Monitoring the Formation of Nickel-Poor and Nickel-Rich Oxide Cathode Materials for Lithium-Ion Batteries with Synchrotron Radiation

The syntheses of Ni-poor (NCM111, LiNi Co Mn O ) and Ni-rich (NCM811 LiNi Co Mn O ) lithium transition-metal oxides (space group 3̅m) from hydroxide precursors (Ni Co Mn (OH) , Ni Co Mn (OH) ) are investigated using synchrotron powder diffraction and near-edge X-ray absorption fine structure spectroscopy. The development of the layered structure of these two cathode materials proceeds two utterly different reaction mechanisms. While the synthesis of NCM811 involves a rock salt-type intermediate phase, NCM111 reveals a layered structure throughout the entire synthesis. Moreover, the necessity and the impact of a preannealing step and a high-temperature holding step are discussed.