As the loss of active material Mg may affect electrode’s discharge capacity and the cycling stability, a more refined mechanism study on cycling capacity degradation should be made. The present investigation is based...As the loss of active material Mg may affect electrode’s discharge capacity and the cycling stability, a more refined mechanism study on cycling capacity degradation should be made. The present investigation is based on the supposition that the capacity degradation of the binary Mg50Ni50 alloy and ternary Mg45Cu5Ni50 alloy electrodes is solely due to the corrosion of Mg, the active hydrogen storage element. That means amount of capacity degradation is determined by the corrosion current time, which is also the time of operation. The corrosion current J corr dependence on cycling time was deduced. A mathematic relation between the cycling capacity retention C N / C 1 (%) and the duration of operation was also deduced. The data calculated from the equations deduced agree well with those of the experiment result. The loss of the active hydrogen absorbing element Mg is proved to be the main cause for cycling capacity deterioration in the present investigation.展开更多
The thermal stability of amorphous ternary hydrides Mg_(50)Ni_(50)H_(54) and Mg_(30)Ni_(70)H_(45) and their corre- sponding amorphous binary alloys Mg_(50)Ni_(50) and Mg_(30)Ni_(70) were studied with X-ray diffraction...The thermal stability of amorphous ternary hydrides Mg_(50)Ni_(50)H_(54) and Mg_(30)Ni_(70)H_(45) and their corre- sponding amorphous binary alloys Mg_(50)Ni_(50) and Mg_(30)Ni_(70) were studied with X-ray diffraction (XRD) and differential scanning calorimetry(DSC). Samples of the amorphous alloys were prepared by mechanical alloying and the amorphous hydrides were obtained by charging the alloys with gas- eous hydrogen at 3.0 MPa and 423 K. It was found that the amorphous hydrides released most of their hydrogen before the crystallization of the essentially hydrogen depleted amorphous alloy. The crystallization temperature of amorphous Mg_(50)Ni_(50)H_(54) elevated and that of amorphous Mg_(30)Ni_(70)H_(45) did not change in relation to the original binary amorphous alloy. This is very excep- tional for amorphous hydrides. The reason for the effects of hydrogen absorption/desorption on the crystallization of amorphous alloys was discussed.展开更多
文摘As the loss of active material Mg may affect electrode’s discharge capacity and the cycling stability, a more refined mechanism study on cycling capacity degradation should be made. The present investigation is based on the supposition that the capacity degradation of the binary Mg50Ni50 alloy and ternary Mg45Cu5Ni50 alloy electrodes is solely due to the corrosion of Mg, the active hydrogen storage element. That means amount of capacity degradation is determined by the corrosion current time, which is also the time of operation. The corrosion current J corr dependence on cycling time was deduced. A mathematic relation between the cycling capacity retention C N / C 1 (%) and the duration of operation was also deduced. The data calculated from the equations deduced agree well with those of the experiment result. The loss of the active hydrogen absorbing element Mg is proved to be the main cause for cycling capacity deterioration in the present investigation.
文摘The thermal stability of amorphous ternary hydrides Mg_(50)Ni_(50)H_(54) and Mg_(30)Ni_(70)H_(45) and their corre- sponding amorphous binary alloys Mg_(50)Ni_(50) and Mg_(30)Ni_(70) were studied with X-ray diffraction (XRD) and differential scanning calorimetry(DSC). Samples of the amorphous alloys were prepared by mechanical alloying and the amorphous hydrides were obtained by charging the alloys with gas- eous hydrogen at 3.0 MPa and 423 K. It was found that the amorphous hydrides released most of their hydrogen before the crystallization of the essentially hydrogen depleted amorphous alloy. The crystallization temperature of amorphous Mg_(50)Ni_(50)H_(54) elevated and that of amorphous Mg_(30)Ni_(70)H_(45) did not change in relation to the original binary amorphous alloy. This is very excep- tional for amorphous hydrides. The reason for the effects of hydrogen absorption/desorption on the crystallization of amorphous alloys was discussed.
