Electric vehicles (EVs) offer an exciting opportunity in China both in terms of the potential to build a domestic manufacturing base and the potential to create a strong domestic market for the product. The Chinese nation stands to benefit from both supply-side and demand-side promotion due to the economic stimulus from EV manufacturing and export, the environmental benefits of reduced air pollution and reduced greenhouse gas emissions, and the energy security benefits of transitioning away from foreign oil dependence. The Chinese have several advantages when it comes to stimulating EV industry development and EV deployment, including: leadership in battery technology, great potential for cost competitiveness, an enormous and emerging number of new car buyers, and high level government support. Yet a number of challenges must be taken into account as well, including: shortfalls in overall automobile R&D spending, consumer concerns about Chinese cars’ safety and reliability, enhancing the appeal of the Chinese brand, and heavy national infrastructure demands. This paper will seek to examine the opportunities and challenges associated with EV deployment in China and identify industry actions and policy measures to facilitate the process.

The rechargeable lithium ion batteries (LIB) are playing increasingly important roles in powering portal commercial electronic devices. They are also the potential power sources of electric mobile vehicles. The first kind of the cathode materials, LiXCoO2, was commercialized by Sony Company in 1980s, and it is still widely used today in LIB. However, the high cost of cobalt source, its environmental unfriendliness and the safety issue of LiXCoO2 have hindered its widespread usage today. Searching for alternative cathode materials with low cost of the precursors, being environmentally benign and more stable in usage has become a hot topic in LIB research and development. In the first part of this study, lithium nickel manganese cobalt oxide (LiNi0.6Mn0.35Co0.05O2) is studied as the electrode. The materials are synthesized at high temperatures by solid state reaction method. The effect of synthesis temperature on the electrochemical performance is investigated, where characterizations by, for example, X-ray diffraction (XRD) and scanning electron microscopy (SEM), for particle size distribution, specific surface area, and charge-discharge property, are done over samples prepared at different conditions for comparison. The electrochemical tests of the rechargeable Li ion batteries using LiNi0.6Mn0.35Co0.05 cathode prepared at optimum conditions are carried out in various voltage ranges, at different discharge rates and at high temperature. In another set of experiments, the material is adopted as anode with lithium foil as the cathode, and its capacitance is tested. In the second part of this study, the iron based cathode material is investigated. Lithium iron orthosilicate with carbon coating is synthesized at 700℃ by solid state reaction, which is assisted by high energy ball milling. Characterizations are done for discharge capacities of the samples with different carbon weight ratio coatings. / published_or_final_version / Physics / Master / Master of Philosophy

Vertically aligned multi walled carbon nanotube (MWCNT) arrays fabricated by xylene pyrolysis in anodized aluminum oxide (AAO) templates without the use of a catalyst, were integrated into a resistive sensor design. The steady state sensitivities as high as 5% and 10% for 100 ppm of NH3 and NO2 respectively at a flow rate of 750 sccm were observed. A study was undertaken to elucidate (i) the dependence of sensitivity on the thickness of amorphous carbon layers, (ii) the effect of UV light on gas desorption characteristics and (iii) the dependence of room temperature sensitivity on different NH3 and NO2 flow rates. An equivalent circuit model was developed to understand the operation and propose design changes for increased sensitivity. Multi Walled Carbon NanoTubes (MWCNTs) – Polymer composite based hybrid sensors were fabricated and integrated into a resistive sensor design for gas sensing applications. Thin films of MWCNTs were grown onto Si/SiO2 substrates via xylene pyrolysis using chemical vapor deposition technique. Polymers like PEDOT:PSS and Polyaniline (PANI) mixed with various solvents like DMSO, DMF, 2-Propanol and Ethylene Glycol were used to synthesize the composite films. These sensors exhibited excellent response and selectivity at room temperature when exposed to low concentrations (100ppm) of gases like NH3 and NO2. Effect of various solvents on the sensor response imparting selectivity to CNT – Polymer nanocomposites was investigated extensively. Sensitivities as high as 28% was observed for a MWCNT – PEDOT:PSS composite sensor when exposed to 100ppm of NH3 and -29.8% sensitivity for a MWCNT-PANI composite sensor to 100ppm of NO2. A novel nanostructured electrode design for Li based batteries and electrochemical capacitor applications was developed and tested. High density and highly aligned metal oxide nanowire arrays were fabricated via template assisted electrochemical deposition. Nickel and Molybdenum nanowires fabricated via cathodic deposition process were converted into respective oxides via thermal treatments and were evaluated as electrodes for batteries and capacitor applications via Cyclic Voltammetery (CV). Several chemical baths were formulated for the deposition of pristine molybdenum nanowires. Superior electrochemical performance of metal (Ni and Mo) oxide nanowires was observed in comparison to the previously reported nano-particle based electrodes.

