The aim of master’s thesis was to develop a method for long-term measuring the influence of temperature on photovoltaic cells and lithium-polymer batteries and to design such measuring system. System was assembled on universal printed circuit board. It consisted of circuits for measuring temperature, illuminance and charging circuit, which charged battery with capacity 110 mAh. The PV cell BSK-SP9261 was used as source. Voltages was recorded by data acquisition device NI-USB 6009 and loged in program developed in LabVIEW 2012 enviroment. Afterwards, temperature, illuminance, voltage on PV cell and internal resistance of battery were computed.

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The goal of this research was to utilize the morphological control inherently imparted by the electrospinning process to improve the active layer performance in energy conversion devices as well as to better understand the relationship between morphology and performance in energy storage devices. Discrete control of the active layer morphology can promote exciton dissociation in organic photovoltaic cells (OPVs), whereas developing efficient ion diffusion pathways and beneficial polymer-ion interaction in polymer-gel electrolytes is demonstrated to result in enhanced battery performance. We demonstrate the ability to develop unique morphologies in Poly(3-hexafluoro propylene) (P3HT) films with energy storage applications using various electrospinning techniques. Electrospinning in a solvent-saturated atmosphere allows for the design of ribbon architectures with polymer domains on the order of 5-10 um. These ribbon structures form what appear to be bi-continuous films, which could then be filled with an acceptor / fullerene type material to create a bulk heterojucton for OPV devices. Dropping chloroform onto the electrospinning needle during the spinning process results in P3HT fibers with porous surfaces. These fibers have diameters of ~ 2 um. Using a coaxial needle to electrospin a P3HT solution in the core, and a CHCl3 sheath solution created hybrid ribbon-fiber structures. These structures have even smaller domain sizes than the ribbons created using a solvent saturated atmosphere. Cospinning P3HT with sacrificial polymers results in P3HT fiber morphologies upon removal of the sacrificial template polymer. Additionally, introducing P3HT into an established fiber matrix results in fibrous P3HT architectures after the template fibers are removed. Developing hybrid polymer-gel electrolytes using crosslinked PEO electrospun fibers results in membranes with high affinity for liquid electrolyte components. These electrospun PEO fiber mats exhibit excellent ionic conductivities at room temperature (12 mS/cm) exceeding an electrospun PVDF control. Furthermore, the PEO fiber mats can absorb nearly three times as much liquid electrolyte as the PVDF control. PEO has been show to interact with lithium salts to aid in dissociation and diffusion during battery cycling. Although the ionic conductivity data suggest PEO to be a superior electrolyte, pulsed-field-gradient NMR shows that lithium diffusion is faster in PVDF samples. From coin cell discharge experiments, PEO is believed to interact strongly with Li+ ions, inhibiting them from diffusing rapidly during fast charge/discharge rates. However, PEO/PETA fiber electrolytes show nearly 100% theoretical capacity discharge at C/100 and a capacity retention of ~ 35% at a C/5 discharge rate in contrast to a glass fiber separator which shows only a capacity that is approximately 85% of the theoretical value. The unique mechanical properties of PEO/PETA electrospun mats could lead to interesting artificial skin and wound healing applications. Upon crosslinking at elevated temperatures (~40 degrees C), the fiber mats exhibit improved tensile strength and much higher ultimate stress at break. The porous nature of the materials lend to easy oxygen diffusion for wound healing, and the hydrophilicity promotes continued adhesion to existing tissue making these mats possible adhesive-less bandages. / Ph. D.

<p>Proton exchange membrane fuel cells and lithium polymer batteries are important as future power sources in electronic devices, vehicles and stationary applications. The development of these power sources involves finding and characterising materials that are well suited r the application.</p><p>The materials investigated in this thesis are the perfluorosulphonic ionomer Nafion^TM(DuPont) and metal oxides incorporated into the membrane form of this material. The ionomer is used as polymer electrolyte in proton exchange membrane fuel cells (PEMFC) and the metal oxides are used as cathode materials in lithium polymer batters (LPB).</p><p>Crystallinity in cast Nafion films can be introduced by ion beam exposure or aging. Spectroscopic investigations of the crystallinity of the ionomer indicate that the crystalline regions contain less water than amorphous regions and this could in part explain the drying out of the polymer electrolyte membrane in a PEMFC.</p><p>Spectroscopic results on the equilibrated water uptake and the state of water in thin cast ionomer films indicate that there is a full proton transfer from the sulphonic acid group in the ionomer when there is one water molecule per sulphonate group.</p><p>The LPB cathode materials, lithium manganese oxide and lithium cobalt oxide, were incorporated <i>in situ</i> in Nafion membranes. Other manganese oxides and cobalt oxides were incorporated <i>in situ</i> inside the membrane. Ion-exchange experiments from HcoO₂to LiCoO₂within the membrane were also successful.</p><p>Fourier transform infrared spectroscopy, Raman spectroscopy and X-ray diffraction were used for the characterisation of the incorporated species and the Nafion film/membrane.</p>

