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Insights into metal-matrix interactions in atomically dispersed catalytic systems are necessary to exploit the true catalytic activity of isolated metal atoms. Distinct from catalytic atoms spatially separated but immobile in a solid matrix, here we demonstrate that a trace amount of platinum naturally dissolved in liquid gallium can drive a range of catalytic reactions with enhanced kinetics at low temperature (318 to 343 K). Molecular simulations provide evidence that the platinum atoms remain in a liquid state in the gallium matrix without atomic segregation and activate the surrounding gallium atoms for catalysis. When used for electrochemical methanol oxidation, the surface platinum atoms in the gallium-platinum system exhibit an activity of [Formula: see text] three orders of magnitude higher than existing solid platinum catalysts. Such a liquid catalyst system, with a dynamic interface, sets a foundation for future exploration of high-throughput catalysis.

The need for enhanced energy storage and improved catalysts has led researchers to explore advanced functional materials for sustainable energy production and storage. Herein, we demonstrate a reductive electrosynthesis approach to prepare a layer-by-layer (LbL) assembled trimetallic Fe-Co-Ni metal-organic framework (MOF) in which the metal cations within each layer or at the interface of the two layers are linked to one another by bridging 2-amino-1,4-benzenedicarboxylic acid linkers. Tailoring catalytically active sites in an LbL fashion affords a highly porous material that exhibits excellent trifunctional electrocatalytic activities toward the hydrogen evolution reaction (eta(j=10) = 116 mV), oxygen evolution reaction (eta(j=10) = 254 mV), as well as oxygen reduction reaction (half-wave potential = 0.75 V vs reference hydrogen electrode) in alkaline solutions. The dispersion-corrected density functional theory calculations suggest that the prominent catalytic activity of the LbL MOF toward the HER, OER, and ORR is due to the initial negative adsorption energy of water on the metal nodes and the elongated O-H bond length of the H2O molecule. The Fe-Co-Ni MOF-based Zn-air battery exhibits a remarkable energy storage performance and excellent cycling stability of over 700 cycles that outperform the commercial noble metal benchmarks. When assembled in an asymmetric device configuration, the activated carbonliFe-Co-Ni MOF supercapacitor provides a superb specific energy and a power of up to 56.2 W h kg(-1) and 42.2 kW kg(-1), respectively. This work offers not only a novel approach to prepare an LbL assembled multimetallic MOF but also provides a benchmark for a multifunctional electrocatalyst for water splitting and Zn-air batteries.

A nanofibrous polyaniline interlayer controls the reaction dynamics of the interfacial polymerization through its reversible acid doping chemistry.

Because of increasing interest in environmentally benign supercapacitors, earth-abundant biopolymers have found their way into value-added applications. Herein, a promising nanocomposite based on an interpenetrating network of polyaniline and sulfonated lignin (lignosulfonate, LS) is presented. On the basis of an appropriate regulation of the nucleation kinetics and growth behavior via applying a series of rationally designed potential pulse patterns, a uniform PANI-LS film is achieved. On the basis of the fast rate of H+ insertion-deinsertion kinetics, rather than the slow SO42- doping-dedoping process, the PANI-LS nanocomposite delivers specific capacitance of 1200 F g-1 at 1 A g-1 surpassing the best conducting polymer-lignin supercapacitors known. A symmetric PANI-LS||PANI-LS device delivers a high specific energy of 21.2 W h kg-1, an outstanding specific power of 26.0 kW kg-1, along with superb flexibility and excellent cycling stability. Thus, combining charge storage attributes of polyaniline and lignosulfonate enables a waste-to-wealth approach to improve the supercapacitive performance of polyaniline.

Even after centuries-old experience in carbonizing materials we can still learn new lessons and find new applications for carbonized materials. In the past decades, laser-assisted syntheses of materials have emerged as versatile tools for the fabrication of micro- and nanostructured functional devices. In this regard, laser-carbonization is of particular interest, as it provides a method for patterning eco-friendly and potentially biodegradable electronic materials for future applications in comparison to the state-of-the-art in flexible electronics. However, using molecular precursors for laser-carbonization has been a challenge for many years. We identified a set of three different precursors and conducted an in-depth morphological and compositional study to understand how molecular precursors must be prepared for the high-speed carbonization reactions used in laser-patterning. The resulting laser-patterned carbons (LP-C) or N-doped carbons (LP-NC) are different from their conventionally pyrolyzed reference products mostly in terms of morphology. A generally porous structure and a carbonization gradient induced by the top-to-bottom energy input are the most remarkable features. Additionally, the microstructure, the elemental composition and the resulting electronic properties are different as demonstrated by X-ray photoelectron spectroscopy (XPS) and wide-angle X-ray scattering (WAXS) analysis.

