Effects of Metal Ions on the Structural and Thermal Stabilities of Li[Ni[sub 1−x−y]Co[sub x]Mn[sub y]]O[sub 2] (x+y≤0.5) Studied by In Situ High Temperature XRD

Highly crystalline , , and ) were synthesized through a coprecipitation method. The capacities of the prepared samples were proportional to the amount of Ni in the host structure. The thermogravimetric analysis (TGA) and in situ high-temperature–X-ray diffraction (HT-XRD) analysis revealed that changes in the amount of manganese ions in the host structure profoundly affect the structural stability of the samples with . , containing the highest manganese content , showed the most stable structural integrity among the samples as confirmed by in situ HT-XRD. The electrochemical performances of the samples in Ni amount with the variation of Co did not significantly vary under the test conditions . The small increase of Mn ions plays an important role in preservation of its initial structural symmetry during the high-temperature heating as well as electrochemical cycling. Furthermore, the structural stability has a relationship with the thermal stability and the electrochemical stability, especially at an elevated temperature . On the basis of the differential scanning calorimetry and TGA results, the sample demonstrated improved thermal stability compared to the other samples.