Layered Li[Ni[sub x]Co[sub 1−2x]Mn[sub x]]O[sub 2] Cathode Materials for Lithium-Ion Batteries

The structure and electrochemical behavior of with and 3/8 is reported for the first time. is prepared by the simultaneous substitution of and for in X-ray diffraction patterns show these materials have a layered -type structure. Both with or 3/8 can deliver a stable capacity of about 160 mAh/g between 2.5 and 4.4 V vs. Li using a specific current of 40 mA/g. If the upper potential of cells with is reduced to 4.2 V vs. Li, its capacity retention behavior is improved and it gives a capacity of 136 mAh/g, which is very close to that of in the same potential window. Studies of the thermal stability of in electrolyte using differential scanning calorimetry indicate that the samples with and are more thermally stable than © 2001 The Electrochemical Society. All rights reserved.