We have developed a novel cathode material based on lithium-nickel- manganese-cobalt oxide, where the manganese concentration remains constant throughout the particle, while the nickel concentration decreases linearly and the cobalt concentration increases from the center to the outer surface of the particle. This full concentration gradient material with a fixed manganese composition (FCG-Mn-F) has an average composition of Li[Ni0.60Co 0.15Mn0.25]O2 and is composed of rod-shaped primary particles whose length reaches 2.5 μm, growing in the radial direction. In cell tests, the FCG-Mn-F material delivered a high capacity of 206 mAh g-1 with excellent capacity retention of 70.3% after 1000 cycles at 55 C. This cathode material also exhibited outstanding rate capability, good low-temperature performance, and excellent safety, compared to a conventional cathode having the same composition (Li[Ni0.60Co 0.15Mn0.25]O2), where the concentration of the metals is constant across the particles.
- concentration gradient
- lithium batteries