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The stable operation of lithium-based batteries at low temperatures is critical for applications in cold climates. However, low-temperature operations are plagued by insufficient dynamics in the bulk of the electrolyte and at electrode|electrolyte interfaces. Here, we report a quasi-solid-state polymer electrolyte with an ionic conductivity of 2.2 × 10 −4 S cm −1 at −20 °C. The electrolyte is prepared via in situ polymerization using a 1,3,5-trioxane-based precursor. The polymer-based electrolyte enables a dual-layered solid electrolyte interphase formation on the Li metal electrode and stabilizes the LiNi 0.8 Co 0.1 Mn 0.1 O 2 -based positive electrode, thus improving interfacial charge-transfer at low temperatures. Consequently, the growth of dendrites at the lithium metal electrode is hindered, thus enabling stable Li||LiNi 0.8 Co 0.1 Mn 0.1 O 2 coin and pouch cell operation even at −30 °C. In particular, we report a Li||LiNi 0.8 Co 0.1 Mn 0.1 O 2 coin cell cycled at −20 °C and 20 mA g −1 capable of retaining more than 75% (i.e., around 151 mAh g −1 ) of its first discharge capacity cycle at 30 °C and same specific current. Low-temperature batteries are detrimentally affected by the sluggish kinetics of the electrolyte. Here, the authors propose a quasi-solid-state polymer electrolyte capable of improving interfacial charge transfer and enabling stable Li metal cell operation even at −30 °C.

The two natural allotropes of carbon, diamond and graphite, are extended networks of sp 3 -hybridized and sp 2 -hybridized atoms, respectively 1 . By mixing different hybridizations and geometries of carbon, one could conceptually construct countless synthetic allotropes. Here we introduce graphullerene, a two-dimensional crystalline polymer of C 60 that bridges the gulf between molecular and extended carbon materials. Its constituent fullerene subunits arrange hexagonally in a covalently interconnected molecular sheet. We report charge-neutral, purely carbon-based macroscopic crystals that are large enough to be mechanically exfoliated to produce molecularly thin flakes with clean interfaces—a critical requirement for the creation of heterostructures and optoelectronic devices 2 . The synthesis entails growing single crystals of layered polymeric (Mg 4 C 60 ) ∞ by chemical vapour transport and subsequently removing the magnesium with dilute acid. We explore the thermal conductivity of this material and find it to be much higher than that of molecular C 60 , which is a consequence of the in-plane covalent bonding. Furthermore, imaging few-layer graphullerene flakes using transmission electron microscopy and near-field nano-photoluminescence spectroscopy reveals the existence of moiré-like superlattices 3 . More broadly, the synthesis of extended carbon structures by polymerization of molecular precursors charts a clear path to the systematic design of materials for the construction of two-dimensional heterostructures with tunable optoelectronic properties. A two-dimensional crystalline polymer of C 60 , termed graphullerene, is synthesized by chemical vapour transport, and mechanically exfoliated to produce molecularly thin flakes with clean interfaces for potential optoelectronic applications.

Porous carbons are the active materials of choice for supercapacitor applications because of their power capability, long-term cycle stability, and wide operating temperatures. However, the development of carbon active materials with improved physicochemical and electrochemical properties is generally carried out via time-consuming and cost-ineffective experimental processes. In this regard, machine-learning technology provides a data-driven approach to examine previously reported research works to find the critical features for developing ideal carbon materials for supercapacitors. Here, we report the design of a machine-learning-derived activation strategy that uses sodium amide and cross-linked polymer precursors to synthesize highly porous carbons (i.e., with specific surface areas > 4000 m 2 /g). Tuning the pore size and oxygen content of the carbonaceous materials, we report a highly porous carbon-base electrode with 0.7 mg/cm 2 of electrode mass loading that exhibits a high specific capacitance of 610 F/g in 1 M H 2 SO 4 . This result approaches the specific capacitance of a porous carbon electrode predicted by the machine learning approach. We also investigate the charge storage mechanism and electrolyte transport properties via step potential electrochemical spectroscopy and quasielastic neutron scattering measurements. Machine-learning technology provides a data-driven approach to find the critical features for ideal carbon-based supercapacitors. Here, the authors report machine-Learning assisted discovery of oxygen rich highly porous carbons that exhibits a high specific capacitance.

We report a stereolithographic three-dimensional printing approach for polymeric components that uses a mobile liquid interface (a fluorinated oil) to reduce the adhesive forces between the interface and the printed object, thereby allowing for a continuous and rapid print process, regardless of polymeric precursor. The bed area is not size-restricted by thermal limitations because the flowing oil enables direct cooling across the entire print area. Continuous vertical print rates exceeding 430 millimeters per hour with a volumetric throughput of 100 liters per hour have been demonstrated, and proof-of-concept structures made from hard plastics, ceramic precursors, and elastomers have been printed.

Photocrosslinked gelatin methacryloyl (GelMA) hydrogels have attracted great concern in the biomedical field because of their good biocompatibility and tunable physicochemical properties. Herein, different approaches to synthesize GelMA were introduced, especially, the typical method using UV light to crosslink the gelatin-methacrylic anhydride (MA) precursor was introduced in detail. In addition, the traditional and cutting-edge technologies to characterize the properties of GelMA hydrogels and GelMA prepolymer were also overviewed and compared. Furthermore, the applications of GelMA hydrogels in cell culture and tissue engineering especially in the load-bearing tissue (bone and cartilage) were summarized, followed by concluding remarks.

