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Sodium-Vanadium Bronze $Na_{9}V_{14}O_{35}$: An Electrode Material for Na-Ion Batteries
| Content Provider | MDPI |
|---|---|
| Author | Kirsanova, Maria A. Akmaev, Alexey S. Gorbunov, Mikhail V. Mikhailova, Daria Abakumov, Artem M. |
| Copyright Year | 2021 |
| Description | $Na_{9}V_{14}O_{35}$ $(η-Na_{x}V_{2}O_{5}$) has been synthesized via solid-state reaction in an evacuated sealed silica ampoule and tested as electroactive material for Na-ion batteries. According to powder X-ray diffraction, electron diffraction and atomic resolution scanning transmission electron microscopy, $Na_{9}V_{14}O_{35}$ adopts a monoclinic structure consisting of layers of corner- and edge-sharing $VO_{5}$ tetragonal pyramids and $VO_{4}$ tetrahedra with Na cations positioned between the layers, and can be considered as sodium vanadium(IV,V) oxovanadate Na_{9}V_{10}^{4.1+}O_{19}(V^{5+}$O_{4})_{4}$. Behavior of $Na_{9}V_{14}O_{35}$ as a positive and negative electrode in Na half-cells was investigated by galvanostatic cycling against metallic Na, synchrotron powder X-ray diffraction and electron energy loss spectroscopy. Being charged to 4.6 V vs. $Na^{+}$/Na, almost 3 Na can be extracted per $Na_{9}V_{14}O_{35}$ formula, resulting in electrochemical capacity of ~60 mAh $g^{−1}$. Upon discharge below 1 V, $Na_{9}V_{14}O_{35}$ uptakes sodium up to Na:V = 1:1 ratio that is accompanied by drastic elongation of the separation between the layers of the $VO_{4}$ tetrahedra and $VO_{5}$ tetragonal pyramids and volume increase of about 31%. Below 0.25 V, the ordered layered $Na_{9}V_{14}O_{35}$ structure transforms into a rock-salt type disordered structure and ultimately into amorphous products of a conversion reaction at 0.1 V. The discharge capacity of 490 mAh $g^{−1}$ delivered at first cycle due to the conversion reaction fades with the number of charge-discharge cycles. |
| Starting Page | 86 |
| e-ISSN | 14203049 |
| DOI | 10.3390/molecules27010086 |
| Journal | Molecules |
| Issue Number | 1 |
| Volume Number | 27 |
| Language | English |
| Publisher | MDPI |
| Publisher Date | 2021-12-24 |
| Access Restriction | Open |
| Subject Keyword | Molecules Electrochemistry Na-ion Batteries Sodium-vanadium Bronzes Electrochemical Cycling |
| Content Type | Text |
| Resource Type | Article |
