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Beaulieu, Luc Yvon. "Mechanically alloyed Sn-Mn-C anodes for Li-ion batteries." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0016/MQ57272.pdf.
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Deng, Haokun. "Nanostructured Si and Sn-Based Anodes for Lithium-Ion Batteries." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/612405.
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Lithium-ion batteries (LIBs) are receiving significant attention from both academia and industry as one of the most promising energy storage and conservation devices due to their high energy density and excellent safety. Graphite, the most widely used anode material, with limitations on energy density, can no longer satisfy the requirements proposed by new applications. Therefore, further improvement on the electrochemical performance of anodes has been long pursued, along with the development of new anode materials. Among potential candidates, Si and Sn based anodes are believed to be the most promising. However, the dramatic volume expansion upon Li-intercalation and contraction upon Li de-intercalation cause mechanical instability, and thus cracking of the electrodes. To overcome this issue, many strategies have been explored. Among them the most efficient strategies include introduction of a nanostructure, coupled with a buffering matrix and coating with a protective film. However, although cycling life has been significantly increased using these three strategies, the capacity retention still needs improvement, especially over extensive charge-discharge cycles. In addition, more efforts are still needed to develop new fabrication methods with low costs and high efficiency. To further improve mechanical stability of electrodes, understanding of the failure mechanisms, particularly, the failure mechanisms of Si and Sn nanomaterials is essential. Therefore, some of the key factors including materials fabrication and microstructural changes during cycling are studied in this work. Hollow Si nanospheres have proved to be have a superior electrochemical performance when applied as anode materials. However, most of fabrication methods either involve use of processing methods with low throughput, or expensive temporary templates, which severely prohibits large-scale use of hollow Si spheres. This work designed a new template-free chemical synthesis method with high throughput and simple procedures to fabricate Si hollow spheres with a nanoporous surface. The characterization results showed good crystallinity and a uniform hollow sphere structure. The substructure of pores on the surface provides pathways for electrolyte diffusion and can alleviate the damage by the volume expansion during lithiation. The success of this synthesis method provides valuable inspiration for developing industrial manufacturing method of hollow Si spheres.3D graphene is the most promising matrix that can provide the necessary mechanical support to Sn and Si nanoparticles during lithiation. 2D graphene, however, results in Sn/graphene nanocomposites with a continuous capacity fade during cycling. It is anticipated that this is due to microstructural changes of Sn, however, no studies have been performed to examine the morphology of such cycled anodes. Hence, a new Sn/2D graphene nanocomposite was fabricated via a simple chemical synthesis, in which Sn nanoparticles (20-200 nm) were attached onto the graphene surface. The content of Sn was 10 wt.% and 20 wt.%. These nanopowders were cycled against pure Li-metal and, as in previous studies, a significant capacity decrease occurred during the first several cycles. Transmission and scanning electron microscopy revealed that during long term cycling electrochemical coarsening took place, which resulted in an increased Sn particle size of over 200 nm, which could form clusters that were 1 m. Such clusters result in a poor electrochemical performance since it is difficult for complete lithiation of the Sn to occur. It is hence concluded that the inability of Sn/2D graphene anodes to retain high capacities is due to coarsening that occurs during cycling. In addition to using forms of carbon to buffer the Sn expansion, it has been proposed to alloy Sn with S, which has a low redox potential vs Li⁰/Li⁺. Therefore, another new anode proposed here is that of SnS attached to graphite. The as prepared powders had a flower-like structure of the SnS alloy. Electrochemical cycling and subsequent microstructural analysis showed that after electrochemical cycling this pattern was destroyed and replaced by Sn and SnS nanoparticles. Based on the electron microscopy and XRD analysis, it was concluded that selective leaching of S occurs during lithiation of SnS particles, which results into nano SnS and Sn particles to be distributed throughout the electrolyte or SEI layer, without being able to take part in the electrochemical reactions. This mechanism has not been noted before for SnS anodes and indicates that it may not be possible to retain the initial morphology of SnS alloy during cycling, or the ability of SnS to be active throughout long term cycling. To conclude it should be stated that the goal and novelty of this thesis was (i) the fabrication of new Si, Sn/graphene and SnS/C nanostructures that can be used as anodes in Li-ion batteries and (ii) the documentation of the mechanisms that disrupt the initial structural stability of Sn/2D graphene and SnS/C anodes and result in severe capacity loss during long term cycling (over 100 cycles). These systems are of high interest to the electrochemistry community and battery developers.
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Taubert, Franziska. "Thermodynamische Untersuchungen in den Systemen Lithium-Silicium und Lithium-Zinn." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2017. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-229567.
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Lithium-Ionen-Batterien besitzen ein ausgezeichnetes Potential für die Energiespeicherung. Das derzeit dominierende Anodenmaterial in Lithium-Ionen-Batterien mit einer Energiespeicherkapazität von 339 mAh/g ist Graphit. Als Alternative hierfür bieten sich Lithiumsilicide und Lithiumstannide an. Diese Materialien zeichnen sich durch eine viel größere Speicherkapazität und geringere Selbstentladungspotentiale aus. Für die kommerzielle Anwendung dieser beiden Systeme in Lithium-Ionen-Batterien werden grundlegende und verlässliche thermodynamische Daten benötigt.
Derzeit ist die Existenz von sieben Lithiumsiliciden sicher nachgewiesen. Dazu zählen die sechs stabilen Phasen Li17Si4, Li16.42Si4, Li13Si4, Li7Si3, Li12Si7, die Hochdruckphase LiSi und die metastabile Phase Li15Si4. Für die ersten fünf genannten Phasen wurden in der ersten Förderperiode des Schwerpunktprogrammes 1473 Wärmekapazitäten und Standardentropien bestimmt. Bei den Lithiumstanniden sind derzeit sieben Phasen gesichert belegt. Allerdings existiert für keine Phase der Lithiumstannide ein verlässlicher thermodynamischer Basisdatensatz. Aus diesem Grund wurden für die beiden zuletzt genannten Lithiumsilicide (Li15Si4 und LiSi), sowie für die Lithiumstannide Li17Sn4, Li7Sn2, Li13Sn5 und Li7Sn3 die fehlenden thermodynamischen Daten experimentell bestimmt.
