Academic literature on the topic 'Ion Conducting Polymer Electrolytes'

This work comprises the manufacture and characterization of solid polymer lithium ion conducting electrolytes for structural batteries. In the study, polymer films are produced in situ via a rapid versatile UV irradiation polymerization route, in which ethylene oxide methacrylates are polymerized into thermoset networks. In the first part of the study, the simplicity and efficiency of this manufacturing route is emphasized. Polymer electrolytes are pro-duced with an ionic conductivity ranging from 5.8×10-10 S cm-1 up to 1.5×10-6 S cm-1, and a storage modulus of up to 2 GPa at 20°C. In the sec-ond part, the effect of the lithium salt content is studied, both for tightly crosslinked systems with a glass transition temperature (Tg) above room temperature but also for sparsely crosslinked system with a Tg below. It is shown that for these systems, there is a threshold amount of 4% lithium salt by weight, above which the ion conducting ability is not affected to a larger extent when the salt content is increased further. It is also shown that the influence of the salt content on the ionic conductivity is similar within both systems. However, the Tg is more affected by the addition of lithium salt for the loosely crosslinked system, and since the Tg is the main affecting parame-ter of the conductivity, the salt content plays a larger role here. In the third part of the study, a thiol functional compound is added via thiol-ene chemistry to create thio-ether segments in the polymer network. This is done in order to expand the toolbox of possible building blocks usable in the design of structural electrolytes. It is shown that solid polymer electrolytes of more homogeneous networks with a narrower glass transition region can be produced this way, and that they have the ability to function as an electrolyte. Finally, the abilities of reinforcing the electrolytes by nano fibrilar cellulose are investigated, by means to improve the mechanical properties without decreasing the ionic conductivity at any larger extent. These composites show conductivity values close to 10-4 S cm-1 and a storage modulus around 400 MPa at 25 °C.<br><p>QC 20140410</p>

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. T1&#961; 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.<br>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 T1&#961; 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.

The use of liquid electrolytes in energy storage devices are associated with several constraints pertaining to safety. Polymer electrolytes are suitable candidates to overcome several problems associated with free-flowing liquid electrolytes. The current thesis deals with the development of proton, lithium, and zinc conducting gel polymer electrolytes for electrochemical energy storage devices such as supercapacitors, lithium-metal batteries, and zinc-metal batteries. Special emphasis is given to the improvement of electrode|electrolyte interface in polymer electrolyte-based energy storage devices by the ultraviolet-light-induced in situ processing strategy. Ultimately, the prospects of employing polymer electrolytes as an alternative to liquid electrolytes in energy storage devices is revisited in this dissertation through four dedicated working chapters.<br>University Grants Commissions (UGC), India CSIR, India<br>AcSIR