1,720,971 research outputs found
Evaluation of metal nitrides as the negative electrode in sodium-ion batteries and as a protective coating in lithium metal batteries
No full textIn this project, an experimental study of the application of Sn3N4 as a high capacity negative electrode material is assessed in sodium-ion batteries, using a new synthesis method to make Sn3N4 microcrystalline and nanocrystalline powders. The underlying mechanism is interrogated using ex situ experimental characterisation (X-ray diffraction, extended X-ray absorption fine structure and X-ray absorption near edge structure). The project also assesses the suitability of Li3N as a protective layer on the surface of lithium metal negative electrodes; for secondary lithium metal battery and lithium-sulfur applications. a method was developed for nitriding electrodeposited lithium electrodes that were characterised by scanning transmission X-ray microscopy and X-ray photoelectron spectroscopy. The electrochemical performance of nitrided electrodes was also assessed by galvanostatic cycling techniques. Finally, the stability of the nitrided lithium electrode towards polysulfide species was assessed by X-ray photoelectron spectroscopy and scanning transmission X-ray microscopy. This study offers a unique assessment for the stability of unmodified and modified electrodeposited lithium electrodes towards polysulfide intermediates formed within a Li-S battery.<br/
Dataset for: LiFePO4 battery material for the production of lithium from brines: Effect of brine composition and benefits of dilution
No full textDataset to support article in journal ChemSusChem. "LiFePO4 battery material for the production of lithium from brines: Effect of brine composition and benefits of dilution". DOI 10.1002/cssc.202102182
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Solvothermal synthesis of Sn<sub>3</sub>N<sub>4</sub> as a high capacity sodium-ion anode: theoretical and experimental study of its storage mechanism
No full textA new simple and scalable method to synthesise spinel-structured Sn3N4 has been developed using SnCl4 and LiNH2 precursors under solvothermal conditions. Nanocrystalline Sn3N4 with a crystallite size < 10 nm was produced and tested as anode material in sodium half cells, demonstrating a very high reversible (de-sodiation) capacity of ∼850 mA h g-1 measured over 50 cycles, the highest reported reversible capacity for a sodium anode apart from sodium itself. Ex situ X-ray absorption spectroscopy and X-ray diffraction show that the electrochemical reactions are reversible and that Sn3N4 is recovered upon re-oxidation. X-ray diffraction shows that the peaks associated with Sn3N4 reflections become narrower during discharge (reduction), evidencing that the smaller Sn3N4 particles are primarily involved in the electrochemical reactions, and broadening of the peaks is reversibly recovered upon oxidation. The analysis of the near edge X-ray absorption data (XANES) shows that the Sn oxidation state decreases during reduction and nearly recovers the initial value during oxidation. DFT calculations suggest that the insertion of Na into the Sn3N4 surface followed by substitution of tetrahedral Sn by Na is energetically favourable, and evidence of the removal of tetrahedral Sn from the spinel Sn3N4 structure is obtained from the analysis of the extended X-ray absorption fine-structure (EXAFS) measurements of reduced electrodes, which also show the recovery of the pristine structure at the end of oxidation. DFT also shows that Sn substitution by Na is only favourable at the Sn3N4 surface (not for bulk Sn3N4), in agreement with the electrochemical characterisation that shows that controlling the nanoparticle size is crucial to achieve full utilisation of Sn3N4 (and thus high capacity).</p
In situ GISANS study on the electrodeposition of bismuth telluride on titanium nitride from non-aqueous solution.
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Understanding the size limits of silica pore formation by in situ grazing incidence small angle X-ray scattering
No full textDataset from experiment si20593-1 at Diamond Light Source I07.</span
Dataset for: Solvothermal Synthesis of Sn3N4 as a High Capacity Sodium-Ion Anode: Theoretical and Experimental Study of its Storage Mechanism
No full textDataset supporting published paper:
Fitch, S, Cibin, G, Hepplestone, S, Garcia-Araez, N & Hector, AL 2020, 'Solvothermal Synthesis of Sn3N4 as a High Capacity Sodium-Ion Anode: Theoretical and Experimental Study of its Storage Mechanism' Journal of Materials Chemistry A.</span
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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