Al-Zn-Si-RE coating with high Al content was deposited on mild steel by arc spraying. The electrochemical behavior of Al-Zn-Si-RE coating in 3.5%NaCl solution was systematically studied by potentiodynamic polarization...Al-Zn-Si-RE coating with high Al content was deposited on mild steel by arc spraying. The electrochemical behavior of Al-Zn-Si-RE coating in 3.5%NaCl solution was systematically studied by potentiodynamic polarization, corrosion potential (φcor ) and electrochemical impedance spectroscopy techniques (EIS). The impedance data were fitted to appropriate equivalent circuits to explain the different electrochemical processes occurring at the electrode-electrolyte interface. The results indicate that Al-Zn-Si-RE coating reveals the similar polarization behavior as Zn-15Al coating. The coating has no passive region in the anodic polarization, but far lower corrosion current and much higher corrosion potential. Al-Zn-Si-RE coating provides effective sacrificial protection for steel substrate and the sacrificial anodic protection plays dominant role during the immersion process. In addition, theφcor evolution and EIS plots indicate that the corrosion process can be divided into five stages: pitting-dissolution-redeposition, activation corrosion, cathodic protection, physical barriers and the coating failure.展开更多
Si(111)electrode has been widely used in electrochemical and photoelectrochemical studies.The potential dependent measurements of the second harmonic generation(SHG)were performed to study Si(111)electrode interface.A...Si(111)electrode has been widely used in electrochemical and photoelectrochemical studies.The potential dependent measurements of the second harmonic generation(SHG)were performed to study Si(111)electrode interface.At different azimuthal angles of the Si(111)and under different polarization combinations,the curve of the intensity of SHG with extern potential has a different form of line or parabola.Quantitative analysis showed that these differences in the potential-dependence can be explained by the isotropic and anisotropic contribution of the Si(111)electrode.The change in the isotropic and anisotropic contribution of the Si(111)electrode may be attributed to the increase in the doping concentration of Si(111)electrodes.展开更多
In this work, a density functional theory （DFT） based first-principles study is carried out to investigate tile potential of phosphorene-like SiS and SiSe monolayers as anode materials for sodium-ion （Na-ion） bat-...In this work, a density functional theory （DFT） based first-principles study is carried out to investigate tile potential of phosphorene-like SiS and SiSe monolayers as anode materials for sodium-ion （Na-ion） bat- teries. Results show that both SiS and SiSe have large adsorption energies towards single Na atom of 0.94 and -0.43 eV, owing to the charge transfers from Na to SiS or SiSe. In addition, it is found that the highest Na concentration for both SiS and SiSe is x = 1 with the chemical formulas of NaSiS and NaSiSe, corresponding to the high theoretical specific capacities for Na storages of 445.6 and 250.4 mAh g 1, respectively. Moreover, Na diffusions are very fast and show strong directional behaviors on SiS and SiSe monolayers, with the energy barriers of only 0.135 and 0.158 eV, lower than those of con- ventional anode materials for Na-ion batteries such as Na2Ti3O7 （0.19 eV） and Na3Sb （0.21 eV）. Finally, although SiS and SiSe show semiconducting behaviors, they transform to metallic states after adsorbing Na atoms, indicating enhanced electrical conductivity during battery cycling. Given these advantages, it is expected that both SiS and SiSe monolayers are promising anode materials for Na-ion batteries, and in principle, other Na-based batteries as well.展开更多
We report the fabrication of CuI-Si heterojunction solar cells with carbon nanotubes （CNTs） as a transparent electrode. A flexible CNT network was transferred onto tile top of a polycrystalline CuI layer, making a c...We report the fabrication of CuI-Si heterojunction solar cells with carbon nanotubes （CNTs） as a transparent electrode. A flexible CNT network was transferred onto tile top of a polycrystalline CuI layer, making a conformal coating with good contact with the underlying CuI. The solar cells showed power conversion efficiencies in the range of 6% to 10.5%, while the efficiency degradation was less than 10% after the device was stored in air for 8 days. Compared with conventional rigid electrodes such as indium tin oxide （ITO） glass, the flexibility of the CNT films ensures better contact with the active layers and removes the need for press-contact electrodes. Degraded cells can recover their original performance by acid doping of the CNT electrode. Our results suggest that CNT films are suitable electrical contacts for rough materials and structures with an uneven surface.展开更多
基金Project(CXLX12_0149)supported by Funding of Jiangsu Innovation Program for Graduate Education,ChinaProject(BA2011029)supported by Special Fund of Transformation of Sci-tech Achievements of Jiangsu Province,China+1 种基金Project(BY2011101)supported by the Creative Fund of Combination of Industry,Academia and Research of Jiangsu Province,China-Prospective Joint Research ProjectProject(kfjj120217)supported by Open Funds of NUAA Innovation Base(Laboratory)for Graduate Students
文摘Al-Zn-Si-RE coating with high Al content was deposited on mild steel by arc spraying. The electrochemical behavior of Al-Zn-Si-RE coating in 3.5%NaCl solution was systematically studied by potentiodynamic polarization, corrosion potential (φcor ) and electrochemical impedance spectroscopy techniques (EIS). The impedance data were fitted to appropriate equivalent circuits to explain the different electrochemical processes occurring at the electrode-electrolyte interface. The results indicate that Al-Zn-Si-RE coating reveals the similar polarization behavior as Zn-15Al coating. The coating has no passive region in the anodic polarization, but far lower corrosion current and much higher corrosion potential. Al-Zn-Si-RE coating provides effective sacrificial protection for steel substrate and the sacrificial anodic protection plays dominant role during the immersion process. In addition, theφcor evolution and EIS plots indicate that the corrosion process can be divided into five stages: pitting-dissolution-redeposition, activation corrosion, cathodic protection, physical barriers and the coating failure.
