PDF Publication Title:
Text from PDF Page: 006
Polymers 2021, 13, 1150 6 of 14 higher than the usual solvation number of free lithium cation equal to 4. The solvation of anions in dipolar aprotic solvents is known to be much weaker than cations. From the above, it follows that the sorption of solvent occurs not only due to the solvation of lithium cations by the highly polar EC and/or SL molecules but also due to some other changes in the membrane. Figure 3b shows the conductivity isotherm at room temperature for Li-Nafion mem- branes saturated with EC/SL mixtures of varying compositions at a mixing temperature of 40 ◦C. For samples saturated with the EC/SL mixtures enriched with ethylene carbonate (ω(SL) < 0.2), it was not possible to measure the conductivity: on cooling from 40 to 25 ◦C, an excess amount of EC released from the membrane (syneresis) was solidified on the membrane surface. This phase separation agrees with the phase diagram of the EC–SL system [31]: liquidus temperatures for EC/SL mixtures with ω(SL) < 0.2 are above 25 ◦C. Thus, the non-conductive layer of solid plasticiser forming between the membrane and electrodes makes impedance measurements impossible. The best transport properties of Li-Nafion provided EC/SL mixtures enriched with ethylene carbonate. The membrane conductivity rapidly decreases with ω(SL) in the range of 0.2 to 0.7 (eutectic composition), but then it remains practically unchanged up to pure sulfolane (Figure 3b). Although the decrease in conductivity may be caused by an increase in viscosity with SL content in the mixture [32], this can also be explained in terms of changes in ionic equilibria with the EC/SL mixture composition (since EC and SL differ in solvating ability [26]) or a decrease in the solvent uptake (Figure 3a) influencing the conduction channels within the membrane [1]. 3.3. Influence of Mixing Temperature on Solvent Uptake In order to study the influence of the mixing temperature on the solvent uptake of Li-Nafion, pure EC and SL were selected along with binary EC/SL mixtures of two compositions: ω(SL) = 0.2 and 0.7. The choice of these binary compositions was due to the EC-enriched mixture with ω(SL) = 0.2 providing the highest conductivity values of Li-Nafion (Figure 3b) and being homogeneous at room temperature, which prevents phase separation upon cooling, while the mixture with ω(SL) = 0.7 corresponds to the eutectic point of the EC–SL system [31]. Measurements of the W–T dependencies were carried out by sequential heating (40 to 80 ◦C with 10 ◦C steps) and cooling (80 to 40 ◦C with 20 ◦C steps). Figure 4 displays the results obtained. It can be seen that the mixing temperature has a powerful effect on the solvent uptake of Li-Nafion regardless of the plasticiser composition: the higher the mixing temperature, the greater the solvent uptake. However, this characteristic was observed only in the heating cycle (Figure 4); during the cooling cycle, the decrease in solvent uptake was barely noticeable. As a result, the W value obtained for the highest temperature was virtually maintained for all other annealing temperatures at the cooling mode for all plasticiser compositions studied (Figure 4). Upon cooling from 80 ◦C, the W value for this temperature was almost preserved after thermal treatment at 60 and 40 ◦C. If cooling was carried out from 60 ◦C, again, a similar W value was retained after thermal treatment at 40 ◦C (Figure 4a). At the end of measurements, long-term (60 days) isothermal treatment was carried out at 40 ◦C to check that the equilibrium state of the swollen samples during the cooling cycle was achieved. However, this procedure did not influence the obtained W values. This observation suggests either that the samples are close to the equilibrium state or that syneresis requires a very long time. The observed hysteresis in solvent uptake between the heating and cooling curves supports the hypothesis that an irreversible rearrangement of the supermolecular structure occurs under the influence of a plasticiser and elevated temperatures. Here, it should be noted that all membrane samples retained their integrity upon swelling despite significant mechanical properties changes.PDF Image | Li-Nafion Membrane Plasticised with Ethylene Carbonate Sulfolane
PDF Search Title:
Li-Nafion Membrane Plasticised with Ethylene Carbonate SulfolaneOriginal File Name Searched:
polymers-13-01150.pdfDIY PDF Search: Google It | Yahoo | Bing
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
IT XR Project Redstone NFT Available for Sale: NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Be part of the future with this NFT. Can be bought and sold but only one design NFT exists. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Turbine IT XR Project Redstone Design: NFT for sale... NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Includes all rights to this turbine design, including license for Fluid Handling Block I and II for the turbine assembly and housing. The NFT includes the blueprints (cad/cam), revenue streams, and all future development of the IT XR Project Redstone... More Info
Infinity Turbine ROT Radial Outflow Turbine 24 Design and Worldwide Rights: NFT for sale... NFT for the ROT 24 energy turbine. Be part of the future with this NFT. This design can be bought and sold but only one design NFT exists. You may manufacture the unit, or get the revenues from its sale from Infinity Turbine. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Supercritical CO2 10 Liter Extractor Design and Worldwide Rights: The Infinity Supercritical 10L CO2 extractor is for botanical oil extraction, which is rich in terpenes and can produce shelf ready full spectrum oil. With over 5 years of development, this industry leader mature extractor machine has been sold since 2015 and is part of many profitable businesses. The process can also be used for electrowinning, e-waste recycling, and lithium battery recycling, gold mining electronic wastes, precious metals. CO2 can also be used in a reverse fuel cell with nafion to make a gas-to-liquids fuel, such as methanol, ethanol and butanol or ethylene. Supercritical CO2 has also been used for treating nafion to make it more effective catalyst. This NFT is for the purchase of worldwide rights which includes the design. More Info
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
Infinity Turbine Products: Special for this month, any plans are $10,000 for complete Cad/Cam blueprints. License is for one build. Try before you buy a production license. May pay by Bitcoin or other Crypto. Products Page... More Info
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)