The depolymerisation of BPA-PC in the presence of diols enables its upcycling into BPA monomers and carbonate-containing diols which can be polymerised into aliphatic PCs as promising electrolytes for energy storage applications.
In this work, we develop novel single-ion polymer electrolytes by mixing poly(lithium 1-[3-(methacryloyloxy) propylsulfonyl]-1-(trifluoromethanesulfonyl) imide) (PLiMTFSI) and poly(ethylene oxide) (PEO) with different molecular weights. The impact of PLiMTFSI on the crystallization and conductivity of the blends was explored in detail. When PLiMTFSI (an amorphous polymer) is added to PEO, the crystallization ability of PEO decreases. However, blends with high-molecular weight PEO (1000 kg/mol) experience a lower reduction in crystallinity and melting points. As a result, lower conductivity values were obtained in these blends, which is why most of the study was then focused on blends incorporating a lower-molecular weight PEO (100 kg/mol). We show that the melting point, degree of crystallinity, spherulitic growth, and overall crystallization kinetics decrease in the presence of PLiMTFSI, which are all signs of miscibility. Furthermore, the blends show a single glass transition temperature over the whole composition range. Therefore, our results indicate that PEO and PLiMTFSI are miscible, as corroborated by applying the Nishi−Wang equation and obtaining negative χ 12 values (i.e., the Flory−Huggins interaction parameter) for all blends. Our results show that intermediate molecular weight blends (100 kg/mol PEO and 50 kg/mol PLiMTFSI) showed the highest ionic conductivity value. Interestingly, a value of 2.1 × 10 −4 S/cm was obtained at 70 °C, which is one of the highest reported so far for a free-standing film of single-ion conducting polymer electrolytes. Finally, employing dielectric spectroscopy, the contribution of ion density and ion mobility to ionic conductivity could be separated. It was found that ion mobility is the parameter that has a greater weight in the conduction process.
Solid-state lithium batteries are considered one of the most promising battery systems due to their high volumetric energy density and safety. Poly(ethylene oxide) (PEO) is the most commonly used solid...
Mixed ionic-electronic conductors, such as poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) are postulated to be the next generation materials in energy storage and electronic devices. Although many studies have aimed to enhance the electronic conductivity and mechanical properties of these materials, there has been little focus on ionic conductivity. In this work, blends based on PEDOT stabilized by the polyelectrolyte poly(diallyldimethylammonium) (PolyDADMA X) are reported, where the X anion is either chloride (Cl), bis(fluorosulfonyl)imide (FSI), bis(trifluoromethylsulfonyl)imide (TFSI), triflate (CF3SO3) or tosylate (Tos). Electronic conductivity values of 0.6 S cm−1 were achieved in films of PEDOT:PolyDADMA FSI (without any post-treatment), with an ionic conductivity of 5 × 10−6 S cm−1 at 70 °C. Organic ionic plastic crystals (OIPCs) based on the cation N-ethyl-N-methylpyrrolidinium (C2mpyr+) with similar anions were added to synergistically enhance both electronic and ionic conductivities. PEDOT:PolyDADMA X / [C2mpyr][X] composites (80/20 wt%) resulted in higher ionic conductivity values (e.g., 2 × 10−5 S cm−1 at 70 °C for PEDOT:PolyDADMA FSI/[C2mpyr][FSI]) and improved electrochemical performance versus the neat PEDOT:PolyDADMA X with no OIPC. Herein, new materials are presented and discussed including new PEDOT:PolyDADMA and organic ionic plastic crystal blends highlighting their promising properties for energy storage applications.
Optical Microscopy (PLOM). DSC results reveal a competition between the nucleating effect of Hec, which was particularly important at low amounts, and the PEG confinement effect at higher filler loadings. Applying a self-nucleation protocol, the nucleation efficiency of the hectorite was shown to be up to 67%. The isothermal crystallization kinetics accelerated at low Hec contents (nucleation), went through a maximum and then decreased (confinement) as Hec content increased. Additionaly, a clear correlation between filler content and the Avrami index was obtained supporting the increase in confinement as filler loading increased.
Poly(ethylene oxide) (PEO) is the most widely used polymer in the field of solid polymer electrolytes for batteries. It is well known that the crystallinity of polymer electrolytes strongly affects the ionic conductivity and its electrochemical performance. Nowadays, alternatives to PEO are actively researched in the battery community, showing higher ionic conductivity, electrochemical window, or working temperature range. In this work, we investigated polymer electrolytes based on aliphatic polyethers with a number of methylene units ranging from 2 to 12. Thus, the effect of the lithium bis(trifluoromethanesulfone) imide (LiTFSI) concentration on the crystallization behavior of the new aliphatic polyethers and their ionic conductivity was investigated. In all the cases, the degree of crystallinity and the overall crystallization rate of the polymers decreased drastically with 30 wt % LiTFSI addition. The salt acted as a low molecular diluent to the polyethers according to the expectation of the Flory–Huggins theory for polymer–diluent mixtures. By fitting our results to this theory, the value of the interaction energy density (B) between the polyether and the LiTFSI was calculated, and we show that the value of B must be small to obtain high ionic conductivity electrolytes.
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