During the past decade, flexible/stretchable energy storage devices have garnered increasing attention, with the successful development of wearable electronics. However, due to the repeated deformation accompanied with the electrochemical depletion process, these devices suffer from unavoidable damage, including cracks, crazing, puncture and delamination, which can lead to serious performance degradation or even safety issues. Simultaneously, inspired by biological organs, self-healing capability is found to be a promising approach to address these issues by restoring the mechanical and electrochemical performance. This review first summarizes the structural design and features of various flexible/stretchable energy storage devices, from 1D to 3D configurations. Then, basic concepts and three self-healing mechanisms, including capsule-based systems, vascular-based systems, and intrinsic healing systems are analyzed along with a brief look at existing applications. Then we review all the important parts of state-of-art flexible/stretchable self-healing supercapacitors and batteries including electrodes, electrolytes, substrates and encapsulation. Moreover, a detailed evaluation of methodologies for flexibility, stretchability and self-healing capabilities are described in detail. Finally, the critical challenges and prospects of future promising solutions for self-healing flexible/stretchable energy storage devices or even electronics are provided.

It is well-understood that during the liquid-to-solid phase transition of alloys, elements segregate in the bulk phase with the formation of microstructures. In contrast, we show here that in a Bi–Ga alloy system, highly ordered nanopatterns emerge preferentially at the alloy surfaces during solidification. We observed a variety of transition, hybrid and crystal-defect-like patterns, in addition to lamellar and rod-like structures. Combining experiments and molecular dynamics simulations, we investigated the influence of the superficial Bi and Ga2O3 layers during surface solidification and elucidated the pattern-formation mechanisms, which involve surface-catalysed heterogeneous nucleation. We further demonstrated the dynamic nature and robustness of the phenomenon under different solidification conditions and for various alloy systems. The surface patterns we observed enable high-spatial-resolution nanoscale-infrared and surface-enhanced Raman mapping, which reveal promising potential for surface- and nanoscale-based applications. During a liquid-to-solid phase transition, a Bi–Ga alloy forms ordered nanostructured patterns on its surface.

Wearable solar charging systems are now developing rapidly. However, their insufficient overall efficiency and poor charging rate remain daunting challenges. Herein, we report the rational design of a wearable solar charging unit based on a miniature GaAs solar cell and an ultrafast rechargeable Zn micro-battery. This integrated system demonstrates a high overall efficiency of 23.11%. Upon solar charging for 5 s, the system delivers a continuous supply of power for 110 s at 0.5 mA cm−2, showing favorable fast charging performance characteristics. With the aid of in-depth characterization combined with theoretical simulations, the electrochemical energy storage mechanism of the zinc ion battery is elucidated as the synergy of hydroxyl anion intercalation with surface pseudocapacitive reaction. This work provides an innovative strategy to construct wearable solar charging units with high efficiency and advanced charging capabilities.

The demand for high rate energy storage systems is continuously increasing driven by portable electronics, hybrid/electric vehicles and the need for balancing the smart grid. Accordingly, Nb2O5 based materials have gained great attention because of their fast cation intercalation faradaic charge storage that endows them with high rate energy storage performance. In this review, we describe the crystalline features of the five main phases of Nb2O5 and analyze their specific electrochemical characteristics with an emphasis on the intrinsic ion intercalation pseudocapacitive behavior of T-Nb2O5. The charge storage mechanisms, electrochemical performance and state-of-the-art characterization techniques for Nb2O5 anodes are summarized. Next, we review recent progress in developing various types of Nb2O5 based fast charging electrode materials, including Nb2O5 based mixed metal oxides and composites. Finally, we highlight the major challenges for Nb2O5 based materials in the realm of high rate rechargeable energy storage and provide perspectives for future research.

