Development of Quantitative Techniques for Lithium Compounds for Next Generation Batteries with Focused Ion Beam Scanning Electron Microscopy PDF Download
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Author: Ste̹phanie Bessette
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
"Electric vehicles have started to make their appearance in the transportation industry. At Quebec's scale especially, since electricity is already sustained by an extensive network of dams and reservoir, Hydro-Quebec puts a lot of focus towards green gas emission reduction via transportation electrification. To be widely accepted, batteries used in electric vehicles must have high ranges, long durability, be safe and an economical choice in the long run for its user to abandon gasoline-powered automobiles. In that matter, the company's Center of Excellence in Transportation Electrification and Energy Storage works tirelessly on the development of new generation battery materials using elements available in large quantities, with high performance chemistry. Materials characterization with Scanning Electron Microscopy is one of the most important steps in developing new materials, since it links the microstructure of the material to its fabrication process and properties down to the nanometer scale. This study focuses on the development of quantitative techniques for lithium in battery materials since this light element is the key element in the operation of a battery. In this work energy dispersive X-ray spectroscopy (EDS), electron energy-loss spectroscopy (EELS) and secondary ion mass spectrometry are evaluated in relation to their capabilities to both detect and quantify lithium atoms in battery materials. A portable time-of-flight secondary ion mass spectrometer (TOF-SIMS) that can attach to a standard dual beam microscope(FIB-SEM) was found to fulfill both aspects while allowing high resolution imaging andchemical analysis of the samples. An experimental calibration curve of lithium content in standard nickel cobalt manganese oxide cathodes was built using TOF-SIMS detector. The calibration curve allows identification of lithium content in cathodes with different state of charge and according to different charging rates. TOF-SIMS allows visualization of ionic distributions in material. Furthermore, it can help observe differences in crystallographic orientation with respect to the beam in between primary particles and permits identification of chemical hotspots of lithium." --
Author: Ste̹phanie Bessette
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
"Electric vehicles have started to make their appearance in the transportation industry. At Quebec's scale especially, since electricity is already sustained by an extensive network of dams and reservoir, Hydro-Quebec puts a lot of focus towards green gas emission reduction via transportation electrification. To be widely accepted, batteries used in electric vehicles must have high ranges, long durability, be safe and an economical choice in the long run for its user to abandon gasoline-powered automobiles. In that matter, the company's Center of Excellence in Transportation Electrification and Energy Storage works tirelessly on the development of new generation battery materials using elements available in large quantities, with high performance chemistry. Materials characterization with Scanning Electron Microscopy is one of the most important steps in developing new materials, since it links the microstructure of the material to its fabrication process and properties down to the nanometer scale. This study focuses on the development of quantitative techniques for lithium in battery materials since this light element is the key element in the operation of a battery. In this work energy dispersive X-ray spectroscopy (EDS), electron energy-loss spectroscopy (EELS) and secondary ion mass spectrometry are evaluated in relation to their capabilities to both detect and quantify lithium atoms in battery materials. A portable time-of-flight secondary ion mass spectrometer (TOF-SIMS) that can attach to a standard dual beam microscope(FIB-SEM) was found to fulfill both aspects while allowing high resolution imaging andchemical analysis of the samples. An experimental calibration curve of lithium content in standard nickel cobalt manganese oxide cathodes was built using TOF-SIMS detector. The calibration curve allows identification of lithium content in cathodes with different state of charge and according to different charging rates. TOF-SIMS allows visualization of ionic distributions in material. Furthermore, it can help observe differences in crystallographic orientation with respect to the beam in between primary particles and permits identification of chemical hotspots of lithium." --
