There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Electrolytes have been identified as some of the most influential components in the performance of electrochemical supercapacitors (ESs), which include: electrical double-layer capacitors, pseudocapacitors and hybrid supercapacitors. This paper reviews recent progress in the research and development of ES electrolytes. The electrolytes are classified into several categories, including: aqueous, organic, ionic liquids, solid-state or quasi-solid-state, as well as redox-active electrolytes. Effects of electrolyte properties on ES performance are discussed in detail. The principles and methods of designing and optimizing electrolytes for ES performance and application are highlighted through a comprehensive analysis of the literature. Interaction among the electrolytes, electro-active materials and inactive components (current collectors, binders, and separators) is discussed. The challenges in producing high-performing electrolytes are analyzed. Several possible research directions to overcome these challenges are proposed for future efforts, with the main aim of improving ESs' energy density without sacrificing existing advantages (e.g., a high power density and a long cycle-life) (507 references).

A review of electrolyte materials and compositions for electrochemical supercapacitors

EVOLUTION: Of Mice . . .

One-dimensional carbon nanotubes and two-dimensional graphene nanosheets with unique electrical, mechanical and thermal properties are attractive reinforcements for fabricating light weight, high strength and high performance metal-matrix composites. Rapid advances of nanotechnology in recent years enable the development of advanced metal matrix nanocomposites for structural engineering and functional device applications. This review focuses on the recent development in the synthesis, property characterization and application of aluminum, magnesium, and transition metal-based composites reinforced with carbon nanotubes and graphene nanosheets. These include processing strategies of carbonaceous nanomaterials and their composites, mechanical and tribological responses, corrosion, electrical and thermal properties as well as hydrogen storage and electrocatalytic behaviors. The effects of nanomaterial dispersion in the metal matrix and the formation of interfacial precipitates on these properties are also addressed. Particular attention is paid to the fundamentals and the structure–property relationships of such novel nanocomposites.

Recent progress in the development and properties of novel metal matrix nanocomposites reinforced with carbon nanotubes and graphene nanosheets

Electrolytes are one of the vital constituents of electrochemical energy storage devices and their physical and chemical properties play an important role in these devices' performance, including capacity, power density, rate performance, cyclability and safety. This article reviews the current state of understanding of the electrode–electrolyte interaction in supercapacitors and battery–supercapacitor hybrid devices. The article discusses factors that affect the overall performance of the devices such as the ionic conductivity, mobility, diffusion coefficient, radius of bare and hydrated spheres, ion solvation, viscosity, dielectric constant, electrochemical stability, thermal stability and dispersion interaction. The requirements needed to design better electrolytes and the challenges that still need to be addressed for building better supercapacitive devices for the competitive energy storage market have also been highlighted.

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Electrolyte selection for supercapacitive devices: a critical review

Interdiffusion kinetics of the intermetallic coatings on AZ91D magnesium alloy formed in molten salts at lower temperatures

The effect of complexing agents on the oriented growth of electrodeposited microcrystalline cuprous oxide film

Electrochemically prepared cuprous oxide film for photo-catalytic oxygen evolution from water oxidation under visible light

Hollow Co3O4 microspheres with thin spherical shells were produced using a one-step method at a low hydrothermal temperature (120 °C), and could be obtained without the use of a solid template, organic reagent or subsequent calcination. These hollow Co3O4 microspheres possess a diameter of ca. 500 nm and a thin shell thickness of ca. 50 nm. The samples were characterized by field emission scanning electron microscope (SEM), transmission electron microscope (TEM) and powder X-ray diffraction (PXRD). A multistep-splitting growth mechanism was proposed to reveal the formation of hollow Co3O4 microspheres. The successful fabrication of the hollow spherical morphology of these microspheres highlighted the importance of H2O2 dosage and the nitrate concentration. Electrochemical performance tests of the as-prepared samples indicated that the hollow Co3O4 microspheres exhibited ultrahigh specific capacitances of 1227, 1169, 1116, 1035 F g−1 at current densities of 1, 2, 4, 8 A g−1, respectively. After 1000 cycles, the specific capacitance of hollow Co3O4 microspheres showed high charge–discharge reversibility and only a slight decay of less than 3% at a current density of 2 A g−1.

Hollow Co3O4 microspheres with nano-sized shells: one-step large-scale synthesis, growth mechanism and supercapacitor properties

Four new cycloheptapeptides, fuscasins A–D (1–4), were isolated from the marine sponge Phakellia fusca collected from the South China Sea. Their planar structures were fully characterized by spectroscopic methods, and the absolute configurations of amino acid residues were determined using the advanced Marfey’s method. Structurally, 1 is a unique cycloheptapeptide with a backbone bearing a pyrrolidine-2,5-dione unit. Among the isolated compounds, 1 exhibited potent growth-inhibitory activity against HepG2 cells with an IC50 value of 4.6 μM, whereas it did not show apparent inhibitory effects against the other five human cancer cell lines, MCF-7, HeLa, NCI-H460, PC9, and SW480. Encouragingly, 1 exhibited no cytotoxicity against nonmalignant cells even with a concentration up to 100 μM. These findings suggest that 1 may display a selective inhibitory effect on the growth of HepG2 cells.

Lei Liu

Papers

Interdiffusion kinetics of the intermetallic coatings on AZ91D magnesium alloy formed in molten salts at lower temperatures

The effect of complexing agents on the oriented growth of electrodeposited microcrystalline cuprous oxide film

Electrochemically prepared cuprous oxide film for photo-catalytic oxygen evolution from water oxidation under visible light

Hollow Co3O4 microspheres with nano-sized shells: one-step large-scale synthesis, growth mechanism and supercapacitor properties

Fuscasins A-D, Cycloheptapeptides from the Marine Sponge Phakellia fusca.