Advanced search options

Advanced Search Options 🞨

Browse by author name (“Author name starts with…”).

Find ETDs with:

in
/  
in
/  
in
/  
in

Written in Published in Earliest date Latest date

Sorted by

Results per page:

Sorted by: relevance · author · university · dateNew search

You searched for subject:(Lithium sodium niobate). Showing records 1 – 3 of 3 total matches.

Search Limiters

Last 2 Years | English Only

No search limiters apply to these results.

▼ Search Limiters


Indian Institute of Science

1. Das, Suman. Synthesis and Investigations of a Few Anode Materials for Alkali-based Rechargeable Batteries.

Degree: PhD, Faculty of Science, 2019, Indian Institute of Science

The present Thesis explores a few novel anode materials for both lithium-ion and sodium-ion rechargeable batteries. A series of layered metal titanium niobates have been synthesised and their electrochemical energy storage properties, ion transport, and reaction mechanisms are studied in detail. Alkali-titanium niobates such as Li-Ti-niobate (and it’s sodium counterpart) store lithium (sodium) via the conventional intercalation mechanism. Detailed experimental and theoretical investigations reveal interesting and non trivial ion transport, which are found to be strongly correlated to the electrochemical properties. Apart from intercalation, where amount of energy storage is limited by the crystal structure, energy storage via an alloying reaction is an important alternative strategy to boost specific capacities and energy densities of various battery systems. However, drastic volume changes during alloying/dealloying is detrimental for stable electrochemical function of the cell. The volume expansion problem associated with alloying anodes materials e.g. Sn for alkali-ion batteries have been tackled here via two different strategies. While one uses a flexible layered structure resulting in simultaneous intercalation and alloying process, the other approach uses a porous electrospun carbon fiber encapsulation for alloying compounds. The electrochemical properties as a function of Sn-content in a binary SnX (X: Sb) compound anode have been explicitly probed. This study provided invaluable information on alloying reaction mechanisms as well as identified the most optimum Sn-content for the long term stable battery operations. Usage of graphite as an anode in high energy density Li-ion cell has already been shown to be associated with severe safety issues. The thesis demonstrates a novel and very simple strategy to develop a stable non-carbonaceous anode for operation in the Li-ion (full) cell configuration. The thesis comprises of six chapters and a brief discussion of the content and highlights of the individual chapters are discussed below: Chapter 1 briefly reviews the different materials (mainly anodes) and storage mechanisms in the context of lithium-ion and sodium-ion rechargeable batteries. Energy storage via different mechanisms in metal-ion batteries has it’s own advantages and disadvantages. Thus, design of alternative novel materials is absolutely essential to nullify the detrimental factors associated with various storage methods leading to highly efficient and safe alkali metal-ion rechargeable battery systems. Development of materials for efficient alkali metal-ion batteries are very pertinent even today as the next generation high energy density rechargeable batteries based on metal-S/metal-O2 are still in the stages of infancy. They are far away from widespread commercialization and thus, do not pose any threat to the rechargeable alkali metal-ion batteries. This chapter discusses the importance of diffusion of ions inside the electrode materials, which essentially determines the rate capability of… Advisors/Committee Members: Bhattacharyya, Aninda Jiban (advisor), Row, T N Guru (advisor).

Subjects/Keywords: Rechargeable Batteries; Lithium-ion Battery; Sodium-ion Battery; Potassium Titanium Niobate; KTiNbO5; Li-Ti-niobate; M-Ti-niobate; Na-Ti-niobate; Lithium Manganese Oxide; LiMn2O4; Solid State and Structural Chemistry

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

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

APA (6th Edition):

Das, S. (2019). Synthesis and Investigations of a Few Anode Materials for Alkali-based Rechargeable Batteries. (Doctoral Dissertation). Indian Institute of Science. Retrieved from http://etd.iisc.ac.in/handle/2005/4272

Chicago Manual of Style (16th Edition):

Das, Suman. “Synthesis and Investigations of a Few Anode Materials for Alkali-based Rechargeable Batteries.” 2019. Doctoral Dissertation, Indian Institute of Science. Accessed October 24, 2020. http://etd.iisc.ac.in/handle/2005/4272.

MLA Handbook (7th Edition):

Das, Suman. “Synthesis and Investigations of a Few Anode Materials for Alkali-based Rechargeable Batteries.” 2019. Web. 24 Oct 2020.