Author: William Huang
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Lithium-ion batteries are common in everyday life, while being strategically critical to the decarbonization and electrification of transportation. To meet higher range demands and lower costs per kWh of storage, higher energy density battery chemistries relying on new anode chemistries such as silicon or lithium metal are needed. These new chemistries are attractive for commercialization, but their deployment is hindered by a lack of understanding of their degradation and failure modes, which are dominated by a poorly understood structure on the anode surface called the solid-electrolyte interphase (SEI). Recent breakthroughs in cryogenic transmission electron microscopy (cryo-TEM) now enable the characterization of this highly reactive and radiation sensitive structure, allowing new insight and understanding to be developed towards practical silicon and lithium metal anodes. My PhD dissertation entails the use of cryo-TEM to gain functional insight into the degradation of these materials, which may provide guidance and design rules for practical next-generation lithium battery chemistries. In Chapter 1, I will give an overview of modern lithium-ion batteries, their history and shortcomings, and motivate the need for higher capacity silicon and lithium metal anodes. Chapter 2 will introduce the technique of transmission electron microscopy, an immensely powerful technique for the structural and chemical characterization of materials with atomic resolution, along with the need for cryogenic stabilization when used with lithiated anode materials. Chapter 3 will show how cryo-TEM can be used to derive new insight into the failure modes of the silicon anode, along with the working mechanism of electrolyte additives. Chapter 4 will move beyond lithium-ion chemistries, where I will show how cryo-TEM can be used to refine the SEI nanostructure of the Li metal anode beyond conventional models derived from surface analysis techniques such as x-ray photoelectron spectroscopy. In Chapter 5, I will investigate the capacity loss of the lithium metal anode during storage, a critical parameter for electric vehicles, and use cryo-TEM to elucidate the nanoscopic origins of the rapid capacity loss during storage. Finally, in Chapter 6, I will conclude the dissertation with broader insights gained from my studies and an outlook for the battery field, and how cryo-TEM can fit within the suite of modern battery characterization tools.
Author: Simon Greiner
Publisher: Springer Nature
ISBN: 3658289856
Category : Science
Languages : en
Pages : 107
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Book Description
Simon Greiner investigates the molecular-level stabilization of polyoxovanadate (POV) compounds by rational design for the application as active cathode material in lithium-ion batteries. Formation of a complex hydrogen-bonding network locks the POVs in place and prevents thermal decomposition during electrode fabrication. The molecular vanadium oxide clusters can be electrochemically analyzed and show promising results for storage of multiple electrons per cluster, making these materials highly attractive for energy storage applications. Analytical methods comprise ATR-FTIR, powder and single-crystal XRD, electron microscopy, EDX, electrochemical analysis and battery testing.
Author: Cai Shen
Publisher: CRC Press
ISBN: 1000867641
Category : Science
Languages : en
Pages : 533
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Book Description
The past three decades have witnessed the great success of lithium-ion batteries, especially in the areas of 3C products, electrical vehicles, and smart grid applications. However, further optimization of the energy/power density, coulombic efficiency, cycle life, charge speed, and environmental adaptability are still needed. To address these issues, a thorough understanding of the reaction inside a battery or dynamic evolution of each component is required. Microscopy and Microanalysis for Lithium-Ion Batteries discusses advanced analytical techniques that offer the capability of resolving the structure and chemistry at an atomic resolution to further drive lithium-ion battery research and development. • Provides comprehensive techniques that probe the fundamentals of Li-ion batteries. • Covers the basic principles of the techniques involved as well as its application in battery research. • Describes details of experimental setups and procedure for successful experiments. This reference is aimed at researchers, engineers, and scientists studying lithium-ion batteries including chemical, materials, and electrical engineers, as well as chemists and physicists.
