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You searched for subject:(Vanadium oxide Experiments). Showing records 1 – 2 of 2 total matches.

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Georgia Tech

1. Wyrwas, Richard Ben, Jr. Vanadium Oxide Anions Clusters: Their Abundances, Structures and Reactions with SO₂.

Degree: PhD, Chemistry and Biochemistry, 2004, Georgia Tech

Early transition metal oxide clusters have been a focus of study for several years. The production of vanadium oxide cluster anions in a pulsed helium flow reactor provides a relatively precise way of introducing defect sites and controlling the oxidation state of the vanadium atoms. The composition of the clusters can be changed from the V2O5 stoichiometry, where the vanadium atom is in a +5 oxidation state, to more reduced stoichiometries yielding a mixture of oxidation states containing atoms in the +2 oxidation state. The subsequent addition of reactant gases such as H2O and SO2 yields very intense adsorption reactions as well as a demonstration of the robustness of particular defect free clusters. For example, the cluster has been identified as a defect free cluster where all vanadium atoms are in the +5 oxidation state and all oxygen atoms are predicted to be in the 2- state. The cluster has been shown to not adsorb SO2- while clusters in a reduced oxidation state, such as and readily adsorb one or more SO2 molecules. The adsorption process has been shown to be size dependent, with the smallest monovanadium oxide anions being the most reactive. Advisors/Committee Members: Whetten, Robert L. (Committee Chair), El-Sayed, Mostafa A (Committee Member), First, Phillip N (Committee Member), Sherrill, C. David (Committee Member), Wine, Paul H. (Committee Member).

Subjects/Keywords: Time-of-flight mass spectrometry; Cluster reactivities; Carbon anion clusters; Gas phase cluster reactions; Sulfuric acid production; Vanadium oxide clusters; Metal oxide cluster anions; Vanadium oxide Synthesis Experiments; Vanadium oxide Experiments; Transition metal compounds Synthesis Experiments; Surface active agents Experiments

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Wyrwas, Richard Ben, J. (2004). Vanadium Oxide Anions Clusters: Their Abundances, Structures and Reactions with SO₂. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/4908

Chicago Manual of Style (16th Edition):

Wyrwas, Richard Ben, Jr. “Vanadium Oxide Anions Clusters: Their Abundances, Structures and Reactions with SO₂.” 2004. Doctoral Dissertation, Georgia Tech. Accessed April 02, 2020. http://hdl.handle.net/1853/4908.

MLA Handbook (7th Edition):

Wyrwas, Richard Ben, Jr. “Vanadium Oxide Anions Clusters: Their Abundances, Structures and Reactions with SO₂.” 2004. Web. 02 Apr 2020.

Vancouver:

Wyrwas, Richard Ben J. Vanadium Oxide Anions Clusters: Their Abundances, Structures and Reactions with SO₂. [Internet] [Doctoral dissertation]. Georgia Tech; 2004. [cited 2020 Apr 02]. Available from: http://hdl.handle.net/1853/4908.

Council of Science Editors:

Wyrwas, Richard Ben J. Vanadium Oxide Anions Clusters: Their Abundances, Structures and Reactions with SO₂. [Doctoral Dissertation]. Georgia Tech; 2004. Available from: http://hdl.handle.net/1853/4908

2. Wen Chao, Lee. A new chemical synthesis for vanadium sulfide as high performance cathode.

Degree: 2014, IUPUI

Indiana University-Purdue University Indianapolis (IUPUI)