Vancouver:

Das S. Synthesis and Investigations of a Few Anode Materials for Alkali-based Rechargeable Batteries. [Internet] [Doctoral dissertation]. Indian Institute of Science; 2019. [cited 2020 Oct 24]. Available from: http://etd.iisc.ac.in/handle/2005/4272.

Council of Science Editors:

Das S. Synthesis and Investigations of a Few Anode Materials for Alkali-based Rechargeable Batteries. [Doctoral Dissertation]. Indian Institute of Science; 2019. Available from: http://etd.iisc.ac.in/handle/2005/4272


University of St Andrews

2. Dixon, Charlotte A. L. Crystal structure and phase transitions in various functional perovskites.

Degree: PhD, 2018, University of St Andrews

There has been specific interest over the past decade in the discovery and development of new piezoelectric and ferroelectric materials for the use in functional devices, specifically with the aim of replacing the widespread use of PbZrxTi1−xO3. The work detailed in this thesis focuses on the structural characterisation and thermal behaviour of several perovskites possessing interesting physical characteristics, such as ferroelectricity or magnetism. Structural evolution and phase behaviour is characterised using Rietveld refinement techniques on high resolution powder neutron diffraction data. Additional analytical techniques such as symmetry mode analysis, permittivity measurements and second harmonic generation measurements are also often exploited. The work on the LixNa1−xNbO3 system demonstrated a susceptibility to softening of the T4 octahedral tilt mode up to a composition of at least x = 0.12, indicating that the LNN-X solid solution could yield a number of unique perovskite structures. A rationale for how this T4 mode varies across the composition range is offered. The higher doped composition at a value of x = 0.20, displays even more intriguing structural behaviour with the adoption of not one but two variants of the very rare a+a+c− Glazer tilt system. A detailed bond length/bond angle analysis as a function of temperature is used to rationalise the nature of the octahedral distortion that drives the c > a crossover in the rare earth orthoferrite LaFeO3. Symmetry mode analysis is exploited to assist in the structural comparison to the related compound Bi0.5La0.5FeO3, highlighting the anomalous behaviour it exhibits as a result of magnetoelectric coupling effects. The nature of the paraelectric – ferroelectric transition in the layered perovskitelike Dion Jacobson phase, CsBi0.6La0.4Nb2O7 is identified as a direct “avalanche” type transition, making it an example of a hybrid improper ferroelectric. Ferroelectricity in this case does not occur as a result of traditional second-order Jahn-Teller distortions, but is achieved via a mechanism known as trilinear coupling. Experimental analysis is important in understanding the intricacies of this trilinear coupling mechanism. Symmetry mode analysis of CsBi0.6La0.4Nb2O7 shows that two zone boundary primary order parameters (M2+ and M5−) associated with octahedral tilting condense simultaneously, and couple to a zone centre ferroelectric distortion mode (Γ4−). The similar temperature dependency for the two octahedral tilt modes excludes the presence of an intermediary phase, suggesting that the trilinear coupling in this layered phase is strong. Detailed structural characterisations such as those highlighted in this thesis are of fundamental importance as they can identify new design-led approaches to functional materials.

Subjects/Keywords: Symmetry mode analysis; Neutron powder diffraction; Perovskites; Ferroelectricity; Hybrid-improper ferroelectricity; Lithium sodium niobate; Dion-Jacobson phase; LaFeO3; Impedance spectroscopy; ISODISTORT analysis; QD181.O1D5; Perovskite; Oxides – Analysis

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

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

APA (6th Edition):

Dixon, C. A. L. (2018). Crystal structure and phase transitions in various functional perovskites. (Doctoral Dissertation). University of St Andrews. Retrieved from http://hdl.handle.net/10023/16572

Chicago Manual of Style (16th Edition):

Dixon, Charlotte A L. “Crystal structure and phase transitions in various functional perovskites.” 2018. Doctoral Dissertation, University of St Andrews. Accessed October 24, 2020. http://hdl.handle.net/10023/16572.

MLA Handbook (7th Edition):

Dixon, Charlotte A L. “Crystal structure and phase transitions in various functional perovskites.” 2018. Web. 24 Oct 2020.

Vancouver:

Dixon CAL. Crystal structure and phase transitions in various functional perovskites. [Internet] [Doctoral dissertation]. University of St Andrews; 2018. [cited 2020 Oct 24]. Available from: http://hdl.handle.net/10023/16572.

