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

Dissolution-inhibiting lithium-sulfur cathode active material based on alternating layers of molybdenum-sulfur compounds and carbon

This technology features a cathode active material structure that physically prevents the dissolution of lithium-sulfur compounds into the electrolyte during charge and discharge cycles by repeatedly stacking molybdenum (Mo) and sulfur (S) compound layers with carbon layers, all enclosed within a carbon shell.

In conventional lithium-sulfur batteries, polysulfides generated during charge and discharge cycles dissolve into the electrolyte, leading to a loss of active material and a rapid decline in cycle life and capacity retention.

This technology involves mixing molybdenum, sulfur, and carbon sources, followed by sequential primary and secondary heat treatments to inherently position metal compound layers between carbon layers and form an outer carbon shell, structurally confining the lithium-sulfur compounds. It can be applied to lithium-sulfur batteries in fields where energy-to-weight ratio is critical, such as drones, high-altitude UAVs, and lightweight electric aircraft, minimizing sulfur active material loss over long-term cycling.

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Key Features:

• Carbon layers consisting of graphene or graphene oxide layers, stacked alternately and repeatedly
• Metal compound layers containing molybdenum and sulfur, inherently confined between the carbon layers
• A carbon shell layer that externally surrounds the entire stack of alternating carbon and metal compound layers
• A step of mixing molybdenum, sulfur, and main carbon sources, followed by primary heat treatment to produce an intermediate

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This invention was developed with support from the Austrian Institute of Technology's project, "Novel layered dichalcogenide with high performance anode materials for lithium ion batteries."

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