Advances on secondary lithium ion batteries imply the use of solid polymer electrolytes, which represent a promising solution to improve safety issues in high energy density batteries. Through dissolution of lithium salts into a polymeric host, such as poly(ethylene oxide) (PEO), ion conducting polymers are obtained. The Li+ ions will be localized in the proximity of the oxygen atoms in the PEO chains and thus, their motion strongly correlated with the segmental reorientation of the polymer. Nuclear magnetic resonance (NMR) spectroscopy, translational diffusion coefficients and transverse relaxation times (T2) contribute to the understanding of the involved structures and the ongoing dynamical processes in ionic conductivity. Nuclei with different motional freedom can present different T2 times. T2xT2 exchange experiments enable studying exchange processes between nuclei from different motional regimes. In this work, three different ion conducting polymers were studied. First, PEG was doped with different amounts of LiClO4. 7Li NMR relaxometry measurements were done to study dynamical behavior of the lithium ions in the amorphous phase. All samples presented two lithium types with clearly differentiated T2 times, indicating the presence of two regions with different dynamics. The mobility and consequently the T2 times, increases with temperature. It was observed, that the doping ratio strongly influences the dynamics of the lithium ions, as the amount of crystalline PEG is reduced while increasing the polarity of the sample. A local maximum of the mobility was observed for y = 8. With the T2xT2 exchange experiments exchange rates between both lithium sites were quantified. Second, the triblock copolymer PS-PEO-PS doped with LiTFSI was studied with high resolution solid state NMR techniques as well as with 7Li relaxometry measurements. T1ρ and spin diffusion measurements gave insight on the influence of the doping and the PS/PEO ratio on the mobility of the different segments and on interdomain distances of the lamellar phases. Third, multiple quantum diffusion measurements were applied on poly(ethylene glycol) distearate (PEGD) doped with LiClO4. Therefore, triple quantum states of the 3/2 nucleus 7Li were excited. After optimizing the experimental procedure, it was possible to obtain reliable diffusion coefficients using triple quantum states. / O avanço da tecnologia em baterias secundárias de íons lítio envolve o uso de polímeros condutores iônicos como eletrólitos, os quais representam uma solução promissora para obter baterias de maior densidade de energia e segurança. Polímeros condutores são formados através da dissolução de sais de lítio em uma matriz polimérica, como o poli(óxido de etileno) (PEO). Os íons de lítio estão localizados próximos aos oxigênios do PEO, de tal forma que seu movimento está correlacionado com a reorientação das cadeias poliméricas. Espectroscopia por Ressonância magnética nuclear (RMN), junto com medidas de difusão translacional e tempos de relaxação transversal (T2) contribuem para elucidar as estruturas e os processos dinâmicos envolvidos na condutividade iônica. Núcleos com diferente liberdade de movimentação podem ter tempos de T2 diferentes. Experimentos de T2xT2 permitem correlacionar sítios de diferentes propriedades dinâmicas. Neste trabalho, três diferentes polímeros condutores iônicos foram estudados. Primeiro, PEG foi dopado com LiClO4. As propriedades dinâmicas dos íons lítio na fase amorfa foram estudadas com medidas de relaxometria por RMN do núcleo 7Li. Todas as razões de dopagem apresentaram dois T2 diferentes, indicando dos tipos de lítio com dinâmica diferente. A mobilidade, e consequentemente os tempos T2 aumentam com aumento da temperatura. Foi identificado que a dopagem fortemente influencia a dinâmica dos íons lítio, devido à redução da fase cristalina PEG e o aumento da polaridade na amostra. Um máximo local da mobilidade foi observado para y = 8. Com o experimento T2xT2 foram quantificadas as rações de troca entre os dois tipos de lítio. Segundo, o copolímero tribloco PS-PEO-PS dopado com LiTFSI foi analisado através de técnicas de RMN de estado sólido de alta resolução assim como através de medidas de relaxação de 7Li. Medidas de T1ρ e difusão de spin mostraram a influência da dopagem e da razão PS/PEO na mobilidade dos diferentes segmentos e nas distâncias interdomínio das fases lamelares. Terceiro, medidas de difusão através de estados de múltiplos quanta foram feitas em diesterato de polietileno glicol (PEGD) dopado com LiClO4. Estados de triplo quantum foram criados no núcleo 7Li, spin 3/2. Após garantir a eficiência das ferramentas desenvolvidas, foi possível obter coeficientes de difusão confiáveis.

