DJL

A stretchable wire-shaped lithium-ion battery is produced from two aligned multi-walled carbon nanotube/lithium oxide composite yarns as the anode and cathode without extra current collectors and binders. The two composite yarns can be well paired to obtain a safe battery with superior electrochemical properties, such as energy densities of 27 Wh kg⁻¹ or 17.7 mWh cm⁻³ and power densities of 880 W kg⁻¹ or 0.56 W cm⁻³, which are an order of magnitude higher than the densities reported for lithium thin-film batteries. These wire-shaped batteries are flexible and light, and 97 % of their capacity was maintained after 1000 bending cycles. They are also very elastic as they are based on a modified spring structure, and 84 % of the capacity was maintained after stretching for 200 cycles at a strain of 100 %. Furthermore, these novel wire-shaped batteries have been woven into lightweight, flexible, and stretchable battery textiles, which reveals possible large-scale applications.

Super-stretchy: A novel and safe wire-shaped lithium-ion battery consists of two composite yarns, which were made from aligned multi-walled carbon nanotubes (MWCNT) and lithium titanium oxide (LTO) or lithium manganese oxide (LMO), as the anode and cathode. These wire-shaped batteries were woven into light, flexible, and stretchable battery textiles.

Atomic and electronic structures of hydrated ferritin are characterized using electron microscopy and spectroscopy through encapsulation in single layer graphene in a biocompatible manner. Graphene's ability to reduce radiation damage levels to hydrogen bond breakage is demonstrated. A reduction of iron valence from 3+ to 2+ is measured at nanometer-resolution in ferritin, showing initial stages of iron release by ferritin.

More-efficient charge collection and suppressed trap recombination in colloidal quantum dot (CQD) solar cells is achieved by means of a bulk nano-heterojunction (BNH) structure, in which p-type and n-type materials are blended on the nanometer scale. The improved performance of the BNH devices, compared with that of bilayer devices, is displayed in higher photocurrents and higher open-circuit voltages (resulting from a trap passivation mechanism).

The absorbing layer in state-of-the-art colloidal quantum-dot solar cells is fabricated using a tedious layer-by-layer process repeated ten times. It is now shown that methanol, a common exchange solvent, is the main culprit, as extended exposure leaches off the surface halide passivant, creating carrier trap states. Use of a high-dipole-moment aprotic solvent eliminates this problem and is shown to produce state-of-the-art devices in far fewer steps.

Flowerlike MoS₂ microspheres were synthesized through a hydrothermal method. 2H-MoS₂ nanoparticles, MoS₂/MoO₃ heterojunctions, and α-MoO₃ nanoplates were prepared by annealing the MoS₂ microspheres under different reaction conditions. The formation and growth mechanism of the samples from flowerlike MoS₂ microspheres to α-MoO₃ nanoplates is explained in detail. The photocatalytic properties of the four samples for the degradation of rhodamine B (RhB) under visible-light irradiation were studied. The results showed that the flowerlike MoS₂ microspheres, MoS₂/α-MoO₃ heterojunctions, and α-MoO₃ nanoplates all have excellent photocatalytic activities. In particular, the flowerlike MoS₂ microspheres exhibit the highest photocatalytic activity for the degradation of RhB.

Flowerlike MoS₂ microspheres are used as a precursor for the preparation of 2H-MoS₂ nanoparticles, MoS₂/α-MoO₃ heterojunctions, and α-MoO₃ nanoplates. The growth mechanism is studied in detail. Among the four samples, the MoS₂/α-MoO₃ heterojunctions and MoS₂ microspheres show excellent photocatalytic activity.

Impedance spectroscopy is used as a method to predict the current–voltage curve in organic photovoltaic devices. This technique allows the quantification of the recombination rate, series resistance, carrier density, and lifetime very close to normal operating conditions. The current density is reconstructed from the generation and recombination rates. Excellent agreement with measured results is observed using this simple model. The order of recombination is found to be strongly bias dependent, displaying a shift in the dominant form of recombination from trap-mediated at low carrier densities to bimolecular at high carrier densities. Mobility is shown for a range of intensities and is found to vary significantly with fabrication conditions.

Impedance spectroscopy is used to study recombination in poly-3-hexylthiophene (P3HT):phenyl-C₆₁-butyric acid methyl ester (PC₆₁BM) solar cells. A shift from trap-mediated to bimolecular recombination is observed, in addition to the observation of evidence of geminate recombination under certain processing conditions. Mobility is seen to increase with illumination intensity. The current–voltage curve is reconstructed from the measured recombination rate.

WS₂ nanoflakes with monolayer thickness and abundant edges were synthesized through a high-temperature solution-phase method that is described by Z. Liu, Y. G. Li et al. in their Communication on page 7860 ff. These nanoflakes exhibited impressive activity and durability in electrocatalytic hydrogen-evolution reactions in acids and thus represent an attractive low-cost alternative to the precious platinum benchmark catalyst.

This Progress Report discusses the chemical sensitivity of Kβ valence to core X-ray emission spectroscopy (vtc-XES) and its applications for investigating 3d-transition-metal based materials. Vtc-XES can be used for ligand identification and for the characterization of the valence electronic levels. The technique provides information that is similar to valence band photoemission spectroscopy but the sample environment can be chosen freely and thus allows measurements in presence of gases and liquids and it can be applied for measurements under in situ/operando or extreme conditions. The theoretical basis of the technique is presented using a one-electron approach and the vtc-XES spectral features are interpreted using ground state density functional theory calculations. Some recent results obtained by vtc-XES in various scientific fields are discussed to demonstrate the potential and future applications of this technique. Resonant X-ray emission spectroscopy is briefly introduced with some applications for the study of 3d and 5d-transition-metal based systems.

The chemical bond is usually described in terms of molecular orbitals, which are not physically observable. For transition-metal-based systems, Kβ valence to core X-ray emission spectroscopy combined with ground state density-functional-theory calculations provide the bridge between the real chemical world and the tools we use to describe it. The technique is bulk-sensitive, element-selective, and probes the occupied electronic levels of the material under investigation.