Electrochemical properties of 0.3Li2MnO3·0.7LiNi0.5Mn0.5O2 composite cathode powders prepared by large-scale spray pyrolysis

0.3Li2MnO3·0.7LiNi0.5Mn0.5O2 composite cathode powders with a mixed-layer crystal structure comprising Li2MnO3 and LiNi0.5Mn0.5O2 phases are prepared by spray pyrolysis. The composition of the cathode powders is found to be Li1.19Ni0.39Mn0.61O2 by ICP analysis. At a constant current density of 30 mA g−1, the initial discharge capacities of the composite cathode powders post-treated at 700, 750, 800, and 850 °C are 177, 202, 215, and 212 mAh g−1, respectively. The discharge capacity of the composite cathode powders post-treated at 800 °C decreases from 215 mAh g−1 to 205 mAh g−1 by the 40th cycle, in which the capacity retention is 95%. The first cycle has a low Coulombic efficiency of 75%. However, in the subsequent cycles, the Coulombic efficiency is retained at nearly 100%. The dQ/dV curves show that Mn exists as Mn4+ in the sample. The Mn4+ ions in the cathode powders become increasingly active as the cycle number increases and participate in the electrochemical reaction.

0.3Li2MnO3·0.7LiNi0.5Mn0.5O2 composite cathode powders with a mixed-layer crystal structure comprising Li2MnO3 and LiNi0.5Mn0.5O2 phases are prepared by large-scale spray pyrolysis. The discharge capacity of the composite cathode powders post-treated at 800 °C decreases from 215 mAh g−1 to 205 mAh g−1 by the 40th cycle, in which the capacity retention is 95%. The Mn4+ ions in the cathode powders become increasingly active as the cycle number increases and participate in the electrochemical reaction.Figure optionsDownload as PowerPoint slideHighlights
► 0.3Li2MnO3·0.7LiNi0.5Mn0.5O2 composite cathode powders are prepared by large-scale spray pyrolysis.
► The composite cathode powders have a high initial discharge capacity of 215 mAh g−1 and have good cycle properties.
► The Mn4+ ions in the cathode powders become increasingly active as the cycle number increases.