Council of Science Editors:

Dixon CAL. Crystal structure and phase transitions in various functional perovskites. [Doctoral Dissertation]. University of St Andrews; 2018. Available from: http://hdl.handle.net/10023/16572


Indian Institute of Science

3. Vanishri, S. Studies On Growth And Physical Properties Of Certain Nonlinear Optical And Ferroelectric Crystals.

Degree: PhD, Faculty Of Science, 2007, Indian Institute of Science

Nonlinear optics and ferroelectrics have been recognized for several decades as promising fields with important applications in the area of opto-electronics, photonics, memory devices, etc. High performance electro-optical switching elements for telecommunications and optical information processing are based on the material properties. Hence, there is always a continuous search for new and better materials. In this thesis we have investigated the growth and physical properties of four crystals viz. two NLO and two ferroelectric crystals. This thesis consists of eight chapters. The first chapter gives an overview of historical perspectives of nonlinear optical phenomenon, ferroelectricity and materials developed therein. The second chapter gives a brief description of the underlying theories of crystal growth, nonlinear optics and ferroelectricity. A major portion of this chapter consists of gist of the earlier work carried out on compounds of our interest viz. urea L-malic acid, sodium p-nitrophenolate dihydrate, glycine phosphite and lithium niobate. Synthesis, growth, crystal structure details and some physical properties of these materials are briefed. The third chapter describes the experimental techniques needed to grow as well as characterize these crystals. The experiments are performed on single crystals grown in the laboratory using the solution growth setup and Czochralski crystal puller. These growth units are described in detail. Preliminary characterization techniques like powder Xray diffraction, optical transmission, scanning electron microscopy, Vickers and Knoop hardness are described briefly. Various experimental methods viz. dielectric, polarization reversal, photoacoustic spectroscopy and laser induced damage for characterizing the grown crystals are explained. Urea L-malic acid (ULMA) is a new NLO organic material which is reported to exhibit second harmonic efficiency three times that of the widely used inorganic crystal, KDP. Hence, this material is selected for detailed investigation and the results obtained are discussed in chapter 4. This chapter contains details of single crystal growth and characterization of ULMA. The crystals are grown by slow cooling technique. The complete morphology of the crystal is evaluated using optical goniometry. The grown crystals are characterized for their optical and thermal properties. The defect content in the grown crystal is evaluated by chemical etching. As the surface damage of the crystal by high power lasers limits its performance in NLO applications, a detailed laser induced damage studies are performed on ULMA. Both single shot and multiple shot damage threshold values for 1064 nm and 532 nm laser radiation are determined and correlated with the mechanical hardness. In addition, the thermal diffusivity and thermal conductivity of ULMA along various crystallographic orientations are evaluated using laser induced photoacoustic spectroscopy and the results are interpreted in terms of crystal bonding environment. Another NLO crystal taken up for… Advisors/Committee Members: Bhatt, H L (advisor).

Subjects/Keywords: Ferroelectric Materials; Ferroelectric Crystals; Nonlinear Optical Materials; Nonlinear Optics; Ferroelectricity; Nonlinear Optical Crystals; Urea L-malic acid (ULMA); Sodium p-Nitrophenolate Dihydrate (NPNa.2H2O); Glycine Phosphite; Lithium Niobate (LiNbO3); Crystal Growth; Crystal Structure; Nonlinear Optical Crystal; Magnetism

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

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

APA (6th Edition):

Vanishri, S. (2007). Studies On Growth And Physical Properties Of Certain Nonlinear Optical And Ferroelectric Crystals. (Doctoral Dissertation). Indian Institute of Science. Retrieved from http://etd.iisc.ac.in/handle/2005/320

Chicago Manual of Style (16th Edition):

Vanishri, S. “Studies On Growth And Physical Properties Of Certain Nonlinear Optical And Ferroelectric Crystals.” 2007. Doctoral Dissertation, Indian Institute of Science. Accessed October 24, 2020. http://etd.iisc.ac.in/handle/2005/320.

MLA Handbook (7th Edition):

Vanishri, S. “Studies On Growth And Physical Properties Of Certain Nonlinear Optical And Ferroelectric Crystals.” 2007. Web. 24 Oct 2020.

Vancouver:

Vanishri S. Studies On Growth And Physical Properties Of Certain Nonlinear Optical And Ferroelectric Crystals. [Internet] [Doctoral dissertation]. Indian Institute of Science; 2007. [cited 2020 Oct 24]. Available from: http://etd.iisc.ac.in/handle/2005/320.

Council of Science Editors:

Vanishri S. Studies On Growth And Physical Properties Of Certain Nonlinear Optical And Ferroelectric Crystals. [Doctoral Dissertation]. Indian Institute of Science; 2007. Available from: http://etd.iisc.ac.in/handle/2005/320

.