In order to investigate the effect of the particle morphology on the fast-charging characteristics of highnickel layered-cathode materials, single-crystalline and secondary-particle type cathode with different primary/secondary particle sizes were synthesized via careful microstructure design. The effect of crystalline and particle size on the fast-charging performance was identified by comparing the charging characteristics at various current rates. Also, the effect of rapid charging on the cycle-life performance of the high-nickel cathode materials was confirmed through repeated fast-charging experiments. The size of the primary particle (crystalline size) has a greater effect on the rapidcharging performance than the entire particle size. In addition, to suppress the performance degradation of high-nickel cathode during fast charging, it is important to suppress the increase in the surface area through micro-crack suppression, and it is also necessary to precisely control the size of the primary particle for efficient lithium diffusion during fast charging.