http://localhost:8081/jspui/handle/123456789/4966 2026-05-07T20:56:06Z http://localhost:8081/jspui/handle/123456789/20410 Title: DESIGN AND DEVELOPMENT OF NEXT-GENERATION BINDER-FREE LITHIUM-ION BATTERY Authors: Tandon, Abhinav Abstract: Rechargeable lithium-ion batteries (LIBs) are being used extensively to power various portable electronic appliances such as laptop computers, mobile phones, etc. Research is being carried out towards improving parameters like energy/power density, long-term cyclability, safety and reducing the cost so that LIBs can be used in electric vehicles and stationary backup power supplies. Many of the above parameters significantly depend upon the intrinsic and extrinsic nature of the electrode materials, and it is essential to investigate new electrode materials that exhibit high energy density, high rate performance, long lifespan, and cost-effectiveness. Most of the commercial LIBs employ LiCoO2 as the cathode (positive electrode), non-aqueous Li-ion electrolyte, and graphite as the anode (negative electrode). But graphitic carbon exhibits poor experimental capacity (330 mAh g−1), low insertion potential (∼0.2 vs. Li/Li+), poor tap density, and safety issues at a high current rate, which are the main hurdles for its implementation in the high-end applications of LIBs. Therefore, continuous efforts are being made to develop alternative anode materials for next-generation LIBs. In this context, ternary metal oxide, specifically manganese (Mn) based oxides, are recognized as prospective anode materials due to their high theoretical capacity, nontoxic properties, rich resources, lower cost, greater number of oxidation states of Mn, lower working potential, and environmentally acceptable nature. However, this class of materials suffers from rapid capacity decay and low cyclability due to excessive volume fluctuation during lithiation/delithiation, sluggish ion diffusion kinetics, large irreversible capacity loss, and poor electrical conductivity, which hinder their commercialization. To overcome these drawbacks and improve the Li-storage performance of Mn-based oxides, several strategies have been utilized. A common technique to prevent unit-cell volume variation during cycling is the incorporation of an electrochemically inactive matrix component (such as MgO) into the Mn-based oxides. Further, nanostructuring of active electrode materials has also shown a constructive impact on the Li-storage properties. Particularly, the 1D nanofibric morphology of active materials can offer a high aspect ratio and surface area that can provide an efficient transport pathway for electrons/ions, leading to enhanced Li-ion kinetics. Moreover, incorporating oxygen vacancies into Mn-based oxides is another effective strategy to enhance the Li-storage properties. The oxygen vacancies constructed an internal electric field, enhanced the conductivity, and increased the adsorption energy with Li-ion, thus improving the electrochemical performance of the as-prepared electrodes. Another viable strategy for achieving maximum capacity for Mn-based oxides is to utilize compounds that contain metal ions capable of undergoing Li-cycling via both conversion and alloying-de-alloying reactions. Furthermore fabricating electrodes without binder can also improve LIBs' overall energy density. The electrodes without binders provide a well-connected path between active materials and current collectors, ensuring efficient electronic and ionic movement within the electrode materials. In the present thesis, all the above-mentioned strategies are systematically employed in the ternary Mn-based oxide (MgMn2O4; MMO) nanofibers (NFs) fabricated via electrospinning technique and investigated their Li-storage properties. Firstly, the binder-free electrodes of MMO NFs are fabricated via electrophoretic deposition (EPD) technique and then analysed the effect of EPD voltage on the surface morphology of the fabricated electrodes and their electrochemical performance. The electrochemical investigations confirm that the deposition voltage of the EPD considerably modifies the surface microstructures of the deposited electrodes and, hence, efficiently controls their Li-storage properties. At a particular EPD voltage (100 V), the MMO NFs electrode attained the optimum gaps/cracks on its surface with a 3D porous morphology. The porous structure allows fast Li-ion diffusion within the electrode materials during lithiation/delithiation process. Further, the properties (electrical, Li-storage, and surface) of MMO NFs have been tuned by creating oxygen defects in them. The oxygen defects are generated by heat treatment at different temperatures (450, 600, and 750 °C). XPS and EPR analysis revealed the presence of a higher concentration of oxygen defects in MMO-600 NFs compared