Carbon molecular sieve (CMS) membranes with precise molecular discrimination ability and facile scalability are attractive next-generation membranes for large-scale, energy-efficient gas separations. Here, structurally engineered CMS membranes derived from a tailor-made cross-linkable copolyimide with kinked structure are reported. We demonstrate that combining two features, kinked backbones and cross-linkable backbones, to engineer polyimide precursors while controlling pyrolysis conditions allows the creation of CMS membranes with improved gas separation performance. Our results indicate that the CMS membranes provide a versatile platform for a broad spectrum of challenging gas separations. The gas transport properties of the resulting CMS membranes are interpreted in terms of a model reflecting both molecular sieving Langmuir domains and a disordered continuous phase, thereby providing insight into structure evolution from the cross-linkable polyimide precursor to a final CMS membrane. With this understanding of CMS membrane structure and separation performance, these systems are promising for environmentally friendly gas separations.Carbon molecular sieves (CMS) are formed from pyrolysis of polymeric precursors, forming complex morphologies that enable gas separations. Here, by combining kinked and cross-linkable structures in the precursor, CMS membranes are reported that enable a broad spectrum of challenging gas separations.

The creation of nanoparticles with controlled and uniform dimensions and spatially defined functionality is a key challenge. The recently developed living crystallization-driven self-assembly (CDSA) method has emerged as a promising route to one-dimensional (1D) and 2D core–shell micellar assemblies by seeded growth of polymeric and molecular amphiphiles. However, the general limitation of the epitaxial growth process to a single core-forming chemistry is an important obstacle to the creation of complex nanoparticles with segmented cores of spatially varied composition that can be subsequently exploited in selective transformations or responses to external stimuli. Here we report the successful use of a seeded growth approach that operates for a variety of different crystallizable polylactone homopolymer/block copolymer blend combinations to access 2D platelet micelles with compositionally distinct segmented cores. To illustrate the utility of controlling internal core chemistry, we demonstrate spatially selective hydrolytic degradation of the 2D platelets—a result that may be of interest for the design of complex stimuli-responsive particles for programmed-release and cargo-delivery applications.The synthesis of two-dimensional nanostructures with controlled dimensions from polymeric precursors remains challenging. Now, two-dimensional nanoparticles with chemically different spatially defined cores have been fabricated through seeded growth and are shown to undergo a programmable degradation process.

Anticorrosive protection efficiency of novel tetrafunctional epoxy prepolymer, namely 2,3,4,5-tetraglycidyloxy pentanal (TGP), for mild steel in 1 M HCl medium was assessed through potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), contact angle (CA), adsorption isotherm model, temperature effect and thermodynamic parameters. The synthesized TGP was characterized and confirmed by Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR). The inhibitory efficiencies found at lower concentration of the prepolymer TGP were85% (PDP) and 87.17% (EIS). PDP measurement illustrated that the TGP behaved as a mixed-type inhibitor in the realized solution. SEM and EDS analysis showeda significant decrease in the corrosion of the MS surface in the presence of the inhibitory prepolymer compared with the blank (1 M HCl). Langmuir adsorption isotherm is the most acceptable modelto describe the TGP epoxy prepolymer on the MS area.

Biological systems sense and respond to mechanical stimuli in a complex manner. In an effort to develop synthetic materials that transduce mechanical force into multifold changes in their intrinsic properties, we report on a mechanochemically responsive nonconjugated polymer that converts to a conjugated polymer via an extensive rearrangement of the macromolecular structure in response to force. Our design is based on the facile mechanochemical unzipping of polyladderene, a polymer inspired by a lipid natural product structure and prepared via direct metathesis polymerization. The resultant polyacetylene block copolymers exhibit long conjugation length and uniform trans-configuration and self-assemble into semiconducting nanowires. Calculations support a tandem unzipping mechanism of the ladderene units.

Next-generation wearable electronics require enhanced mechanical robustness and device complexity. Besides previously reported softness and stretchability, desired merits for practical use include elasticity, solvent resistance, facile patternability and high charge carrier mobility. Here, we show a molecular design concept that simultaneously achieves all these targeted properties in both polymeric semiconductors and dielectrics, without compromising electrical performance. This is enabled by covalently-embedded in-situ rubber matrix (iRUM) formation through good mixing of iRUM precursors with polymer electronic materials, and finely-controlled composite film morphology built on azide crosslinking chemistry which leverages different reactivities with C–H and C=C bonds. The high covalent crosslinking density results in both superior elasticity and solvent resistance. When applied in stretchable transistors, the iRUM-semiconductor film retained its mobility after stretching to 100% strain, and exhibited record-high mobility retention of 1 cm 2 V −1 s −1 after 1000 stretching-releasing cycles at 50% strain. The cycling life was stably extended to 5000 cycles, five times longer than all reported semiconductors. Furthermore, we fabricated elastic transistors via consecutively photo-patterning of the dielectric and semiconducting layers, demonstrating the potential of solution-processed multilayer device manufacturing. The iRUM represents a molecule-level design approach towards robust skin-inspired electronics. Next-generation skin-inspired electronics require enhanced mechanical robustness and device complexity including elasticity, solvent resistance, and facile patternability. Here, the authors show a molecular design concept that simultaneously achieves all these requirements by covalently linking an in-situ formed rubber matrix with polymer electronic materials.