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Flexible ultrathin copper films are desired for use as flexible electromagnetic shielding, smart clothing, and energy storage devices. The fabrication of such films can be realized through plasma assisted surface coating on flexible polymer thin films. Unfortunately, the use of plasma treatment leads to substantial damage to the polymer substrates, which is particularly serious for ultrathin films. Here, we report the fabrication of stretchable, ultrathin, yet ultrastrong hybrid copper films via simple nanoconfinement. The hybrid films are prepared by the conformal electroless deposition of copper nanoparticles on nanofibrils of ultrastrong ultrahigh molecular weight polyethylene (UHMWPE) membranes. These flyweight hybrid copper films (0.3 mg cm−2) possess a high mechanical strength of 390 MPa, 26% larger than pure copper foils; a low resistivity of 5 × 10−8 Ω m at a cyclic extensional strain of 1%; and macroscopic shape recovery after applying a biaxial extension strain of 10%. The shape recoverability and the high mechanical strength of the hybrid copper film were derived from the unique nanofibrous network of the ultrastrong UHMWPE substrate. As an application, we fabricated a lithium-ion battery using the CuPE as the current collector at the graphite anode and observed a near 100% and 10% increase in energy density concerning the total mass and total volume of the anode, respectively. [ABSTRACT FROM AUTHOR]

Flexible all solid-state batteries that combine polymer electrolytes and lithium metal are required for powering wearable electronic devices as they embody high flexibility, safety and energy density. However, it has been challenging to develop room temperature flexible solid-state batteries because of the low ionic conductivities of polymeric ion conductors. Here, we report a highly conductive polymer electrolyte based on lowly viscous polyethylene oxide ion conductors confined inside an ultrastrong and ultrathin nanofibrous polyethylene membrane. The newly developed solid polymer electrolyte exhibits high room temperature charge transfer conductance (0.07 S) and excellent compatibility with Li metal (cycling time > 3500 hours at 0.1 mA cm−2) at 30 °C. Large-scale molecular dynamics simulations show that the high ionic conductivity is because of the enhanced segmental mobility of confined PEO inside the nanomembrane and the strong charge–dipole interactions between the PEO and lithium ions. This work provides a viable solution toward room temperature workable solid-state batteries that meet the requirements for wearable electronic devices. [ABSTRACT FROM AUTHOR]

Solid Polymer Electrolytes (SPEs) exhibit great potential for application in high energy density solid-state lithium metal batteries owing to their excellent flexibility and high safety. However, the growth of lithium dendrites and poor interfacial contact between the electrolyte and electrode seriously hinder the wide commercial application. In this work, a composite solid electrolyte from halloysite nanotubes (HNTs), comb-like poly-ε-caprolactone (PCL), and lithium bis(fluorosulfonyl)imide (LiFSI) is fabricated via solvent-free in situ photoinitiated radical polymerization. On account of HNTs, the composite solid electrolyte (CSE) exhibits significantly improved room temperature ionic conductivity (6.62 × 10−5 S cm−1), a greater lithium transference number (0.55), and a higher electrochemical stability window (5.4 V) compared with the analog without HNTs (PSE). This is because the negatively charged outer silica surfaces of HNTs are enriched with Li+, while the positively charged aluminol inner surfaces accommodate FSI− anions, as clearly observed by TEM. As a bonus, the growth of lithium dendrites is remarkably alleviated. The superior electrochemical properties, in conjunction with refined interfacial contact by the in situ fabrication technique, enable the CSE-based lithium metal battery (at 1C and 60 °C for the LiFePO4 cathode) to have excellent cycling performance of high initial discharge capacity (155 mA h g−1), outstanding average coulombic efficiency (>99%), and extraordinary capacity retention (>92% over 600 cycles). Coupled with the high voltage LiMn0.5Fe0.5PO4 cathode (4.25 V), the solid-state lithium metal cell with the CSE also exhibits superior cycling performance, with an initial capacity of 134 mA h g−1 and a capacity retention of 87% over 250 cycles at 0.2C and 60 °C. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries (LIBs) have become one of the most prevalent techniques for feasible and fascinating energy storage devices used in portable electronics and electric vehicles; however, they still face a significant challenge due to the complicated electrode–electrolyte interface (EEI), which is closely related to the chemical/electrochemical instability of high-capacity high-voltage electrodes and electrolytes. In particular, the decomposition of an electrolyte on the electrode surface is unambiguously regarded as a crucial controlling factor for the obtainable capacity, rate capacity, and interfacial chemistries of batteries. Previously, significant efforts have been devoted toward modifying the EEI with remarkable progress. The incorporation of a small dose of foreign molecules, called film-forming additives, is regarded as one of the most economical and effective approaches to circumvent these predicaments. In this regard, this review provides an overview of various film-forming additives used for classified anodes and cathodes, aiming at emphasizing the state-of-the-art developments in the electrolyte research. Moreover, the authors intend to help the readers arouse new ideas and easily identify the additives suitable for their target materials, paving the way for greater progress in the lithium-ion battery community. [ABSTRACT FROM AUTHOR]

