13718-26-8Relevant articles and documents
Sodium-vanadium bronze Na9V14O35: An electrode material for na-ion batteries
Abakumov, Artem M.,Akmaev, Alexey S.,Gorbunov, Mikhail V.,Kirsanova, Maria A.,Mikhailova, Daria
, (2021/12/29)
Na9V14O35 (η-NaxV2O5) 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, Na9V14O35 adopts a monoclinic structure consisting of layers of corner-and edge-sharing VO5 tetragonal pyramids and VO4 tetrahedra with Na cations positioned between the layers, and can be considered as sodium vanadium(IV,V) oxovanadate Na9V104.1+O19 (V5+O4)4. Behavior of Na9V14O35 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 Na9V14O35 formula, resulting in electrochemical capacity of ~60 mAh g?1. Upon discharge below 1 V, Na9V14O35 uptakes sodium up to Na:V = 1:1 ratio that is accompanied by drastic elongation of the separation between the layers of the VO4 tetrahedra and VO5 tetragonal pyramids and volume increase of about 31%. Below 0.25 V, the ordered layered Na9V14O35 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.
Synthesis, Characterization, and Photocatalytic Activities of BiVO4 by Carbon Adsorption Hydrothermal Method
Niu,Guo
, p. 1661 - 1665 (2020/08/19)
A new idea of prepared method for BiVO4 nano-powders hydrothermal synthesis process was developed to avert the existent shortcomings of hydrothermal method. The thermal stability, phase structure, light absorption property, and morphology of the catalyst prepared were characterized by thermogravimetric analyzer (TG), X-ray diffraction (XRD), ultraviolet visible spectrophotometer (UV/Vis), and transmission electron microscopy (TEM), respectively. Using methyl orange (MO) as the target degradation material and a 500-W dysprosium lamp as the visible light source to investigate photocatalytic performance of BiVO4. We successfully prepared BiVO4 powders with small particle size, less agglomeration and uniform distribution by carbon adsorption hydrothermal method, and the absorption wavelength of light was red-shifted, these all rendered the absorption capacity of visible light region enhancing with 94 % high photocatalytic degradation rate of methyl orange at 60 min. And the possible mechanism was also discussed in this study.
Tailoring NaVO3 as a novel stable cathode for lithium rechargeable batteries
Chen, Long,Wu, Honglun,Wang, Huiming,Chen, Liang,Pu, Xiangjun,Chen, Zhongxue
, p. 224 - 231 (2019/04/17)
Vanadium-based compounds hold great promise as high capacity cathode candidate for future lithium rechargeable batteries. However, developing highly stable vanadium-based cathode materials with long cycle life remains a great challenge. Herein, we report a novel layered sodium vanadium oxide, NaVO3, as a promising cathode electrode contender. This material is capable of delivering a capacity of 224.8 mAh g?1 at the current density of 150 mA g?1, and a high rate capability of 85 mAh g?1 even at a high current density of 3 A g?1. Moreover, outstanding capacity retention of 77% after 1000 cycles is achieved. Ex situ characterizations verify that the excellent electrochemical performance of NaVO3 is attributed to superior structural stability and electrochemical reversibility upon long-term cycling. Furthermore, the lithium ion de/intercalation mechanism for NaVO3 is also revealed involving one electron transfer reaction between V5+ and V4+ redox couple. Considering the low cost and material sustainability as well as the outstanding electrochemical performances, we believe that NaVO3 is a highly promising cathode material for lithium rechargeable batteries and our findings may help to pave the way for developing vanadium-based layered structure materials for high-performance alkali and alkaline-earth ion batteries.