基金supported by the National Natural Science Foundation of China(No.21673251,No.21773258,No.21873104,and No.91856121)the Chinese Academy of Sciences(No.JKYYQ20180014)。
文摘Si(111)electrode has been widely used in electrochemical and photoelectrochemical studies.The potential dependent measurements of the second harmonic generation(SHG)were performed to study Si(111)electrode interface.At different azimuthal angles of the Si(111)and under different polarization combinations,the curve of the intensity of SHG with extern potential has a different form of line or parabola.Quantitative analysis showed that these differences in the potential-dependence can be explained by the isotropic and anisotropic contribution of the Si(111)electrode.The change in the isotropic and anisotropic contribution of the Si(111)electrode may be attributed to the increase in the doping concentration of Si(111)electrodes.
基金supported by the grant from the Research Grants Council of the Hong Kong Special Administrative Region, China (16213414)
文摘In this work, a density functional theory （DFT） based first-principles study is carried out to investigate tile potential of phosphorene-like SiS and SiSe monolayers as anode materials for sodium-ion （Na-ion） bat- teries. Results show that both SiS and SiSe have large adsorption energies towards single Na atom of 0.94 and -0.43 eV, owing to the charge transfers from Na to SiS or SiSe. In addition, it is found that the highest Na concentration for both SiS and SiSe is x = 1 with the chemical formulas of NaSiS and NaSiSe, corresponding to the high theoretical specific capacities for Na storages of 445.6 and 250.4 mAh g 1, respectively. Moreover, Na diffusions are very fast and show strong directional behaviors on SiS and SiSe monolayers, with the energy barriers of only 0.135 and 0.158 eV, lower than those of con- ventional anode materials for Na-ion batteries such as Na2Ti3O7 （0.19 eV） and Na3Sb （0.21 eV）. Finally, although SiS and SiSe show semiconducting behaviors, they transform to metallic states after adsorbing Na atoms, indicating enhanced electrical conductivity during battery cycling. Given these advantages, it is expected that both SiS and SiSe monolayers are promising anode materials for Na-ion batteries, and in principle, other Na-based batteries as well.
基金This work is supported by the National Natural Science Foundation of China （NSFC, Grant No.50972067） and the 863 Program （No. 2009AA05Z423）. A. Cao acknowledges the support by the National Science Foundation of China （NSFC, No. 51072005） and C. Huang acknowledges NSFC No. 90922004 for financial support.
文摘We report the fabrication of CuI-Si heterojunction solar cells with carbon nanotubes （CNTs） as a transparent electrode. A flexible CNT network was transferred onto tile top of a polycrystalline CuI layer, making a conformal coating with good contact with the underlying CuI. The solar cells showed power conversion efficiencies in the range of 6% to 10.5%, while the efficiency degradation was less than 10% after the device was stored in air for 8 days. Compared with conventional rigid electrodes such as indium tin oxide （ITO） glass, the flexibility of the CNT films ensures better contact with the active layers and removes the need for press-contact electrodes. Degraded cells can recover their original performance by acid doping of the CNT electrode. Our results suggest that CNT films are suitable electrical contacts for rough materials and structures with an uneven surface.