to their counterparts. These defects lead to facile Li-kinetics during the cycling process at high current density and, thus, provide good rate performance (228 mAh g−1 at 5 A g−1) and notable cyclability (817 mAh g−1 at 1 A g−1 after 400 cycles) in MMO-600 electrode. Further, the viable strategy of employing the compounds that contain metal ions which can undergo the Li-cycling via both conversion and alloying-de-alloying reactions to achieve maximum and stable capacity of a given compound has been proven for Mn-based oxide system, such as ZnxMg1−xMn2O4 (x = 0.1, 0.25, and 0.5). As an anode for LIB, MMO NFs with 0.5 mol of Zn exhibits good cyclic stability (947 mAh g−1 at 50 mA g−1 after 100 cycles and 186 mAh g−1 at 2.5 A g−1 after 2000 cycles) and improved electrochemical potential (1.27 V vs Li/Li+). For the commercial viability of MMO and Zn-doped MMO NFs anode, full cell performances were investigated against the binder-free LiNi1/3Mn1/3Co1/3O2 (NMC) cathode. The energy densities for the NMC//MMO and NMC//Zn-doped MMO are calculated to be 166 and 180 Wh Kg−1 (as per total active mass of anode and cathode), respectively. These obtained energy densities are found to be better than many reported full cells in the literature and are comparable to the commercial products. Hence, in this study, we have observed that all the strategies coupled with each other enable the high-performance in Mn-based oxides as binder-free anode for next-generation LIBs. 2024-01-01T00:00:00Z http://localhost:8081/jspui/handle/123456789/20406 Title: INORGANIC HALIDE PEROVSKITE NANOCRYSTALS FOR OPTOELECTRONICS APPLICATION Authors: Suhail, Atif Abstract: The work presented in this thesis discusses the significance of halide perovskite nanocrystals (NCs) in the field of optoelectronics. Halide perovskites are materials with the chemical formula ABX3, where A represents an organic or inorganic cation, B denotes a metal cation, and X is a halide ion. These nanocrystals exhibit remarkable optical and photoelectric properties, making them appealing for various applications because of their low cost and simple synthesis. Halide perovskite structures are categorized into organometallic halide perovskites (OHPs) and inorganic halide perovskites (IHPs) based on the type of A ion present. OHPs have shown promise but face challenges due to their instability, sensitivity to environmental factors, and low lattice energies. In contrast, IHPs, which replace organic functional groups with inorganic cations, exhibit improved stability and are considered more suitable for practical applications. A pioneering study by Protesescu et al. in 2015 focused on inorganic halide perovskite nanocrystals (IHPNCs). They successfully synthesized CsPbX3 (X = Cl, Br, I) NCs with controlled bandgap energies, tunable emission, and remarkable stability. This work generated increased interest among researchers in IHPNCs for their unique properties. IHPNCs have drawn significant focus in recent years due to their improved stability, superior photophysical properties, and defect-tolerant nature, which allows for high carrier mobility and efficient charge transport in various optoelectronic devices. The bandgap and size of halide perovskite NCs can be tuned through various approaches, including cation/anion exchange, ligand modification, and precursor concentration adjustment. Several approaches have been made to improve the stability of the perovskite NCs, including the perovskite NCs-polymer composite, with limited success. The exciton binding energy, a critical parameter for optoelectronic materials, is examined in this thesis which is not well understood due to the wide variation of structural properties. It determines the material's response to excitation and influences its optical characteristics. The research problem and motivation are presented, emphasizing halide perovskite nanocrystal research progress and its potential applications. However, challenges related to stability and optical properties persist. The research objectives include improving the stability and photoluminescence of perovskite NCs, understanding their structural and optical properties, and exploring their potential applications in photodetectors. This thesis highlights the growing interest in halide perovskite nanocrystals for their exceptional optical and electronic properties. 