Die hergestellten Phasen wurden zunächst mittels Röntgenbeugung, thermischer und chemischer Analyse charakterisiert. Ein Schwerpunkt dieser Arbeit lag auf der experimentellen Bestimmung der Wärmekapazitäten in einem Temperaturbereich von 2 K bis zur jeweiligen Zersetzungstemperatur der untersuchten Verbindungen. Hierfür wurden zwei unterschiedliche Kalorimeter verwendet: ein Physical Property Measurement System (Quantum Design) von 2 K bis 300 K und eine DSC 111 (Setaram), beginnend ab 300 K. Die experimentellen Daten konnten mit Messunsicherheiten von 1 % bis 2 % über 20 K und bis zu 20 % unterhalb von 20 K angegeben werden. Die Messungen bei niedrigen Temperaturen erlauben zudem die Berechnung der Standardentropien, sowie die Bestimmung von elektronischen Beiträgen und Gitterschwingungsbeiträgen zur Wärmekapazität. Weiterhin ist Fokus dieser Arbeit die Bestimmung der Standardbildungsenthalpien der Lithiumsilicide und Lithiumstannide auf Basis von Wasserstoffsorptionsmessungen mittels einer Sieverts-Apparatur. Hierfür wurden erstmals Messungen an den Lithiumsiliciden ausgehend von Li17Si4, LiH:Si (Li:Si = 17:4), Li16.42Si4 und LiSi durchgeführt. Für die Lithiumstannide dienten als Ausgangsmaterial Li17Sn4, LiH:Sn (Li:Sn =17:4), sowie Li7Sn2 und LiH:Sn (Li:Sn = 7:2). Die Anwendung des van´t-Hoff-Plots resultierte in Messunsicherheiten von mindestens 10 %. Aus diesem Grund wurde eine alternative Auswertemethode gewählt, bei der die ermittelten Wärmekapazitäten und Standardentropien mit den Gleichgewichtsdrücken aus den Wasserstoffsorptionsmessungen miteinander verknüpft werden. Auf diese Weise konnten Standardbildungsenthalpien für die untersuchten Phasen mit Fehlern kleiner 1 % ermittelt werden. Aus den Ergebnissen dieser Arbeit resultierte ein vollständiger, gesicherter thermodynamischer Datensatz für das System Li-Si. Das berechnete Li-Si-Phasendiagramm ist im sehr guten Einklang mit experimentellen literaturbekannten Daten. Für die Lithiumstannide erfolgte eine Validierung der ermittelten thermodynamischen Werte.
Die in dieser Arbeit erzielten Ergebnisse liefern einen wesentlichen Beitrag zur Verbesserung der Datenbasis für thermodynamische Berechnungen und für das Verständnis von Phasensequenzen und Gleichgewichten beim Einsatz von Lithiumsiliciden bzw. Lithiumstanniden als Anodenmaterialien in Lithium-Ionen-Batterien.
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Bazin, Laurent. "Anodes nanostructurées pour microbatteries 3D Li-ion." Toulouse 3, 2009. http://thesesups.ups-tlse.fr/815/.
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Cette thèse a pour sujet l'élaboration et la caractérisation d'anodes nano-architecturées pour des applications en microbatteries Li-ion 3D. Ces électrodes sont basées sur un collecteur de courant nano-structuré, constitué d'un tapis de nano-piliers de cuivre (Ø200nm, L=2µm) alignés verticalement. L'objectif de ce travail a été de montrer les avantages d'une électrode tridimensionnelle en revêtant ce substrat avec différents matériaux actifs en utilisant différentes techniques. De l'étain métallique Sn a pu être déposé par voie électrochimique et forme une couche conforme sur la nanostructure de cuivre. L'électrode obtenue cycle à une capacité de 0,02 mAh. Cm-2 durant plus de 500 cycles, ainsi que 75% de rétention de capacité entre 0,05 et 6C. L'alliage Cu6Sn5 formé à l'interface cuivre/étain a été identifié comme responsable de cette bonne tenue en cyclage. Suite à ce résultat, on a tenté de réaliser un dépôt conforme de matériau actif par électrophorèse (EPD). Dans un premier temps, la faisabilité de ce dépôt a été prouvée en utilisant des nanoparticules de silice SiO2. Ces expériences ont permis de mettre en lumière l'importance de la qualité de la dispersion lors d'un dépôt électrophorétique sur un substrat nanométrique de géométrie complexe. Le dépôt EPD de nanoparticules d'oxyde d'étain SnO2 a ensuite été réalisé. Les tests électrochimiques de l'anode obtenue ont montrés un comportement identique à celui de l'anode de Sn. Ceci confirme l'intérêt de la technique d'EPD pour l'élaboration d'électrodes nanostructurées<br>The aim of this thesis is to elaborate and characterise nano-architectured anodes for Li-ion 3D microbatteries. These electrodes are based on a nanostructured current collector, consisting in vertically-aligned arrays of copper nanopillars (Ø200nm, L=2µm). The goal of this work is to highlight the merits of a 3D electrode prepared by coating this substrate using different techniques and active materials. Tin metal has been deposited by ELD and formed a conformal layer onto the Cu current collectors. The obtained electrode showed a capacity of 0,02 mAh. Cm-2 during more than 500 cycles and a retention capacity of 75 % between 0,05 and 6C. Cu6Sn5 alloy, formed at the Cu/Sn interface was identified as responsible of this good cycling behaviour. Then, we attempted to realise a conformal coating using the electrophoretic deposition technique. In a first step, the feasibility of this deposition was proved using silica nanoparticules. These experiments enlighted the importance of the quality of the dispersion during EPD onto a nanostructured substrate. After this, an EPD depositin of SnO2 nanoparticle has been realised. Electrochemical charactyerisations of the obtained SnO2 anodes show similar behavior as Sn anodes. This confirms the interest of EPD techniques for elaboration nanostructured electrodes
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Viaud, Pierre. "Composés organostanniques α-aminés chiraux : utilisation pour la réaction de transmétallation Sn/Li/B et désulfonylation électrochimique". Nantes, 2011. http://www.theses.fr/2011NANT2064.
