Positive Electrode Primer Layer for High-Density Battery Sheets

The patent introduces a primer layer as an intermediary between the positive electrode active material and the aluminum foil current collector. This primer layer acts as a protective mediator that prevents direct contact and mechanical crushing of the oxide film by the active material particles, thereby resolving the contradiction between achieving high compacted density for energy density and maintaining oxide film integrity for battery safety.

The patent applies preliminary action by forming the primer layer on the aluminum foil surface before applying the positive electrode active material. This preliminary protective layer is prepared in advance to prevent the harmful effect of oxide film destruction that would occur during subsequent high-density compaction, thereby allowing energy density improvement without compromising oxide film protection.

The patent controls the thickness of the primer layer within a specific range (1-10 μm) to optimize the balance between safety improvement and structure simplicity. By precisely controlling this parameter, the primer layer provides adequate protection without excessive thickness that would increase device complexity or reduce energy density, thus resolving the contradiction between safety enhancement and structural simplicity.