Sharif Digital Repository

Due to the technology advancement and the large-scale application of lithium-ion batteries in recent years, the market demand for lithium is growing rapidly and the availability of land lithium resources is decreasing significantly. As such, the focus of lithium extraction technologies has shifted to water lithium resources involving salt-lake brines and sea water. The ion exchange process is a promising method for lithium extraction from brine and seawater having low concentrations of this element. Among various aqueous recovery technologies, the lithium ion-sieve (LIS) technology is considered the most promising one. This is because LISs are excellent adsorbents with high lithium uptake... 

In present research work, methods of preparing ion exchange membranes, especially anion exchange membranes, were studied and chemical modification of polysulfone was chosen as a safe and economical method for preparing anion exchange membranes. The chloromethylated polysulfone was characterized by HNMR spectroscopy and functionalization degree was determined according to peak area integration. Membranes were produced by mixing and amination of the chloromethylated and normal polysulfone (40-100% wt). Morphology and chemical structure of membranes were investigated by SEM images and FTIR spectroscopy.The ionic conductivity, ion exchange capacity and water content of samples were measured. The... 

Nanostructured graphene based membranes demonstrated excellent capabilities in various applications in nanofiltration and energy conversion due to unique atomically smooth surfaces and adjustable pore size or interlayers spacing at Angstrom scales.In addition to graphitic surface and physical confinement on ions in Graphene-oxide (GO) laminates, surface charges on such 2D-slits provide an attractive aspects to have more channels walls interactions with ions. There are some reports on the osmotic power generation using physical confinements and electrostatic interactions between ions and GO membranes. However, the results indicated insufficient power densities (1 W=m2 ) can be achieved... 

In recent years, metallic nanoparticles, specially gold and silver nanoparticles, have received great attention for biological and metal ions analysis, due to the surface plasmon resonance phenomena. Gold nanoparticles (AuNPs) have recently gained much interest in colorimetric probe based on aggregation or anti-aggregation of AuNPs, due to their simplicity and having high order of magnitude extinction coefficients, in addition to the dependence of surface plasmon resonance wavelength and intensity on the interparticles distances. In the first part of this thesis, a highly sensitive colorimetric method for detection of copper ions based on anti-aggregation of citrate capped AuNPs was... 

Recently, the nano-bio communication networks have received significant attention. Among different communication mechanisms proposed for nano communication, diffusion based molecular communication (DMC) is the most promising scheme. This thesis focuses on DMC and first proposes a theoretical model for this scheme. In the next part of the thesis, inspired by the molecule transport mechanisms in the biological cells, two biosynthetic modulator structures are proposed.In first structure, an ion channel based modulator for DMC is proposed which controls the rate of molecule release from the transmitter by modulating a gating parameter signal. The corresponding average modulated signal, i.e., the... 

Fresh water has always been one of the basic needs of human. Thus using different methods for water purification becomes more important in recent years. In classic methods such as distillation chamber and thermal method, water flux was always low and salt rejection wasn’t satisfactory. So investigating new methods such as nanofiltration becomes more important. This method has high efficiency and good water flux in compare with old methods. One of the useful materials in nanofiltration is grapheme oxide (GO). GO sheets make an array of nanochannels and this membrane improves filtration and water flux. Different parameters affect water flux and salt rejection in this membrane. Restructuring... 

Today, the use of graphene quantum dots has been very much considered due to easy synthesis methods, strong fluorescence emission, and many sources of synthesis. In this study, the effect of changing capping agent of graphene quantum dots toward iron (Ⅲ), copper (Ⅱ) and mercury (Ⅱ) ions was studied. The linear range of response of the graphene quantum dots synthesized with ethylenediamine for mercury (Ⅱ) and iron (Ⅲ) ions was 10-70 µM, and this sensor also responded to Cu (Ⅱ) ions. Urea synthesized graphene quantum dots also responded to all three ions. The linear range of the response for mercury (Ⅱ) , iron (Ⅲ) and copper (Ⅱ) ions was 5-25, 10-70 and 120-120 μM respectively. The linear... 

Folic acid is a pterin derivative containing a glutamyl moiety and essential for biological reactions. Pterins are a class of heterocyclic compounds with unique structures and biological functions. Tetrahydrobiopterine has been known to be essential for catalytic hydroxylation of aromatic amino acids by metal ions-containing aromatic amino acid hydroxylases. Metal ions at the active site of these enzymes have been inferred to be closely associated with the pterin cofactors in the catalytic reactions.Information on pterin-metal interaction may give clues to the role of metal ions in enzymatic reactions. With these points in mind, studies have been conducted to verify the formation of ternary... 

In the Ion Implanter system a controled current through a tungesten filament, supplies the heat which causes the thermoionic emmition to ionize the gas molecules. Then the negativly charged electrones that are boiled off the filament, and also the ones that are removed from the outer ring of the gas molecules during the ionization process, are attracted by an adjustable voltage source. In this thesis, two resonant converter topologies are proposed to designe and to implement the adjustable current and voltage sources for ion implantation system. Unlike the PWM converters soft switching techniques, used auxiliary circuits to reduce the switching losses and EMI noises, in the proposed resonant... 

Due to the technology advancement and the large-scale application of lithium-ion batteries in recent years, the market demand for lithium is growing rapidly and the availability of land lithium resources is decreasing significantly. As such, the focus of lithium extraction technologies has shifted to water lithium resources. Among various aqueous recovery technologies, the lithium ion-sieve (LIS) technology is considered the most promising one. This is because LISs are excellent adsorbents with high lithium uptake capacity, superior lithium selectivity, and good cycle performance. TiO2-based nanotubes are an appropriate option for adsorbing lithium from solution due to their high specific... 

Recently lithium iron silicate (Li2FeSiO4) has been used as a new cathode material for lithium ion battery. Li2FeSiO4 has such benefits like low raw material price so lower production cost, lower environmental pollution, higher safety, electro chemical and cyclic stability and high theoretical capacity of 166 mAh/g against other cathode materials like LiMn2O4, LiBNiO2, LiCoO2 and LiFePO4. In this research Li2FeSiO4 was synthesized through sol gel synthesis method and effect of chelating agent concentration, calcination temperature and time has been investigated. To determine the appropriate calcination temperature range, TG/DTA was performed. Then the dried gel powder was calcined at each... 

Interest in lithium sources has been increasing because of wide applications of the metal in high-energystorage lithium batteries and its compounds in otherfields.Lithium appears in lake, brines and several minerals such as spodumene, petallite, and lepidolite. Several methods such as ion exchange (adsorption), solvent extraction, and coprecipitation have been investigated for the extraction of lithium from seawater, brine, and geothermal water. The adsorption method is suitable for recovery of lithium from seawater because certain inorganicion-exchange materials show extremely high selectivity for lithium ions only.The objective of this study is to evaluate the applicability of nano... 

In this study, orthosilicate materials with chemical formula of Li2MSiO4 (M one or two transition metal/metals) were investigated experimentally and theoretically as cathode material of Li-ion batteries. The most important material in this category i.e. Li2FeSiO4 was synthesized by three methods including nitrate-based sol-gel, oxalate-based solid state reaction and oxide-based solid state reaction. Based on XRD and SEM evaluations, grain size of synthesized powders was estimated to be between 15 to 100 nanometers. Of these three methods, oxide-based solid state reaction was employed in this study for the first time. This syntheses method is very important due to the significant lower... 

In this work, butyl methylimidazolium tetrafluoroborate and butyl methylimidazolium hexafluorophosphate are used as ionic liquid and lithium perchlorate and lithium hexafluorophosphate as lithium salt. Dimethyl carbonate and propylene carbonate are used as solvent to prepare diffrent kinds of organic - ionic liquids solvent for lithium ion batterries. In preliminary expriment it was distinguished that in the mixture of organic solvent lithium hexaflourophosphat has more conductivity in comparison with lithium perchlorate. There for,in this work, all organic-ionic liquid solvent electrolytes are considered based on lithium hexaflourophosphat salt. Different compositions of organic-ionic... 

Li-ion batteries have been widely applied as power sources for portable electronic devices. Recently, Li-ion batteries are considered as the most promising energy storage technology for electric vehicle applications however, fundamental improvements are needed. TiO2 (B) is attractive candidate for anodes in rechargeable Li-ion batteries, due to their low cost, non-toxicity and favorable channel structure for fast lithium mobility. It is predicted that synthesis of doped nanostructure of this material, through reducing the diffusion pathway and formation of crystal defects, will increase the capacity of TiO2(B). In this investigation, Co and V doped TiO2(B) nanowires are synthesized by... 

Titanium nitride-carbon nanocomposites are synthesized by the reaction of TiCl4 and NaN3 in supercritical benzene medium that also serves as a carbon source. In order to improve the crystallinity of the as-prepared precursor (SI), it is further heat-treated at 1000 ˚C for 3-10 h using anhydrous ammonia and UHP nitrogen atmospheres at 1000 ˚C (SIII-SV). Moreover, to improve electrochemical behavior, the synthesized nanocomposite (SIV) is modified with Pt nanoparticles using a polyol process. For better understanding of synthesized catalyst nature and justifying their variant ORR activity several analyses are done. X-ray diffraction (XRD), Raman spectrum, field emission scanning electron... 

In this study, the effect of temperature on the microstructure and electrochemical properties of the NMC batteries has been studied. An extensive set of accelerated aging tests has been carried out employing a Li-ion high energy 18650 system (2.2 Ah, negative electrode: carbon, positive electrode: Li(Ni0.5Mn0.3Co0.2) O2. Different influence factors on cycle aging, such as temperature and discharge rate have been investigated. The aged 18650 cells have been inspected via scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), impedance spectroscopy, and X-ray diffraction (XRD) after disassembly to find more information about the chemical reasons of the degradation and... 

Prognostics is necessary to ensure the reliability and safety of lithium-ion batteries for hybrid electric vehicles or satellites. This process can be achieved by capacity estimation, which is a direct fading indicator for assessing the state of health of a battery. However, the capacity of a lithium-ion battery onboard is difficult to monitor. This paper presents a data-driven approach for capacity estimation. First, new features are extracted from cyclic charge/discharge cycles and used as health indicators. Three algorithms are used to characterize the relationship between extracted features and battery capacity. Decision tree, random forest and boosting algorithms are trained using a... 

Quantum Theory leads to results that are consistent with the very high accuracy with experience and also includes a wide range of empirical phenomena. Hence, quantum mechanics is accepted as the best and most acclaimed physical theory. However, there is still no consensus between physicists on the interpretation of parts of this theory. One of the unresolved issues in quantum mechanics is the measurement problem. The basis of the measurement problem is a kind of transition from the quantum world to the classical world. The fundamental question that arises here is, where is the boundary between quantum mechanics and classical mechanics? and how can be described the transition from quantum... 

Battery thermal management system is the indispensable part of the electric vehicles working with Lithium-ion batteries. Accordingly, Lithium-ion batteries modelling, battery heat generation and thermal management is the main focus of researchers and car manufacturers. While Computational Fluid Dynamics (CFD) has been used quite successfully for battery thermal management, CFD models can be too large and too slow for assembling in battery pack level models or vehicle models. In this research a much smaller reduced order model is developed, which is in the core is based on CFD models. Thus, without losing the accuracy, this model can be implemented in the vehicle model. The developed model...