Dual-Coated Cathode Active Material for Slurry Gelation Control

The patent applies parameter changes by precisely controlling the sintering temperature (900-950°C) and atmosphere (oxygen flow rate 50-200 mL/min) to maintain the R-3m layered structure and prevent phase transformation to Fm-3m rock-salt structure. This controlled parameter approach prevents NiO formation and maintains low resistance while ensuring particle stability.

The patent uses an oxygen atmosphere during sintering to prevent unwanted phase changes and NiO formation. The controlled oxygen environment (50-200 mL/min flow rate) acts as a protective atmosphere that maintains the desired R-3m layered structure and prevents harmful phase transformations that would increase resistance.

The patent applies preliminary action by forming a protective coating layer on the particle surface during the sintering process itself, before the slurry preparation stage. This pre-coating prevents Li byproduct from contacting and alkalizing the solvent later, avoiding slurry gelation without adding separate coating steps.

The patent introduces a coating layer as an intermediary barrier between the Li byproduct on the particle surface and the external environment (solvent, binder). This intermediate layer prevents direct contact and chemical reaction, stopping the alkalization process that would cause slurry gelation.

The patent uses segmentation by dividing the positive electrode active material into primary particles (1-5 μm) that are then aggregated into secondary particles with controlled morphology. This segmented structure allows the material to withstand higher electrode densities without collapse, as the primary particles maintain structural integrity while being packed densely.

The patent creates a composite structure where primary particles are aggregated into secondary particles with specific morphological characteristics. This composite architecture provides both the density needed for high energy density and the structural resilience needed to prevent collapse during long-term charge-discharge cycles, maintaining life characteristics.