Tailoring vanadium oxide crystal orientation for high-performance aqueous zinc-ion batteries.

Due to the increasing demand for higher security and low-cost energy storage systems, the main research focus has been developing a suitable substitute for lithium-ion batteries. Aqueous zinc ion batteries (AZIBs) are considered the best alternative to lithium-ion batteries in large-scale energy storage devices. Owing to its high capacity, vanadate is a promising cathode material for AZIBs. The crystallographic orientation of cathode materials dramatically influences the rate performance and cycling life. Here, Mg0.57V5O12·2.3H2O (MgVO) with favorable (001) crystal orientation and significantly improved electrochemical performance is prepared by a simple stirring method. The crystal growth orientations of MgVO are altered by adjusting the aging time of the reactant solution. The (001)-orientated grain growth of MgVO delivers a 232.5 mA h g-1 capacity at 5 A g-1 with a 94% capacity retention rate after 1400 cycles. The zinc ion storage performance of MgVO demonstrates that the orientation-controlled method can design effective cathode materials for high-performance ZIBs.

Capacity-enhanced and kinetic-expedited zinc-ion storage ability in a Zn3V3O8/VO2 cathode enabled by heterostructural design.

Heterostructured double-phase composites are promising electrode candidates for high-performance secondary metal batteries due to their superior capacity and ion transfer kinetics compared with the pristine phase. Herein, a Zn3V3O8/VO2 (ZVO/VO) heterostructure with abundant phase boundaries was designed as the cathode for aqueous zinc-ion batteries (ZIBs). The preparation method is based on a solid pre-intercalation approach, and the Zn content in the ZVO/VO heterostructure can be precisely controlled. The electrochemical performance of ZVO/VO containing different amounts of Zn, pristine ZVO, and VO phases was compared. ZVO/VO showed superior capacity and cycling stability compared to pristine ZVO and VO. The ZVO/VO heterostructure showed a capacity of 328.4 mA h g-1 at 0.3 A g-1 after 200 cycles. The long-term cycling performance of ZVO/VO was evaluated at 3 A g-1, and it delivered a capacity retention of 90.5% after 1000 cycles. The ion storage mechanism of the ZVO/VO electrode was analyzed by ex situ X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). This work provides a simple strategy for designing vanadium-based heterostructure composites as advanced cathodes for ZIBs.

Static and dynamical isomerization of Cu38 cluster.

The lowest-energy geometrical and electronic structures of Cu38 cluster are investigated by density-functional calculations combined with a genetic algorithm based on a many body semi-empirical interatomic potential, the traditional FCC-truncated Octahedron (OH) and an incomplete-Mackay icosahedron (IMI) are recognized as the two lowest energy structures (energetically degenerate isomers) but with different electronic structures: a semiconductor-type with the energy-gap of 0.356 eV for the IMI and a metallic-type with negligible gap for the OH, which is in good agreement with the experimental results. The electron affinity and ionization potential of Cu38 are also discussed and compared with the observations of the ultraviolet photoelectron spectroscopy experiments. The dynamical isomerization of the OH-like and IMI-like structures of Cu38 is revealed to dominate the pre-melting stage through the investigation by the molecular dynamics annealing simulations.

Effects of Nitrogen and Hydrogen Codoping on the Electrical Performance and Reliability of InGaZnO Thin-Film Transistors.

Despite intensive research on improvement in electrical performances of ZnO-based thin-film transistors (TFTs), the instability issues have limited their applications for complementary electronics. Herein, we have investigated the effect of nitrogen and hydrogen (N/H) codoping on the electrical performance and reliability of amorphous InGaZnO (α-IGZO) TFTs. The performance and bias stress stability of α-IGZO device were simultaneously improved by N/H plasma treatment with a high field-effect mobility of 45.3 cm2/(V s) and small shifts of threshold voltage (Vth). On the basis of X-ray photoelectron spectroscopy analysis, the improved electrical performances of α-IGZO TFT should be attributed to the appropriate amount of N/H codoping, which could not only control the Vth and carrier concentration efficiently, but also passivate the defects such as oxygen vacancy due to the formation of stable Zn-N and N-H bonds. Meanwhile, low-frequency noise analysis indicates that the average trap density near the α-IGZO/SiO2 interface is reduced by the nitrogen and hydrogen plasma treatment. This method could provide a step toward the development of α-IGZO TFTs for potential applications in next-generation high-definition optoelectronic displays.

Rational Design of ZnO:H/ZnO Bilayer Structure for High-Performance Thin-Film Transistors.

The intriguing properties of zinc oxide-based semiconductors are being extensively studied as they are attractive alternatives to current silicon-based semiconductors for applications in transparent and flexible electronics. Although they have promising properties, significant improvements on performance and electrical reliability of ZnO-based thin film transistors (TFTs) should be achieved before they can be applied widely in practical applications. This work demonstrates a rational and elegant design of TFT, composed of poly crystalline ZnO:H/ZnO bilayer structure without using other metal elements for doping. The field-effect mobility and gate bias stability of the bilayer structured devices have been improved. In this device structure, the hydrogenated ultrathin ZnO:H active layer (∼3 nm) could provide suitable carrier concentration and decrease the interface trap density, while thick pure-ZnO layer could control channel conductance. Based on this novel structure, a high field-effect mobility of 42.6 cm(2) V(-1) s(-1), a high on/off current ratio of 10(8) and a small subthreshold swing of 0.13 V dec(-1) have been achieved. Additionally, the bias stress stability of the bilayer structured devices is enhanced compared to the simple single channel layer ZnO device. These results suggest that the bilayer ZnO:H/ZnO TFTs have a great potential for low-cost thin-film electronics.

Effect of Cydonia oblonga Mill. leaf extract on serum lipids and liver function in a rat model of hyperlipidaemia.

ETHNOPHARMACOLOGICAL RELEVANCE: Cydonia oblonga Mill. leaves are traditionally used in Uyghur medicine to treat or prevent cardiovascular disease. Beyond a demonstrated effect on thrombosis, we tested it for an effect on dyslipidemia, in a rat model of hyperlipidemia. METHODS: Seventy healthy Sprague Dawley rats were randomly divided into 6 groups: normal controls, model controls, simvastatin, and low-, medium- and high-dose Cydonia oblonga Mill. leaf extracts (COM), orally for 56 days. The normal controls were fed a normal diet, all other groups a high fat diet. Rat weights were recorded over time. Total cholesterol (TC), triglycerides (TG), low and high-density lipoproteins (LDL, HDL), as well as AST, ALT and total protein (TP) were measured in serum at the end of the study. The antioxidant capacity of glutathione peroxidase (GSH-PX), superoxide dismutase (SOD), malondialdehyde (MDA) was measured in liver samples, along with lipoprotein lipase (LPL), and hepatic lipase (HL). Liver pathology was described. RESULTS: COM dose-dependently reduced TC, TG, LDL-C and MDA, inhibited the activity of ALT, AST and LPS, increased HDL-C content, increased the activity of SOD, GSH-PX, LPL and HL, and reduced liver steatosis in hyperlipidaemia rats, which was significant at medium and high doses. The effect of COM was similar to that of simvastatin except for increased LPL and HL which were reduced by COM but not by simvastatin. CONCLUSION: Cydonia oblonga Mill. leaf extracts have hypolipidaemic and hepatoprotective effects, probably related to increasing antioxidant capacity and lipoprotein metabolism in the liver, and inhibition of lipogenesis.