Comparison of Li[Li[sub 1∕9]Ni[sub 1∕3]Mn[sub 5∕9]]O[sub 2], Li[Li[sub 1∕5]Ni[sub 1∕5]Mn[sub 3∕5]]O[sub 2], LiNi[sub 0.5]Mn[sub 1.5]O[sub 4], and LiNi[sub 2∕3]Mn[sub 1∕3]O[sub 2] as High Voltage Positive Electrode Materials

, , , and were prepared from appropriate coprecipitated hydroxides. The hydroxides were heated with lithium hydroxide in air to make the lithium transition metal oxides. "Head to head" comparisons among these materials were made by X-ray diffraction, scanning electron microscopy, electrochemical tests, and accelerating rate calorimetry, which suggest that all of them have one or more remaining problem to overcome before they can be used widely. We encourage the needed research.