Proton exchange membrane fuel cells and lithium polymer batteries are important as future power sources in electronic devices, vehicles and stationary applications. The development of these power sources involves finding and characterising materials that are well suited r the application. The materials investigated in this thesis are the perfluorosulphonic ionomer NafionTM (DuPont) and metal oxides incorporated into the membrane form of this material. The ionomer is used as polymer electrolyte in proton exchange membrane fuel cells (PEMFC) and the metal oxides are used as cathode materials in lithium polymer batters (LPB). Crystallinity in cast Nafion films can be introduced by ion beam exposure or aging. Spectroscopic investigations of the crystallinity of the ionomer indicate that the crystalline regions contain less water than amorphous regions and this could in part explain the drying out of the polymer electrolyte membrane in a PEMFC. Spectroscopic results on the equilibrated water uptake and the state of water in thin cast ionomer films indicate that there is a full proton transfer from the sulphonic acid group in the ionomer when there is one water molecule per sulphonate group. The LPB cathode materials, lithium manganese oxide and lithium cobalt oxide, were incorporated in situ in Nafion membranes. Other manganese oxides and cobalt oxides were incorporated in situ inside the membrane. Ion-exchange experiments from HcoO2 to LiCoO2 within the membrane were also successful. Fourier transform infrared spectroscopy, Raman spectroscopy and X-ray diffraction were used for the characterisation of the incorporated species and the Nafion film/membrane.

La technologie Lithium-air développée par EDF utilise une électrode à air qui fonctionne avec un électrolyte aqueux ce qui empêche l’utilisation de lithium métal non protégé comme électrode négative. Une membrane céramique (LATP:Li1+xAlxTi2-x(PO4)3) conductrice d’ion Li+ est utilisée pour séparer le milieu aqueux de l’électrode négative. Cependant, cette céramique n'est pas stable au contact du lithium, il est donc nécessaire d'intercaler entre le lithium et la céramique un matériau conducteur des ions Li+. Celui-ci devant être stable au contact du lithium et empêcher ou fortement limiter la croissance dendritique. Ainsi, ce projet s'est intéressé à l'étude d'électrolytes copolymères à blocs (BCE).Tout d'abord, l'étude des propriétés physico-chimiques spécifiques de ces BCEs en cellule lithium-lithium symétrique a été réalisée notamment les propriétés de transport (conductivités, nombre de transport), et la résistance à la croissance dendritique du lithium. Puis dans un second temps, l'étude des composites BCE-céramique a été mise en place. Nous nous sommes en particulier focalisés sur l'analyse du transfert ionique polymère-céramique.Plusieurs techniques de caractérisation ont été utilisées telles que la spectroscopie d'impédance électrochimique (transport et interface), le SAXS (morphologies des BCEs), la micro-tomographie par rayons X (morphologies des interfaces et des dendrites).Pour des électrolytes possédant un nombre de transport unitaire (single-ion), nous avons obtenus des résultats remarquables concernant la limitation à la croissance dendritique. La micro-tomographie des rayons X a permis de montrer que le mécanisme de croissance hétérogène dans le cas des single-ion est très différent de celui des BCEs neutres (t+ < 0.2). / The lithium-air (Li-air) technology developed by EDF uses an air electrode which works with an aqueous electrolyte, which prevents the use of unprotected lithium metal electrode as a negative electrode. A Li+ ionic conductor glass ceramic (LATP:Li1+xAlxTi2-x(PO4)3) has been used to separate the aqueous electrolyte compartment from the negative electrode. However, this glass-ceramic is not stable in contact with lithium, it is thus necessary to add between the lithium and the ceramic a buffer layer. In another hand, this protection should ideally resist to lithium dendritic growth. Thus, this project has been focused on the study of block copolymer electrolytes (BCE).In a first part, the study of the physical and chemical properties of these BCEs in lithium symmetric cells has been realized especially transport properties (ionic conductivities, transference number), and resistance to dendritic growth. Then, in a second part, the composites BCE-ceramic have been studied.Several characterization techniques have been employed and especially the electrochemical impedance spectroscopy (for the transport and the interface properties), the small angle X-ray scattering (for the BCE morphologies) and the hard X-ray micro-tomography (for the interfaces and the dendrites morphologies). For single-ion BCE, we have obtained interesting results concerning the mitigation of the dendritic growth. The hard X-ray micro-tomography has permitted to show that the mechanism involved in the heterogeneous lithium growth in the case of the single-ion is very different from the one involved for the neutral BCEs (t+ < 0.2).