Tough Polymer Gel Electrolytes for Aluminum Secondary Batteries Based on Urea: AlCl3, Prepared by a New Solvent-Free and Scalable Procedure

© 2020 by the authorsPolymer gel electrolytes have been prepared with polyethylene oxide (PEO) and the deep eutectic mixture of AlCl3: urea (uralumina), a liquid electrolyte which has proved to be an excellent medium for the electrodeposition of aluminum. The polymer gel electrolytes are prepared by mixing PEO in the liquid electrolyte at T > 65 °C, which is the melting point of PEO. This procedure takes a few minutes and requires no subsequent evaporation steps, being a solvent-free, and hence more sustainable procedure as compared to solvent-mediated ones. The absence of auxiliary solvents and evaporation steps makes their preparation highly reproducible and easy to scale up. PEO of increasing molecular weight (Mw = 1 × 105, 9 × 105, 50 × 105 and 80 × 105 g mol−1), including an ultra-high molecular weight (UHMW) polymer, has been used. Because of the strong interactions between the UHMW PEO and uralumina, self-standing gels can be produced with as little as 2.5 wt% PEO. These self-standing polymer gels maintain the ability to electrodeposit and strip aluminum, and are seen to retain a significant fraction of the current provided by the liquid electrolyte. Their gels’ rheology and electrochemistry are stable for months, if kept under inert atmosphere, and their sensitivity to humidity is significantly lower than that of liquid uralumina, improving their stability in the event of accidental exposure to air, and hence, their safety. These polymer gels are tough and thermoplastic, which enable their processing and molding into different shapes, and their recyclability and reprocessability. Their thermoplasticity also allows the preparation of concentrated batches (masterbatch) for a posteriori dilution or additive addition. They are elastomeric (rubbery) and very sticky, which make them very robust, easy to manipulate and self-healing.This research was funded by the European Union H2020-FETOPEN-1-2016-2017 call (G.A. No. 766581, SALBAGE project).Peer reviewe

Nemateriālo aktīvu grāmatvedības metodoloģiskās problēmas Latvijas Republikā

Nonfluorinated hydrophobic surfaces are of interest for reduced cost, toxicity, and environmental problems. Searching for such surfaces together with versatile processing, A200 silica nanoparticles are modified with an oligodimethylsiloxane and used by themselves or with a polymer matrix. The goal of the surface modification is controlled aggregate size and stable suspensions. Characterization is done by NMR, microanalysis, nitrogen adsorption, and dynamic light scattering. The feasibility of the concept is then demonstrated. The silica aggregates are sprayed in a scalable process to form ultrahydrophobic and imperceptible coatings with surface topographies of controlled nanoscale roughness onto different supports, including nanofibrillated cellulose. To improve adhesion and wear properties, the organosilica was mixed with polymers. The resulting composite coatings are characterized by FE-SEM, AFM, and contact angle measurements. Depending on the nature of the polymer, different functionalities can be developed. Poly­(methyl methacrylate) leads to almost superhydrophobic and highly transparent coatings. Composites based on commercial acrylic car paint show “pearl-bouncing” droplet behavior. A light-emitting polyfluorene is synthesized to prepare luminescent and water repellent coatings on different supports. The interactions between polymers and the organosilica influence coating roughness and are critical for wetting behavior. In summary, the feasibility of a facile, rapid, and fluorine-free hydrophobization concept was successfully demonstrated in multipurpose antiwetting applications

Microestructura molecular y propiedades físicas del PVC : nuevas correlaciones con configuaraciones locales terminales de secuencias tácticas

En esta tesis doctoral se ha estudiado el efecto de la microestructura sobre algunas de las propiedades físicas del policloruro de vinilo: interacción intermolecular con compuestos carbonilicos, degradación térmica, algunos aspectos de la transición vítrea, la relajación beta y el fenómeno de la antiplastificacion, envejecimiento físico y, finalmente la orientación molecular en películas estiradas. Por microestructura entendemos el conjunto de discontinuidades estructurales de la cadena polimerica inherentes a las secuencias tácticas aisladas de la cadena, las configuraciones terminales de las secuencias isotacticas y sindiotacticas, y las conformaciones locales asociadas a estas ultimas. El objetivo de este trabajo es encontrar correlaciones entre esta microestructura y las propiedades físicas antes mencionadas, con el fin de comprender su fundamento molecular

Ionic Conductivity Enhancement in UHMW PEO Gel Electrolytes Based on Room-Temperature Ionic Liquids and Deep Eutectic Solvents

Physical gels made of poly(ethylene oxide) (PEO) and deep eutectic solvents urea-Li bis(trifluoromethanesulfonyl)imide (TFSI) and ethylene glycol/LiTFSI, or pyrrolidinium ionic liquid solutions PYR13TFSI-LiTFSI and PYR14TFSI-LiTFSI, are prepared by a fast, single-step process, which involves no auxiliary solvents or intermediates and is reproducible and scalable. The properties of these gels are studied as a function of the PEO content and its molecular weight and the nature of the liquid electrolyte. The gels prepared with a low concentration (1-5 wt %) of ultrahigh molecular weight (UHMW) PEO are tough, stretchable materials which resemble soft elastomers and are also self-healing and transparent. Their rheology shows the conventional behavior of physical polymer gels, so that the higher the molecular weight of PEO, the lower the polymer concentration needed to produce the gel. However, the ion conductivities and diffusivities of the gels are striking, in many cases being equal to or significantly higher than those of pure liquid electrolytes. This ion conductivity enhancement is the highest for the lowest PEO concentration with the highest molecular weight. This unprecedented molecular weight dependence of conductivity and diffusivity is the result of two combined effects: the liquid electrolyte chemical structure modification as a consequence of the addition of PEO and the development of elastic networks, where ion mobility and rheology are uncoupled when the PEO added is of UHMW.We are grateful to the Characterization Service of ICTP-CSIC for the PGSE NMR measurements included in this work and to Ana López-Cudero for fruitful discussions and revision of the final manuscript. Funding by EU projects SALBAGE H2020-FETOPEN-1-2016-27 G.A 766581 and AMAPOLA H2020-EIC-FETPROACT-2019 G.A. 951902 is gratefully acknowledged