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Les composés organostanniques α–aminés chiraux constituent des précurseurs d'anions α-aminés optiquement actifs très utiles en synthèse organique. L'étude méthodologique de la réaction de transmétallation étain-lithium a permis d'en montrer les possibilités et les limites. Des analyses par RMN 1H, 119Sn et 6Li à basse température ont été réalisées afin d'obtenir des informations sur les conformations des composés organostanniques et des organolithiens correspondants en solution. Par la suite, cette réaction de transmétallation a été appliquée à la synthèse d'esters boroniques α–aminés chiraux et de nombreuses difficultés ont été rencontrées pour leur déprotection. Ceci nous a amené à considérer d'autres cas de déprotections très délicates sur des motifs N-sulfonylés et dans ce cas, nous avons pu, par une approche raisonnée du problème, réaliser la déprotection électrochimique de sulfonamides chiraux α-stannylés en évitant à la fois la β-fragmentation et l'épimérisation<br>Enantioenriched α-aminoorganostannanes have emerged as useful reagents for organic synthesis. A methodoligical study about tin-lithium exchange is described, showing possibilities and limits of this reaction. 1H,119Sn and 6Li NMR spectra were recorded at low temperature in order to obtain information on the structure of these compounds. In a second part, this transmetalation reaction was applied to the synthesis of α-aminoboronic esters but numerous difficulties were encountered for their deprotection. Therefore, we consider other cases of very delicate deprotection of N-sulfonylated moeity and, we were able to achieve the electrochemical deprotection of chiral α-stannylated sulfonamides by avoiding both β-fragmentation and epimerization
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Suter, Max. "Über Reaktionen von Li[AlH4] mit Diolen und Untersuchungen zur Synthese von Vebindungen mit Al-Ge und Al-Sn-Bindung." Diss., lmu, 2002. http://nbn-resolving.de/urn:nbn:de:bvb:19-7272.
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Drüe, Martin [Verfasser], Markus Gutachter] Rettenmayr, Hans Jürgen [Gutachter] [Seifert, and Torsten [Gutachter] Markus. "Bildung und Stabilität von Phasen aus Li, Sn, Si und C / Martin Drüe ; Gutachter: Markus Rettenmayr, Hans Jürgen Seifert, Torsten Markus." Jena : Friedrich-Schiller-Universität Jena, 2018. http://d-nb.info/1170396682/34.
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Simons, Bethany Jane. "Processes controlling critical metal (Li, Be, Ga, Ge, Nb, Ta, In, Sn, Sb, W and Bi) distribution in the peraluminous granites of the Cornubian Batholith." Thesis, University of Exeter, 2015. http://hdl.handle.net/10871/17997.
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Critical metals are of growing economic importance for the low carbon sector but are susceptible to resource restrictions and have no viable substitutes in their applications. In this study, 134 samples of the Cornubian Batholith, SW England, with associated early Permian mafic and ultramafic rocks were sampled and analysed by ICP-MS and XRF for their major, trace and critical metal (Li, Be, Ga, Ge, Nb, Ta, In, Sb, W and Bi) abundance. The mineral chemistry of feldspars, micas, tourmaline, topaz and cordierite was determined for 8 samples by EPMA and LA-ICP-MS. The Cornubian Batholith is a peraluminous, composite pluton intruded into Devonian and Carboniferous metasedimentary and volcanic rocks. Geochemical fractionation trends recorded by whole rock geochemistry and mineral chemistry permit trace element modelling of two distinct fractional crystallisation series, biotite-muscovite (>282 Ma) and biotite-tourmaline (<282 Ma). The biotite-muscovite granites formed through muscovite and minor biotite dehydration melting of a metagreywacke source at moderate temperatures and pressures. Fractionation of an assemblage dominated by feldspars and biotite, enriched muscovite granites in Li (average 340 ppm), Be (13 ppm), Nb (16 ppm), Ta (3.7 ppm), In (77 ppb), Sn (17 ppm), W (12 ppm) and Bi (2.6 ppm) and are spatially associated with greisen style Sn-W mineralisation. Muscovite is the major host of In, Sn and W, and as muscovite is late-stage / subsolidus this implies these metals are highly incompatible in magmatic minerals and likely to partition into fluids exsolving from evolved muscovite granites. The biotite-tourmaline granites formed through higher-T melting than the first suite due to underplating of the region by mantle-derived melts during tectonic extension. Fractionation of feldspars, biotite and cordierite enriched Li (average 525 ppm), Ga (28 ppm), In (122 ppb), Sn (14 ppm), Nb (30 ppm), Ta (5.5 ppm), W (7.1 ppm) and Bi (2.7 ppm) in the tourmaline granites with retention of Be in the biotite granite due to partitioning of Be into cordierite. Distribution of Nb and Ta is controlled by accessory phases such as columbite within the evolved tourmaline granites, promoting disseminated Nb and Ta mineralisation. Lithium, In, Sn and W are hosted in biotite group micas which may prove favourable for breakdown on ingress of hydrothermal fluids and partitioning of the critical metals into mineralising fluids emanating from evolved tourmaline granites. Topaz granites are analogues of Rare Metal Granite described in France and Germany. They contain albite, polylithionite and topaz as major minerals and show differing trends on major and trace element plots relative to the other two granite series. These granites are enriched in Li (average 1363 ppm), Ga (38 ppm), Sn (21 ppm), W (24 ppm), Nb (52 ppm) and Ta (15 ppm) and formed through partial melting of a biotite-rich residue left after melting that formed early biotite granites.
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Costa, Clovis Fernando de Moura. "Evolução geológica da região de Pitinga (Amazonas) e suas implicações na gênese da mineralização de Sn-Nb-Ta-F (Y, ETR, Li) associada ao granito madeira." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2011. http://hdl.handle.net/10183/36790.
