Cathode active material for lithium-sulfur batteries and manufacturing method thereof

Lithium-sulfur cathode material incorporating polysulfanes via vulcanization of porous organic crystals

This technology utilizes sulfur-containing porous organic crystals (such as TTCA) as a soft template. By subjecting the internal pores and thiol groups to a vulcanization reaction with elemental sulfur, a composite structure with bonded polysulfanes is formed, which suppresses sulfur leaching and enhances lithium-ion conductivity.

Conventional lithium-sulfur batteries have faced challenges including the low electrical conductivity of sulfur in the cathode, capacity degradation caused by the shuttle mechanism of soluble polysulfides generated during charge/discharge cycles, and sharp performance drops during high-speed charging and discharging.

This technology involves manufacturing a cathode active material where linear polysulfanes (5–7 sulfur atoms) are chemically bonded within a TTCA structure. This is achieved by using trithiocyanuric acid (TTCA) crystals as a template, filling them with sulfur at 160°C, and performing a vulcanization reaction at 220°C or higher. By blocking the external leaching of polysulfides, this method can be used to improve both the quality and productivity of cathode materials for lithium secondary batteries.

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Key Features:

• A manufacturing method that involves filling a porous structure having a sulfur-containing molecular structure with sulfur, and vulcanizing the sulfur within the porous structure with the filled sulfur.
• A cathode active material for lithium-sulfur batteries characterized by cross-linked polysulfanes bonded within the pores of a porous structure.
• A configuration that forms a cathode active material by using sulfur-containing porous organic crystals as a soft template.
• A configuration that forms a composite structure with bonded polysulfanes by vulcanizing internal pores and thiol groups with elemental sulfur.

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