Lithium cobaltate:a novel host material enables high-rate and stable lithium-sulfur batteries

Element sulfur is highly attractive due to their potentially low cost and environmental compatibility.However, polysulfides dissolution hinders the lithiumsulfur(Li-S) batteries toward commercialization. To overcome these issues, in this work, lithium cobaltate as a commercial material, for the first time, was devoted to engineering the electrode structure and composition to improve the performance. When incorporated with 80% sulfur powder, the synergetic effects of cobalt atoms and interlayer spaces effectively enable the production of Li-S batteries with a relatively high discharge capacity of 1420 mAh·g-1at the low surface current density of 1 mA·cm-2and stable capacity retention of 650 mAh·g-1at high surface current density of 6 mA·cm-2. The introduction of lithium cobaltate is a viable approach for successfully developing practical Li-S batteries.

Nickel-free sealing technology for anodic oxidation film of aluminum alloy at room temperature

Different additives were added into the potassium fluorozirconate solution to prepare different nickelfree sealing reagents,with which the anodic oxidation film of aluminum alloy was sealed at room temperature.The phosphor chromic acid weight loss method was used to evaluate the sealing effects.Using electron scanning microscopy(SEM),the surface and cross-sectional micromorphologies of the anodic oxidation films sealed by different fluorozirconate sealants were observed.The position and state of zirconium element distribution in the film hole were investigated by the further quantitative and distribution analysis of Zr element.This study provides an experimental evidence for the theoretical studies of fluorozirconate-sealed anodic oxidation films.It is shown that the fluorozirconate has good sealing effects and has a wide prospect for sealing the aluminum alloy samples.Its products were highly corrosion resistant,and were filled in the openings of the micropores in the oxide film.

Design and fabrication of a low modulus β-type Ti-Nb-Zr alloy by controlling martensitic transformation

In this paper, high density of dislocations, grain boundaries and nanometer-scale α precipitates were intro- duced to a metastable Ti-36Nb-5Zr alloy （wt%） through a thermo-mechanical approach including severe cold rolling and short-time annealing treatment. The martensitic trans- formation was retarded, and the β phase with low content of β stabilizers was retained at room temperature after the thermo-mechanical treatment. As a result, both low mod- ulus （57 GPa） and high strength （950 MPa） are obtained. The results indicate that it is a feasible strategy to control martensitic transformation start temperature through microstructure optimization instead of composition design, with the aim of fabricating low modulus β-type Ti alloy.

Characteristics of Ce-Mn film on 6061 alloys and its improved performance

HF2- was applied to accelerate the Ce-Mn film formation on 6061A1 alloy in the Ce3+-MnO4-solution.The process of film formation,the composition and structure of the film were analyzed by scanning electron microscopy(SEM) equipped with energy-dispersive spectroscopy(EDS),X-ray photoelectron spectroscopy(XPS)and X-ray diffractometer(XRD).The film formation process includes three stages.At the initial stage,a threedimensional(3D) skeleton was formed quickly,and then the skeleton was fully filled with cerium oxide and manganese oxide,resulting in a dense structure.Subsequently,a new skeleton was formed and also filled.Al,Ce,O and Mn were detected in the film.Ce existed mainly in the form of Ce4+(89%).The film existed in an amorphous form and was composed of ceria(cerium hydroxide),manganese dioxide and aluminum oxide.After electrostatically spraying fluorocarbon powder,the resultant products satisfied the required mechanical performance and exhibited almost non-filament corrosion compared with commercially available chromium-free conversion film.Its corrosion resistant time to acetate spray can reach 2000 h,which is consistent with that of fluorocarbon paint.The results showed that Ce-Mn film can offer an attractive prospect to eliminate volatile organic compounds(VOC) problem arisen by using fluorocarbon paint in the process of industrial production.