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A jazida do granito Madeira, associada à fácies albita granito, é um depósito de classe mundial com minério disseminado de Sn, Nb, Ta e F (Y, ETR, Li, U, Th) e, em sua parte central, contém um depósito de criolita maciça com 10 Mt (teor de 38% de Na3AlF6). O objetivo do trabalho foi compreender que contexto geológico permitiu a formação desta associação rocha-minério única no mundo. Para tanto, foram efetuados estudos isotópicos (Sm-Nd, Rb-Sr e Pb-Pb) e estudos tectônicos, enfocando o granito Madeira, seus correlatos e as rochas regionais. Durante uma primeira fase extensional, formaram-se as rochas vulcânicas do Grupo Iricoumé (1.890 a 1881 Ma), constituindo um complexo de caldeiras, e os corpos graníticos associados da Suíte Intrusiva Mapuera, ambos gerados a partir de fontes mantélicas. Concomitantemente aos estágios finais do vulcanismo iniciou-se a sedimentação na bacia Urupi (possivelmente um rift), acompanhada por um segundo pico de vulcanismo há 1.825 Ma. Fluidos mantélicos migraram para a zona afetada pela extensão regional, ascenderam acompanhando as isotermas e iniciaram a fenitização da crosta. Na continuidade deste processo, durante uma segunda fase extensional, rochas até refratárias tornaram-se fusíveis e originaram 5 magmas diferentes, todos com assinatura de fonte crustal e mantélica, que se posicionaram, entre 1.839 e 1.824 Ma, em estruturas geradas na fase anterior, formando os 3 corpos graníticos da Suíte Madeira. Numa terceira fase tectônica, desta feita transtensiva, fluidos mantélicos, possivelmente de natureza carbonatítica, fenitizaram rochas de nível crustal mais alto, enriquecidas em Sn, e nelas introduziram F, Nb, Y, ETR, U e Th em concentrações anômalas. Da fusão destas rochas resultou o magma do albita granito que se alojou, há 1.822 Ma, dentro do granito Madeira, mas com uma orientação N-S discordante da orientação geral NE-SW do granito Madeira e da estrutura que o aloja.<br>The deposit of the Madeira granite, associated with albite granite facies is a world-class deposit with disseminated ore of Sn, Nb, Ta and F (Y, REE, Li, U, Th), and its central part contains a deposit of massive cryolite with 10 Mtons (containing 38% of Na3AlF6). The objective was to understand the geological context to the formation of ore-rock association unique in the world. Therefore isotopic studies were performed (Sm-Nd, Rb-Sr and Pb-Pb) and tectonic studies focusing on the Madeira granite, its related and regional rocks. During a first extensional phase volcanic rocks of the Iricoumé Group (1890 to 1881 Ma) was originated forming a caldera complex and granitic bodies associated with Mapuera Intrusive Suite, both generated from mantle sources. At the same time the final stages of volcanism began the sedimentation in Urupi basin (possibly a rift), followed by a second peak of volcanism in 1825 Ma ago. Mantle fluids migrated to the area affected by regional extension rose following the isotherms and started the fenitization crust. Continuing this process in a second extensional phase , rocks become refractory and fuses originating 5 different magmas, all with crustal signature and mantle source, which is positioned between 1839 and 1824 Ma, in structures generated in previous phase, forming 3 granitic bodies of Madeira suite . In a third tectonic phase,, this time transtensive, mantle fluid, possibly of a carbonatitic fenitizated rocks from higher crustal level , enriched in Sn, and introduced F, Nb, Y, REE , U and Th in anomalous concentrations. The fusion of these rocks resulted in the albite granite magma that has positioned, there in 1822 Ma, within the Madeira granite, but with a NS orientation ,discordant of the general NE-SW of Madeira granite and the structure that it was contained.
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Legros, Hélène. "Les systèmes métallogéniques hydrothermaux à tungstène et métaux rares (Nb-Ta-Li-Sn) de la période Jurassique-Crétacé au sud de la province de Jiangxi (Chine)." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0266/document.
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Le tungstène est défini comme “ressource minérale critique” par la Commission Européenne. La province de Jiangxi, située au sud-est de la Chine, dans le bloc Cathaysia, représente 90 % des réserves en tungstène chinoises. Ce travail est basé sur l’étude des gisements hydrothermaux à W-Sn de Maoping et Piaotang, tous deux situés dans le district de Dayu (sud de la province de Jiangxi). Cette thèse a permis de (i) développer des traceurs pétrographiques et minéralogiques de processus minéralisateurs à travers des études paragénétiques détaillées et la géochimie des micas lithinifères et donc d’apporter un modèle impliquant des fluides multiples se chevauchant dans le temps et associés à plusieurs épisodes distincts de mise en place de minéralisations en métaux rares, (ii) définir par l’étude d’inclusions fluides deux processus fluides comme seul responsables de la précipitation de la minéralisation dans ces gisements « géants » : la différenciation magmatique de granites peralumineux et des processus de mélange, et (iii) de développer des approches de datation associés à ces systèmes montrant que la minéralisation en tungstène se met en place aux alentours de 160 Ma, antérieurement à la plupart des âges obtenus sur les minéraux de gangue datés dans cette zone et défini alors une remise à zéro majeure des systèmes isotopiques par de multiples circulations fluides entre 150 et 155 Ma. De plus, les stades post-minéralisations ont pu être définis pour la première fois et révèlent l’implication de magmatisme peralcalin impliqué dans la précipitation de minéralisations à Nb-Ta-Y-REE aux alentours de 130 Ma. A la lumière de cette observation, cette thèse s’est aussi tournée vers le développement de méthodes de datation in situ sur columbo-tantalite<br>Tungsten is defined as a “critical mineral resource” by the European Commission. The Jiangxi province, located in the southeastern part of China, in the Cathaysia block, represents 90% of the Chinese tungsten resources. This work is based on the study of the Maoping and Piaotang W-Sn hydrothermal deposits located in the Dayu district (southern Jiangxi). This thesis managed to (i) develop mineralogical and petrological tracers of ore-forming processes through detailed paragenetic sequences and geochemistry of Li-micas and shows that multiple overlapping fluids associated to several and distinct rare-metal mineralizing stages, (ii) distinguish by fluid inclusions studies that peraluminous magmatic differentiation and mixing processes are the only prequisite for the formation of these giant deposits, and (iii) develop dating approaches associated to these systems to demonstrate that the W mineralization formed at ca. 160 Ma, prior to most ages obtained on gangue minerals in the area, defining a major resetting of isotopic systems due to multiple fluid circulations around 150-155 Ma. Moreover, post-“silicate-oxide” stages have been defined for the first time and reveal the implication of peralkaline new fluid sources involved in the precipitation of Nb-Ta-Y-REE minerals at ca. 130 Ma. In the light of these results, this thesis gives new developments for in situ direct dating of ore-bearing minerals such as columbo-tantalite
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Ebougué, Zachée. "Magmas ultimes peralumineux à métaux rares (Be, Li, Nb, Ta, Sn) : mise en évidence de processus de différenciation extrême dans des dykes (Région de Blond, Massif Central français)." Nancy 1, 1995. http://www.theses.fr/1995NAN10150.
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Cette étude a pour but de contraindre les mécanismes d'enrichissement en métaux rares dans les magmas peralumineux. Elle est menée dans des dykes de la région de Blond, choisis pour disposer d'une gamme importante de degré d'enrichissement en ces métaux. Un échantillonnage en coupe transversale permet de suivre l'évolution métrologique entre centre et épontes des dykes. Les résultats (1) montrent une augmentation du caractère lithinifère des micas du centre vers les épontes des dykes, sous contrainte du contraste thermique et de l'augmentation de l'activité du fluor et du lithium au cours de la cristallisation. (2) cinq processus de différenciation sont retenus: (a) le fractionnement mécanique des phénocristaux par effet Bagnold, (b) la diffusion chimique par effet Soret, (c) le gradient de la pression fluide du centre vers les épontes des dykes, (d) la progression de la solidification des épontes vers le centre des dykes, (e) le fluage continu du magma au centre des dykes après solidification des épontes. (3) la comparaison de l'évolution des magmas des dykes à celle des massifs granitiques à métaux rares met en évidence une anomalie négative en fluor et lithium au cours de la différenciation. Son interprétation permet de proposer un modèle de genèse des magmas peralumineux a métaux rares base sur (a) la géochimie des micas, (b) le rôle du fluor dans la différenciation magmatique et la concentration des métaux rares, (c) le modèle de différenciation magmatique par cristallisation fractionnée, (d) la composition du magma initial. Ce modèle peut servir de guide de prospection des granites peralumineux à métaux rares
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Kaspar, Jan [Verfasser], Ralf [Akademischer Betreuer] Riedel, and Gian Domenico [Akademischer Betreuer] Sorarù. "Carbon-Rich Silicon Oxycarbide (SiOC) and Silicon Oxycarbide/Element (SiOC/X, X= Si, Sn) Nano-Composites as New Anode Materials for Li-Ion Battery Application / Jan Kaspar. Betreuer: Ralf Riedel ; Gian Domenico Soraru." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2014. http://d-nb.info/1110902336/34.
