Cathode material for lithium secondary batteries containing calcium sulfate, manufacturing method thereof, and lithium secondary battery comprising the same

High-Nickel NCM Cathode Materials with Dual-Functionalized CEI Formed via Calcium Sulfate Heat Treatment

This technology improves interfacial stability by adding calcium sulfate (CaSO4) to the surface of NCM cathode materials and performing heat treatment to form an artificial cathode-electrolyte interphase (CEI) layer functionalized with Ca2+ and SO42- ions.

High-nickel NCM cathode materials face issues where unstable Ni4+ generated during charging accelerates electrolyte decomposition. The accumulation of decomposition byproducts on the cathode surface blocks lithium-ion transport, leading to a rapid decline in cycling performance.

This technology involves mixing 0.1–0.5 wt% calcium sulfate with NCM cathode active material and heat-treating it to create a dual-functionalized CEI layer where Ca2+ bonds with oxygen and SO42- bonds with cations, including residual lithium. Applicable to NCM811-based high-energy EV batteries and long-life energy storage cells, it reduces the burden of residual lithium and slows the accumulation of surface byproducts.

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Key Features:

• Calcium sulfate (CaSO4) additive that separates into Ca2+ and SO42- ions within the cathode material during heat treatment
• Ca2+ ions that separate from calcium sulfate and bond with oxygen (O) elements in the cathode material
• SO42- ions that separate from calcium sulfate and bond with cation species containing Li+
• Step of heat-treating a mixture of NCM-based cathode active material and 0.1–0.5 wt% calcium sulfate additive relative to the cathode material weight

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