Three-dimensional macroporous structures (‘opals’ and ‘inverse opals’) can be produced by colloidal crystal templating, one of the most intensively studied areas in materials science today. There are several potential advantages of lithium-ion battery electrodes based on inverse opal structures. High electrode surface, easier electrolyte access to the bulk of electrode and reduced lithium diffusion lengths allow higher discharge rates. Highly open structures provide for better mechanical stability to volume swings during cycling. Silicon is one of the most promising anode materials for lithium-ion batteries. Its theoretical capacity exceeds capacities of all other materials besides metallic lithium. Silicon is abundant, cheap, and its use would allow for incorporation of microbattery production into the semiconductor manufacturing. Performance of silicon is restricted mainly by large volume changes during cycling. The objective of this work was to investigate how the inverse opal structures influence the performance of silicon electrodes. Several types of silicon-based inverse opal films were synthesised, and their electrochemical performance was studied. Amorphous silicon inverse opals were fabricated via chemical vapour deposition and characterised by various techniques. Galvanostatic cycling of these materials confirmed the feasibility of the approach taken, since the electrodes demonstrated high capacities and decent capacity retentions. The rate performance of amorphous silicon inverse opals was unsatisfactory due to low conductivity of silicon. The conductivity of silicon inverse opals was improved by crystallisation. Nanocrystalline silicon inverse opals demonstrated much better rate capabilities, but the capacities faded to zero after several cycles. Silicon-carbon composite inverse opal materials were synthesised by depositing a thin layer of carbon via pyrolysis of a sucrose-based precursor onto the silicon inverse opals in an attempt to further increase conductivity and achieve mechanical stabilisation of the structures. The amount of carbon deposited proved to be insufficient to stabilise the structures, and silicon-carbon composites demonstrated unsatisfactory electrochemical behaviour. Carbon inverse opals were coated with amorphous silicon producing another type of macroporous composites. These electrodes demonstrated significant improvement both in capacity retentions and in rate capabilities. The inner carbon matrix not only increased the material conductivity, but also resulted in lower silicon pulverisation during cycling.

Titanium dioxide, TiO₂, materials have received much attention in recent years due to their potential use as intercalation negative electrodes for rechargeable lithium-ion batteries. The aim of this doctoral work was to synthesise and characterise new titanium dioxide nanomaterials and to investigate their electrochemical behaviour. Three morphologies of TiO₂(B) phase: micro-sized (bulk), nanowires and nanotubes, were synthesised. All three exhibit properties which make them excellent hosts for lithium intercalation. The nanotubes show the best capability of accommodating lithium in the structure, being able to host over one molar equivalent of lithium at low current rates (5 mA g⁻¹). The lithium insertion mechanism in the TiO₂(B) was studied using powder neutron diffraction. In addition, the nature of the irreversible capacity of the nanotubes was studied and ways of reducing it proposed. Nanotubes of another titanium dioxide polymorph, anatase, were synthesised and characterised. Their electrochemical performance was compared with that of commercially available counterparts with different morphologies and particle sizes. The interrelation between particle size/morphology and electrochemical properties has been established. The insertion of lithium which leads to phase variations was studied using in situ Raman microscopy and neutron powder diffraction. It has been demonstrated that doping of the TiO₂(B) nanotubes with vanadium improves their electronic conductivity which is essential for practical applications. Remarkably good electrochemical performance is exhibited by the 6% V-doped TiO₂(B) nanotubes.

