A comparative study of particle size and hollowness of LiNi1/3Co1/3Mn1/3O2 cathode materials for high-power Li-ion batteries: effects on electrochemical performance

It is well known that reducing particle size and/or hollowing the particles improves the electrochemical performance, especially the rate capability, of cathode material in Li-ion batteries. However, there has been no report comparing each effect quantitatively. In this research, a series of LiNi1/3Co1/3Mn1/3O2 cathode materials with different particle sizes and with different amounts of hollowness was synthesized by controlling the mass-ratio between the low-density core and the high-density shell as well as the size of the core of the Ni1/3Co1/3Mn1/3(OH)2 precursors, then compared and evaluated quantitatively. Increasing the hollowness increased the electrochemical reaction area and reduced the Li-ion diffusion distance more than reducing particle size. Due to these effects on the particle morphology, increasing hollowness greatly improved the cycle durability as well as the rate capability, as compared to reducing particle size.