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Electrochemically Driven Phase Transition in LiCoO 2 Cathode.
- Source :
- Materials (1996-1944); Jan2021, Vol. 14 Issue 2, p242-242, 1p
- Publication Year :
- 2021
-
Abstract
- Lithium cobalt oxide (LiCoO<subscript>2</subscript>), which has been successfully applied in commercial lithium-ion batteries for portable devices, possesses a theoretical specific capacity of 274 mAh g<superscript>−1</superscript>. However, its actual capacity is only half of the theoretical specific capacity, because the charging voltage is restricted below 4.2 V. If a higher charging voltage is applied, an irreversible phase transition of LiCoO<subscript>2</subscript> during delithiation would occur, resulting in severe capacity fading. Therefore, it is essential to investigate the electrochemically driven phase transition of LiCoO<subscript>2</subscript> cathode material to approach its theoretical capacity. In this work, it was observed that LiCoO<subscript>2</subscript> partially degraded to Co<subscript>3</subscript>O<subscript>4</subscript> after 150 charging-discharging cycles. From the perspective of crystallography, the conventional cell of LiCoO<subscript>2</subscript> was rebuilt to an orthonormal coordinate, and the transition path from layered LiCoO<subscript>2</subscript> to cubic Co<subscript>3</subscript>O<subscript>4</subscript> proposed. The theoretical analysis indicated that the electrochemically driven phase transition from LiCoO<subscript>2</subscript> to Co<subscript>3</subscript>O<subscript>4</subscript> underwent several stages. Based on this, an experimental verification was made by doping LiCoO<subscript>2</subscript> with Al, In, Mg, and Zr, respectively. The doped samples theoretically predicted behavior. The findings in this study provide insights into the electrochemically driven phase transition in LiCoO<subscript>2</subscript>, and the phase transition can be eliminated to improve the capacity of LiCoO<subscript>2</subscript> to its theoretical value. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 19961944
- Volume :
- 14
- Issue :
- 2
- Database :
- Complementary Index
- Journal :
- Materials (1996-1944)
- Publication Type :
- Academic Journal
- Accession number :
- 148342752
- Full Text :
- https://doi.org/10.3390/ma14020242