Esta tese apresenta os resultados de estudo de eletrólitos poliméricos obtidos a partir de agar com o propósito de serem aplicados em dispositivos eletrocrômicos (ECDs). Modificações físico-químicas foram efetuadas no agar através da adição do plastificante glicerol, bem como de formaldeído, além da adição de uma fonte de prótons, a partir de ácido acético, ou uma fonte de íons, utilizando-se LiClO4, para promover a condutividade iônica dos filmes. Foram também preparadas blendas a partir de agar com gelatina, com quitosana e com poli(etileno dióxido de tiofeno):poli(estireno) (PEDOT:PSS) com o objetivo de se obter novos materiais alternativos, para serem utilizados como eletrólitos poliméricos. O estudo revelou que todas as membranas apresentaram-se homogêneas, com estabilidade térmica até 200°C e com a estrutura predominantemente amorfa, com valores de temperatura vítrea em torno de -70 °C e transparência no visível de 90%. O manuseio das amostras obtidas revelou boa maleabilidade e aderência ao vidro. Os valores de condutividade iônica das membranas variaram entre 1x10-6 S/cm e 1,1x10-4 S/cm dependendo da composição e quantidade de ácido ou sal de lítio adicionado. No caso das amostras onde foi adicionado PEDOT:PSS, os resultados de condutividade obtidos foram na ordem de 10-4 S/cm, no entanto as amostras apresentaram a transparência somente de 17%. Foi feito um estudo preliminar, de aplicação dos melhores eletrólitos em ECDs revelando mudança de coloração entre o estado colorido e transparente de 25%, reversível inserção de carga entre 11 e 5,0 mC/cm2 e tempo de coloração de 15 segundos e de descoloração de 2 s. / With the aim to develop new electrochromic devices (ECDs), we present a study on polymer electrolytes obtained from agar. Agar was submitted to physicochemical modifications by adding glycerol as plasticizer and formaldehyde; besides, to promote ionic conductivity of the films, a proton source such as acetic acid, or an ion source, LiClO4, were also added. Moreover new alternative materials to be used as polymer electrolytes composed by blends of agar with gelatin, chitosan and poly (ethylene dioxide thiophene):poly(styrene sulfonate) (PEDOT:PSS) were also prepared and characterized. The study revealed that the membranes were homogeneous, with thermal stability up to 200°C and predominantly amorphous. The glass transition values were found to be around -70 °C and the transparency in the visible region of 90%. The ionic conductivity values were in the range of 1x10-6 S/cm to 1.1x10-4 S/cm, depending on composition and amount of added acid or salt. The ionic conductivity of the samples containing PEDOT:PSS were of the order of 10-4 S/cm, however, the corresponding transparencies were found to be about 17%, only. A preliminary study to qualify the performance of our best electrolytes in ECDs have shown a color change of 25%, reversible inserted charge of 5 to 11 mC/cm2 and coloring/bleaching times of 15 and 2 seconds, respectively.

Neste trabalho foi estudado o eletrólito sólido polimérico obtido através da plastificação do amido rico em amilopectina com glicerol em porcentagem de 30% em ralação a massa do amido utilizado, e contendo perclorato de litio (LiClO4), com uma razão [0]/[Li] = 10 (AGL). Com o objetivo de estudar a influência da umidade relativa nas propriedades de transporte iônico do eletrólito, foi utilizada a técnica de Ressonância Magnética Nuclear RMN. Neste trabalho, também, foram utilizadas outras técnicas de caracterização como: DSC, TGA e condutividade A.C. No estudo de RMN, foram realizadas medidas da forma de linha e da taxa de relaxação spin-rede do 1H e do 7Li em função da temperatura, a fim, de estudar a mobilidade do próton e do íon lítio no complexo polimérico. Os resultados desacoplamento do 7Li {1H} medidos na temperatura de 183K mostraram que 80% da largura de linha foi atribuída a interação heteronuclear Li-H. Os resultados da relaxação mostraram um aumento na mobilidade do complexo polimérico e do íon lítio com o aumento da hidratação do eletrólito. Os valores para a energia de ativação são da ordem de 0.20eV para o próton e 0.23eV para o lítio, consistente com os valores encontrados em outros eletrólitos sólidos poliméricos (0.2 - 0.3eV) / In this work we report the study of solid polymer electrolyte obtained from amylopectin rich starch plasticized with 30% in mass of glycerol and lithium perchlorate (LiClO4) with a reason [0]/[Li] = 10. With the objective to study the influence of the relative humidity in the properties of ionic transport of the electrolyte, the technique of Nuclear Magnetic Resonance - NMR was used. The samples were also characterized by DSC, TGA and A.C. conductivity. The mobility of protons and lithium ion were study through the temperature dependence of 1H and 7Li NMR lineshape and spin-lattice relaxation times. The 7Li {1H} decoupling results measured in the temperature of 183K, shows that 80% of the width of line was attributed to Li-H heteronuclear interaction. The relaxation results showed an increase of mobility of proton and lithium ion in the polymer complex with the increase of the relative humidity of the electrolyte. Activation energy of the arder of 0.20eV for the proton and 0.23eV for lithium were obtained from NMR measurements, consistent with the values found in other solid polymer electrolyte (0,2 - 0.3eV)

