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Vanadium oxides are widely used for microsupercapacitors (MSCs) due to their multiple‐valence and high theoretical capacitance. A conceptually new approach of electric discharge machining (EDM) with computer‐aided control is developed to one‐step fabricate Mo‐doped VO0.2‐based electrodes and devices with designable geometry. The results demonstrate that the Mo@VO0.2 integrated interdigital MSCs (IIMSCs) with the narrowest electrode distance of 300 μm show the best capacitive performance, which is furtherly manifested by the electric field simulation. Moreover, this work concentrates on expounding the relationships between the EDM machining current, surface morphology of Mo@VO0.2, and the capacitive behavior of Mo@VO0.2 IIMSCs. Compared to the machining current of 2 and 3 A, the machining current of 1 A facilitates synthesizing smaller Mo@VO0.2 particles with more porosity and higher surface area and thus achieving a larger capacitance value for Mo@VO0.2 IIMSCs device, which is achieving 32 mF cm−2 at 1 mV s−1, working well up to an ultrahigh scan rate of 30 V s−1, and obtaining a good cyclic stability of 88.61% after 5000 cycles. Moreover, this innovative EDM approach opens a new avenue for one‐step synthesis of various ceramic metal oxides for various microdevices such as microbatteries and microsensors. [ABSTRACT FROM AUTHOR]

Cyrene is a new biodegradable solvent, which represents a green alternative to many traditional toxic solvents for advanced polymers. Therefore, this investigation is motivated by interest in applications of Cyrene for polymer processing. The feasibility of solubilization of polymethyl methacrylate (PMMA) and polyethyl methacrylate (PEMA) in Cyrene is demonstrated. The ability to form relatively concentrated solutions of the high molecular mass polymers is an important factor for the formation of PMMA and PEMA films by a dip coating method. It was found that the polymer coatings provide corrosion protection of stainless steel in 30 g L−1 NaCl solutions. Another important finding is that the use of Cyrene facilitates the fabrication of stable suspensions of hydroxyapatite (HAp), microdiamond, and nanodiamond particles. Therefore, the problems of the dispersant selection for dispersion of chemically inert diamond and development of biocompatible dispersants are avoided using Cyrene. For the fabrication of composite films, HAp nanorods with reduced particle size are obtained using rutin as a chelating capping agent. Composite films containing HAp, microdiamond and nanodiamond in the PMMA or PEMA matrix are obtained. The composite films are promising for biomedical applications. It was found that the film morphology, composition and microstructure are influenced by the solvent–particle–polymer interactions and processing conditions. [ABSTRACT FROM AUTHOR]

This study is focused on overcoming obstacles in the implementation of metallic Zn for zinc‐ion batteries. The major limiting factors of Zn anodes include dendrite growth, hydrogen evolution, and by‐product formation. Herein, the challenges are addressed by the application of a redox‐active electrode‐electrolyte interphase. Cationic polypyrrole(PPy)/anionic Tiron anolyte is formulated as the mixed conducting interphase to push the limits of zinc‐based energy storage. The doping/de‐doping behavior of PPy stimulates the surface adsorption/desorption of Tiron attributed to the ion‐induced nucleation. Testing results show that PPy as a passivating corrosive‐resistant layer improves the interfacial stability of Zn metal; while releasing the redox‐active anolyte boosts the charge transfer of cells by the phenol‐quinone transformations. The Zn//Zn cells demonstrate an improved life from 50 to 2500 cycles with a reduced overpotential at 2 mA cm−2 and 1 mAh cm−2. In situ UV–vis spectroscopic measurements, combined with density functional theory calculations, address the redox mechanisms of PPy/Tiron anolyte. The testing of α‐MnO2//Zn cells shows that the PPy/Tiron anolyte exhibits enhanced capacity and rate performance due to the pseudocapacitive effects. This study unveils a conceptually new approach based on the modification of conducting polymer with redox‐active dopants toward the fabrication of high‐performance Zn‐anolyte batteries. [ABSTRACT FROM AUTHOR]