The ongoing surge in demand for sustainable energy technologies with little to no environmental impacts calls for the exploration of advanced energy storage materials. Inspiration from nature is undoubtedly a promising approach to comply with environmental legislations. Herein, we describe a facile and green electrosynthesis approach to fabricate a polydopamine (PDA) nanofilm supported on oxygen-functionalized carbon cloth (FCC). The surface functionalization of carbon cloth facilitates the PDA nanofilm adhesion and endows the as-prepared PDA-FCC electrode with excellent flexibility, good electrical conductance (22.6 mS), and outstanding wettability to the aqueous electrolyte. Owing to these merits, the PDA-FCC electrode delivers a favorable capacitance of 626 F g−1 at 1.0 A g−1 (617 mF cm−2 at 2.2 mA cm−2, and 1296 mF cm−3 at 5.3 mA cm−3), in which the catechol, amine, and imine moieties of PDA are responsible for its excellent pseudocapacitive behavior. The symmetric all-solid-state flexible PDA-FCC||PDA-FCC device covers almost the entire thermodynamic stability window of aqueous electrolytes (1.2 V), delivers a high specific energy of 11.7 W h kg−1, superb specific power of up to 6.4 kW kg−1, and excellent flexibility along with outstanding cycling stability (81% retention of the initial capacitance after 10 000 cycles). These performance characteristics are in part due to the binder-free PDA biopolymer film that adopts the inherent texture of the carbon cloth, enabling the pores to play the role of temporary ion-buffering reservoirs that facilitate effective mass transport. This new approach to fabricate electrodes from green sources is considered an important step toward environmentally-benign energy storage technologies.

Surface modification offers a straightforward means to alter and enhance the properties and performance of materials, such as nanofiltration membranes for water softening. Herein, we demonstrate how a membrane's surface charge can be altered by grafting different electrostatically varying copolymers onto commercial membrane surfaces using perfluorophenylazide (PFPA) photochemistry for enhanced ion separation performance. The native membrane's performance-i.e., in terms of divalent cation separation-with copolymer coatings containing a positively charged quaternary ammonium (-N(Me)3+), a negatively charged sulfonate (-SO3-), and an essentially neutral zwitterion (sulfobetaine, -N(Me)2R2+, and -SO3-), respectively, indicates that: (a) the sulfonated polymer induces robust Coulombic exclusion of divalent anions as compared to the negatively charged native membrane surface on account of its higher negative charge; (b) the positively charged ammonium coating induces exclusion of cations more effectively than the native membrane; and significantly, (c) the zwitterion polymer coating, which reduces the surface roughness and improves wettability, in spite of its near-neutral charge enhances exclusion of both divalent cations and anions on account of aperture sieving by the compact zwitterion polymer that arises from its ability to limit the size of ions that transport through the polymer along with dielectric exclusion. The outcomes thereby inform new pathways to achieve size- and charge-based exclusion of ionic, molecular, and other species contained in liquid streams.

Liquid metals can play an essential role in the generation of electrically conductive composites for electronic devices and environmental sensing and remediation applications. Here, a method for gr...

Unlike growth on tissue, microbes can grow freely on implantable devices with minimal immune system intervention and often form resilient biofilms that continuously pump out pathogenic cells. The efficacy of antibiotics used to treat infection is declining due to increased rates of pathogenic resistance. A simple, one-step zwitterionic surface modification is developed to significantly reduce protein and microbial adhesion to synthetic materials and demonstrate the successful modification of several clinically relevant materials, including recalcitrant materials such as elastomeric polydimethylsiloxane. The treated surfaces exhibit robust adhesion resistance against proteins and microorganisms in both static and flow conditions. Furthermore, the surface treatment prevents the adhesion of mammalian fibroblast cells while displaying no cytotoxicity. To demonstrate the clinical efficacy of the novel technology in the real-world, a surface-treated, commercial silicone foley catheter is developed that is cleared for use by the U.S. Food and Drug Administration (K192034). 16long-term catheterized patients received surface-treated catheters and completed a Patient Global Impression of Improvement (PGI-I) questionnaire. 10out of 16patients described their urinary tract condition post implantation as "much better" or "very much better" and 72% (n=13) of patients desire to continue using the surface-treated catheter over conventional latex or silicone catheters.

The interfacial properties within a composite structure of membranes play a vital role in the separation properties and application performances. Building an interlayer can facilitate the formation of a highly selective layer as well as improve the interfacial properties of the composite membrane. However, it is difficult for a nanomaterial-based interlayer to increase the flux and retention of nanofiltration membranes simultaneously. Here, we report a nanofiltration membrane with a hybrid dimensional titania interlayer that exhibits excellent separation performance. The interlayer, composed of Fe-doped titania nanosheets and titania nanoparticles, helps the formation of an ultrathin (∼30 nm thick) and defect-free polyamide selective layer with an ideal nanostructure. The hybrid dimensional interlayer endows the membrane with a superior permeability and alleviates flux decline. In addition, the rigid interlayer framework on a PVDF support drastically improves the pressure resistance of nanofiltration membranes and shows negligible flux loss up to 1.5 MPa of pressure.

