Browsing by Subject "Lithium-ion batteries"

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    Bayesian Optimization of Active Materials for Lithium-Ion Batteries
    (SAE, 2021-04) Valladares, Homero; Li, Tianyi; Zhu, Likun; El-Mounayri, Hazim; Tovar, Andres; Hashem, Ahmed; Abdel-Ghany, Ashraf E.; Mechanical Engineering, School of Engineering and Technology
    The design of better active materials for lithium-ion batteries (LIBs) is crucial to satisfy the increasing demand of high performance batteries for portable electronics and electric vehicles. Currently, the development of new active materials is driven by physical experimentation and the designer’s intuition and expertise. During the development process, the designer interprets the experimental data to decide the next composition of the active material to be tested. After several trial-and-error iterations of data analysis and testing, promising active materials are discovered but after long development times (months or even years) and the evaluation of a large number of experiments. Bayesian global optimization (BGO) is an appealing alternative for the design of active materials for LIBs. BGO is a gradient-free optimization methodology to solve design problems that involve expensive black-box functions. An example of a black-box function is the prediction of the cycle life of LIBs. The cycle life cannot be predicted using a simple closed-form expression but only through the cycling performance test or a numerical simulation. BGO has two main components: a surrogate probabilistic model of the black-box function and an acquisition function that guides the optimization. This research employs BGO in the design of cathode active materials for LIB cells. The training data corresponds to the initial capacity and cycle life of five coin cells with different compositions of LiNixMn2 − xO4 in their cathode, where x is the content of Ni. BGO utilizes the experimental data to identify five new compositions that can produce cells with high initial capacity and\or large cycle life. The surrogate models of the initial capacity and cycle life are Gaussian Processes. The acquisition function is the constrained multi-objective expected improvement. The results show that BGO can identify high-performance active materials for LIBs. Designers can use the data generated during the optimization to decide the composition of the next batch of active materials to be tested, i.e., guide the physical experimentation.
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    Design and Fabrication of High Capacity Lithium-Ion Batteries using Electro-Spun Graphene Modified Vanadium Pentoxide Cathodes
    (2019-08) Ahmadian, Amirhossein; Agarwal, Mangilal; Xie, Jian; Dalir, Hamid
    Electrospinning has gained immense interests in recent years due to its potential application in various fields, including energy storage application. The V2O5/GO as a layered crystal structure has been demonstrated to fabricate nanofibers with diameters within a range of ~300nm through electrospinning technique. The porous, hollow, and interconnected nanostructures were produced by electrospinning formed by polymers such as Polyvinylpyrrolidone (PVP) and Polyvinyl alcohol (PVA), separately, as solvent polymers with electrospinning technique. In this study, we investigated the synthesis of a graphene-modified nanostructured V2O5 through modified sol-gel method and electrospinning of V2O5/GO hybrid. Electrochemical characterization was performed by utilizing Arbin Battery cycler, Field Emission Scanning Electron Microscopy (FESEM), X-ray powder diffraction (XRD), Thermogravimetric analysis (TGA), Mercury Porosimetry, and BET surface area measurement. As compared to the other conventional fabrication methods, our optimized sol-gel method, followed by the electrospinning of the cathode material achieved a high initial capacity of 342 mAh/g at a high current density of 0.5C (171 mA/g) and the capacity retention of 80% after 20 cycles. Also, the prepared sol-gel method outperforms the pure V2O5 cathode material, by obtaining the capacity almost two times higher. The results of this study showed that post-synthesis treatment of cathode material plays a prominent role in electrochemical performance of the nanostructured vanadium oxides. By controlling the annealing and drying steps, and time, a small amount of pyrolysis carbon can be retained, which improves the conductivity of the V2O5 nanorods. Also, controlled post-synthesis helped us to prevent aggregation of electro-spun twisted nanostructured fibers which deteriorates the lithium diffusion process during charge/discharge of batteries.