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Tallapally, Venkatesham. "Colloidal Synthesis and Photophysical Characterization of Group IV Alloy and Group IV-V Semiconductors: Ge1-xSnx and Sn-P Quantum Dots." VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5568.
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Nanomaterials, typically less than 100 nm size in any direction have gained noteworthy interest from scientific community owing to their significantly different and often improved physical properties compared to their bulk counterparts. Semiconductor nanoparticles (NPs) are of great interest to study their tunable optical properties, primarily as a function of size and shape. Accordingly, there has been a lot of attention paid to synthesize discrete semiconducting nanoparticles, of where Group III-V and II-VI materials have been studied extensively. In contrast, Group IV and Group IV-V based nanocrystals as earth abundant and less-non-toxic semiconductors have not been studied thoroughly. From the class of Group IV, Ge1-xSnx alloys are prime candidates for the fabrication of Si-compatible applications in the field of electronic and photonic devices, transistors, and charge storage devices. In addition, Ge1-xSnx alloys are potentials candidates for bio-sensing applications as alternative to toxic materials. Tin phosphides, a class of Group IV-V materials with their promising applications in thermoelectric, photocatalytic, and charge storage devices. However, both aforementioned semiconductors have not been studied thoroughly for their full potential in visible (Vis) to near infrared (NIR) optoelectronic applications. In this dissertation research, we have successfully developed unique synthetic strategies to produce Ge1-xSnx alloy quantum dots (QDs) and tin phosphide (Sn3P4, SnP, and Sn4P3) nanoparticles with tunable physical properties and crystal structures for potential applications in IR technologies.
Low-cost, less-non-toxic, and abundantly-produced Ge1-xSnx alloys are an interesting class of narrow energy-gap semiconductors that received noteworthy interest in optical technologies. Admixing of α-Sn into Ge results in an indirect-to-direct bandgap crossover significantly improving light absorption and emission relative to indirect-gap Ge. However, the narrow energy-gaps reported for bulk Ge1-xSnx alloys have become a major impediment for their widespread application in optoelectronics. Herein, we report the first colloidal synthesis of Ge1-xSnx alloy quantum dots (QDs) with narrow size dispersity (3.3±0.5 – 5.9±0.8 nm), wide range of Sn compositions (0–20.6%), and composition-tunable energy-gaps and near infrared (IR) photoluminescence (PL). The structural analysis of alloy QDs indicates linear expansion of cubic Ge lattice with increasing Sn, suggesting the formation of strain-free nanoalloys. The successful incorporation of α-Sn into crystalline Ge has been confirmed by electron microscopy, which suggests the homogeneous solid solution behavior of QDs. The quantum confinement effects have resulted in energy gaps that are significantly blue-shifted from bulk Ge for Ge1-xSnx alloy QDs with composition-tunable absorption onsets (1.72–0.84 eV for x=1.5–20.6%) and PL peaks (1.62–1.31 eV for x=1.5–5.6%). Time-resolved PL (TRPL) spectroscopy revealed microsecond and nanosecond timescale decays at 15 K and 295 K, respectively owing to radiative recombination of dark and bright excitons as well as the interplay of surface traps and core electronic states. Realization of low-to-non-toxic and silicon-compatible Ge1-xSnx QDs with composition-tunable near IR PL allows the unprecedented expansion of direct-gap Group IV semiconductors to a wide range of biomedical and advanced technological studies.
Tin phosphides are a class of materials that received noteworthy interest in photocatalysis, charge storage and thermoelectric devices. Dual stable oxidation states of tin (Sn2+ and Sn4+) enable tin phosphides to exhibit different stoichiometries and crystal phases. However, the synthesis of such nanostructures with control over morphology and crystal structure has proven a challenging task. Herein, we report the first colloidal synthesis of size, shape, and phase controlled, narrowly disperse rhombohedral Sn4P3, hexagonal SnP, and amorphous tin phosphide nanoparticles (NPs) displaying tunable morphologies and size dependent physical properties. The control over NP morphology and crystal phase was achieved by tuning the nucleation/growth temperature, molar ratio of Sn/P, and incorporation of additional coordinating solvents (alkylphosphines). The absorption spectra of smaller NPs exhibit size-dependent blue shifts in energy gaps (0.88–1.38 eV) compared to the theoretical value of bulk Sn3P4 (0.83 eV), consistent with quantum confinement effects. The amorphous NPs adopt rhombohedral Sn4P3 and hexagonal SnP crystal structures at 180 and 250 °C, respectively. Structural and surface analysis indicates consistent bond energies for phosphorus across different crystal phases, whereas the rhombohedral Sn4P3 NPs demonstrate Sn oxidation states distinctive from those of the hexagonal and amorphous NPs owing to complex chemical structure. All phases exhibit N(1s) and ʋ(N-H) energies suggestive of alkylamine surface functionalization and are devoid of tetragonal Sn impurities.
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Han, Sang-Do. "Elaboration et étude de nouveaux matériaux d'électrodes : les « nano-crystallite-insertion-materials » (NCIMs)." Phd thesis, Université Sciences et Technologies - Bordeaux I, 1994. http://tel.archives-ouvertes.fr/tel-00140026.
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Une nouvelle stratégie pour la réalisation de matériaux d'électrodes, les NCIMs (Nano-Crystallite-Insertion-Materials) a été proposée. Les matériaux LixTiO2, LixSnO2 et LixWO3, ont été préparés sous forme de poudre en utilisant une voie originale (voie polymère). Ils présentent une texture nanocristalline, ce qui permet de disposer d'une surface électrochimiquement active importante sur laquelle les ions Li+ peuvent se greffer reversiblement.
