Abstract
0.3Li 2MnO 3·0.7LiNi 0.5Mn 0.5O 2 composite cathode powders with a mixed-layer crystal structure comprising Li 2MnO 3 and LiNi 0.5Mn 0.5O 2 phases are prepared by spray pyrolysis. The composition of the cathode powders is found to be Li 1.19Ni 0.39Mn 0.61O 2 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 Mn 4+ in the sample. The Mn 4+ ions in the cathode powders become increasingly active as the cycle number increases and participate in the electrochemical reaction.
| Original language | English |
|---|---|
| Pages (from-to) | 2022-2026 |
| Number of pages | 5 |
| Journal | Materials Research Bulletin |
| Volume | 47 |
| Issue number | 8 |
| DOIs | |
| Publication status | Published - 2012 Aug |
| Externally published | Yes |
Bibliographical note
Funding Information:This study was supported by the Converging Research Center Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology ( 2011-50210 ). This study was also supported by a grant ( M2009010025 ) from the Fundamental R&D Program for Core Technology of Materials funded by the Ministry of Knowledge Economy (MKE) , Republic of Korea. This study was also supported by Seoul R&BD Program ( WR090671 ).
Keywords
- A. Layered compounds
- B. Chemical synthesis
- C. Electrochemical measurements
- D. Energy storage
ASJC Scopus subject areas
- General Materials Science
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering