Sharif Digital Repository

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... 

The goal of the present study is to analyze the effect of CaF2 and nano-TiO2 as additives on formulation and properties of common dental glass-ceramics. To achieve the goal, a glass system based on SiO2-Al2O3-Li2O-K2O-P2O5-ZnO-ZrO2 was considered to produce glass-ceramic samples and the additives, nano-TiO2 and CaF2, with the 0.5, 1, and 1.5 %Wt was added to the system. After the melting process, the glass samples poured in the water and ferrite was produced. In the next step, the ferrite was milled and pressed. In the heat treatment step, the samples were treated in the temperature range of 650-850°C in order to gain lithium disilicate glass-ceramics. In the last step, the chemical... 

Lithium has 9 isotopes which two isotopes are stable and remaining isotopes are unstable and have half-life. Lithium stable isotopes include 6Li and 7Li that their abundance is 7.53% and 92.47% respectively. Importance of lighter lithium isotope appears for its small cross section against thermal neutron and producing fusion reactors fuel in nuclear industries. Thermal neutron absorption cross section for 6Li and 7Li are 950 barn and 37 mbarn respectively. Interesting of these isotopes in nuclear industry is due to the large difference in the absorption cross section.6Li compounds implied for tritium producing in coat of nuclear fusion reactor with DT fuel. Following tritium is used in... 

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 the present study, the process of recycling spent lithium batteries by co-precipitation method has been investigated. The process of regeneration of lithium batteries by co-deposition method consists of four stages. In the first stage, the cathodic material is separated from the aluminum foil using NMP solution, and then the cathodic material is heat treated at a temperature of 700 degrees. In the second stage, using sulfuric acid and hydrogen peroxide, the cathode material is leached at 60 ° C, pulp density 55 g / l, time 100 minutes, sulfuric acid concentration 3.25 M and volume percentage of hydrogen peroxide. 10% More than 99% of lithium, nickel, cobalt and manganese are leached. In... 

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... 

Lithium-ion batteries have the ability to store a significant amount of energy and work at high power, which has led to the wide spread of their use in various industries. In high-power applications, battery heat management increases lifespan, safety, and reduces battery power loss. In this study, the heat management of a very common and widely used 18650 battery using multi-layered phase change material has been investigated. The reason for using multiple layers is that each phase change material has its own weaknesses in addition to its advantages. It is expected that with the proper use of several phase change materials in the thermal management system, the materials will reduce the... 

In this study, Lithium recovery process from lithium-ion battery was investigated by electrodialysis method. First, the cathode of the battery was leached in NMP to separate cathode from aluminum foil. Then, the cathode was leached in sulfuric acid with concentration 3.25 M and 10 volume percent hydrogen peroxide that pulp density was 55 g/L at 60°C for 100 minutes. in the next step, an electrodialysis cell was designed and created to recover lithium. And the influence of time, voltage, flow rate of feed solution, concentration of electrode solution and concentration of feed solution on process was investigated. Purpose of this project were investigated lithium ion recovery rate, lithium... 

This research is divided in three parts. In the first part of this research, we report the one-pot synthesis of carbonate-coated nanostructured LLO (Li2CO3@LLO) through a polyol-assisted method as a Li-ion battery cathode. Carbonate protects the cathode from adverse reactions with the electrolyte, also reduces the layered-to-spinel phase transition, thereby stabilizing the cathode structure. LLO nanostructure provides a fast Li+ diffusion. The target material exhibits excellent long-term stability with 77% capacity retention after 1000 cycles at 0.2C-rate. In the second part of research, Li(Na-doped)-Mn-Ni-O oxides were synthesized by different LiOH.H2O amount, type and amount of reducing... 

One of the problems that affects the lifetime and cycle life of lithium ion batteries is the localized corrosion of aluminum current collector (during the storage and charging cycle). Since applying corrosion-resistant coating has always been one of the ways to reduce corrosion of materials in different environments, in the present project, this method has been used to prevent corrosion of aluminum in lithium-ion batteries. For this purpose, the graphene oxide coating, which has desirable anti-corrosion properties, was coated on aluminum by Electrophoretic deposition and doctor blade methods. linear polarization, cyclic voltammetry and electrochemical impedance spectroscopy were performed to... 

Among the various materials, silicon anodes have the highest lithium absorption in lithium-ion batteries. But this high lithium absorption capacity can cause 300 percent volume expansion and large stresses. Experimental observations show that charge and discharge cycles may cause plastic deformation in some parts of the electrode particle. On the other hand, there is a possibility of a ratcheting phenomenon due to changing in elastic properties of the electrode material during the charging and discharging processes. However, this phenomenon has not been reported for silicon spherical electrode particles yet.This study aims to model the elastic-plastic behavior of silicon spherical electrode... 

In the current era, the urgent need to reduce the use of fossil fuels and limit carbon emissions has highlighted the importance of shifting from traditional gasoline-powered vehicles to electric vehicles. The evolving landscape and challenges in the field of electric vehicles highlight the importance of ensuring the safety and reliability of energy storage systems. Lithium-ion batteries play a central role in electric vehicle technology, requiring thorough research efforts. Notably, the detection of internal short circuit, a common issue in lithium-ion batteries, has become a focus of researchers in recent years. This study aims to investigate the internal short circuit fault in lithium-ion... 

Brines are one of the main resources for lithium extraction and Iran has got many high magnesium and low lithium brine resources. In order to extract lithium, it is required to carefully identify these resources and their associated compounds and then an appropriate method can be adopted to extract lithium. Among the Previous researches, Bahadori, Jandaghi and Moazeni developed methods for removal of undesirable brines elements, Deposition of lithium from refined brine and lithium adsorption anatase ion-sieves membrane respectively; in this study it has been tried to investigate the optimization of the adsorption process, onto the TiO2-B ion sieve with nanotube morphology. TiO2-B nanotubes... 

During the last few years, the number of electric devices using lithium-ion batteries as a source of energy has increased drastically. The lifespan of these batteries is very short (2-3 years) and according to the statistics only 25% of which is recycled. However, considering the variety of materials used in these batteries, recycling them can be highly gainful. One of the technical challenges in the way of recycling Li-ion batteries is the presence of polyvinylidene fluoride (PVDF), that besides raising issues during recycling processes causes the production of toxic fluorine or hydrogen fluoride effluents. The second issue is the presence of metals with high oxidation states in these... 

One of the basic resources for lithium extraction is brine which is very abundance in Iran. It is important to characterize these brines and their compositions to select a suitable method for lithium recovery from them. By investigation of the local brines and determining lithium and other alkali metals composition in them, the ion exchange process using titanium dioxide ion-sieve with nanotube morphology is suggested as highly effective method for lithium extraction from Iranian brines. Due to high advantages of hydrothermal process, TiO2 nanotubes were produced by this method and the optimum parameters of hydrothermal reactions were reported. In this way, hydrogen titanate nanotubes with... 

Today, considering the global demand for reducing greenhouse gas emissions, rechargeable batteries are considered as a source of energy in electric vehicles, hybrid electric vehicles and smart grids. In all these applications for secondary batteries, the battery management system requires an accurate estimate state of charge of each cell. However, this estimate is difficult particularly for battery aging. In this study, a lithium-ion battery is modeled by using multidimensional multiphysics modeling and simulated in a comsol. In this simulation, the effect of the thermal conductivity coefficient on the battery temperature, initial salt concentration in electrolyte and the rate of discharge... 

Dye-Sensitized solar cells are the third generation of solar cells that have the potential to increase efficiency as much as solar cells of previous generations, along with lower prices. The cathode electrode of the pigmented solar cell as one of the essential components of the cell plays the role of accelerating the oxidation reaction reduction of the electrolyte. Platinum often is used as a catalyst layer. To reduce production costs and maintain cell viability, platinum should replace with other materials at a lower cost and higher electrochemical activity. Recently, carbon materials have been considered for the production of inexpensive solar cells with suitable performance. Among... 

In this project, a model which had been suggested for a lithium battery is used with the assumption of using C.N.T instead of activated carbon for the cathode. This battery include lithium foil, C.N.T and solution as anode, cathode and electrolyte. The electrolyte solution consist of lithium salt and a separator. The mathematical solving of the model consisted of using two CPM and DFM methods. In DFM method, a concentration gradient was considered as the driving force for diffusion and in the CPM method chemical potential as the driving force. Furthermore CPM method considered energy interaction between ions. Changing physical parameters of cathode and modification of model parameters... 

The air cathode of li-air batteries plays a pivotal role in the overall performance of Li-air batteries. Graphene-based cathodes have been investigated as cathode catalysts for lithium-air batteries due to their extraordinary potential for accelerating and facilitating oxygen reduction reaction (ORR).In this study graphene oxide have been synthesized via modified Hummers’ method. Consequently, the as obtained graphene oxide have been reduced using chemical, electrochemical, and hydrothermal methods. Results of elechtrochemical evaluations demonstrate that the graphene oxide reduced via hydrothermal method possesses the most positive ORR onset potential (+0.55V vs SHE) among the other samples... 

To ensure stable and optimal operation of lithium-ion batteries (LIBs), it is necessary to use a management system for online monitoring and accurate estimation of battery State of Charge (SOC). Due to LIBs' complex dynamics and effective factors such as temperature and side reactions, battery SOC estimation has become one of the greatest challenges for experts in the field. In this research, an adaptive sliding mode observer has been designed and evaluated for a cylindrical lithium manganese oxide battery with a capacity of 1258 mAh. At first, rigorous simulation of lithium-ion battery has been performed by utilizing the P2D electrochemical as well as thermal and aging model to be the main...