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    Effect of Cationic (Na+) and Anionic (F-) Co-Doping on the Structural and Electrochemical Properties of LiNi1/3Mn1/3Co1/3O2 Cathode Material for Lithium-Ion Batteries
    (MDPI, 2022-06-17) Wang, Hua; Hashem, Ahmed M.; Abdel-Ghany, Ashraf E.; Abbas, Somia M.; El-Tawil, Rasha S.; Li, Tianyi; Li, Xintong; El-Mounayri, Hazim; Tovar, Andres; Zhu, Likun; Mauger, Alain; Julien, Christian M.; Mechanical and Energy Engineering, School of Engineering and Technology
    Elemental doping for substituting lithium or oxygen sites has become a simple and effective technique to improve the electrochemical performance of layered cathode materials. Compared with single-element doping, this work presents an unprecedented contribution to the study of the effect of Na+/F- co-doping on the structure and electrochemical performance of LiNi1/3Mn1/3Co1/3O2. The co-doped Li1-zNazNi1/3Mn1/3Co1/3O2-zFz (z = 0.025) and pristine LiNi1/3Co1/3Mn1/3O2 materials were synthesized via the sol-gel method using EDTA as a chelating agent. Structural analyses, carried out by X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy, revealed that the Na+ and F- dopants were successfully incorporated into the Li and O sites, respectively. The co-doping resulted in larger Li-slab spacing, a lower degree of cation mixing, and the stabilization of the surface structure, which substantially enhanced the cycling stability and rate capability of the cathode material. The Na/F co-doped LiNi1/3Mn1/3Co1/3O2 electrode delivered an initial specific capacity of 142 mAh g-1 at a 1C rate (178 mAh g-1 at 0.1C), and it maintained 50% of its initial capacity after 1000 charge-discharge cycles at a 1C rate.
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    Fabrication and Characterization of Lithium-ion Battery Electrode Filaments Used for Fused Deposition Modeling 3D Printing
    (2022-08) Kindomba, Eli; Zhang, Jing; Zhu, Likun; Schubert, Peter
    Lithium-Ion Batteries (Li-ion batteries or LIBs) have been extensively used in a wide variety of industrial applications and consumer electronics. Additive Manufacturing (AM) or 3D printing (3DP) techniques have evolved to allow the fabrication of complex structures of various compositions in a wide range of applications. The objective of the thesis is to investigate the application of 3DP to fabricate a LIB, using a modified process from the literature [1]. The ultimate goal is to improve the electrochemical performances of LIBs while maintaining design flexibility with a 3D printed 3D architecture. In this research, both the cathode and anode in the form of specifically formulated slurry were extruded into filaments using a high-temperature pellet-based extruder. Specifically, filament composites made of graphite and Polylactic Acid (PLA) were fabricated and tested to produce anodes. Investigations on two other types of PLA-based filament composites respectively made of Lithium Manganese Oxide (LMO) and Lithium Nickel Manganese Cobalt Oxide (NMC) were also conducted to produce cathodes. Several filaments with various materials ratios were formulated in order to optimize printability and battery capacities. Finally, flat battery electrode disks similar to conventional electrodes were fabricated using the fused deposition modeling (FDM) process and assembled in half-cells and full cells. Finally, the electrochemical properties of half cells and full cells were characterized. Additionally, in parallel to the experiment, a 1-D finite element (FE) model was developed to understand the electrochemical performance of the anode half-cells made of graphite. Moreover, a simplified machine learning (ML) model through the Gaussian Process Regression was used to predict the voltage of a certain half-cell based on input parameters such as charge and discharge capacity. The results of this research showed that 3D printing technology is capable to fabricate LIBs. For the 3D printed LIB, cells have improved electrochemical properties by increasing the material content of active materials (i.e., graphite, LMO, and NMC) within the PLA matrix, along with incorporating a plasticizer material. The FE model of graphite anode showed a similar trend of discharge curve as the experiment. Finally, the ML model demonstrated a reasonably good prediction of charge and discharge voltages.
