Engineering materials that can store electrical energy in structural load paths can revolutionize lightweight design across transport modes. Stiff and strong batteries that use solid‐state ...electrolytes and resilient electrodes and separators are generally lacking. Herein, a structural battery composite with unprecedented multifunctional performance is demonstrated, featuring an energy density of 24 Wh kg−1 and an elastic modulus of 25 GPa and tensile strength exceeding 300 MPa. The structural battery is made from multifunctional constituents, where reinforcing carbon fibers (CFs) act as electrode and current collector. A structural electrolyte is used for load transfer and ion transport and a glass fiber fabric separates the CF electrode from an aluminum foil‐supported lithium–iron–phosphate positive electrode. Equipped with these materials, lighter electrical cars, aircraft, and consumer goods can be pursued.
Structural battery composites offer mass‐less energy storage for electrical vehicles and devices. Structural batteries are enabled by the recently discovered multifunctional properties of carbon fibers and the development of a structural electrolyte matrix material. The emergent multifunctional properties reach a level that allows lightweight vehicles and innovations across and beyond all transport modes.
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•Use of a green and sustainable synthetic strategy to CHA-based polyesters.•Low temperature (35–55 °C) polycondensation in scCO2 achieved.•The valuable epoxy groups of the monomers ...were preserved.•Our process led to reasonably high molecular weight polyesters.
There is significant potential for industrial use of renewables for a wide range of materials demanded by society. Plants, trees and algae are increasingly attracting attention as sustainable sources for functionalised and polymerizable building blocks. In particular, the outer bark of the birch tree (Betula pendula) is a side stream of the forestry industry with so far very little utilisation besides energy recovery. It is composed of a macromolecular network, suberin, that could provide a renewable, low cost and competitive resource. Within raw suberin is the potentially very useful multifunctional extract cis-9,10-epoxy-18-hydroxyoctadecanoic acid (CHA). Our drive has been to develop a green and sustainable synthetic strategy to CHA-based polyesters, by exploiting supercritical carbon dioxide (scCO2) as a reaction medium and leveraging the regio- and chemo-selective properties of the biocatalyst Novozym 435 (Lipase B). Low temperature (35–55 °C) polycondensation in scCO2 shows significant advantages compared to traditional polymerisation methods leading to reasonably high molecular weight polyesters. The mild synthetic conditions also preserve the valuable epoxy groups of the CHA which we show can be exploited by post-polymerisation functionalisation to create sustainable resins for bio-renewable coatings.
Abstract
Structural batteries are multifunctional composite materials that can carry mechanical load and store electrical energy. Their multifunctionality requires an ionically conductive and stiff ...electrolyte matrix material. For this purpose, a bi-continuous polymer electrolyte is used where a porous solid phase holds the structural integrity of the system, and a liquid phase, which occupies the pores, conducts lithium ions. To assess the porous structure, three-dimensional topology information is needed. Here we study the three-dimensional structure of the porous battery electrolyte material using combined focused ion beam and scanning electron microscopy and transfer into finite element models. Numerical analyses provide predictions of elastic modulus and ionic conductivity of the bi-continuous electrolyte material. Characterization of the three-dimensional structure also provides information on the diameter and volume distributions of the polymer and pores, as well as geodesic tortuosity.
An extremely stable water dispersion of cerium oxide nanoparticles was prepared by colloidal synthesis, using nitrilotriacetic acid (NTA) as a stabilizer. Based on FT-IR measurements, the surface ...characteristics of NTA-stabilized ceria nanoparticles are clarified and a fundamental stabilization mechanism is proposed. The mechanism is based on the combination of the ionic nature of cerium oxide surface and the inner-sphere complexation model. From an application perspective it is remarkable that ceria nanoparticle dispersions stabilized by NTA are stable at neutral pH, which makes them a potential successful additive in UV screening applications.
Surface initiated ring-opening polymerisation (SI-ROP) of trimethylene carbonate (1,3-dioxane-2-one, TMC) from cellulose surfaces has been studied for the first time. Specifically, organocatalytic ...systems employing 1,8-diazabicyclo5.4.0undec-7-ene (DBU) or 1,5,7-triazabicyclo4.4.0dec-5-ene (TBD) were implemented in the ROP of TMC, initiated by the hydroxyl groups on the cellulose chain, to form polymer grafts on the surface of filter papers. A sacrificial initiator was added to the reaction solution, resulting in the formation of free, unbound polymer formed in parallel to the surface grafting. The properties of the polymer grafted paper were studied utilising infrared spectroscopy, thermal gravimetric analysis, scanning electron microscopy and contact angle measurements. The free polymers were characterised with nuclear magnetic resonance spectroscopy and size exclusion chromatography. The grafting resulted in hydrophobic papers in as little as one minute and the ability to control the grafting length of the polymer from the surface was demonstrated by either altering the time of the polymerisation or the ratio of free initiator to monomer. This polymerisation route provides milder conditions than conventional metal-catalysed ROP, greatly reduces reaction times and thus is an attractive method for modification of natural biopolymers compared to previously described methods.
Nanocomposites with high volume fractions (15–50vol%) of nanofibrillated cellulose (NFC) were prepared by impregnation of a wet porous NFC network with acetone/epoxy/amine solution. Infrared ...spectroscopy studies revealed a significant increase in curing rate of epoxy (EP) in the presence of NFC. The NFC provided extremely efficient reinforcement (at 15vol%: 3-fold increase in stiffness and strength to 5.9GPa and 109MPa, respectively), and ductility was preserved. Besides, the glass transition temperature increased with increasing NFC content (from 68°C in neat epoxy to 86°C in 50vol% composite). Most interestingly, the moisture sorption values were low and even comparable to neat epoxy for the 15vol% NFC/EP. This material did not change mechanical properties at increased relative humidity (90% RH). Thus, NFC/EP provides a unique combination of high strength, modulus, ductility, and moisture stability for a cellulose-based biocomposite. Effects from nanostructural and interfacial tailoring are discussed.
Wide-spread use of cellulose nanofibril (CNF) biocomposites and nanomaterials is limited by CNF moisture sensitivity due to surface hydration. We report on a versatile and scalable interface ...tailoring route for CNF to address this, based on technically important epoxide chemistry. Bulk impregnation of epoxide-amine containing liquids is used to show that CNF hydroxyls can react with epoxides at high rates and high degree of conversion to form covalent bonds. Reactions take place inside nanostructured CNF networks under benign conditions, and are verified by solid state NMR. Epoxide modified CNF nanopaper shows significantly improved mechanical properties under moist and wet conditions. High resolution microscopy is used in fractography studies to relate the property differences to structural change. The cellulose-epoxide interface tailoring concept is versatile in that the functionality of molecules with epoxide end-groups can be varied over a wide range. Furthermore, epoxide reactions with nanocellulose can be readily implemented for processing of moisture-stable, tailored interface biocomposites in the form of coatings, adhesives and molded composites.
Photopolymerization is a key enabling technology offering spatial and temporal control to allow for future functional materials to be made to meet societal needs. However, gaining access to robust ...experimental techniques to describe the evolution of nanoscale morphology in photo-initiated polymeric systems has proven so far to be a challenging task. Here, we show that these physical transformations can be monitored and quantified at the nanoscale in situ and in real-time. It is demonstrated that the initial structural features of the liquid precursors significantly affect the final morphology and the physical properties of the resulting solid via the occurrence of local heterogeneities in the molecular mobility during the curing transformation. We have made visible how local physical arrestings in the liquid, associated with both cross-linking and vitrification, determine the length scale of the local heterogeneities forming upon curing, found to be in the 10-200 nm range.
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