Positive-electrode active material comprising Iron doped Lithium rich oxide for lithium secondary battery and manufacturing method thereof

Long-term cycle stability iron-doped lithium manganese oxide (LMO)

The present invention relates to a cathode active material for lithium ion secondary batteries, and to an iron-doped lithium excess oxide cathode active material and a manufacturing method.

Among secondary batteries, lithium-ion batteries (LIB) using an anode material with a layered structure have the highest energy density, so NCM batteries, which are ternary batteries of nickel (Ni), cobalt (Co), and manganese (Mn), are widely used. However, due to limited availability and high prices, research on Li2MnO3 (LMO), an overlithiated layered oxide (OLO) material, is being conducted. Although progress was being made, it had the disadvantage of low lifespan stability. To solve these problems, this technology proposes a method of doping iron to reduce costs and improve structural stability and rate characteristics.

The cathode active material of this technology does not use any expensive cobalt or nickel in Li2MnO3, but dopes it with cheap and eco-friendly iron. It is a groundbreaking technology to be used in the Iithum battery industry as it has cost reduction effects and excellent performance with capacity and long-term cycle stability as much as existing LiNiMnCoO2 (NCM) batteries.

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Key Features:

• Provision of a cathode active material represented by the chemical formula Li2Mn1-xFexO3, in which iron is doped into lithium manganese oxide (LMO)
• Mixing a lithium supply compound, a manganese supply compound, and an iron supply compound in a solvent, followed by the addition of a chelating agent and a basic solution
• Drying the reaction solution to obtain a gel, then heat-treating it to secure a precursor
• Heat-treating at 850 to 950 °C for 3 to 7 hours in an O2 atmosphere

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This technology was developed through support from the National Research Foundation of Korea's research project on functional interface structures for high-capacity energy storage based on lithium cathodes.

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