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Aboulaich, Abdelmaula. "Electrodes négatives pour batteries rechargeables lithium ion : dispersion d'espèces électroactives dans une matrice." Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 2007. http://tel.archives-ouvertes.fr/tel-00355604.
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Ce travail concerne la recherche et le développement de nouveaux matériaux à base d'étain, pour une application comme électrode négative des batteries rechargeables lithium ion. Afin de comprendre la relation Structure-texture-propriétés permettant d'optimiser le matériau, un ensemble de techniques de caractérisation complémentaires (Diffraction des rayons X, Microscopie électronique à balayage, analyse thermiques et gravimétriques ATD-ATG, spectroscopie Mössbauer de 119Sn et absorption X) ont été associées pour caractériser l'ordre global et l'ordre local dans le matériau. Une analyse détaillée du mécanisme de fonctionnement du matériau composite [Sn-BPO4], réalisée en couplant des méthodes électrochimiques et spectroscopiques, a permis de comprendre la réversibilité du système et de mettre en évidence les intermédiaires réactionnels grâce notamment à la spectroscopie Mössbauer in situ de 119Sn. Le matériau composite testé dans des cellules de laboratoire, montre des caractéristiques électrochimiques intéressantes, une capacité massique de 500 mAh/g et une bonne tenue en cyclage. Ces performances sont liées fortement à la meilleure dispersion de l'élément électroactif et à un solide accrochage à la surface de la matrice grâce à une interface amorphe formée entre les deux composants. Le matériau optimisé a été testé dans des conditions industrielle proposées par la société SAFT-Bordeaux, dans le but d'étudier l'effet de la technologie d'électrode sur les performances électrochimiques
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Rommel, Stefan Verfasser], Richard [Akademischer Betreuer] Weihrich, Arno [Akademischer Betreuer] [Pfitzner, and Frank-Michael [Akademischer Betreuer] Matysik. "Synthesis and characterization of nano- and microcrystalline ternary MAX-Materials (M = Ni, Co; A = Li, In, Sn, Pb, Tl; X = S, Se, PO4) Diffusion/Intercalation of metals into binaries as mechanism of formation and application as electrode materials / Stefan Rommel ; Richard Weihrich, Arno Pfitzner, Frank-Michael Matysik." Regensburg : Universitätsbibliothek Regensburg, 2016. http://d-nb.info/1130155153/34.
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Thomas, Rajesh. "Investigations on Graphene/Sn/SnO2 Based Nanostructures as Anode for Li-ion Batteries." Thesis, 2013. http://etd.iisc.ernet.in/2005/3460.
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Li-ion thin film battery technology has attracted much attention in recent years due to its highest need in portable electronic devices. Development of new materials for lithium ion battery (LIB) is very crucial for enhancement of the performance. LIB can supply higher energy density because Lithium is the most electropositive (-3.04V vs. standard hydrogen electrode) and lightest metal (M=6.94 g/mole). LIBs show many advantages over other kind of batteries such as, high energy density, high power density, long cycle life, no memory effect etc. The major work presented in this thesis is on the development of nanostructured materials for anode of Li-ion battery. It involves the synthesis and analysis of grapheme nanosheet (GNS) and its performance as anode material in Li ion battery. We studied the synthesis of GNS over different substrates and performed the anode studies. The morphology of GNS has great impact on Li storage capacity. Tin and Tin oxide nanostructures have been embedded in the GNS matrix and their electrochemical performance has been studied.
Chapter 1 gives the brief introduction about the Li ion batteries (LIBs), working and background. Also the relative advantages and characterization of different electrode materials used in LIBs are discussed.
Chapter 2 discusses various experimental techniques that are used to synthesize the electrode materials and characterize them.
Chapter3 presents the detailed synthesis of graphene nanosheet (GNS) through electron cyclotron resonance (ECR) microwave plasma enhanced chemical vapor deposition (ECR PECVD) method. Various substrates such as metallic (copper, Ni and Pt coated copper) and insulating (Si, amorphous SiC and Quartz) were used for deposition of GNS. Morphology, structure and chemical bonding were analyzed using SEM, TEM, Raman, XRD and XPS techniques. GNS is a unique allotrope of carbon, which forms highly porous and vertically aligned graphene sheets, which consist of many layers of graphene. The morphology of GNS varies with substrate.
Chapter 4 deals with the electrochemical studies of GNS films. The anode studies of GNS over various substrates for Li thin film batteries provides better discharge capacity. Conventional Li-ion batteries that rely on a graphite anode have a limitation in the capacity (372 mAh/g). We could show that the morphology of GNS has great effect in the electrochemical performance and exceeds the capacity limitation of graphite. Among the electrodes PtGNS shown as high discharge capacity of ~730 mAh/g compare to CuGNS (590 mAh/g) and NiGNS (508 mAh/g) for the first cycle at a current density of 23 µA/cm2. Electrochemical impedance spectroscopy provides the various cell parameters of the electrodes.
Chapter 5 gives the anodic studies of Tin (Sn) nanoparticles decorated over GNS matrix. Sn nanoparticles of 20 to 100nm in size uniformly distributed over the GNS matrix provides a discharge capacity of ~1500 mAh/g mAh/g for as deposited and ~950 mAh/g for annealed Sn@GNS composites, respectively. The cyclic voltammogram (CV) also shows the lithiation and delithiation process on GNS and Sn particles.
Chapter 6 discusses the synthesis of Tinoxide@GNS composite and the details of characterization of the electrode. SnO and SnO2 phases of Tin oxide nanostructures differing in morphologies were embedded in the GNS matrix. The anode studies of the electrode shows a discharge capacity of ~1400 mAh/g for SnO phase (platelet morphology) and ~950 mAh/g for SnO2 phase (nanoparticle morphology). The SnO phase also exhibits a good coulumbic efficiency of ~95%.
Chapter 7 describes the use of SnO2 nanowire attached to the side walls of the GNS matrix. A discharge capacity of ~1340 mAh/g was obtained. The one dimensional wire attached to the side walls of GNS film and increases the surface area of active material for Li diffusion. Discharge capacity obtained was about 1335 mAhg-1 and the columbic efficiency of ~86% after the 50th cycle.
The research work carried out as part of this thesis, and the results have summarized in chapter 8.
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Hein, Sebastian Boris [Verfasser]. "Gasphasensynthese einiger ausgewählter oxidischer Partikel : Stoffsysteme: Si-Ti-O, Si-Sn-O, Sn-Ti-O, Al-Si-O, Al-Ti-O, Li-Al-Si-O und Li-Al-Ti-O / von Sebastian Boris Hein." 2007. http://d-nb.info/997341459/34.