abstract: There is a fundamental attractiveness about harnessing renewable energy in an age when sustainability is an ethical norm. Lithium ion batteries and hydrogen fuels are considered the most promising energy source instead of fossil fuels. This work describes the investigation of new cathode materials and devices architectures for lithium ion batteries, and photocatalysts for their usage in water splitting and waste water treatment. LiCoO2 and LiNi1/3Mn1/3Co1/3O2 were exfoliated into nanosheets using electrochemical oxidation followed by intercalation of tetraethylammonium cations. The nanosheets were purified using dialysis and electrophoresis. The nanosheets were successfully restacked into functional cathode materials with microwave hydrothermal assistance, indicating that new cathodes can be obtained by reassembling nanosheets. This method can pave the way for the synthesis of materials with novel structures and electrochemical properties, as well as facilitate the fabrication of hybrid and composite structures from different nanosheets as building blocks. Paper folding techniques are used in order to compact a Li-ion battery and increase its energy per footprint area. Full cells were prepared using Li4Ti5O12 and LiCoO2 powders deposited onto current collectors consisting of paper coated with carbon nanotubes. Folded cells showed higher areal capacities compared to the planar versions. Origami lithium-ion battery made in this method that can be deformed at an unprecedented high level, including folding, bending and twisting. Spray pyrolysis was used to prepare films of AgInS2 with and without Sn as an extrinsic dopant. The photoelectrochemical performance of these films was evaluated after annealing under a N2 or S atmosphere with different amounts of the Sn dopant. Density Function Theory (DFT) was used to calculate the band structure of AgInS2 and understand the role of Sn doping in the observed properties. Cr(VI) removal was investigated using multiple oxide photocatalyst and additives. The efficiency for Cr(VI) removal using these photocatalysts was investigated in synthetic neutral and alkaline water, as well as in cooling tower blowdown water. While sulfite alone can chemically reduce Cr(VI), sulfite in combination with a photocatalyst resulted in faster and complete removal of Cr(VI) in 10 min using a SO32−/Cr(VI) ratio >35 in pH ∼ 8 solutions. / Dissertation/Thesis / Doctoral Dissertation Materials Science and Engineering 2016

abstract: Lithium ion batteries prepared with a ceramic separator, have proven to possess improved safety, reliability as well as performance characteristics when compared to those with polymer separators which are prone to thermal runaway. Purely inorganic separators are highly brittle and expensive. The electrode-supported ceramic separator permits thinner separators which are a lot more flexible in comparison. In this work, it was observed that not any α-alumina could be used by the blade coating process to get a good quality separator on Li4Ti5O12 (LTO) electrode. In this work specifically, the effect of particle size of α-alumina, on processability of slurry was investigated. The effect of the particle size variations on quality of separator formation was also studied. Most importantly, the effect of alumina particle size and its distribution on the performance of LTO/Li half cells is examined in detail. Large-sized particles were found to severely limit the ability to fabricate such separators. The α-alumina slurry was coated onto electrode substrate, leading to possible interaction between α-alumina and LTO substrate. The interaction between submicron sized particles of α-alumina with the substrate electrode pores, was found to affect the performance and the stability of the separator. Utilizing a bimodal distribution of submicron sized particles with micron sized particles of α-alumina to prepare the separator, improved cell performance was observed. Yet only a specific ratio of bimodal distribution achieved good results both in terms of separator formation and resulting cell performance. The interaction of α-alumina and binder in the separator, and its effect on the performance of substrate electrode was investigated, to understand the need for bimodal distribution of powder forming the separator. / Dissertation/Thesis / Masters Thesis Chemical Engineering 2017

