Nitrogen-Doped Highly Graphitized Porous Carbon Structure, Lithium-Sulfur Battery Comprising the Same, and Manufacturing Method Thereof

Lithium-Sulfur Cathode with High-Loading Sulfur Supported on MOF-Derived Nitrogen-Doped Hierarchical Porous Carbon

This technology utilizes a highly graphitic carbon structure—characterized by nitrogen doping, hierarchical micro-meso-macro porosity, and a concave dodecahedral shape—as a sulfur host to enhance sulfur loading efficiency and suppress the shuttle effect in lithium-sulfur batteries.

Lithium-sulfur batteries have historically faced challenges due to the low electrical conductivity of sulfur and the shuttle effect, where lithium polysulfides generated during sulfur reduction migrate between electrodes. These issues lead to reduced cycle life caused by electrode volume expansion and make it difficult to achieve the high sulfur loading required for commercial operation.

This technology employs metallothermic reduction using ZIF-8 metal-organic frameworks and a magnesium metal reducing agent, followed by acid etching, to produce a highly graphitic carbon structure with a specific surface area of 500–1000 m²/g and a mesopore volume fraction of over 50%. This structure stably anchors sulfur to mitigate electrode volume changes, while the doped nitrogen enhances affinity with polysulfides. Suitable for applications where weight is critical, such as cathodes for lithium-sulfur batteries in drones, high-altitude unmanned aerial vehicles, and electric aircraft, it minimizes polysulfide loss even at high loading levels of 5–15 mg/cm², enabling practical areal capacity.

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Key Features:

• A porous graphitic carbon structure comprising a nitrogen-doped metal-organic framework with at least one concave face at the center
• A carbon structure containing micro-pores (≥0.1 nm), meso-pores (≥2 nm), and macro-pores (≥50 nm)
• Sulfur supported on the carbon structure at a loading of 5 to 15 mg/cm² to serve as the cathode active material
• A step of producing an intermediate structure via metallothermic reduction of a solid-state mixture of a nitrogen-containing metal-organic framework and a powdered metal reducing agent

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