Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 156-167).

Thesis (M. S.)--Chemical Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Kohl, Paul; Committee Member: Fuller, Tom; Committee Member: Gray, Gary; Committee Member: Liu, Meilin; Committee Member: Meredith, Carson; Committee Member: Rincon-Mora, Gabriel.

Li-ion batteries have become one of the chosen energy storage devices that are used in applications such as power tools, cellular phones and electric vehicles (EV). With the demand for portable high energy density devices, the rechargeable Li-ion battery has become one of the more viable energy storage systems for large scale commercial EVs because of their higher energy density to weight or volume ratio when compared to other current commercial battery energy storage systems. Various safety procedures for the use of Li-ion batteries in both consumer and EV applications have been developed by the international associations. The test procedures studied in this dissertation demonstrated the importance of determining the true capacity of a cell at various discharge rates. For this, the well known Peukert test was demonstrated. The study also showed that cells with different battery geometries and chemistries would demonstrate different thermal heating during discharge and slightly different Ragone results if different test methods were used as reported in the literature. Accelerated ageing tests were done on different cells at different Depth-of-Discharge (DoD) regions. The different DoD regions were determined according to expected stresses the electrode material in a cell would experience when discharged to specific DoD that follows the discharge voltage profile. Electrochemical Impedance Spectroscopy (EIS) was used to measure various electrochemical changes within these cells. The EIS results showed that certain observed modelled parameters would change similarly to the ageing of the cell as it aged due to the accelerated testing. EIS was also done on cells at different State-of-Charge (SoC) and temperatures. The results showed that EIS can be used as an effective technique to observe changes within a Li-ion cell as the SoC or temperature changed. For automotive vehicles that are powered by a fuel cell or battery, a supercapacitor can be coupled to a battery in order to increase and optimize the energy and power densities of the drive systems. A test procedure in the literature that evaluated the use of capacitors with Pb-acid batteries was applied to Li-ion type cells in order to quantify the increased power due to the use of a supercapacitor with a Li-ion cell. Both a cylindrical LiCoO2 cell and a VRLA Pb-acid cell showed some additional charge acceptance and delivery when connected to the supercapacitors. A LiMn2O4 pouch cell showed significant charge acceptance and delivery when connected to supercapacitors. The amount of additional charge acceptance and delivery of the different combinations could be explained by EIS, in particular, the resistance and capacitance of the cell in comparison to the combination of the cell and supercapacitor. A large capacity LiCoO2 cell showed high charge acceptance and delivery without connection with a supercapacitor. The study proved that EIS can be used to model the changes within cells under the different conditions and using different test procedures.

Thesis (Ph.D.(Physics)) -- University of Limpopo, 2020 / We employ molecular dynamics simulations, using DL_POLY code, to study the structural behaviour of β-MnO2 cathode material during discharging through lithium-ion intercalation into the bulk, nanoparticle, nanorod, nanosheet, and nanoporous β-MnO2. It is shown that lithium-ions have an average coordination number of about 5.70 and prefer surface sites with high oxygen coordination. The average lattice parameter values at intercalation of 0.85 Li/Mn are found to be under 4% relative to the experimental values obtained at 0.92 Li/Mn. Moreover, all the lithiated β-MnO2 structures did not collapse at 0.85 Li/Mn as observed in the β-MnO2 mesoporous in experimental work. As lithium is limited, sodium is a good alternative charge carrier in lithium-ion batteries. As a result, we have also performed studies on sodium intercalation into bulk, nanoparticle, nanorod, nanosheet and nanoporous β-MnO2. The microstructures and radial distribution functions show that the β-MnO2 structures could be intercalated up to 0.24 Na/Mn without any obvious structural degradation. Beyond this sodium concentration, the microstructure collapses and become amorphous thus predicting a potentially lower capacity for Na-MnO2-β batteries. Also, as the voltage is an important factor in the energy density of lithium-ion batteries, we have studied the trends in the average intercalation potentials in relation to the various nano architectures. The trend, in increasing value of average intercalation potentials, were found to be bulk structure, nanorod, nanosheet, nanoporous and nanoparticle. This suggests that nanostructuring can enhance cell voltage. Mechanical properties studies on the pure and lithiated bulk and nanorod β-MnO2 were also performed through uniaxial compressive and tensile strain application. The results show that under compressive strain the bulk structure and nanorod mitigate stress through the contraction and collapse of the inherent tunnel structures, known to cause electrochemical inactivity, and also through the shifting of the MnO6 octahedral planes. The collapsing of tunnels was found to occur more on the bulk structure and less on the nanorod, while the MnO6 octahedral plane shifts were found to occur more on the nanorod and less on the bulk structure. Unoccupied 1x2 or conjoined 1x2 were found to result in structural collapse irrespective of the host nanoarchitecture. The X-ray diffraction pattern (v) plots suggest that lithium intercalation and compressive stress application have a similar impact on the underlying structure of the various nanostructures. The microstructure analysis for bulk β-MnO2 under tensile strain reveals that fracture occurred in the brookite region and along the dislocation/stacking fault. The nanorod β-MnO2 mitigated stress through a rutile-to-brookite phase transition which occurred in the unstrained Li0.73MnO2-β and under tensile strain in LixMnO2-β for x = 0.00, 0.03, 0.12, and 0.24. In both the bulk and nanorod β-MnO2 the brookite phase was succeeded by structural breakdown leading to fracture and served as an indicator for imminent structural failure upon more tensile strain application. / National Research Foundation (NRF)

