Cathode active material for lithium secondary batteries containing B and Ti on the surface and its manufacturing method

Manufacturing method for NCM811 cathode materials with reduced residual lithium using B·Ti island-type artificial CEI heat treatment

This technology forms an island-type artificial Cathode Electrolyte Interphase (CEI) layer on the surface of Ni-rich cathode active materials by mixing H3BO3 (B precursor) and TiO2 (Ti precursor) followed by heat treatment. This layer contains Li3BO3, which ensures conductivity by reacting with residual lithium, and TiO2, which enhances mechanical strength.

Residual lithium (LiOH) on the surface of Ni-rich cathode active materials causes side reactions with the electrolyte, leading to gas generation and increased interfacial resistance. Additionally, micro-cracks within the particles significantly degrade electrochemical performance and cell lifespan.

This technology functionalizes the interface by mixing 0.5–1 wt% of H3BO3 and TiO2 (in a 3:7 weight ratio) relative to the cathode active material, followed by heat treatment at 300–500℃ for 2–4 hours. H3BO3 consumes residual lithium to reduce internal cell gas pressure, while TiO2 reinforces particle hardness to suppress structural micro-cracks during charge/discharge. It can be applied to mass production lines for pouch-type EV cells and small polymer batteries sensitive to gas swelling, reducing adoption costs by simply adding a low-temperature post-treatment step to existing calcination equipment.

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Key Features:

• Mixing boron precursor H3BO3 and titanium precursor TiO2 with LiNi0.8Co0.1Mn0.1O2 cathode active material powder
• Including H3BO3 at 0.5–1 wt% relative to the cathode active material weight and mixing H3BO3 and TiO2 in a 3:7 weight ratio
• Heat-treating the mixture of H3BO3 and TiO2 at 300–500℃ for 2–4 hours
• Slowly cooling the heat-treated cathode active material mixture to room temperature to obtain the final cathode active material

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