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許凱捷. "Chemical Vapor Deposition of Sn@C Core-Shell Nanocomposites as Anodes for Li-Ion Batteries." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/23210178343032230075.
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碩士<br>國立交通大學<br>應用化學研究所<br>98<br>Here, we present a simple preparation of Sn@C core-shell nanocomposites as stable anode materials. Sn@C anocomposites were synthesized by reacting tin
dioxide particles directly with a flowing mixture of cetylene and argon gas at 700 oC. The presence of the hair-like heterostructures is the principal feature of the Sn@C core-shell nanocomposites. The obtained Sn@C nanocomposites were several tens micrometers in length. The carbon shell was about 20 – 50 nm in thickness. Based on
the observed results, we propose the “phase segregation” model that may be used to rationalize its growth.
The nanocomposites were investigated as a potential anode material for Li-ion batteries. The Sn@C nanocomposite electrode exhibited a cyclic performance and maintained a reversible capacity of approximately 180 mAhg-1 after 50 cycles at 1 C current density. On the other hand, the data of the unprocessed, pure SnO2 particles showed a severe capacity degradation, which occurred within the first 50 cycles and led to a reversible capacity of only 15 mAhg-1 at 1 C current density. We anticipate that further improvement of the new composites may enhance the cyclability of the electrode.
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Lin, Yu-Sheng, and 林育生. "Improving the Electrochemical Performance of Li-ion Secondary Batteries by Optimizing the Sn / C Composite Anode Materials." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/79277912413262010523.
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Martins, Tânia da Costa. "Multidisciplinary study of pegmatites and associated Li and Sn-Nb-Ta mineralisation from the Barroso-Alvão region." Tese, 2009. https://repositorio-aberto.up.pt/handle/10216/83857.
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Tsai, Liang-Feng, and 蔡亮峰. "Photodetector, Photocatalyst, Li Ion Battery of Sn-Se Nanomaterials, and Photocatalytic Property of SnO2/SnS2 Heterostructure Nanoflakes." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/77p8py.
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碩士<br>國立臺灣科技大學<br>材料科學與工程系<br>107<br>In this thesis, three different kinds of materials were being investigated, SnO2/SnS2 heterostructure nanoflakes, SnxSe(1-x) nanowires and SnSe2/SnSe heterostructure nanoflakes.
For the first part, SnO2/SnS2 heterostructure nanoflakes was fabricated with CVD method and the composition can be controlled by adjusting the cooling time during the process. Here, four kinds of nanoflakes were being synthesized, SnO2, SnS2, SnO2/SnS2 (SnO2 rich) and SnO2/SnS2 (SnS2 rich), respectively. Afterwards, these nanoflakes were then used to photodegrade methyl blue solution under 5 W, 475 nm LED light source to probe the influence of SnO2/SnS2 heterojunction to photocatalytic performance. On the basis of the result from UV-Vis spectrometer, the SnO2/SnS2 heterojunction can improve the degraded performance. Base of the band structure of SnO2 and SnS2, the SnO2/SnS2 is a type II heterojunction that will separate electrons and holes to enhance carrier life time and further ameliorate the photodegraded property.
For the second part, SnxSe(1-x) nanowires, in order to control the composition, the AAO template supporting die casting process was being adopted, and the SnxSe(1-x) nanowires with different x were fabricated by directly changing the composition of SnxSe(1-x) bulks. In this report, 8 kinds of SnxSe(1-x) (x=0.47~0.53) nanowires have been synthesized. Those SnxSe(1-x) (x=0.47~0.53) nanowires were used to fabricate the photodetector to detect the light from visible light to infrared light. As result, the photoresponse will rise with the increasing x. To understand the mechanism, the band structure simulation with different concentration of Sn and Se vacancies were being employed and the consequence shown that the band gap will decrease when the defect concentration is ascending. Moreover, under the same defect concentration, the inducing of Se vacancies demonstrate much lower band gap than Sn vacancies. In other words, the free electrons inside SnxSe(1-x) increase as x increase, which mean Sn0.53Se0.47 can generate more electrons and holes than SnSe under the same power density of the irradiation light source and further enhance the photoresponse.
For the third part, SnSe2/SnSe heterostructure nanoflakes were prepared by using H2Cr2O7 or NaOH as an etching solution to etch Sn0.39Se0.61(SnSe-SnSe2 eutectic phase) bulk through selective etching between SnSe and SnSe2. Depend on the XRD and Raman spectrum, the SnSe2 phase is the priority etching phase even for NaOH or H2Cr2O7 solution. Here, the Sn0.39Se0.61 bulk was soaked in H2Cr2O7 solution to obtain SnSe2/SnSe and SnSe nanoflakes, and used in Li-ion battery. Even though the theoretical capacitance of SnSe2 (800 mAh/g) is lower than SnSe (847 mAh/g), SnSe2/SnSe nanoflakes also display the higher reversible capacitance than SnSe nanoflakes. It can be attributed to the build in electric field at SnSe2/SnSe heterojunction that can enhance the carrier mobility to lower charge transfer resistance of SnSe2/SnSe nanoflakes. Besides, we also investigate the influence of heat treatment on precursor Sn0.39Se0.61 bulk (3 types: quench, annealing after quench and slow cooling rate) and the obtained SnSe2/SnSe nanoflakes. These three kinds of SnSe2/SnSe nanoflakes were used as photocatalyst to degrade MB dye under 5 W, 475 nm LED. Since the carrier live time of the SnSe nanoflakes with high crystallinity is longer than the quenching sample, the annealing and slow cooling SnSe nanoflakes is expected to have better degradation ability, and the results show that the SnSe nanoflake that annealed after quenching really have the best degradation effect.
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Martins, Tânia da Costa. "Multidisciplinary study of pegmatites and associated Li and Sn-Nb-Ta mineralisation from the Barroso-Alvão region." Doctoral thesis, 2009. https://repositorio-aberto.up.pt/handle/10216/83857.
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Bevan, Martin Joseph. "I. Dynamic and thermodynamic investigation of thienyllithium based Li/Te and Li/I ate complexes II. dynamic and thermodynamic investigation of phenyllithium based Li/I, Li/Sb, and Li/Sn ate complexes III. the investigation of sulfur stabilized organolithium reagent ion pair status and reactivity." 2003. http://www.library.wisc.edu/databases/connect/dissertations.html.
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Ferreira, José Jorge do Amaral. "Transition Metals Thermal Crystal Physics: Cu-Sb-S, Cu-Li-Mg, Bi-Sn-Zn and Al-Fe-Ti." Tese, 2012. https://repositorio-aberto.up.pt/handle/10216/72665.