Esta tese apresenta os resultados de estudo de eletrólitos poliméricos obtidos a partir de agar com o propósito de serem aplicados em dispositivos eletrocrômicos (ECDs). Modificações físico-químicas foram efetuadas no agar através da adição do plastificante glicerol, bem como de formaldeído, além da adição de uma fonte de prótons, a partir de ácido acético, ou uma fonte de íons, utilizando-se LiClO4, para promover a condutividade iônica dos filmes. Foram também preparadas blendas a partir de agar com gelatina, com quitosana e com poli(etileno dióxido de tiofeno):poli(estireno) (PEDOT:PSS) com o objetivo de se obter novos materiais alternativos, para serem utilizados como eletrólitos poliméricos. O estudo revelou que todas as membranas apresentaram-se homogêneas, com estabilidade térmica até 200°C e com a estrutura predominantemente amorfa, com valores de temperatura vítrea em torno de -70 °C e transparência no visível de 90%. O manuseio das amostras obtidas revelou boa maleabilidade e aderência ao vidro. Os valores de condutividade iônica das membranas variaram entre 1x10-6 S/cm e 1,1x10-4 S/cm dependendo da composição e quantidade de ácido ou sal de lítio adicionado. No caso das amostras onde foi adicionado PEDOT:PSS, os resultados de condutividade obtidos foram na ordem de 10-4 S/cm, no entanto as amostras apresentaram a transparência somente de 17%. Foi feito um estudo preliminar, de aplicação dos melhores eletrólitos em ECDs revelando mudança de coloração entre o estado colorido e transparente de 25%, reversível inserção de carga entre 11 e 5,0 mC/cm2 e tempo de coloração de 15 segundos e de descoloração de 2 s. / With the aim to develop new electrochromic devices (ECDs), we present a study on polymer electrolytes obtained from agar. Agar was submitted to physicochemical modifications by adding glycerol as plasticizer and formaldehyde; besides, to promote ionic conductivity of the films, a proton source such as acetic acid, or an ion source, LiClO4, were also added. Moreover new alternative materials to be used as polymer electrolytes composed by blends of agar with gelatin, chitosan and poly (ethylene dioxide thiophene):poly(styrene sulfonate) (PEDOT:PSS) were also prepared and characterized. The study revealed that the membranes were homogeneous, with thermal stability up to 200°C and predominantly amorphous. The glass transition values were found to be around -70 °C and the transparency in the visible region of 90%. The ionic conductivity values were in the range of 1x10-6 S/cm to 1.1x10-4 S/cm, depending on composition and amount of added acid or salt. The ionic conductivity of the samples containing PEDOT:PSS were of the order of 10-4 S/cm, however, the corresponding transparencies were found to be about 17%, only. A preliminary study to qualify the performance of our best electrolytes in ECDs have shown a color change of 25%, reversible inserted charge of 5 to 11 mC/cm2 and coloring/bleaching times of 15 and 2 seconds, respectively.

This thesis deals with description of preparation and use of monomers and copolymers for gel polymer electrolytes usable in electrochemical power sources. This thesis is divided in theoretical and experimental part. The theoretical part describes electrolytes focused on gel polymer electrolytes, measuring methods and materials used for experiments. The experimental part deals with calculation of composition of polymer electrolytes, method of preparation and evaluation of measured results. The method of applying GPE to a negative LTO electrode and a positive NMC electrode is described too. Linear Sweep Voltammetry (LSV) and Potentiostatic Electrochemical Impedance Spectroscopy (PEIS), Cyclic Voltammetry (CV) and Galvanostatic Cycling with Potential Limitation (GCPL) were chosen for measurement of properties.

This work deals with the preparation and measurement of an ionic conductivity of the gel polymer electrolytes prepared by various methods. In the theoretical part of the work, the types of conducting membranes, the development and the state of the art of the gel polymer electrolytes are summarized. The preparation and the results on ionic conductivity of the gels based on MMA, EMA and EOEMA are discussed in the experimental part.

