METHOD FOR PREDICTING LIFE OF POSITIVE MATERIAL, POSITIVE MIXTURE COMPRISING THE POSITIVE MATERIAL WITH IMPROVED LIFE CHARACTERISTIC, POSITIVE ELECTRODE, AND SECONDARY BATTERY COMPRISING THE SAME

摘要

In the present invention, as a method of predicting the life of the cathode material, (a) dispersing the cathode material to obtain a cathode material powder; (b) a process of calculating particles having a diameter of 0.4 μm or more and 12.0 μm or less among the cathode material powder using a particle analyzer, and measuring their aspect ratio (short axis/long axis); (c) Among the calculated particles, a particle having a diameter of 0.4 μm or more and less than 6.0 μm and an aspect ratio of 0.8 or more is defined as a small particle sphere, the size of the particle is 6.0 μm or more and 12.0 μm or less, and an aspect ratio of 0.8 or more the process of defining a particle as an allele sphere; (d) pressing the cathode material powder of the process (a) to a size of ^{6 to 7 ton·f/cm 2 ;} (e) For the positive electrode material powder after pressurization, using a particle analyzer to calculate particles having a diameter of 0.4 μm or more and 12.0 μm or less, measure their diameter and aspect ratio again, and, as the basis of the process (c), small particle spheres and the process of determining the opposing sphere; (f) a process of determining particles having a diameter of 0.4 μm or more and 2.0 μm or less and an aspect ratio of less than 0.8 among the positive electrode material powder after pressing as needle-shaped particles; (g) calculating the change in the proportion of spheres from the number of elementary particle spheres and large particle spheres in step (c), and elementary particle spheres and large particle spheres in step (e), and the total positive electrode material in step (f) The process of calculating the ratio of the acicular particles to the powder; and (h) when the acicular particle ratio is less than 15% by number, predicting the lifespan according to the change in the ratio of the spheres; A cathode material life prediction method comprising a, a cathode mixture comprising a cathode material having excellent lifespan characteristics, a cathode, and a secondary battery including the same are provided.