solid electrolyte. This leads to high internal resistance due to poor interfacial contact and the formation of voids, which limits ionic conductivity and reduces battery capacity.

This technology induces an interfacial chemical reaction by wet-mixing the sulfur composite and sulfide-based solid electrolyte in a polar solvent with a polarity index of 3–5. The resulting polysulfido-intermediate compound (3Li+-PS4+n3-) increases interfacial bonding strength to over 0.15N and minimizes voids, securing ion conduction channels within the electrode. Applicable to all-solid-state lithium-sulfur battery cathode manufacturing for drones, UAM, and lightweight EVs, it enhances sulfur utilization and increases capacity per unit weight.

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Key Features:

• Preparing a carrier containing conductive carbon with a transition metal sulfide surface coating
• Mixing the carrier with sulfur raw materials and heating to produce a sulfur-impregnated composite
• Wet-mixing the sulfur composite and sulfide-based solid electrolyte in a polar solvent (polarity 3–5) to produce a powder
• An interface containing a polysulfido-intermediate compound formed by the reaction between sulfur in the composite and PS43- in the sulfide-based solid electrolyte

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This invention was developed with support from the Energy Innovation Research Center for Carbon Neutrality Workforce Development, funded by the Ministry of Trade, Industry and Energy.

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