Transformation of Rusty Stainless-Steel Meshes into Stable, Low-Cost, and Binder-Free Cathodes for High-Performance Potassium-Ion Batteries.

To recycle rusty stainless-steel meshes (RSSM) and meet the urgent requirement of developing high-performance cathodes for potassium-ion batteries (KIB), we demonstrate a new strategy to fabricate flexible binder-free KIB electrodes via transformation of the corrosion layer of RSSM into compact stack-layers of Prussian blue (PB) nanocubes (PB@SSM). When further coated with reduced graphite oxide (RGO) to enhance electric conductivity and structural stability, the low-cost, stable, and binder-free RGO@PB@SSM cathode exhibits excellent electrochemical performances for KIB, including high capacity (96.8 mAh g-1 ), high discharge voltage (3.3 V), high rate capability (1000 mA g-1 ; 42 % capacity retention), and outstanding cycle stability (305 cycles; 75.1 % capacity retention).

Flexible and Foldable Li-O2 Battery Based on Paper-Ink Cathode.

A flexible freestanding air cathode inspired by traditional Chinese calligraphy art is built. When this novel electrode is employed as both a new concept cathode and current collector, to replace conventional rigid and bulky counterparts, a highly flexible and foldable Li-O2 battery with excellent mechanical strength and superior electrochemical performance is obtained.

Artificial Protection Film on Lithium Metal Anode toward Long-Cycle-Life Lithium-Oxygen Batteries.

An artificial while very stable solid electrolyte interphase film is formed on lithium metal using an electrochemical strategy. When this protected Li anode is first used in a Li-O2 battery, the film formed on the anode can effectively suppress the parasitic reactions on the Li anode/electrolyte interface and significantly enhance the cycling stability of the Li-O2 battery.

Photocatalytic degradation of an azo dye using N-doped NaTaO3 synthesized by one-step hydrothermal process.

N-doped NaTaO(3) compounds (NaTaO(3-)(x)N(x)) with nano-cubic morphology were successfully synthesized by one-step hydrothermal method and Methyl Orange (MO) was used as a model dye to evaluate their photocatalytic efficiency under visible-light irradiation. The as-prepared NaTaO(3-)(x)N(x) samples were characterized by various techniques, such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and UV-vis diffuse reflectance spectra and GC-MS. The results indicate that NaTaO(3-)(x)N(x) displays a pure perovskite structure when the synthesis temperature is higher than 180°C. Moreover, as observed by SEM images, the particles of resultant NaTaO(3-)(x)N(x) show cubic morphology with the edge length of 200-500nm, which can be easily removed by filtration after photocatalytic reaction. Doping of N increases the photocatalytic activity of NaTaO(3), and NaTaO(2.953)N(0.047) shows the highest visible-light photocatalytic activity for the degradation of MO. Based on the experiment results, a possible mechanism of the photocatalysis over NaTaO(3-)(x)N(x) and the photodegradation pathway of MO were proposed.

Synthesis and photocatalytic activity of N-doped NaTaO3 compounds calcined at low temperature.

N-doped NaTaO(3) compounds (NaTaO(3-x)N(x)) were successfully synthesized using NaTaO(3) prepared at low calcination temperature as starting material and melamine (C(3)H(6)N(6)) as nitrogen source. The as-prepared NaTaO(3-x)N(x) samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and UV-vis diffuse reflectance spectra. The XRD results indicate that the crystallization temperature of NaTaO(3) is up to 700 degrees C and the doping of N does not lead to significant structural changes. Moreover, as observed by SEM images, the particle sizes of resultant NaTaO(3-x)N(x) are in the range of 100-150 nm, which are much smaller than NaTaO(3) particles synthesized by traditional solid state reaction method. The photocatalytic activities of NaTaO(3-x)N(x) were examined by methylene blue (MB) aqueous solution under UV light. It is found that the photocatalytic activity of NaTaO(3-x)N(x) depend strongly on the doping content of N, and sample NaTaO(2.961)N(0.039) shows the highest photocatalytic activity for the degradation of MB. Furthermore, it is also found that NaTaO(3-x)N(x) catalysts display super structural stabilities during photocatalytic degradation, and could recover their photocatalytic activity after calcination at 500 degrees C, suggesting a promising utilization of such photocatalyst.

[Cytocompatibility of nanophase hydroxyapatite ceramics].

OBJECTIVE: To evaluate the cytocompatibility of nanophase hydroxyapatite ceramics in vitro. METHODS: Hydroxyapatite (HA) was prepared via wet method. The grain size of the hydroxyapatite in the study was determined by scanning electron microscope and atomic force microscope with image analysis software. Primary osteoblast culture was established from rat calvaria. Cell adherence and proliferation on nanophase hydroxyapatite ceramics and conventional hydroxyapatite ceramics were examined at 1, 3, 5, 7 days. Morphology of the cells was observed by microscope. RESULTS: The average grain size of the nanophase and conventional HA was 55 nm and 780 nm, respectively. Throughout 7 days period, osteoblast proliferation on the HA was similar to that on tissue culture borosilicate glass controls, osteoblasts could attach, spread and proliferate on HA. However, compared to conventional ceramics, osteoblast proliferation on nanophase HA was significantly better after 1, 3, 5 and 7 days. CONCLUSION: Cytocompatibility of nanophase HA was significantly better than conventional ceramics.