Manufacturing Method for Lithium Secondary Battery Cathode

LFP Cathode Manufacturing Process Combining Strong Magnetic Field b-axis Alignment and Low-Solvent Slurry

This technology involves applying a strong magnetic field of 10T to 20T after coating a slurry of olivine-structured cathode active materials, such as lithium iron phosphate (LiFePO4), to force the active material crystals to align along the b-axis, which offers high lithium-ion conductivity.

Polycrystalline cathode active materials have inherent limitations in lithium-ion conductivity, and while single-crystal alternatives have been used to address this, they impose significant cost and efficiency burdens in commercial manufacturing. Consequently, there have been constraints on improving the power output and energy density of active materials.

This technology optimizes slurry conditions with a solvent content of 4–6 wt% and a viscosity of 3,000–3,500 cP. By applying a 10T–20T magnetic field to align crystals along the b-axis and subsequently rolling the material while maintaining this oriented structure, it ensures strong adhesion to the current collector and uniform film quality. This process can be applied to cathode production lines for LFP cells used in electric buses and power tools, as well as fast-charging ESS, enabling the creation of electrodes with shorter ion transport paths without the need for expensive single-crystal materials.

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Key Features:

• Cathode active material slurry containing lithium iron phosphate, a conductive agent, and a solvent, with a viscosity ranging from 3,000 cP to 3,500 cP
• A step of aligning the slurry film formed by coating the cathode active material slurry within a space where a 10T to 20T magnetic field is applied
• A step of rolling the slurry film in which the cathode active material crystals have been aligned along the b-axis via a magnetic field
• Slurry composition containing 90 to 92 wt% cathode active material, 2 to 4 wt% conductive agent, and 0.5 to 1.5 wt% binder

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