Despite their low cost, safety, environmentally friendliness, and intrinsic non-flammable nature, the widespread application of aqueous rechargeable zinc-based batteries has been held back by their low coulombic efficiency and the notorious dendritic growth at the zinc-based anodes, along with the fast capacity fading of the cathodes. Herein, an aqueous Zn superbattery that consists of a mixed ZnCO3 MnCO3 grafted onto a graphene aerogel (ZMG) negative electrode and a nanotubular sulfidated Ni-Co-Fe layered double hydroxide (LDHS) positive electrode is reported. The alkaline ZMGLDHS superbattery delivers an excellent capacity and a superb rate capability (356 mA h g(cathode)(-1) (89 mA h g(total mass)(-1)) at 12 A g(-1); 108 mA h g(cathode)(-1) at 300 A g(-1)), extremely high specific energy and power (568 W h kg(cathode)(-1) or 15.8 mW h cm(-3), 429 kW kg(cathode)(-1) or 11.9 W cm(-3)), along with a high output voltage (1.8 V). The device also exhibits unprecedented cycling stability (99.2% capacity retention after 17,000 cycles at 100% depth of discharge) thanks to an electrochemical pulse-driven regenerative mechanism.

Transition-metal chalcogenides have emerged as a promising class of materials for energy storage applications due to their earth abundance, high theoretical capacity, and high electrical conductivity. Herein, we introduce a facile and one-pot electrodeposition method to prepare high-performance nickel selenide NixSey (0.5 Ni3Se2 > NiSe > Ni6Se5. The present study thus provides an appealing approach for tailoring the phase composition of NS as an alternative to the commonly used templated synthesis methods.

Recent advances in wearable and implantable electronics have increased the demand for biocompatible integrated energy storage systems. Conducting polymers, such as polyaniline (PANi), have been suggested as promising electrode materials for flexible biocompatible energy storage systems, based on their intrinsic structural flexibility and potential polymer chain compatibility with biological interfaces. However, due to structural disorder triggering insufficient electronic conductivity and moderate electrochemical stability, PANi still cannot fully satisfy the requirements for flexible and biocompatible energy storage systems. Herein, we report a biocompatible physiological electrolyte activated flexible supercapacitor encompassing crystalline tetra-aniline (c-TANi) as the active electrode material, which significantly enhances the specific capacitance and electrochemical cycling stability with chloride electrochemical interactions. The crystallization of TANi endows it with sufficient electronic conductivity (8.37 S cm-1) and a unique Cl- dominated redox charge storage mechanism. Notably, a fully self-healable and biocompatible supercapacitor has been assembled by incorporating polyethylene glycol (PEG) with c-TANi as a self-healable electrode and a ferric-ion cross-linked sodium polyacrylate (Fe3+-PANa)/0.9 wt% NaCl as a gel electrolyte. The as-prepared device exhibits a remarkable capacitance retention even after multiple cut/healing cycles. With these attractive features, the c-TANi electrode presents a promising approach to meeting the power requirements for wearable or implantable electronics.

A green carbon capture and conversion technology offering scalability and economic viability for mitigating CO

Graphene oxide (GO) membranes have great potential for separation applications due to their low-friction water permeation combined with unique molecular sieving ability. However, the practical use of deposited GO membranes is limited by the inferior mechanical robustness of the membrane composite structure derived from conventional deposition methods. Here, we report a nanostructured GO membrane that possesses great permeability and mechanical robustness. This composite membrane consists of an ultrathin selective GO nanofilm (as low as 32 nm thick) and a postsynthesized macroporous support layer that exhibits excellent stability in water and under practical permeability testing. By utilizing thin-film lift off (T-FLO) to fabricate membranes with precise optimizations in both selective and support layers, unprecedented water permeability (47 L·m-2·hr-1·bar-1) and high retention (>98% of solutes with hydrated radii larger than 4.9 A) were obtained.

Carbon nanodots (CNDs) and graphene/carbon quantum dots (GQDs/CQDs) have emerged as useful components for the fabrication of electrodes in electric double-layer capacitors (EDLCs). In this review, we highlight the emerging trend of employing CNDs and their relatives as active components in EDLCs. We discuss recent progress in converting CNDs with intrinsically low electrical conductivity into conductive electrode materials. Specifically, we highlight advances in improving specific surface area (SSA) and rate capability, as well as employing abundant active sites on CNDs to increase electrode specific capacitance based on conductive carbon, metal compounds, and/or conductive polymers.