Fundação de Amparo a Pesquisa no Estado do Rio Grande do Sul / The increasing industrial development results in a large consumption of products and materials. Among them, stand out the polymeric materials, due to their versatility and low cost, and electrical and electronic equipment (EEE), such as mobile phones and their batteries. In this scenario, an efficient and environmentally friendly recycling technology has a great importance. Therefore, this study presents an alternative to the mechanical recycling of these wastes. The separation of the polymeric mixtures was performed using the triboelectrostatic separation process. The components of lithium-ion batteries were recovered by a corona electrostatic separation process. In polymeric waste processing, the methodology employed was the characterization, washing, drying, comminution, secondary washing, secondary drying, tribocharging and electrostatic separation of the different polymeric blends (HDPE / PP, LDPE / PP and PET / PVC). The variables studied were the tribocharging mechanism, the relative humidity, the tribocharging residence time, the angle of the deflector, the distance of the static electrode, the electrode voltage and the rotation of the roll. In lithium ion batteries waste processing, the methodology employed was the characterization, comminution, drying, particle size separation and electrostatic separation. The selected parameters were the electrodes voltage, cylinder rotation, the distance of the static electrode and the angle of the deflector of the collector. For the polymeric waste processing the best results were: low relative humidity, tribocharging residence time of 5 minutes, angle of the deflector of 2.5 °, the distance of the static electrode of 3 cm, voltage of 30 kV and speed rotation 10 rpm. With these parameters, was obtained the recovery of 92.8% of PP (purity of 95.7%) and 95.9% of HDPE (purity of 93.1%). In the separation of PP and LDPE, was obtained a PP recovery of 90.2% (purity 93.8%) and a LDPE recovery of 94.2% (purity of 90.8%). Also, was achieved a recovery of 96.8% of PET (purity of 95.9%), and recovery of 95.9% for PVC (purity of 96.8%). For lithium ion batteries waste processing the best conditions were: rotation speed of 20 rpm, voltage of 25 kV, distance of the static electrode 6 cm and angle of the deflector 0 °. Through this process, was obtained a conductive fraction with 98.98% of metals content and a nonconductive fraction with 99.6% of polymer. The characterization of the batteries showed the batteries heterogeneity, being the electrostatic separation efficient to the different models tested. Therefore, the application of electrostatic separation is a promising method and efficient to recycling of polymer waste and lithium ion batteries waste. The studied process enabled a significant recovery of the components with a high purity. / O crescente desenvolvimento industrial acarreta em um grande consumo de produtos e materiais. Entre eles, destacam-se os materiais poliméricos, devido à sua versatilidade e baixo custo, e os equipamentos elétricos e eletrônicos (EEE), tais como os telefones celulares e suas baterias. Nesse cenário, tecnologias de reciclagem eficientes e ambientalmente aceitáveis tem uma grande importância. Diante disso, o presente trabalho apresenta uma alternativa para a reciclagem mecânica destes diferentes resíduos. A separação das misturas poliméricas foi realizada através do processo de separação triboeletrostática. Já os diferentes componentes das baterias de íon de lítio foram recuperados por um processo de separação eletrostática por efeito corona. No processamento dos resíduos poliméricos, a metodologia empregada consistiu na caracterização, lavagem, cominuição, lavagem e secagem secundária, tribocarregamento e separação eletrostática das diferentes misturas poliméricas (PEAD/PP, PEBD/PP e PET/PVC). As variáveis estudadas foram o mecanismo de tribocarregamento, a umidade relativa do ar, tempo de tribocarregamento, ângulo do defletor, distância do eletrodo de atração, tensão dos eletrodos e a rotação do rolo. No processamento das baterias de íon de lítio, realizaram-se a caracterização das baterias, cominuição, secagem, separação granulométrica e separação eletrostática. Os parâmetros selecionados foram a tensão dos eletrodos, rotação do rolo, distância do eletrodo de atração e o ângulo do defletor do coletor. Para o processamento dos resíduos poliméricos os melhores resultados foram: umidade relativa do ar de ± 42%, tempo de tribocarregamento de 5 minutos, ângulo do defletor de 2,5°, distância do eletrodo de atração de 3 cm, tensão de 30 kV e velocidade de rotação de 10 rpm. Com esses parâmetros, obteve-se a recuperação de 92,8% de PP (pureza de 95,7%) e 95,9% de PEAD (pureza de 93,1%). Na separação de PP e PEBD, obteve-se uma recuperação de PP de 90,2% (pureza de 93,8%), e uma recuperação de PEBD de 94,2% (pureza de 90,8%). Também, conseguiu-se uma recuperação de 96,8% de PET (pureza de 95,9%), e de 95,9% de PVC (pureza de 96,8%). Para a reciclagem de baterias de íon de lítio as melhores condições foram: velocidade de rotação de 20 rpm, tensão de 25 kV, distância do eletrodo de atração de 6 cm e ângulo do defletor de 0°. Através deste processamento, obteve-se uma fração condutora com 98,98% de metais e uma fração não condutora com 99,6% de polímeros. A caracterização das baterias demonstrou uma heterogeneidade desse tipo de resíduo, sendo o processo de separação eletrostática eficiente para os diferentes modelos testados. Sendo assim, a aplicação da separação eletrostática se mostrou um método eficiente e promissor para a reciclagem de resíduos poliméricos e de resíduos de baterias de íon de lítio. O processo estudado possibilitou a obtenção de uma expressiva recuperação dos componentes com uma alta pureza.

