Electrochemical properties of 0.3Li<sub>2sub>MnO<sub>3sub>路0.7LiNi<sub>0.5sub>Mn<sub>0.5sub>O<sub>2sub> composite cathode powders prepared by large-scale spray pyrolysis
- 作者：Young Jun Hong ; Jung Hyun Kim ; Min Ho Kim ; Yun Chan Kang<sup> ; sup><sup>yckang@konkuk.ac.krsup>
- 关键词：A. Layered compounds ; B. Chemical synthesis ; C. Electrochemical measurements ; D. Energy storage
- 刊名：Materials Research Bulletin
- 出版年：2012
- 期刊代码：60_00255408
- 类别：ms
- 出版时间：August, 2012
- 卷：47
- 期：8
- 页码：2022-2026
- 文件大小：1043 K
摘要
0.3Li<sub>2sub>MnO<sub>3sub>路0.7LiNi<sub>0.5sub>Mn<sub>0.5sub>O<sub>2sub> composite cathode powders with a mixed-layer crystal structure comprising Li<sub>2sub>MnO<sub>3sub> and LiNi<sub>0.5sub>Mn<sub>0.5sub>O<sub>2sub> phases are prepared by spray pyrolysis. The composition of the cathode powders is found to be Li<sub>1.19sub>Ni<sub>0.39sub>Mn<sub>0.61sub>O<sub>2sub> by ICP analysis. At a constant current density of 30 mA g<sup>鈭?sup>, the initial discharge capacities of the composite cathode powders post-treated at 700, 750, 800, and 850 掳C are 177, 202, 215, and 212 mAh g<sup>鈭?sup>, respectively. The discharge capacity of the composite cathode powders post-treated at 800 掳C decreases from 215 mAh g<sup>鈭?sup> to 205 mAh g<sup>鈭?sup> 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 Mn<sup>4+sup> in the sample. The Mn<sup>4+sup> ions in the cathode powders become increasingly active as the cycle number increases and participate in the electrochemical reaction.