Carbon dioxide (CO2) capture from fossil-fuel-based power plants requires scalable membranes with high CO2 permeability and reasonable CO2/N2 selectivity. Conventional membranes based on polyanilin...

The pursuit of new negative electrode materials for redox supercapacitors with a high capacitance, boosted energy, and high rate capability is still a tremendous challenge. Herein, we report a Nile Blue conjugated graphene aerogel (NB–GA) as a negative electrode material with excellent pseudocapacitive performance (with specific capacitance of up to 483 F g–1 at 1 A g–1) in all acidic, neutral, and alkaline aqueous electrolytes. The contribution from capacitive charge storage represents 93.4% of the total charge, surpassing the best pseudocapacitors known. To assess the feasibility of NB–GA as a negative electrode material across the full pH range, we fabricated three devices, namely, a symmetric NB–GA||NB–GA device in an acidic (1.0 M H2SO4) electrolyte, an NB–GA||MnO2 device in a pH-neutral (1.0 M Na2SO4) electrolyte, and an NB–GA||LDH (LDH = Ni–Co–Fe layered double hydroxide) device in an alkaline (1.0 M KOH) electrolyte. The NB–GA||NB–GA device exhibits a maximum specific energy of 22.1 Wh kg–1 and a ...

The nascent field of nanotechnology-enabled metallurgy has great potential. However, the role of eutectic alloys and the nature of alloy solidification in this field are still largely unknown. To demonstrate one of the promises of liquid metals in the field, we explore a model system of catalytically active Bi-Sn nano-alloys produced using a liquid-phase ultrasonication technique and investigate their phase separation, surface oxidation, and nucleation. The Bi-Sn ratio determines the grain boundary properties and the emergence of dislocations within the nano-alloys. The eutectic system gives rise to the smallest grain dimensions among all Bi-Sn ratios along with more pronounced dislocation formation within the nano-alloys. Using electrochemical CO2 reduction and photocatalysis, we demonstrate that the structural peculiarity of the eutectic nano-alloys offers the highest catalytic activity in comparison with their non-eutectic counterparts. The fundamentals of nano-alloy formation revealed here may establish the groundwork for creating bimetallic and multimetallic nano-alloys., The combination of metallurgy concepts and nanotechnology with liquid metal processing has been largely unexplored. Here the authors use liquid-phase ultrasonication to produce a model system of catalytically active nano-alloys, demonstrating electrocatalysis and photocatalysis.

For the past 30 years, thin-film membrane composites have been the state-of-the-art technology for reverse osmosis, nanofiltration, ultrafiltration, and gas separation. However, traditional membrane casting techniques, such as phase inversion and interfacial polymerization, limit the types of material that are used for the membrane separation layer. Here, we describe a novel thin-film liftoff (T-FLO) technique that enables the fabrication of thin-film composite membranes with new materials for desalination, organic solvent nanofiltration, and gas separation. The active layer is cast separately from the porous support layer, allowing for the tuning of the thickness and chemistry of the active layer. A fiber-reinforced, epoxy-based resin is then cured on top of the active layer to form a covalently bound support layer. Upon submersion in water, the cured membrane lifts off from the substrate to produce a robust, freestanding, asymmetric membrane composite. We demonstrate the fabrication of three novel T-FLO membranes for chlorine-tolerant reverse osmosis, organic solvent nanofiltration, and gas separation. The isolable nature of support and active-layer formation paves the way for the discovery of the transport and selectivity properties of new polymeric materials. This work introduces the foundation for T-FLO membranes and enables exciting new materials to be implemented as the active layers of thin-film membranes, including high-performance polymers, two-dimensional materials, and metal-organic frameworks.

Polyaniline was first confirmed as a dark green precipitate on an electrode during the electrochemical polymerization of aniline in 1862. Since then, scientists have been studying the kinetics and growth mechanisms of polyaniline through the electrochemical approach. Studies have shown that p-phenylenediamine, p-aminodiphenylamine, and other aromatic small molecules may serve as initiators for accelerating the polymerization reaction due to the autocatalytic effect of polyaniline. However, little research has been focused on the catalytic effects of introducing oligoanilines. In this paper, quantitative rate constants for the electrochemical polymerization of aniline in both HCl and acetonitrile/HCl solutions with 0.5 mol % of added oligoanilines including diphenylamine, N-phenyl-p-phenylenediamine, 1,4-phenylenediamine, N,N′-diphenyl-1,4-phenylenediamine, 4,4′-diaminodiphenylamine, and tetraaniline in both emeraldine and leucoemeraldine states are reported. Among all the rate constants, N-phenyl-p-phenyl...