Materiais automontados de V2O5, polialilamina (PAH) e nanopartículas de prata (AgNP) foram preparados pelo método camada-por-camada, visando a sua aplicação em baterias de íon-lítio e dispositivos eletrocrômicos. O método adotado permitiu o crescimento linear de filmes visualmente homogêneos de V2O5, V2O5/PAH e V2O5/PAH/AgNP com 15 bicamadas, como observado a partir de microscopia eletrônica de varredura (MEV) e espectroscopia eletrônica na região do visível. De acordo com os espectros de infravermelho com transformada de Fourier (FTIR), verificou-se que a interação entre o oxigênio do grupo vanadila e o grupo amino deve ser responsável pelo crescimento destes filmes, além de permitir uma blindagem eletrostática entre os íons lítio e os sítios com maior densidade de carga negativa, aumentando a velocidade difusional e, consequentemente, aumentando a capacidade de armazenamento de energia e diminuição do tempo de resposta. Resultados eletroquímicos e espectroeletroquímicos mostraram que a presença das AgNPs estabilizadas no PAH aumentou a capacidade de carga do eletrodo, propiciando novos caminhos condutores e aumentando o número de sítios eletroativos na matriz hospedeira. Espontaneamente, novas nanoarquiteturas com interações específicas foram formadas pelo método camada-por-camada, garantindo uma maior velocidade de transporte de massa e transferência de carga em eletrodos para baterias de lítio e dispositivos eletrocrômicos. / Self-assembled Materials from V2O5, polyallylamine (PAH) and silver nanoparticles (AgNP) were prepared by layer-by-layer method, aiming at its application in lithium-ion batteries and electrochromic devices. The adopted method allowed the linear growth of visually homogeneous films from V2O5, and V2O5/PAH, V2O5/PAH/AgNP with 15 bilayers. This was observed from scanning electron microscopy (SEM) and electronic spectroscopy in the visible region. According to the Fourier transform infrared (FTIR) spectra, it was found that the interaction between vanadyl groups oxygen and the amino group should be responsible for the growth of these films. Besides, this interaction allowed an electrostatic shield between the lithium ions and the sites with higher negative charge, increasing the ionic speed and diffusion, thereby increasing energy storages capacity and response times reduction. Electrochemical and spectroelectrochemical results showed that the presence of AGNPs stabilized in PAH increased the electrodes capacity, providing new path-ways and increasing the number of electroactive sites in the host matrix. Spontaneously, new nanoarchitectures to specific interactions were formed by the layer-by-layer method, ensuring a higher rate of mass transport and charge transfer in electrodes for lithium batteries and electrochromic devices application.

Thesis (Ph. D.)--State University of New York at Binghamton, Materials Science and Engineering Program, 2009. / Includes bibliographical references.

In this work, a hybrid power module comprising of a direct methanol fuel cell (DMFC) and a Li-ion battery has been proposed for low power applications. The challenges associated with low power and small DMFCs were investigated and the performance of commercial Li-ion batteries was evaluated. At low current demand (or low power), methanol leakage through the proton exchange membrane (PEM) reduces the efficiency of a DMFC. Consequently, a proton conducting methanol barrier layer made from phospho-silica glass(PSG) was developed. At optimized deposition conditions, the PSG layers had low methanol permeability and moderate conductivity. The accumulation of CO2 inside the fuel tank was addressed by fabricating CO2 vents. Poly (dimethyl siloxane) (PDMS) and poly (1-trimethyl silyl propyne) (PTMSP) base polymers were used as the backbone material for these vents. The selectivity of CO2 transport through the vent was further enhanced by using additives like 1, 6-divinylperfluorohexane. Finally, the effects of self-discharge and voltage loss were evaluated for Panasonic coin cells and thin film LiPON cells. It was observed that the thin film battery outperformed the others in terms of low energy loss. Nonetheless, the performance of small Panasonic coin cells with vanadium oxide cathode was comparable at low discharge rates of less than 0.01% depth of discharge. Lastly, it was also observed that the batteries have stable cycles at low discharge rates.