There is a need for point‐of‐care bacterial sensing and identification technologies that are rapid and simple to operate. Technologies that do not rely on growth cultures, nucleic acid amplification, step‐wise reagent addition, and complex sample processing are the key for meeting this need. Herein, multiple materials technologies are integrated for overcoming the obstacles in creating rapid and one‐pot bacterial sensing platforms. Liquid‐infused nanoelectrodes are developed for reducing nonspecific binding on the transducer surface; bacterium‐specific RNA‐cleaving DNAzymes are used for bacterial identification; and redox DNA barcodes embedded into DNAzymes are used for binding‐induced electrochemical signal transduction. The resultant single‐step and one‐pot assay demonstrates a limit‐of‐detection of 102 CFU mL−1, with high specificity in identifying Escherichia coli amongst other Gram positive and negative bacteria including Klebsiella pneumoniae, Staphylococcus aureus, and Bacillus subtilis. Additionally, this assay is evaluated for analyzing 31 clinically obtained urine samples, demonstrating a clinical sensitivity of 100% and specify of 100%. When challenging this assay with nine clinical blood cultures, E. coli‐positive and E. coli‐negative samples can be distinguished with a probability of p < 0.001. [ABSTRACT FROM AUTHOR]

Metal oxide nanostructures are increasingly important materials for various emerging photocatalytic, photovoltaic and photoelectrochemical (PEC) applications. They are commonly used as photoelectrode materials due to their unique functional properties such as wide bandgap, reactive electronic transitions, and high stability. To increase the effectiveness of semiconductor metal oxides photoelectrodes, researchers seek to use various photoabsorption amplification and colloidal stability enhancement strategies. An effective method for achieving this is the surface functionalization of metal oxide semiconductors with catechol‐type ligands. Catechol‐type ligands are a family of organic molecules that adsorb very strongly onto metal oxides by forming complexes with metal atoms through adjacent phenolic —OH groups. Once adsorbed, catechol‐type ligands facilitate improved particle dispersion by inhibiting agglomeration and enhance photoexcitation in metal oxide semiconductors by improving visible light absorption. Herein, the surface complexation of catechol‐type ligand onto metal oxide semiconductor surfaces and their photoabsorption enhancement mechanisms is described. In addition, recent advances and trends in this area are described by presenting recent advancements made in applications of catechol‐modified metal oxide systems in photocatalysis, PEC biosensing, and solar cells. [ABSTRACT FROM AUTHOR]

Applications of bile acids (BAs) and bile salts (BSs) in the nanotechnology of functional materials are described. The exceptionally strong solubilization and dispersion power of BAs/BSs is a key factor for the solubilization of dyes, drugs, and polymers for electronic, optical, and biomedical devices, fabrication of composites, based on carbon nanotubes, graphene, diamonds, quantum dots, and polymers for applications in energy storage devices, coatings for corrosion protection of metals, sensors and electronic devices. BAs/BSs have attracted attention for synthesis, design, and surface modification of advanced materials. BAs/BSs are used as reducing, capping, chelating and dispersing agents for the synthesis of nanoparticles of metals and alloys, and low temperature synthesis of stoichiometric nanostructured complex oxides. BAs/BSs exhibit unique self‐assembly properties, which are successfully used for the template synthesis of functional nanoparticles of controlled shapes. Particularly important are applications of BAs/BSs in the fabrication of dye sensitized solar cells with enhanced efficiency. Electrochemical strategies are discovered for the deposition of BA films and composites. Of particular interest are the unique gel‐forming properties of BAs/BSs, which provide a basis for the synthesis of nanoparticles of controlled size and fabrication of novel materials with advanced functionality. [ABSTRACT FROM AUTHOR]