Here, novel solid polymer electrolytes were synthesized by solvent-free “thiol-ene” copolymerization with different chain lengths. It was demonstrated that the optimal polymer electrolyte exhibited excellent thermal stability up to 331 °C, considerable ionic conductivity of 5.05 × 10−5 S cm−1 at ambient temperature, a wide electrochemical window (0–5.05 V) and good compatibility with a lithium metal electrode. In addition, a solid-state monopolar LiFePO4//Li battery with an integrated cathode and electrolyte was assembled and delivered a maximum capacity of 167.39 mA h g−1, which is close to the theoretical capacity of the LiFePO4 cathode. Moreover, the discharge capacity remained at 122.17 mA h g−1 after 200 cycles at 60 °C, which represents a capacity retention of 75%. Remarkably, the monopolar cell could cycle well at room temperature, with a stabilized discharge capacity of 100 mA h g−1 at 0.1C in the 60th cycle. In particular, taking advantage of the non-fluidity of solid electrolytes, a bipolar cell with a high voltage of 6.07 V was also assembled, which was extremely beneficial for improving the volumetric energy density and decreasing the cost, as well as enhancing the reliability of cell packs. The bipolar cell delivered an initial specific capacity of 136.3 mA h g−1 with a retention of 76% after 40 cycles. Furthermore, the bipolar cell can work well under conditions of bending, cutting and even penetration by a nail. Consequently, this work provides an advanced strategy for the facile synthesis of polymer electrolytes, as well as the fabrication of bipolar cells with high voltages, which favors improvements in energy density. [ABSTRACT FROM AUTHOR]

This work reports novel, robust, multifunctional covalent-bonded polymer nanofilms based on highly efficient spin-assisted layer-by-layer (LbL) assembly, with a wide range of engineering and bioengineering applications. An active-ester block copolymer, polypentafluorophenylacrylate-block-polystyrene (PPFPA-b-PS), and an amine-rich polymer, branched polyethyleneimine (PEI), were chosen as model polymers. The as-prepared nanofilms show switchable hydrophobicity with controllable thickness. Nanomechanical tests demonstrate that the surface adhesion between the PPFPA-b-PS and PEI layers facilitates excellent film stability under different solvent conditions. Robust and centimeter-scale freestanding nanofilms with good transparency and excellent flexibility could be readily obtained by peeling the films from their silicon substrates without using a sacrifice layer. More importantly, the multi-layer nanofilms containing free pentafluorophenol groups or amine groups can be readily functionalized further to tailor the properties of the films for various applications. As a proof of concept, a multi-layer nanofilm with free ester groups was modified with rhodamine-6G hydrazone and tested as a H+ sensor. The free amine groups in the polymer nanofilms show strong interactions with perfluorooctanoic acid for achieving high surface hydrophobicity. The polymer nanofilms also show exceptional tunable cell-attachment behavior by switching the outmost layer between PPFPA-b-PS and PEI, demonstrating great potential for biomedical applications. [ABSTRACT FROM AUTHOR]

Here is reported the fabrication of a highly porous and hydrophobic melamine sponge based composite (MF-ZIF-8 sponge) with effective catalysis via the simple surface growth of ZIF-8 onto the strut surface of melamine sponge under the condition of the presence of polydopamine possessing a strong adhesive ability through noncovalent adsorption and covalent reaction. The successful integration of melamine sponge and ZIF-8 into one composite was confirmed using scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction and thermogravimetry. Combining the advantages of both materials, MF-ZIF-8 sponge with a high porosity, high hydrophobicity and low density showed excellent oil/water separation performance as its mass-based oil absorption capacity could reach up to 3800 wt%, which is much higher than that of pure ZIF-8. Besides its more effective catalysis compared to the corresponding pure ZIF-8 in a Knoevenagel reaction, since MF-ZIF-8 sponge can be easily separated from the organic liquid reaction mixture it is a potential candidate for the catalysis of various organic reactions. [ABSTRACT FROM AUTHOR]

The development of autonomous micro/nano-scale objects has drawn considerable attention in recent years. Here we describe a two-stage hydrogel rocket that displays promising autonomous motion with a propelling speed of over 20 mm s−1 and more remarkably achieves a long transportation period and the release of self-propelled Janus micromotors. Such an attractive hydrogel rocket holds great potential for the protected delivery of active cargoes and future diverse applications of nano/micro machines. [ABSTRACT FROM AUTHOR]

The dark color of industrial lignin is the main obstacle for their high value-added use in areas such as sunscreen or dyestuff dispersants. Here, a one-step method for reducing the color of lignin is presented and the structural changes of the whitened lignin are characterized by UV, FTIR, NMR, GPC, DLS, AFM, HS-GC and potentiometric titration. The results show that the content of aromatic ring, methoxyl and phenolic hydroxyl groups in the alkali lignin (AL) decreases, while the content of carboxylic groups increases when it is exposed to UV in THF. AL experiences a darkening process before it is gradually whitened. The blue shift of the UV spectrum and the decrease in size and molecular weight indicate AL is not only intermolecular and intramolecular disaggregated, but also partially depolymerized when light colored lignin is obtained. This simple but efficient whitening method is successfully practised in bleaching. The white degree of raw paper increases from 0.438 to 0.917 after being irradiated under sunshine for 3 days. [ABSTRACT FROM AUTHOR]

Owing to the severe environmental and ecological issues arising from oil spills and toxic chemical leakage, the separation of oil from water presents a worldwide challenge to save the endangered environment. A versatile absorbent which can deal with different types of oil contaminants is in high demanded for this issue. In this work, we obtain an ultralight, fire-resistant, and compressible foam (UFC foam) by pyrolysis and post hydrophobic-modified treatment using commercially available poly(melamine formaldehyde) foams as precursors. The present UFC foam not only effectively separates oils from water as expected, but also possesses a very high absorption capacity for the removal of oils from water up to 158 times its own weight. More importantly, due to its fire resistance and compressibility, distillation, combustion and squeezing, or a combination of these can be applied for recycling the foams depending on the type of pollutants, making them versatile and comprehensive absorbents to satisfy various practical separation requirements. [ABSTRACT FROM AUTHOR]