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High Voltage Mg-Doped Na0.67Ni0.3-xMgxMn0.7O2 (x = 0.05, 0.1) Na-Ion Cathodes with Enhanced Stability and Rate Capability.
- Source :
-
Chemistry of Materials . Jul2016, Vol. 28 Issue 14, p5087-5094. 8p. - Publication Year :
- 2016
-
Abstract
- Magnesium substituted P2-structure Na0.67Ni0.3Mn0.7O2 materials have been prepared by a facile solid-state method and investigated as cathodes in sodium-ion batteries. The Mg-doped materials described here were characterized by X-ray diffraction (XRD), 23Na solid-state nuclear magnetic resonance (SS-NMR), and scanning electron microscopy (SEM). The electrochemical performance of the samples was tested in half cells vs Na metal at room temperature. The Mg-doped materials operate at a high average voltage of ca. 3.3 V vs Na/Na+ delivering specific capacities of -120 mAh g-1, which remain stable up to 50 cycles. Mg doping suppresses the well-known P2-O2 phase transition observed in the undoped composition by stabilizing the reversible OP4 phase during charging (during Na removal). GITT measurements showed that the Na-ion mobility is improved by 2 orders of magnitude with respect to the parent P2-Na0.67Ni0.3Mn0.7O2 material. The fast Na-ion mobility may be the cause of the enhanced rate performance. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 08974756
- Volume :
- 28
- Issue :
- 14
- Database :
- Academic Search Index
- Journal :
- Chemistry of Materials
- Publication Type :
- Academic Journal
- Accession number :
- 117084591
- Full Text :
- https://doi.org/10.1021/acs.chemmater.6b01935