The nanocrystalline and amorphous Mg2Ni-type Mg2Ni1-xCox （x = 0, 0.1, 0.2, 0.3, 0.4） alloys were synthesized by melt quenching technology. The structures of the as-cast and quenched alloys were characterized by XRD,...The nanocrystalline and amorphous Mg2Ni-type Mg2Ni1-xCox （x = 0, 0.1, 0.2, 0.3, 0.4） alloys were synthesized by melt quenching technology. The structures of the as-cast and quenched alloys were characterized by XRD, SEM and HRTEM. The gaseous hydrogen storage kinetics of the alloys was measured using an automatically controlled Sieverts apparatus. The alloy electrodes were charged and discharged with a constant current density in order to investigate the electrochemical hydrogen storage kinetics of the alloys. The results demonstrate that the substitution of Co for Ni results in the formation of secondary phases MgCo2 and Mg instead of altering the major phase Mg2Ni. No amorphous phase is detected in the as-quenched Co- ffee alloy, however, a certain amount of amorphous phase is clearly found in the as-quenched alloys substituted by Co. Furthermore, both the rapid quenching and the Co substitution significantly improve the gaseous and electrochemical hydrogen storage kinetics of the alloys, for which the notable increase of the hydrogen diffusion coefficient （D） along with the limiting current density （IL） and the obvious decline of the electrochemical impedance generated by both the Co substitution and the rapid quenching are basically responsible.展开更多
Thermoelectric （TE） materials can convert directly low-grade heat energy to electricity, and vice versa, which is highly expected to play an important role in the future energy management. The application practice d...Thermoelectric （TE） materials can convert directly low-grade heat energy to electricity, and vice versa, which is highly expected to play an important role in the future energy management. The application practice demands efficient TE materials made of non-toxic and inexpensive components. Herein, we report a Ni substituted polycrystalline n-type bulk material In4.xNixSe3 （x = 0-0.1）. Based on density functional theory calculation, Ni tends to substitute at the In3 site in the In4Se3, which causes a monotonous unit cell volume reduction. At x=0.01, Ni substitution results in a sharp decrease in the carder concentration （he） in comparison with that of pure In4Se3, and then ne increases with the increase of Ni concentration. Ni substitution leads to a performance enhancement from 0.6 for pure In4Se3 to an optimum ZTvalue of 0.8 at 450℃.展开更多
基金Funded by National Natural Science Foundations of China(Nos.51161015 and 50961009)Natural Science Foundation of Inner Mongolia,China(Nos.2011ZD10 and 2010ZD05)Higher Education Science Research Project of Inner Mongolia,China(No.NJzy08071)
文摘The nanocrystalline and amorphous Mg2Ni-type Mg2Ni1-xCox （x = 0, 0.1, 0.2, 0.3, 0.4） alloys were synthesized by melt quenching technology. The structures of the as-cast and quenched alloys were characterized by XRD, SEM and HRTEM. The gaseous hydrogen storage kinetics of the alloys was measured using an automatically controlled Sieverts apparatus. The alloy electrodes were charged and discharged with a constant current density in order to investigate the electrochemical hydrogen storage kinetics of the alloys. The results demonstrate that the substitution of Co for Ni results in the formation of secondary phases MgCo2 and Mg instead of altering the major phase Mg2Ni. No amorphous phase is detected in the as-quenched Co- ffee alloy, however, a certain amount of amorphous phase is clearly found in the as-quenched alloys substituted by Co. Furthermore, both the rapid quenching and the Co substitution significantly improve the gaseous and electrochemical hydrogen storage kinetics of the alloys, for which the notable increase of the hydrogen diffusion coefficient （D） along with the limiting current density （IL） and the obvious decline of the electrochemical impedance generated by both the Co substitution and the rapid quenching are basically responsible.
基金supported by National Natural Science Foundation of China(21233009,21225104,91422303,21171168 and 21301175)
文摘Thermoelectric （TE） materials can convert directly low-grade heat energy to electricity, and vice versa, which is highly expected to play an important role in the future energy management. The application practice demands efficient TE materials made of non-toxic and inexpensive components. Herein, we report a Ni substituted polycrystalline n-type bulk material In4.xNixSe3 （x = 0-0.1）. Based on density functional theory calculation, Ni tends to substitute at the In3 site in the In4Se3, which causes a monotonous unit cell volume reduction. At x=0.01, Ni substitution results in a sharp decrease in the carder concentration （he） in comparison with that of pure In4Se3, and then ne increases with the increase of Ni concentration. Ni substitution leads to a performance enhancement from 0.6 for pure In4Se3 to an optimum ZTvalue of 0.8 at 450℃.