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    Multi-scale analysis of cathode microstructural effects on electrochemical and stress responses of lithium-ion batteries
    (Elsevier, 2022-11-15) Lee, Yoon Koo; Park , Juhyun; Shin, Hosop; Mechanical and Energy Engineering, School of Engineering and Technology
    The electrochemical and stress responses of lithium-ion batteries (LIBs) are highly dependent on the three-dimensional (3D) microstructure of electrodes, and substantial fundamental research is required to optimize the electrode design for high-energy, high-power LIBs with fast charging capabilities. Herein, we report a multi-scale LIB model that enables the examination of full-cell battery performance while investigating the detailed electrochemical and stress responses of the cathode using the variational multi-scale enrichment method. With the high computational efficiency of the developed model, the cathode microstructural effects were studied systematically by varying the particle size, volume fraction, and particle arrangement of 3D cathode microstructures at different C-rates. The results show that the arrangement of active material particles and their interconnectivity, rather than the particle size itself, are the determining factors for the spatial lithium-ion concentration and stress distribution of the cathode, affecting the overall electrochemical performance of LIBs. Our study provides valuable insights into the design and optimization of the cathode architecture to maximize the electrochemical performance under different operating conditions.
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    Paper-Based Lithium-Ion Battery
    (Office of the Vice Chancellor for Research, 2013-04-05) Aliahmad, Nojan; Agarwal, Mangilal; Shrestha, Sudhir; Varahramyan, Kody
    Lithium-ion batteries have a wide range of applications including present day portable consumer electronics and large-scale energy storage. Realization of these batteries in flexible, light-weight forms will further expand the usage in current and future innovative electronic devices. Lithium titanium oxide (Li4Ti5O12), lithium magnesium oxide (LiMn2O4) and lithium cobalt oxide (LiCoO2) materials have been consistently studied for application in high capacity batteries, and thus considered in the devices that are presented in the poster. Carbon nanotube (CNT) coated wood microfiber papers are used as current collectors, which provide high surface area, flexibility, and texture of paper, with low CNT utilization (10.1μg/cm2). The CNT microfiber paper is fabricated by layer-by-layer (LbL) nano-assembly of CNT over cellulose microfibers. Results from paper-based half-cell batteries show capacities of 130 mAh/g for LiMn2O4, 150 mAh/g for LiCoO2, and 158 mAh/g for Li4Ti5O12 at C/5 rate. These results are comparable with metallic electrode based cells. The fabrication of CNT microfiber paper, assembly of batteries, experimental methods, and results are presented and discussed.
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    Silver Nanocoating of LiNi0.8Co0.1Mn0.1O2 Cathode Material for Lithium-Ion Batteries
    (MDPI, 2023-04-23) Li, Xintong; Chang, Kai; Abbas, Somia M.; El-Tawil, Rasha S.; Abdel-Ghany, Ashraf E.; Hashem, Ahmed M.; Wang, Hua; Coughlin, Amanda L.; Zhang, Shixiong; Mauger, Alain; Zhu, Likun; Julien, Christian M.; Mechanical and Energy Engineering, School of Engineering and Technology
    Surface coating has become an effective approach to improve the electrochemical performance of Ni-rich cathode materials. In this study, we investigated the nature of an Ag coating layer and its effect on electrochemical properties of the LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode material, which was synthesized using 3 mol.% of silver nanoparticles by a facile, cost-effective, scalable and convenient method. We conducted structural analyses using X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy, which revealed that the Ag nanoparticle coating did not affect the layered structure of NCM811. The Ag-coated sample had less cation mixing compared to the pristine NMC811, which could be attributed to the surface protection of Ag coating from air contamination. The Ag-coated NCM811 exhibited better kinetics than the pristine one, which is attributed to the higher electronic conductivity and better layered structure provided by the Ag nanoparticle coating. The Ag-coated NCM811 delivered a discharge capacity of 185 mAh·g-1 at the first cycle and 120 mAh·g-1 at the 100th cycle, respectively, which is better than the pristine NMC811.