Since 1990s, rechargeable Li-ion batteries have been widely used in consumer electronics such as cell phones, global positioning systems (GPS), personnel digital assistants (PDA), digital cameras, and laptop computers. Recently Li-ion batteries received considerable attention as a major power source for electric vehicles. However, significant technical challenges still exist for widely deploying Li-ion batteries in electric vehicles. For instance, the energy density of Li-ion batteries is not high enough to support a long-distance commute. The Li-ion batteries used for the Nissan Leaf and Chevy Volt only can support 50 – 100 miles per charge. The cost of Li-ion battery packs in electric vehicles is still high. The battery pack for the Chevy Volt costs about 8,000, and the larger one in the Nissan Leaf costs about 12,000. To address these problems, new Li-ion battery electrode materials with high energy density and low cost should be developed. Among Li-ion battery cathode materials, vanadium pentoxide, V2O5, is one of the earliest oxides studied as a cathode for Li-ion batteries because of its low cost, abundance, easy synthesis, and high energy density. However, its practical reversible capacity has been limited due to its irreversible structural change when Li insertion is more than x = 1. Tremendous efforts have been made over the last twenty years to improve the phase reversibility of LixV2O5 (e.g., 0 ≤ x ≤ 2) because of vanadium pentoxides’ potential use as high capacity cathodes in Li-ion batteries. In this thesis, a new strategy was studied to develop vanadium pentoxide cathode materials with improved phase reversibility. The first study is to synthesize vanadium oxide cathodes via a new chemical route – creating a phase transformation from the vanadium sulfide to oxide. The β-Na0.33V2O5 was prepared via a new method of chemical synthesis, involving the chemical transformation of NaVS2 via heat-treatment at 600 °C in atmospheric air. The β-Na0.33V2O5 particles were well crystalized and rod-shaped, measuring 7–15 μm long and 1–3 μm wide with the formation of the crystal defects on the surface of the particles. In contrast to previous reports contained in the literature, Na ions were extracted, without any structural collapse, from the β -Na0.33V2O5 structure and replaced with Li ions during cycling of the cell in the voltage range, 1.5 V to 4.5 V. This eventually resulted in a fully reversible Li intercalation into the LixV2O5 structure when 0.0 ≤ x ≤ 2.0. The second study is to apply the synthesis method to LiVS2 for the synthesis of β׳-LixV2O5 for use as a high performance cathode. The synthesis method is based on the heat treatment of the pure LiVS2 in atmospheric air. By employing this method of synthesis, well-crystalized, rod-shaped β׳-LixV2O5 particles 20 – 30 μm in length and 3 – 6 μm in width were obtained. Moreover, the surface of β׳-LixV2O5 particles was found to be coated by an amorphous vanadium oxysulfide film (~20 nm in…

Advisors/Committee Members: Likun, Zhu, Jing, Zhang, El-Mounayri, Hazim, Anwar, Sohel.

Subjects/Keywords: vanadium sulfide; chemical synthesis; heat treatment; cathode; Li-ion battery; Lithium ion batteries  – Research  – Analysis; Sodium ions  – Synthesis; Vanadium compounds  – Research; Electricity  – Experiments; Vanadium oxide  – Testing; Vanadium pentoxide  – Testing; Cathodes; Lithium cells; Energy storage; Electrochemical analysis  – Research; Heat  – Transmission  – Measurement; Low temperature engineering; Materials at high temperatures; Electric batteries  – Electrodes; Electrodes, Ion selective; Vanadium  – Electrometallurgy; Engineering instruments  – Research

…first study is to synthesize vanadium oxide cathodes via a new chemical route – creating a… …xii phase transformation from the vanadium sulfide to oxide. The β-Na0.33V2O5 was prepared… …chemical synthesis route for creating a phase transformation from the vanadium sulfide to oxide… …by heat treatment in air is a promising method for preparing vanadium oxide cathode… …Synthesis for Vanadium Sulfide as High Performance Cathode. Major Professor: Likun Zhu. Since… 

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Wen Chao, L. (2014). A new chemical synthesis for vanadium sulfide as high performance cathode. (Thesis). IUPUI. Retrieved from http://hdl.handle.net/1805/5500

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Wen Chao, Lee. “A new chemical synthesis for vanadium sulfide as high performance cathode.” 2014. Thesis, IUPUI. Accessed April 02, 2020. http://hdl.handle.net/1805/5500.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Wen Chao, Lee. “A new chemical synthesis for vanadium sulfide as high performance cathode.” 2014. Web. 02 Apr 2020.

Vancouver:

Wen Chao L. A new chemical synthesis for vanadium sulfide as high performance cathode. [Internet] [Thesis]. IUPUI; 2014. [cited 2020 Apr 02]. Available from: http://hdl.handle.net/1805/5500.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Wen Chao L. A new chemical synthesis for vanadium sulfide as high performance cathode. [Thesis]. IUPUI; 2014. Available from: http://hdl.handle.net/1805/5500

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.