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Commercial lithium ion batteries use liquid electrolytes because of their high ionic conductivity (>10-3 S/cm) over a broad range of temperatures, high dielectric constant, and good electrochemical stability with the electrodes (mainly the cathode cathode). The disadvantages of their use in lithium ion batteries are that they react violently with lithium metal, have special packing needs, and have low lithium ion transference numbers (tLi+ = 0.2-0.3). These limitations prevent them from being used in high energy and power applications such as in hybrid electric vehicles (HEVs), plug in electric vehicles (EVs) and energy storage on the grid. Solid polymer electrolytes (SPEs) will be good choice for replacing liquid electrolytes in lithium/lithium ion batteries because of their increased safety and ease of processability. However, SPEs suffer from RT low ionic conductivity and transference numbers. There have been many approaches to increase the ionic conductivity in solid polymer electrolytes. These have focused on decreasing the crystallinity in the most studied polymer electrolyte, polyethylene oxide (PEO), on finding methods to promote directed ion transport, and on the development of single ion conductors, where the anions are immobile and only the Li+ ions migrate (i.e. tLi+ = 1). But these attempts have not yet achieved the goal of replacing liquid electrolytes with solid polymer electrolytes in lithium ion batteries. In order to increase ionic conductivity and lithium ion transference numbers in solid polymer electrolytes, I have focused on the development of multi-ionic lithium salts. These salts have very large anions, and thus are expected to have low tanion- and high tLi+ transference numbers. In order to make the anions dissociative, structures similar to those formed for mono-ionic salts, e.g. LiBF4 and lithium imides have been synthesized. Some of the multi-ionic salts have Janus-like structures and therefore can self-assemble in polar media. Further, it is possible that these salts may not form non-conductive ion pairs and less conductive ion triplets. First, we have prepared nanocomposite electrolytes from mixtures of two polyoctahedral silsesquioxanes (POSS) nanomaterials, each with a SiO1.5 core and eight side groups. POSS-PEG8 has eight polyethylene glycol side chains that have low glass transition (Tg) and melt (Tm) temperatures and POSS-phenyl7(BF3Li)3 is a Janus-like POSS with hydrophobic phenyl groups and -Si-O-BF3Li ionic groups clustered on one side of the SiO1.5 cube. The electron-withdrawing POSS cage and BF3 groups enable easy dissociation of the Li+. In the presence of polar POSS-PEG8, the hydrophobic phenyl rings of POSS-phenyl7(BF3Li)3 aggregate and crystallize, forming a biphasic morphology, in which the phenyl rings form the structural phase and the POSS-PEG8 forms the conductive phase. The -Si-O-BF3- Li+ groups of POSS-phenyl7(BF3Li)3 are oriented towards the polar POSS-PEG8 phase and dissociate so that the Li+ cations are solvated by the POSS-PEG8. The nonvolatile nanocomposite electrolytes are viscous liquids that do not flow under their own weight. POSS-PEG8/POSS-phenyl7(BF3Li)3 at O/Li = 16/1 has a conductivity, σ = 2.5 x 10-4 S/cm at 30°C, 17 x greater than POSS-PEG8/LiBF4, and a low activation energy (Ea ~ 3-4 kJ/mol); σ = 1.6 x 10-3 S/cm at 90°C and 1.5 x 10-5 S/cm at 10°C. The lithium ion transference number was tLi+ = 0.50 ± 0.01, due to reduced mobility of the large, bulky anion and the system exhibited low interfacial resistance that stabilized after 3 days (both at 80°C). Secondly, solid polymer electrolytes have been prepared from the same salt, POSS-phenyl7(BF3Li)3 and polyethylene oxide (PEO). These exhibit high ambient temperature conductivity, 4 x 10-4 S/cm, and transference number, tLi+ = 0.6. A two-phase morphology is proposed in which the hydrophobic phenyl groups cluster and crystallize, and the three -BF3- form an anionic pocket, with the Li+ ions solvated by the PEO phase. The high ionic conductivity results from interfacial migration of Li+ ions loosely bonded to three -BF3- anions and the ether oxygens of PEO. Physical crosslinks formed between PEO/Li+ chains and the POSS clusters account for the solid structure of the amorphous PEO matrix. The solid polymer electrolyte has an electrochemical stability window of 4.6 V and excellent interfacial stability with lithium metal. In order to further enhance the ionic conductivity of solid polymer electrolytes, we have made two improvements. First, we have used so called half cube structures, T4-POSS, that contain 4 phenyl groups on one side of a Si-O- ring, and 4 ionic groups on the other side, and so are true Janus structures. They contain a 4/4 ratio of phenyl/ionic groups, unlike the previous structures that contain 7 phenyl groups/3 ionic groups. At the same O/Li ratio, the ionic conductivity of [PhOSi(OLi)]4 with POSS-PEG8 is higher than POSS-phenyl7Li3 because of more Li+ dissociation in the former case. Second, we have increased the dissociation of the lithium salts by replacing the Si-O-BF3Li groups with Si-(C3H4NLiSO2CF3)4. Both T4-POSS-(C3H4NLiSO2CF3)4 and POSS-(C3H4NLiSO2CF3)8 have been synthesized and characterized, with some preliminary conductivity data obtained. / Chemistry