Cathode Active Material for Lithium Secondary Batteries Using Sub-Battery Grade Lithium Carbonate Containing Magnesium and Manufacturing Method Thereof

Cathode Material Synthesis Using Low-Grade Lithium Carbonate via Magnesium Content Control

This technology controls the magnesium content in sub-battery grade, low-grade lithium carbonate to 1–2 mol%, forming truncated octahedron-shaped particles. This prevents deposition within the reactor and improves both process efficiency and the electrochemical performance (cycle life and discharge capacity) of the cathode active material.

Previous methods faced challenges including high cost due to the use of high-purity lithium carbonate, clogging (deposition) on reactor walls and impellers during the synthesis process, and limitations in the cycle life and discharge capacity ratio of cathode active materials compared to conventional doping methods.

This technology involves reacting carbonate with an aqueous lithium sulfate solution containing magnesium sulfate (1–2 mol%) to produce truncated octahedron-shaped lithium carbonate. This is then mixed with an NCM hydroxide precursor at a weight ratio of 1:1.01–1.05 and calcined at 800–900℃ to synthesize the cathode active material, thereby increasing the value-added potential for lithium secondary battery cathode applications.

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Key Features:

• Step of producing lithium carbonate by adding carbonate to an aqueous lithium sulfate solution containing magnesium sulfate with a magnesium content of 1–2 mol%
• Step of producing sub-battery grade lithium carbonate in the form of suspended particles with a truncated octahedron shape containing magnesium
• Step of synthesizing the cathode active material by mixing the produced lithium carbonate with an NCM hydroxide precursor at a specified ratio
• Configuration that prevents deposition in the reactor by controlling magnesium content, thereby improving process efficiency and cathode active material properties

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