Author: Ali Ghorbani Kashkooli
Publisher:
ISBN:
Category : Lithium ion batteries
Languages : en
Pages : 189
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Book Description
Because of their high energy/power density, long cycle life, and extremely low rate of self-discharge, lithium-ion batteries (LIBs) have dominated portable electronics, smart grid, and electric vehicles (EVs). Although they are the most developed and widely applied energy storage technology, there is still a strong desire to further enhance their energy/power density, cycle life, and safety. While all of these battery requirements are macroscopic and stated at cell/pack scale, they have to be addressed at particle or network of particles scale (mesoscale). At mesoscale, active material particles having different shape and morphologies are bound together with a carbon-doped polymer binder layer. This percolated network of particles serves as the electron conductive path from the reaction sites to the current collector. Even though significant research has been conducted to understand the physical and electrochemical behavior of material at the nanoscale, there have not been comprehensive studies to understand what is happening at the mesoscale. Mathematical models have emerged as a promising way to shed light on complex physical and electrochemical phenomena happening at this scale. The idea of using mathematical model to study multiphysics behavior of LIBs is not new. Traditional models involved homogeneous spherical particles or computer generated electrode structures as the model geometry to simulate electrode/cell performance. While these models are successful to predict the cell performance, heterogeneous electrode's structure at mesoscale questions the accuracy of their findings related to battery internal behavior and property distribution. The new advances in the field of 3D imaging including X-ray computed tomography (XCT) and Focused-ion beam/Scanning electron microscopy (FIB-SEM), have enabled the 3D visualization of the electrode's active particles and structures. In particular, XCT has offered nondestructive imaging and matter penetration capability in short period of time. Although it was commercialized in 70's, with the recent development of high resolution (down to 20 nm) laboratory and synchrotron radiation tomography has been revolutionized. 3D reconstructed electrodes based on XCT data can provide quantitative structural information such as particle and pore size distribution, porosity, solid/electrolyte interfacial surface area, and transport properties. In addition, XCT reconstructed geometry can be easily adopted as the model geometry for simulation purposes. For this, similar to traditional models, a modeling framework based on conservation of mass/charge and electrochemistry needs to be developed. The model links the electrode performance to the real electrode's structure geometry and allows for the detailed investigation of multiphysics phenomena. When combined with mechanical stress, such models can also be used for electrode's failure and degradation studies. The work presented in this dissertation aims to adopt 3D reconstructed structures from nano-XCT as the geometry to study multiphysics behaviour of the LIBs electrodes. In addition, 3D reconstructed structure provides more realistic electrode's morphological and transport properties. Such properties can benefit the homogeneous models by providing highly accurate input parameters. In the first study, a multiscale platform has been developed to model LIB electrodes based on the reconstructed morphology. This multiscale framework consists of a microscale level where the electrode microstructure architecture is modeled and a macroscale level where discharge/charge is simulated. The coupling between two scales is performed in real time unlike using common surrogate based models for microscale. For microscale geometry 3D microstructure is reconstructed based on the nano-XCT data replacing typical computer generated microstructure. It is shown that this model can predict the experimental performance of LiFePO4 (LFP) cathodes at different discharge rates more accurately than the traditional/homogenous models. The approach employed in this study provides valuable insight into the spatial distribution of lithium within the microstructure of LIB electrodes. In the second study, a new model that keeps all major advantages of the single-particle model of LIB and includes three-dimensional structure of the electrode was developed. Unlike the single spherical particle, this model considers a small volume element of an electrode, called the Representative Volume Element (RVE), which represent the real electrode structure. The advantages of using RVE as the model geometry was demonstrated for a typical LIB electrode consisting of nano-particle LFP active material. The model was employed to predict the voltage curve in a half-cell during galvanostatic operations and validated against experimental data. The simulation results showed that the distribution of lithium inside the electrode microstructure is very different from the results obtained based on the single-particle model. In the third study, synchrotron X-ray computed tomography has been utilized using two different imaging modes, absorption and Zernike phase contrast, to reconstruct the real 3D morphology of nanostructured Li4Ti5O12 (LTO) electrodes. The morphology of the high atomic number active material has been obtained using the absorption contrast mode, whereas the percolated solid network composed of active material and carbon-doped polymer binder domain (CBD) has been obtained using the Zernike phase