The CoO/CoVO/Ni nanocomposites were rationally designed and prepared by a two-step hydrothermal synthesis and subsequent annealing treatment. The one-dimensional（1D） CoOnanowire arrays directly grew on Ni foam, wher...The CoO/CoVO/Ni nanocomposites were rationally designed and prepared by a two-step hydrothermal synthesis and subsequent annealing treatment. The one-dimensional（1D） CoOnanowire arrays directly grew on Ni foam, whereas the 1D CoVOnanowires adhered to parts of CoOnanowires.Most of the hybrid nanowires were inlayed with each other, forming a 3D hybrid nanowires network.As a result, the discharge capacity of CoO/CoVO/Ni nanocomposites could reach 1201.8 mAh/g after100 cycles at 100 mA/g. After 600 cycles at 1 A/g, the discharge capacity was maintained at 828.1 mAh/g.Moreover, even though the charge/discharge rates were increased to 10 A/g, it rendered reversible capacity of 491.2 mAh/g. The superior electrochemical properties of nanocomposites were probably ascribed to their unique 3D architecture and the synergistic effects of two active materials. Therefore, such CoO/CoVO/Ni nanocomposites could potentially be used as anode materials for high-performance Li-ion batteries.展开更多
The non-isothermal reduction kinetics and mechanism of Fe2O3-NiO composites with different Fe2O3-NiO compacts using carbon monoxide as reductant were investigated. The results show that the reduction degree increases ...The non-isothermal reduction kinetics and mechanism of Fe2O3-NiO composites with different Fe2O3-NiO compacts using carbon monoxide as reductant were investigated. The results show that the reduction degree increases rapidly with increasing the content of NiO, and the presence of NiO also improves the reduction rate of iron oxides. It is found that NiO is preferentially reduced at the beginning of the reactions, and then the metallic Ni acts as a catalyst promoting the reduction rate of iron oxides. It is also observed that the increase of the Ni O content enhances the formation of awaruite(FeNi3) but decreases the percentage of kamacite(Fe,Ni) and taenite(Fe,Ni). The particle size of the materials tends to be uniform during the reduction process due to the presence of metallic nickel, metallic iron and the formation of Fe-Ni alloy. The concentration of CO in the product gas is greater than that of CO2 at the beginning of the reaction and then slows down. The fastest reduction rate of Fe2O3-NiO composites with CO appears at 400-500 °C, and nucleation growth model can be used to elucidate the reduction mechanism. Nucleation growth process is found to be the rate controlling step when the temperature is lower than 1000 °C.展开更多
基金supported by the National Natural Science Foundation of China(no.51362018)the Foundation for Innovation Groups of Basic Research in Gansu Province(no.1606RJIA322)
文摘The CoO/CoVO/Ni nanocomposites were rationally designed and prepared by a two-step hydrothermal synthesis and subsequent annealing treatment. The one-dimensional（1D） CoOnanowire arrays directly grew on Ni foam, whereas the 1D CoVOnanowires adhered to parts of CoOnanowires.Most of the hybrid nanowires were inlayed with each other, forming a 3D hybrid nanowires network.As a result, the discharge capacity of CoO/CoVO/Ni nanocomposites could reach 1201.8 mAh/g after100 cycles at 100 mA/g. After 600 cycles at 1 A/g, the discharge capacity was maintained at 828.1 mAh/g.Moreover, even though the charge/discharge rates were increased to 10 A/g, it rendered reversible capacity of 491.2 mAh/g. The superior electrochemical properties of nanocomposites were probably ascribed to their unique 3D architecture and the synergistic effects of two active materials. Therefore, such CoO/CoVO/Ni nanocomposites could potentially be used as anode materials for high-performance Li-ion batteries.
基金Projects(51304091,U1302274)supported by the National Natural Science Foundation of ChinaProjects(2013FD009,2013FZ007)supported by Applied Basic Research Program of Yunnan Province,ChinaProject(2012HB009)supported by the Candidate Talents Training Fund of Yunnan Province,China
文摘The non-isothermal reduction kinetics and mechanism of Fe2O3-NiO composites with different Fe2O3-NiO compacts using carbon monoxide as reductant were investigated. The results show that the reduction degree increases rapidly with increasing the content of NiO, and the presence of NiO also improves the reduction rate of iron oxides. It is found that NiO is preferentially reduced at the beginning of the reactions, and then the metallic Ni acts as a catalyst promoting the reduction rate of iron oxides. It is also observed that the increase of the Ni O content enhances the formation of awaruite(FeNi3) but decreases the percentage of kamacite(Fe,Ni) and taenite(Fe,Ni). The particle size of the materials tends to be uniform during the reduction process due to the presence of metallic nickel, metallic iron and the formation of Fe-Ni alloy. The concentration of CO in the product gas is greater than that of CO2 at the beginning of the reaction and then slows down. The fastest reduction rate of Fe2O3-NiO composites with CO appears at 400-500 °C, and nucleation growth model can be used to elucidate the reduction mechanism. Nucleation growth process is found to be the rate controlling step when the temperature is lower than 1000 °C.