2024-01-01T00:00:00Z http://localhost:8081/jspui/handle/123456789/20224 Title: FABRICATION OF TRANSITION METAL NITRIDE THIN FILM BASED BIOCOMPATIBLE AND FLEXIBLE SUPERCAPACITORS Authors: Sharma, Siddharth Abstract: The development of energy sources for implantable biomedical electronics has allowed the devices to be deployed effectively and to treat disease in humans. Implanted medical devices provide continuous monitoring and therapy on a regular schedule or based on patient needs (biological investigation, prognosis, and diagnosis). There are currently millions of implantable medical devices available worldwide for serving/helping living body for better health. Most of them rely on a permanent and sufficient power supply. Unfortunately, the non-biocompatibility of these energy sources can severely affect the wearer's life. The concept of flexible electronic devices that will exist in the near future is fascinating. Implantable devices are predicted to be a feature of the next generation of electronics. They are becoming increasingly popular because of the increasing number of chronic disease patients, health monitoring initiatives and population of elderly people. Researchers have recently published several studies examining the bio-implantable components of microchips, heart valves, and artificial organ transplants that can be used as biological transplants for chronic diseases. To revolutionize the field of implantable devices and raise living standards, it will be necessary to fabricate inexpensive, biocompatible, reliable, and long-lasting energy storage devices. With the rapidly increasing demand for wearable, implantable, and portable electronic energy storage devices, the fabrication and design of energy storage devices are becoming essential. In a wearable and implantable electronic device, a flexible supercapacitor with a prolonged life span, high biocompatibility, and exceptional electrochemical performance would be ideal. Therefore, it is imperative in this regard to utilize thin-film-based flexible and biocompatible supercapacitors. Smart supercapacitors are an efficient energy storage solution to the growing energy demands from technology commercialization, as we strive to pursue a future with sustainable and efficient energy. Supercapacitors have emerged as promising candidates for these applications due to their high-power density, fast charge/discharge rates, and long cycle life. They have become a promising energy storage technology for a variety of applications, including wearable and implantable medical devices. The development of flexible and biocompatible supercapacitors is crucial for the advancement of such devices, as it allows for conformal and comfortable integration with the human body. One of the key challenges in developing such devices is the limited availability of suitable electrode materials that offer high conductivity, stability, and biocompatibility. 2023-10-01T00:00:00Z http://localhost:8081/jspui/handle/123456789/20215 Title: THERAPEUTIC USE OF CuO-BIOPOLYMER BASED NANOPARTICLES FOR TARGETED DRUG DELIVERY TOWARDS BREAST CANCER Authors: Singh, Swati Abstract: Cancer remains a significant threat to human health and a critical challenge in modern clinical settings. Despite laudable strides taken towards ameliorating the lives of cancer patients, the eradication of this debilitating disease demands a thorough exploration of cutting-edge materials. Fortunately, nanomedicine has emerged as a promising avenue for innovative cancer therapeutics by enhancing current systems through the discovery of intelligent targeted nanoparticles (NPs) that can deliver chemotherapeutic agents at a sustained rate directly to cancerous cells, potentially leading to superior efficacy and reduced toxicity for treating primary as well as advanced metastatic tumors. Moreover, amalgamation of biodegradable polymers with metal oxide nanoparticles can help circumvent chemoresistance and enhance the production of reactive oxygen species (ROS), ultimately bolstering targeted therapy approach. Thus, the current thesis is an endeavor to develop copper oxide-biopolymer based nanoparticles for efficacious targeted drug delivery in the breast cancer treatment, with the goal of addressing multifunctionality in novel nanomedicines. First part of the study focusses on the synthesis of CuO nanoparticles via precipitation technique that is loaded with anticancer drug paclitaxel (PTX), and enclosed in a PHBV matrix to enhance its effectiveness. The process of PEGylation is then employed to enhance their water solubility, followed by functionalization with folic acid to enable targeted delivery. Several physicochemical characterization techniques were utilized to validate the formation of CuO-PTX@PHBV-PEG-FA nanoparticles. These NPs were efficiently taken up by cells and elicited synergistic antiproliferative effects in human breast adenocarcinoma (MCF-7) cells at lower concentrations. Hemolysis study ensure the blood biocompatibility and safety of the developed nanosystem for intravenous drug delivery. Moreover, cell-based studies confirm the induction of apoptosis by CuO-PTX@PHBV-PEG-FA NPs morphologically through enhanced ROS production and nuclear fragmentation. 2023-08-01T00:00:00Z