contrast mode. The 3D absorption contrast image revealed that some LTO nano-particles tend to agglomerate and form secondary micro-sized particles with varying degrees of sphericity. The tortuosity of the pore and solid phases were found to have directional dependence, different from Bruggeman's tortuosity commonly used in homogeneous models. The electrode's heterogeneous structure behaviour was also investigated by developing a numerical model to simulate a galvanostatic discharge process using the Zernike phase contrast mode. In the last study, synchrotron X-ray nano-computed tomography has been employed to reconstruct real 3D active particle morphology of a LiMn2O4 (LMO) electrode. For the first time, CBD has been included in the electrode structure as a 108 nm thick uniform layer using image processing technique. With this unique model, stress generated inside four LMO particles with a uniform layer of CBD has been simulated, demonstrating its strong dependence on local morphology (surface concavity and convexity), and the mechanical properties of CBD such as Young's modulus. Specifically, high levels of stress have been found in vicinity of particle's center or near surface concave regions, however much lower than the material failure limits even after discharging rate as high as 5C. On the other hand, the stress inside CBD has reached its mechanical limits when discharged at 5C, suggesting that it can potentially lead to failure by plastic deformation. The findings in this study highlight the importance of modeling LIB active particles with CBD and its appropriate compositional design and development to prevent the loss of electrical connectivity of the active particles from the percolated solid network and power losses due to CBD failure. There are still plenty of opportunities to further develop the methods and models applied in this thesis work to better understand the multiscale multiphysics phenomena happening in the electrode of LIBs. For example, in the multiscale model, microscale solid phase charge transfer and electrolyte mass/charge transfer can be included. In this way, heterogeneous distribution of current density in microscale would be achieved. Also, in both multiscale and RVE models, the exact location of CBD can be incorporated in the electrode structure to specify lithium diffusional path inside the group of particles in the solid matrix. Finally, in the fourth study, the vehicle battery driving cycle can be applied instead of galvanostatic operating condition, to mimic the stress generated inside the electrodes in real practical condition. .
Author: Thomas James Metke
Publisher:
ISBN:
Category :
Languages : en
Pages : 134
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Author: Grace Whang
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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The development of the lithium-ion battery has played an indispensable role in shaping the landscape of portable electronics and emerging electric vehicle industry. While its development has been recognized with a Nobel Prize in 2019, battery technology is far from mature. Since its conception, the battery research landscape has only widened with the rise of electric vehicles and wearable devices, each having a different set of requirements. Therefore, the "next-generation" in the context of this dissertation focuses on two different aspects of the battery field. The first aspect considers the development of high energy density batteries and more specifically the move away from capacity-limited intercalation chemistries. Chapter 3 delves into the interfacial challenges posed by lithium metal anodes during the Li plating/stripping reactions while Chapter 4 visits the complex reaction pathways in FeS2 conversion cathodes to understand charge product formation and identify capacity loss mechanisms. While both Li and FeS2 are commercialized as primary battery electrode materials and have the potential to provide high energy density rechargeable batteries, safety and performance issues have limited their use to primary systems. Ultimately, better understanding of the interfaces and reaction pathways can fuel the design of solutions to improve the performance and safety of these systems. The latter part of the dissertation focuses on the other type of "next-generation" battery, namely, that of miniaturized power sources for IoT technologies. With the vision of an on-chip battery integrated into a device, new materials and processes must be developed to integrate the same semiconductor processing techniques used to make the device to make the batteries as well. Chapter 5 details the development of a conformal, photopatternable separator and the integration of the separator onto various battery architectures. The ability to spatially photopattern a porous separator onto three dimensional architectures provides a path towards high power on-chip batteries. In summary this dissertation aims to provide perspective in the different directions and progress towards the next generation of rechargeable batteries. From better fundamental insights on complex electrochemical pathways to application-driven materials design and development, this dissertation highlights a few of the challenges, discoveries, and advancements of a much larger research landscape of "next-generation" batteries
Author: Zewen Zhang