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Ferreira, José Jorge do Amaral. "Transition Metals Thermal Crystal Physics: Cu-Sb-S, Cu-Li-Mg, Bi-Sn-Zn and Al-Fe-Ti." Doctoral thesis, 2012. https://repositorio-aberto.up.pt/handle/10216/72665.
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Jhan, Yi-Ruei, and 詹益瑞. "Synthesis and Characteristics of Sn-based and Lithium Titanate Anode Materials for High-capacity and High-power Li-ion Batteries." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/98117615856413419070.
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Suter, Max [Verfasser]. "Über Reaktionen von Li[AlH4] mit Diolen und Untersuchungen zur Synthese von Vebindungen mit Al-Ge und Al-Sn-Bindung / von Max Suter." 2002. http://d-nb.info/966649044/34.
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Kaspar, Jan. "Carbon-Rich Silicon Oxycarbide (SiOC) and Silicon Oxycarbide/Element (SiOC/X, X= Si, Sn) Nano-Composites as New Anode Materials for Li-Ion Battery Application." Phd thesis, 2014. https://tuprints.ulb.tu-darmstadt.de/4104/1/%232014-09-01%20Dissertation_v01_pdf_X3.pdf.
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Carbon-rich silicon oxycarbide (SiOC) and silicon oxycarbide/element nano-composites (SiOC/X, X=Si, Sn) are prepared via thermal conversion of polyorganosiloxanes and studied as potential anode material for Li-ion battery application. The obtained materials are characterized by various chemical, structural, electrochemical and electro-analytical methods. The chemical composition and microstructure of the samples is analyzed and correlated with their electrochemical properties and performance. For carbon-rich SiOC, the lithium ion storage process, including the transport and mobility of lithium ions within the material, is investigated.
The electrochemical properties of carbon-rich SiOC strongly correlate with the ceramic microstructure and phase composition, which in turn correlate with the final temperature of pyrolysis. Both, an increasing organization of free carbon within the microstructure and the gradual degradation of the amorphous Si-O-C network lead to reduced capacities and changing voltage profiles. According to electro-analytical studies by PITT, GITT and EIS, the diffusion coefficient of Li-ions within SiOC prepared at 1100°C is in a similar order of magnitude as reported for disordered carbons, but faster than for graphite.
In the case of SiOC/X (X=Si, Sn) nano-composites, an additional Li-alloy forming phase is embedded within the SiOC matrix. For the synthesis of SiOC/Sn, a new innovative single-source precursor approach is introduced, which enables the in-situ precipitation of metallic Sn phase upon the thermal conversion of tin-modified polysiloxanes. Due to this microstructural design, the Li-ion storage capacity of the composite is enhanced, compared to pure SiOC. In addition, the embedding of Si and Sn alloy forming phases within stabilizing SiOC matrices strongly increases their cycling stability upon continuous lithiation and delithiation.
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Nimisha, C. S. "Investigations On Electrodes And Electrolyte Layers For Thin Film Battery." Thesis, 2011. http://etd.iisc.ernet.in/handle/2005/2099.
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The magnificent development of on-board solutions for electronics has resulted in the race towards scaling down of autonomous micro-power sources. In order to maintain the reliability of miniaturized devices and to reduce the power dissipation in high density memories like CMOS RAM, localized power for such systems is highly desirable. Therefore these micro-power sources need to be integrated in to the electronic chip level, which paved the way for the research and development of rechargeable thin film batteries (TFB). A Thin film battery is defined as a solid-state electrochemical source fabricated on the same scale as and using the same type of processing techniques used in microelectronics.
Various aspects of deposition and characterization of LiCoO2/LiPON/Sn thin film battery are investigated in this thesis. Prior to the fabrication of thin film battery, individual thin film layers of cathode-LiCoO2, electrolyte-LiPON and anode-Sn were optimized separately for their best electrochemical performance. Studies performed on cathode layer include theoretical and experimental aspects of deposition of electrochemically active LiCoO2 thin films. Mathematical simulation and experimental validation of process kinetics involved in sputtering of a LiCoO2 compound target have been performed to analyze the effect of process kinetics on film stoichiometry. Studies on the conditioning of a new LiCoO2 sputtering target for various durations of pre-sputtering time were performed with the help of real time monitoring of glow discharge plasma by OES and also by analysing surface composition, and morphology of the deposited films. Films deposited from a conditioned target, under suitable deposition conditions were electrochemically tested for CV and charge/discharge, which showed an initial discharge capacity of 64 µAh/cm2/µm.
Studies done on the deposition and characterization of solid electrolyte layer-LiPON have shown that, sputtering from powder target can be useful for certain compounds like Li3PO4 in which breaking of ceramic target and loss of material are severe problems. An ionic conductivity of 1.1 x10-6 S/cm was obtained for an Nt/Nd ratio of 1.42 for a RF power density of 3 W/cm2 and N2 flow of 30 sccm. Also the reasons for reduction in ionic conductivity of LiPON thin films on exposure to air have been analyzed by means of change in surface morphology and surface chemistry. Ionic conductivity of 2.8 x10-6 S/cm for the freshly deposited film has dropped down to 9.9 x10-10 S/cm due to the reaction with moisture, oxygen and carbon content of exposed air.
Interest towards a Li-free thin film battery has prompted to choose Sn as the anode layer due to its relatively good electrochemical capacity compared with other metallic thin films and ease of processing. By controlling the rate of deposition of Sn, thin films of different surface morphology, roughness and crystallinity can be obtained with different electrochemical performance. The reasons for excessive volume changes during lithiation/delithiation of a porous Sn thin film have been analyzed with the aid of physicochemical characterization techniques. The results suggest that the films become progressively pulverized resulting in increased roughness with an increase in lithiation. Electrochemical impedance data suggest that the kinetics of charging becomes sluggish with an increase in the quantity of Li in Sn-Li alloy.
Thin film batteries with configuraion LiCoO2/LiPON/Sn were fabricated by sequential sputter deposition on to Pt/Si substartes. Pt/Cu strips were used as the current collector leads with a polymer packaging. Electrochemical charge/discharge studies revealed discharge capacities in the range 6-15 µAh/cm2/µm with hundreds of repeated cycles. TFB with a higher capacity of 35 µAh/cm2/µm suffered capacity fade out after 7 cycles, for which reasons were analyzed. The surface and cross-sectional micrographs of cycled TFB showed formation of bubble like features on anode layer reducing integrity of electrolyte-anode interface. The irreversible Li insertion along with apparent surface morphology changes are most likely the main reasons for the capacity fade of the LiCoO2/LiPON/Sn TFB.