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Synthesis and electrochemical performance of Li3NbO4-based cation-disordered rock-salt cathode materials for Li-ion batteries.
- Source :
-
Journal of Alloys & Compounds . Aug2019, Vol. 797, p961-969. 9p. - Publication Year :
- 2019
-
Abstract
- In this reported study, Li 3 NbO 4 -based, Li-excess cathode materials xLi 3 NbO 4 •(1-x)LiMnO 2 (0.2 ≤ x ≤ 0.5) were synthesized using a solid state reaction method. XRD results showed that the fabricated powders with x = 0.3–0.5 could be indexed to a typical rock-salt structure (Fm-3m space group). Rietveld refinements showed that the lattice parameters increased with the increase in Nb5+ content. SEM and TEM images of the product showed that the elements Nb, Mn and O were evenly distributed in the samples, which further confirmed the cubic rock-salt structure of the product. Electrochemical tests of the samples showed that the sample with x = 0.4 exhibited the best electrochemical performance (232 mAh/g in the first cycle and more than 175 mAh/g in 50 cycles, as well as relatively high discharge capacity at high discharge current density). The redox mechanism analysis of the experimental results indicated that there were two stages in charge process: one was the Mn3+/4+ oxidation reaction below 4.3 V, and the other was related to the oxidation of O2− to O− or the release of O 2 , which improved the reversible capacity of the material. The structural evolution analysis of the samples showed that a spinel phase structure was present during the cycling process and the shift in the XRD peaks indicated that the sample with x = 0.4 exhibited the best structural stability. The electrochemical impedance spectroscopy analysis showed that the sample with x = 0.4 had the smallest R ct. The results for the kinetics of lithium ion diffusion indicated that the sample with x = 0.4 had largest D Li +, which was consistent with the best electrochemical performance for this material, especially the rate capability. • The good crystallized Li 3 NbO 4 -based materials are synthesized by a solid state reaction method. • The material 0.4Li 3 NbO 4.•0.6LiMnO 2 shows excellent electrochemical performance. • The highest Li+ diffusion coefficient and structure stability are response for the best performance. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 09258388
- Volume :
- 797
- Database :
- Academic Search Index
- Journal :
- Journal of Alloys & Compounds
- Publication Type :
- Academic Journal
- Accession number :
- 136981573
- Full Text :
- https://doi.org/10.1016/j.jallcom.2019.05.163