ZnSn(OH)6 (ZSH) nanocubes with a uniform size of 40-80 nm were synthesized by using a simple hydrothermal route and then combined with graphene sheets (rGO) via the electrostatic interaction. The formed composite of ZnSn(OH)6 nanocube-graphene (ZSH-rGO) was used as an anode material for Li-ion batteries and it exhibited significantly enhanced electrochemical performance. For instance, a capacity of 540 mA h g(-1) at 500 mA g(-1) was retained after 40 cycles.
A renewable-biomolecule-based electrode is developed through a facile synchronous reduction and self-assembly process, without any binder or additional conductive agent. The hybridized electrodes can be fabricated with arbitrary size and shape and exhibit superior capacity and cycle performance. The renewable-biomaterial-based high-performance electrodes will hold a place in future energy-storage devices.
The heavy fragments in heavy-ion collisions are finally formed after the hot prefragments undergo sequential decay, of whom the temperature should be much lower than that of prefragments. Using the double ratio (DR) method, the isotopic thermometer (Tiso) for heavy fragment is constructed using the yield of heavy isotopes. Tiso of heavy fragment is obtained by analyzing the measured data in the 1A GeV 124,136Xe and 140A MeV 48Ca/64Ni reactions. Result shows that Tiso varies from 0.5 MeV to 10 MeV. But most Tiso is around 1 ± 0.5 MeV, which is much lower than temperature of light particles. Result also indicates that the difference between Tiso of heavy fragments in different reactions is very small, and Tiso is independent on the size of the reaction system, the incident energy and the neutron-richness of the projectile.
As a new member of metal oxide family, two-dimensional (2D) amorphous metal oxide nanosheets have attracted considerable research interest in various fields, because of their unique surface electronic structure. However, some 2D amorphous metal oxide nanosheets produced by strong acid weak alkali salts (such as FeCl3, ZrCl4, CrCl3, SnCl4, and AlCl3) are difficult to synthesize, because of their tendency to precipitate and aggregate under facile conditions. Thus, developing a common route to prepare these 2D amorphous metal oxide nanosheets is urgently needed. Herein, we report a universal method to synthesize a series of 2D amorphous metal oxide, including Fe2O3, Cr2O3, ZrO2, SnO2, and Al2O3. In this method, lamellar oleate is introduced as a host matrice to restrict the ion exchange reaction that occurs between Cu2O and metal ions. By controlling calcination temperature to remove the oleate, the corresponding 2D amorphous metal oxide ultrathin nanosheets are successfully obtained. This facial method may open a new avenue to fabricate promising 2D amorphous metal oxide nanosheets for practical applications.
Aluminium nitride films were synthesized by electron gun evaporation of aluminium on Si(111) wafer and glassy carbon, with simultaneous bombardment of 5-20 keV nitrogen ions. The resultant films were characterized by X-ray photoelectron spectroscopy, X-ray diffraction and Rutherford backscattering spectrometry. Under specific experimental condition, polycrystalline AlN films, with a hexagonal structure of fine crystallinity, were obtained. The correlation between experimental parameters and the resulting structure as well as the stoichiometry of the AlN films is also discussed.
Performance degradation of prismatic lithium ion batteries (LIBs) with LiCoO2 and mesocarbon microbead as active materials is investigated at an elevated temperature for shallow depth of discharge. Aged LIBs are disassembled to characterize the interface morphology, bulk structure, and reversible capacity of an individual electrode. It is found that the formation of interfacial blocking layer (IBL) on the anode results in the cathode state of charge (SOC) offset, which is the primary reason for the cathode degradation. The main capacity degradation of the anode is attributed to the IBL on the anode surface that impedes the intercalation and deintercalation of lithium ions. Because the full battery capacity is limited by the cathode during aging, the cathode SOC offset is the most important reason for the full battery capacity loss. Interestingly, the capacity of aged LIBs can be recovered to a relative high level after adding the electrolyte, rather than the solvent. This recovery is attributed to the relief of the cathode SOC offset and the dissolution of the anode IBL, which reopens the intercalation and deintercalation paths of lithium ions on the anode. Moreover, it is revealed that the relief of cathode SOC offset and the dissolution of anode IBL trigger and promote mutually to drive the recovery of LIBs.
As a promising anodic material for rechargeable batteries, Sb2O3 has drawn increasing attention due to its high theoretical capacity and abundant natural deposits. However, poor cyclability and rate performance of Sb2O3 derived from a large volume change during insertion/desertion reactions as well as a sluggish kinetic process restrict its practical application. Herein, we report a facile amorphous-to-crystalline strategy to synthesize a densely packed Sb2O3 nanosheet-graphene aerogel as a novel anode for sodium ion batteries (SIBs). This Sb2O3/graphene composite displays a reversible capacity as high as 657.9 mA h g-1 even after 100 cycles at 0.1 A g-1, along with an excellent rate capacity of 356.8 mA h g-1 at 5.0 A g-1. The superior electrochemical performance is attributed to the synergistic effects of densely packed Sb2O3 nanosheets and graphene aerogel, which serves as both a robust support and stable buffer layer to maintain the structural stability of the nanocomposite, and enhances the electrode kinetics of electrolyte diffusion and electron transfer simultaneously. Hence, this densely-packed two-dimensional Sb2O3 nanosheet-graphene aerogel can be a promising anode material for rechargeable SIBs due to its facile synthesis process and outstanding electrochemical performance.
A novel nucleation technique based on electron cyclotron resonance microwave plasma was developed to grow diamond films. A nucleation density higher than 10 8 nuclei/cm 2 was achieved on an untreated, mirror-polished Si substrate. Uniform diamond films were obtained by combining this nucleation method with growth by the common microwave plasma chemical vapor deposition method. Atomic force microscopy, Raman spectroscopy and scanning electron microscopy were used to characterize the phase composition and morphology of the samples after the nucleation and growth stages.
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