Lithium Secondary Cell Positive Electrode Active Material

The patent applies porous materials by controlling the pore diameter of positive electrode active material particles to be 0.5 μm or more and 5 μm or less. This porous structure allows the particles to absorb pressurization energy through pore collapse rather than particle crushing, enabling electrode density improvement while maintaining particle integrity. The specific pore size range creates an optimal balance between density and mechanical strength.

The patent changes physical parameters by precisely controlling pore diameter (0.5-5 μm) and secondary particle diameter (5-20 μm) of the positive electrode active material. These parameter changes transform the particle structure to resist crushing during pressurization, allowing electrode density to increase from conventional levels to above 3.0 mAh/cm² without particle failure.

The patent optimizes the pore diameter parameter to a specific range of 0.5 μm or more and 5 μm or less. This parameter change creates particles with sufficient strength to resist crushing while maintaining compact structure for high electrode density. The controlled pore size prevents both particle crushing and excessive volume expansion.

The patent creates a composite structure within particles by combining dense regions with controlled porous regions. This composite architecture provides both mechanical strength from the dense framework and volume efficiency from the optimized pore distribution, resolving the contradiction between particle strength and electrode density.