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Electrochemical energy technologies, such as batteries, are essential for decarbonizing our economy and enabling clean energy storage for a sustainable future. Underlying the battery technology are multiple coupled dynamic processes that span many length scales including electron transport, ionic diffusion, ion solvation/desolvation, surface adsorption, interfacial evolution and interphase formation, intermediate states, and phase/chemical transformations. The advancement in scientific understanding and technological innovations for batteries entail an atomic- and molecular-resolution understanding of the key materials and fundamental processes governing the operation and failure of the systems. However, these key components are often highly sensitive and remain difficult to resolve with conventional interrogation methods. The rapid progress in cryogenic electron microscopy (cryo-EM) for physical sciences starts to offer researchers new tools and methods to probe many otherwise inaccessible length scales and time scales of components and phenomena in electrochemical energy science. Specifically, weakly bonded and reactive materials, interfaces and phases that typically degrade under high energy electron-beam irradiation and environmental exposure can potentially be protected and stabilized by cryogenic methods. Such initial efforts bring up thrilling opportunities to address many crucial yet unanswered questions in electrochemical energy science, which can eventually lead to new scientific discoveries and technological breakthroughs. My PhD dissertation entails the use and the development of cryo-EM methods for batteries to gain functional insights into the critical battery interfaces, which may provide guidance and design principles for practical next-generation lithium battery chemistries. In Chapter 1, I will give an introduction to lithium batteries on the history and current limitations, and motivate the need to resolve the interfaces with high spatial and chemical resolution. In Chapter 2, I will briefly introduce transmission electron microscopy (TEM) and cryo-EM, as well as relevant analytical capabilities for the atomic resolution of structural and chemical characterization of materials. In Chapter 3, I will show how cryo-EM can be used to derive new insights into the cathode electrolyte interphase (CEI), allowing for new engineering principles for cathode interfacial protection. In Chapter 4, I will introduce method advancement in cryo-EM for batteries in which we incorporate liquid electrolytes into the investigation, and used Li metal anode solid-electrolyte interphase (SEI) analysis as an example to show how these studies can be leveraged to refine the SEI model and guide the electrolyte design and engineering for next generation batteries. In Chapter 5, I will talk about how we advance from 2D analysis into 3D, and use cryo-EM tomography (cryo-ET) to resolve nanoscale heterogeneities developed in Li metal anodes in 3D. In Chapter 6, I will conclude the dissertation with broader insights gained from my studies and an outlook for how we could push the boundary of understanding dynamic processes during battery operations to guide the rational design of next generation batteries.
Author: Megan Diaz
Publisher:
ISBN:
Category :
Languages : en
Pages : 121
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Although the past twenty years have seen dramatic advancement in lithium-ion batteries (LIBs), these batteries are nearing their theoretical limit. Next generation energy storage technologies must therefore be developed to meet the ever-increasing demands for batteries with higher capacity, longer cycle lifetime, and increased safety. All-solid-state lithium battery (ASSLIB) technology is one of the promising candidates. It is equipped with a solid-state electrolyte (SSE) replacing the flammable organic liquid electrolyte used in current LIBs. The SSE's high modulus is expected to prevent lithium dendrites and enables the use of a lithium metal anode to contribute to its high capacity without creating safety concerns. However, many cases are reported where lithium penetrates the SSE, causing a short circuit that leads to premature failures of the battery. The fundamental mechanism of this process is still under debate. This work seeks to understand the complex electrochemomechanics at the interface between the SSE and lithium metal during the lithium plating and penetration process. To achieve this goal, a unique in situ transmission electron microscopy (TEM) technique was developed to evaluate the mechanical stress imposed at the lithium metal and SSE interface. The method was successfully used to directly observe the penetration of lithium in an SSE from a nano-scale defect at the surface, and it quantified the stress evolution in the process. A reduction in the mechanical strength of the SSE when altering the electrochemical charge/discharge bias condition was revealed. A first principles atomistic simulation was performed to confirm that disorder in the crystal structure of the SSE, both in lithium deficient and excess states, contributes to reduced mechanical properties. The results of this work suggest the importance of minimizing defects at the surface and grain boundaries to improve the stability of the SSE. Interfaces and boundaries can be bottlenecks for lithium diffusion, creating a concentration gradient. This can reduce the mechanical stabilities of the SSE, accelerating lithium penetration and degradation in ASSLIBs. The insights obtained in this study provide useful information towards understanding the dendrite growth mechanism and designing the necessary materials and structures to solve this issue, thus contributing to the advancement of energy storage technologies.
Author: Julian Kalhoff
Publisher:
ISBN:
Category :
Languages : en
Pages : 187
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Book Description