Ionic Liquid-Based Thermoplastic Solid Electrolytes Processed by Solvent-Free Procedures

A series of thermoplastic polymer electrolytes have been prepared employing poly(ethylene oxide) (PEO) as a polymer matrix, bis(trifluoromethane sulfonimide) (LiTFSI), and different room-temperature ionic liquids (RTIL) with bis(fluorosulfonyl)imide (FSI) or TFSI anions. This formulation makes them safe and non-flammable. The electrolytes have been processed in the absence of solvents by melt compounding at 120 °C, using sepiolite modified with d-α-tocoferol-polyethyleneglycol 1000 succinate (TPGS-S) as a physical cross-linker of PEO. Several concentrations of RTILs, lithium salt, and TPGS-S have been tested in order to obtain the highest ionic conductivity (σ) without losing electrolytes’ mechanical stability. The materials’ rheology and ionic conductivity have been extensively characterized. The excellent crosslinking ability of TPGS-S makes the electrolytes behave as thermoplastic materials, even those with the highest liquid concentration. The electrolytes with the highest concentrations of FSI anion present a σ over 10−3 S·cm−1 at 25 °C and close to 10−2 S·cm−1 at 70 °C, and notably behave as solids at temperatures up to 90 °C despite over 65 wt % of their formulation being liquid. The electrolytes thus obtained are safe solid thermoplastics prepared by industrially scalable procedures and are suitable for energy storage devices, proving the adequacy of polymer-based materials as solid electrolytes for batteries or supercapacitors.This study was supported by the Comunidad de Madrid (Project Ref. LIQUORGAS-CM, S2013/MAE-2800). Francisco González is grateful to CONACYT-SENER for the scholarship granted (CVU 559770/Registro 297710 and S2013/MAE-2800)

Addressing Manufacturability and Processability in Polymer Gel Electrolytes for Li/Na Batteries

Gel electrolytes are prepared with Ultra High Molecular Weight (UHMW) polyethylene oxide (PEO) in a concentration ranging from 5 to 30 wt.% and Li- and Na-doped 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (PYR14-TFSI) by a simple procedure consisting of dissolving PEO by melting it directly in the liquid electrolyte while stirring the blend. This procedure is fast, reproducible and needs no auxiliary solvents, which makes it sustainable and potentially easy to scale up for mass production. The viability of the up-scaling by extrusion has been studied. Extrusion has been chosen because it is a processing method commonly employed in the plastics industry. The structure and morphology of the gel electrolytes prepared by both methods have been studied by DSC and FTIR, showing small differences among the two methods. Composite gels incorporation high concentrations of surface modified sepiolite fibers have been successfully prepared by extrusion. The rheological behavior and ionic conductivity of the gels have been characterized, and very similar performance of the extruded and manually mixed gels is detected. Ionic conductivity of all the gels, including the composites, are at or over 0.4 mS cm−1 at 25 °C, being at the same time thermoreversible and self-healing gels, tough, sticky, transparent and stretchable. This combination of properties, together with the viability of their industrial up-scaling, makes these gel electrolyte families very attractive for their application in energy storage devices

In-Situ approaches for the preparation of polythiophene-derivative cellulose composites with high flexibility and conductivity

Composite materials of conjugated polymers/cellulose were fabricated by incorporating different polythiophene-derivative polymers: Poly(3,4-ethylenedioxythiophene) (PEDOT) and an alkylated derivative of poly(3,4-propylenedioxythiophene) (PProDOT). These conjugated polythiophenes were deposited by casting or spray coating methodologies onto three different cellulose substrates: Conventional filters papers as cellulose acetate, cellulose grade 40 Whatman® and cellulose membranes prepared from cellulose microfibers. The preparation of composite materials was carried out by two methodologies: (i) by employing in-situ polymerization of 3,4-ethylenedioxithiophene (EDOT) or (ii) by depositing solutions of poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) or lab-synthetized PProDOT. Composite materials were studied in terms of electrical conductivity and surface morphology assessed by impedance spectroscopy, surface conductivity, SEM, and 3D optical profilometry. In-situ composite materials prepared by spray coating using iron trifluoromethane sulfonate as oxidizing agent can be handled and folded as the original cellulose membranes displaying a surface conductivity around 1 S∙cm−1. This versatile procedure to prepare conductive composite materials has the potential to be implemented in flexible electrodes for energy storage applications.This research was supported by CDTI research project IDI- 20180087. We also thanks the Consejo Nacional de Ciencia y Tecnología for CVU 559770/Registro 297710 and S2013/MAE-2800.Peer reviewe