Des nanotubes de dioxyde de titane (TiO2nts) sont étudiés comme électrodes négatives potentielles pour des microbatteries Li-ion 3D. Ces TiO2nts lisses et hautement auto-organisés sont élaborés par anodisation du Ti dans des électrolytes organiques à base de glycérol ou d'éthylène glycol contenant des ions fluor et de l'eau en faible quantité. Les structures présentant un diamètre de 100 nm et une longueur variant de 1,5 à 14 µm sont particulièrement appropriés pour l'application visée. Les TiO2nts ont été tapissés de manière conforme par un électrolyte polymère (PMA-PEG) comportant un sel de lithium (LiTFSI) grâce à la technique d'électropolymérisation. Les études morphologiques menées par SEM et TEM ont montré que les nanotubes sont entièrement recouverts d'un film mince polymère de 10 nm d'épaisseur, ce qui permet de préserver la structure 3D de l'électrode. Les tests électrochimiques portant sur les nanotubes seuls ainsi que sur les TiO2nts tapissés d'électrolyte polymère ont été effectués en demi-cellule et en cellule complète en utilisant un électrolyte polymère à base de MA-PEG contenant du LiTFSI. En demi-cellule, les TiO2nts de 1,5 µm de long delivrent une capacité surfacique de 22 µAh cm-2 relativement stable sur 100 cycles. La performance de la demi-cellule est améliorée de 45% à une cinétique de 1C lorsque les TiO2nts sont tapissés de manière conforme par un electrolyte polymère (PMA-PEG). Cet effet résulte d'un meilleur transport de charges lié à l'augmentation de la surface de contact entre l'électrode et l'électrolyte. / Titania nanotubes (TiO2nts) as potential negative electrode for 3D lithium-ion microbatteries have been reported. Smooth and highly-organized TiO2nts are fabricated by electrochemical anodization of Ti foil in glycerol or ethylene glycol electrolyte containing fluoride ions and small amount of water. As-formed TiO2nts shows the open tube diameter of 100 nm and the length from 1.5 to 14 µm which are suitable for the fabrication of the 3D microcbatteries. The deposition of PMA-PEG polymer electrolyte carrying LiTFSI salt into TiO2nts has been achieved by the electropolymerization reaction. The morphology studies by SEM and TEM reveal that the nanotubes are conformally coated with 10 nm of the polymer layer at the inner and outer walls from the bottom to the top without closing the tube opening. 1H NMR and SEC show that the electropolymerization leads to PMA-PEG that mainly consists of trimers. XPS confirms the presence of LiTFSI salt in the oligomers.The electrochemical studies of the as-formed TiO2nts and polymer-coated TiO2nts have been performed in the half-cells and full cells using MA-PEG gel electrolyte containing LiTFSI in Whatman paper as separator. The half-cell of TiO2nts (1.5 µm long) delivers a stable capacity of 22 µAh cm-2 over 100 cycles. The performance of the half-cell is improved by 45% at 1C when TiO2nts are conformally coated with the polymer electrolyte. The better performance results from the increased contact area between electrode and electrolyte, thereby improving the charge transport.

Dans les accumulateurs au lithium, l'électrolyte joue un rôle important car ses propriétés physicochimiques et électrochimiques conditionnent l'efficacité du générateur électrochimique. Actuellement, les électrolytes organiques utilisés induisent des difficultés pour la mise en oeuvre et l'utilisation de la batterie (composants volatils et inflammables). De nouveaux électrolytes à base de sels fondus à température ambiante, dit liquides ioniques, sont des candidats potentiels plus sécuritaires (faible inflammabilité, basse pression de vapeur saturante, point éclair élevé), qui présentent en outre une large fenêtre électrochimique. Dans un premier temps, le travail de thèse a été de concevoir de nouvelles voies de synthèses plus économes, tenant compte des exigences environnementales (limitation des déchets, pas de solvant) et proposant des liquides ioniques de haute pureté >99.5% compatibles avec une production industrielle. De nouveaux liquides ioniques dérivés du cation imidazolium ont alors été conçus afin de moduler leurs propriétés physicochimiques et optimiser leurs performances dans les batteries. Ils ont été évalués dans diverses technologies de batteries (Graphite/LiFePO4) et (Li4Ti5O12/LiFePO4) dans différentes conditions expérimentales, à 298 K et 333 K, cette dernière température étant proscrite pour les batteries conventionnelles. Ce travail de thèse a permis d'identifier les modifications chimiques pour conduire aux électrolytes les plus prometteurs et à mis en exergue l'importance de l'étude de la compréhension des phénomènes d'interphase liquides ioniques/ électrodes / In lithium ion batteries, the electrolyte plays an important role because its physicochemical and electrochemical properties determine their efficiency. Currently, the used organic electrolytes induce difficulties in the manufacturing and the use of the battery (volatile and flammable components). New electrolytes based on molten salts at room temperature, called ionic liquids, are safer potential candidates (low flammability, low vapor pressure, high flash point) with a wide electrochemical window. The first stage of this PhD was to design new and more efficient synthetic routes, taking into account the environmental requirements (waste minimization, no solvent) and allowing the elaboration of ionic liquids with high purity> 99.5%, compatible with an industrial production. New ionic liquids derived from imidazolium cation were then designed in order to modulate their physicochemical properties, and to optimize their performance in batteries. They were evaluated in various battery technologies (Graphite/LiFePO4) and (Li4Ti5O12/LiFePO4) under different experimental conditions, 298 K and 333 K, when the conventional lithium ion batteries (organic electrolyte) are used only under 313 K. This PhD work has identified the chemical modifications to yield the most promising electrolytes, and highlighted the importance of the study on the understanding of ionic liquid/electrode interphase phenomena