Materiais automontados de V2O5, polialilamina (PAH) e nanopartículas de prata (AgNP) foram preparados pelo método camada-por-camada, visando a sua aplicação em baterias de íon-lítio e dispositivos eletrocrômicos. O método adotado permitiu o crescimento linear de filmes visualmente homogêneos de V2O5, V2O5/PAH e V2O5/PAH/AgNP com 15 bicamadas, como observado a partir de microscopia eletrônica de varredura (MEV) e espectroscopia eletrônica na região do visível. De acordo com os espectros de infravermelho com transformada de Fourier (FTIR), verificou-se que a interação entre o oxigênio do grupo vanadila e o grupo amino deve ser responsável pelo crescimento destes filmes, além de permitir uma blindagem eletrostática entre os íons lítio e os sítios com maior densidade de carga negativa, aumentando a velocidade difusional e, consequentemente, aumentando a capacidade de armazenamento de energia e diminuição do tempo de resposta. Resultados eletroquímicos e espectroeletroquímicos mostraram que a presença das AgNPs estabilizadas no PAH aumentou a capacidade de carga do eletrodo, propiciando novos caminhos condutores e aumentando o número de sítios eletroativos na matriz hospedeira. Espontaneamente, novas nanoarquiteturas com interações específicas foram formadas pelo método camada-por-camada, garantindo uma maior velocidade de transporte de massa e transferência de carga em eletrodos para baterias de lítio e dispositivos eletrocrômicos. / Self-assembled Materials from V2O5, polyallylamine (PAH) and silver nanoparticles (AgNP) were prepared by layer-by-layer method, aiming at its application in lithium-ion batteries and electrochromic devices. The adopted method allowed the linear growth of visually homogeneous films from V2O5, and V2O5/PAH, V2O5/PAH/AgNP with 15 bilayers. This was observed from scanning electron microscopy (SEM) and electronic spectroscopy in the visible region. According to the Fourier transform infrared (FTIR) spectra, it was found that the interaction between vanadyl groups oxygen and the amino group should be responsible for the growth of these films. Besides, this interaction allowed an electrostatic shield between the lithium ions and the sites with higher negative charge, increasing the ionic speed and diffusion, thereby increasing energy storages capacity and response times reduction. Electrochemical and spectroelectrochemical results showed that the presence of AGNPs stabilized in PAH increased the electrodes capacity, providing new path-ways and increasing the number of electroactive sites in the host matrix. Spontaneously, new nanoarchitectures to specific interactions were formed by the layer-by-layer method, ensuring a higher rate of mass transport and charge transfer in electrodes for lithium batteries and electrochromic devices application.

The newly emerging Stimulated Raman Scattering (SRS) Microscopy has been proved to be a powerful tool in biomedical research. This advanced imaging platform offers high spatiotemporal resolution and chemical specificity, which greatly empowers the label-free biomedical imaging and small molecule metabolite tracing. Throughout the research introduced in this thesis, we focus on the exploration of more applications of SRS microscopy beyond aforementioned. Particularly, this new expedition involves more chemistry and answered two major questions: what SRS can do for chemistry and what chemistry can do for SRS. Chapter 1 introduces the basics of SRS microscopy, such as the physical fundamentals and start-of-art instrumentations. Besides, this chapter discusses the design principles of vibrational reporters through a chemistry view. Chapter 2 introduces one of the major progresses of SRS microscopy beyond biomedical study. We use SRS microscopy to study the ion transportation and concentration polarization phenomena in lithium metal batteries (LMBs), with a strong focus in solid-state polymer electrolyte. A self-induced phase separation process over lithium metal electrode is observed and correlated with local lithium ion concentrations, which inspires a protection mechanism for durable LMB design. Chapter 3 discusses the use of SRS microscopy for in-vivo drug tracing in mammalian cells. A novel alkyne tag is incorporated into bio-engineered natural depsi-peptides and serves as Raman reporter. The mode-of-action of the labeled drug is visualized with SRS microscopy. Chapter 4 heavily focuses on the development of synthetic molecular probes for super-multiplexed optical imaging. We systematically synthesize a library of molecular probes based on 9-cyanopyronin, and their Raman features are characterized to build a model that correlates photophysical properties with structures. The Raman shifts of probes can be tuned with high precision. The multiplexing capability of the new library is demonstrated in labeling fixed and living cell samples.

This master´s thesis deals with stability of electrolytes and electrodes using electrochemical methods of Li-ion batteries. The first part of the project is devoted to the characteristics of Li-ion batteries, electrochemical reactions and characteristics of electrode materials. Consenquetial part is concentrated on preparation and measurement of elektrolyte EC : DMC with 1M LiPF6. The elektrolyte was investigated using galvanostatic method, cyclic voltammetry and impedance spectroscopy.