Pseudocapacitive materials are used for supercapacitor applications due to their exceptionally high capacitance and low cost. Good capacitive performance of the pseudocapacitive materials at high active mass loadings is vital for the development of the next generation of supercapacitor devices. This review describes recent advances in materials and nanotechnologies, which allows the development of advanced pseudocapacitive devices with high active mass. An important breakthrough is the discovery of novel dispersing and capping agents for the colloidal processing of nanoparticles. Particularly important are novel co‐dispersants that exhibit enhanced adsorption on materials of different types, such as inorganic nanoparticles, carbon nanotubes, and graphene. Conceptually new strategies are designed to fabricate coated particles. Recent innovations pave the way for the development of multifunctional redox‐active dopants‐dispersants and dopants‐oxidants to manufacture conductive polymer composites. Among the most important advances in nanotechnology is the development of template methods and heterocoagulation techniques for composite manufacturing. The progress in the design of novel surface modification techniques and materials, discovery of advanced anchoring groups, and development of liquid–liquid extraction allows agglomerate‐free processing of nanomaterials and composites. This review describes fundamental aspects of novel technologies and their applications in the manufacturing of pseudocapacitive devices for energy storage. [ABSTRACT FROM AUTHOR]

This paper reports the fabrication of an electrochemical supercapacitor (ES) with high gravimetric and areal capacitances, achieved at a high mass ratio of active material to current collector. The active material, polypyrrole, is in situ polymerized in an aerogel-based current collector composed of crosslinked cellulose nanocrystals (CNCs) and multiwalled carbon nanotubes (MWCNTs). Mechanical robustness, flexibility, and low impedance of the current collectors are achieved by the chemical crosslinking of CNC aerogels and efficient dispersion of MWCNTs through the use of bile acid as a dispersant. Furthermore, the advanced electrode design results in low contact resistance. A single-electrode areal capacitance of 2.1 F cm−2 is obtained at an active mass loading of 17.8 mg cm−2 and an active material to current collector mass ratio of 0.57. Large area ES electrodes and devices show flexibility, excellent compression stability at 80% compression, and electrochemical cyclic stability over 5000 cycles. Moreover, good retention of capacitive properties is achieved at high charge-discharge rates and during compression cycling. The results of this investigation pave the way for the fabrication of advanced lightweight ES, which can be used for energy storage in wearable electronic devices and other applications. [ABSTRACT FROM AUTHOR]

ABSTRACT In this study, the aromatic sulfonate compound Tiron with high charge to mass ratio is used as an anionic dopant for synthesis of polypyrrole (PPy). The fabricated PPy is investigated for electrochemical supercapacitor (ES) application. Testing results show that Tiron allows reduced PPy agglomeration, smaller particle size and improved charge storage properties of PPy. High capacitance and improved capacitive retention at high scan rates are achieved by the fabrication of PPy/multiwalled carbon nanotube (MWCNT) composite electrode using safranin (SAF) as a co-dispersant. The Tiron-doped PPy electrode shows the highest capacitance of 7.8 F cm−2 with a mass of 27 mg cm−2. The Tiron-doped PPy/MWCNT composite electrode shows good capacitance retention with a capacitance of 1.0 F cm−2 at the scan rate of 100 mV s−1. Symmetric supercapacitor cells are fabricated using PPy based active materials. An energy density of 0.36 mWh cm−2 is achieved. The energy/power density and capacitance retention of the Tiron-doped PPy/MWCNT ES is significantly improved in comparison with PPy-based ES, prepared without Tiron or MWCNT. The Tiron-doped PPy/MWCNT symmetric supercapacitor presents good cycling performance with 91.4% capacitance retention after 1000 charge-discharge cycles. The PPy/MWCNT composites, prepared using Tiron and SAF co-dispersant, are promising electrodes for ES. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42376. [ABSTRACT FROM AUTHOR]

ABSTRACT Experimental results on cathodic electrosynthesis of MnO2 electrodes for electrochemical supercapacitors are presented. The deposition yield data at different pulse durations and electrosynthesis mechanism are discussed. Electron microscopy investigations show porous structure of the electrodes, which is beneficial for good electrolyte access to the active material. The capacitance of 2.6 F cm-2 (199 F g-1), energy density of 20 Wh kg-1 and power density of 28 kW kg-1 are achieved for 13 mg cm-2 electrodes. The electrodes show improved capacitance retention at high scan rates. The Ni plaque-based MnO2 electrodes are promising for energy storage applications in electrochemical supercapacitors. [ABSTRACT FROM AUTHOR]