Method for manufacturing fluorine compounds for lithium secondary battery cathode active materials using solid-state reactions, and a cathode and lithium secondary battery containing the same

Method for Manufacturing Fluorophosphate Cathode Materials Supplemented with Fluorine Using Organic or Ammonium Fluoride Compounds

This technology enables the synthesis of high-purity fluorophosphate (LiMPO4F) cathode active materials for lithium-ion secondary batteries. By adding fluorine-containing organic compounds (such as PTFE or PVDF) or ammonium compounds (NH4F) to compensate for fluorine loss during high-temperature reactions, the process achieves high-purity compounds through a single-step solid-state reaction.

Conventional fluorophosphate synthesis faces challenges due to the high binding energy of LiF, which makes decomposition difficult and leads to the loss of fluorine through evaporation. This hinders the production of high-purity compounds, and existing two-step reaction methods are costly and limited in terms of commercial viability.

This technology involves mixing a lithium precursor, a metal precursor, and a phosphate precursor with a "fluorine source" (organic fluorine compounds or ammonium fluoride) at a weight ratio of 10–200% relative to the precursors. By performing a single solid-state synthesis reaction at 500–750°C, it enhances the value-added potential of lithium secondary battery cathode material applications.

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Key Features:

• A method for manufacturing fluorine compounds for lithium secondary battery cathodes that produces compounds of a specific chemical formula through a single solid-state synthesis reaction.
• A composition comprising a mixture of a lithium precursor, a metal precursor, a phosphate precursor, and a fluorine-containing organic or ammonium compound.
• A composition involving heating a precursor mixture consisting of one or more fluorine-containing organic or ammonium compounds.
• A composition that synthesizes fluorophosphate in a single step by adding fluorine-containing compounds to compensate for fluorine lost during high-temperature reactions.

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