Synthesis, Characterization, and Thermal Stability of LiCo[sub 1−z][MnMg][sub z/2]O[sub 2]

samples were prepared from precursors. The hydroxide precursors were heated with at for 3 h to prepare the oxides. Electrochemical studies of the samples were used to measure the rate of capacity reduction with content, found to be about . The results of in situ X-ray diffraction and differential capacity measurements show that irreversible loss of oxygen, along with lithium extraction, from the compound with occurs during the first charge between 4.4 and 4.6 V. The impact of Mn and Mg cosubstitution on the thermal stability of samples was studied via accelerating rate calorimetry. There is little or no improvement in thermal stability caused by Mn and Mg cosubstitution.