因應能源缺乏及大量的空氣汙染，運用氫氣作為新能源選項為世界的趨勢。而將氫氣作為燃料時，其運輸及應用上需要儲氫材料將氫氣儲存，儲氫材料中使用儲氫合金是其中效果較好且安全性佳的選擇。其中LaNi5儲氫合金為相當適合之選項，LaNi5儲氫合金能夠應用於常溫常壓中，對於日常生活的運輸或車用是非常優秀的材料，但其應用時，會因使用次數上升，導致其儲氫效果愈來愈差，使用壽命因此減短。但若在其中摻雜些許原子半徑較Ni大之過渡元素，則能夠效提升其使用壽命，增加儲氫合金的循環穩定性。
因此本研究於LaNi5儲氫合金中摻入Al及Cu作為改性之材料，將5種儲氫合金LaNi5、LaNi4.75Al0.25、LaNi4.5Al0.5、LaNi4.75Cu0.25及LaNi4.5Cu0.5，通過50 ℃及100 ℃兩種溫度，研究其吸放氫情形觀察是否達到目的。經研究後發現，Al添加後的效果，於循環穩定性上十分優秀，不論是50 ℃或100 ℃中的表現，皆明顯優於其餘合金。但因Al的添加，會造成儲氫量為略遜於其餘合金，而添加之Al含量愈多，會使儲氫量下降愈多。在50 ℃時LaNi4.75Al0.25和LaNi4.5Al0.5儲氫量分別為0.989 wt%及0.969 wt%，而100 ℃時LaNi4.75Al0.25和LaNi4.5Al0.5的儲氫量為0.924 wt%和0.902 wt%，循環穩定性表現為LaNi4.5Al0.5效果較佳。而摻雜Cu的效果和Al類似，Cu含量升高會使循環穩定性增加，卻導致儲氫量下降，但在50 ℃時儲氫表現優異，LaNi4.75Cu0.25和LaNi4.5Cu0.5儲氫量達1.024 wt%和1.014 wt%，循環穩定性表現甚至優於含Al之儲氫合金；100 ℃時，含Cu之合金的儲氫性能表現類似LaNi5大幅降低，剩餘約0.75 wt%，而循環穩定性LaNi4.5Cu0.5表現較佳。
於LaNi5中摻雜Al及Cu的效果證明，較大原子填入時明顯循環穩定性提升，但會導致儲氫量的下降。50 ℃時，LaNi4.5Cu0.5儲氫效果最佳，循環穩定性表現甚至優於含 Al 之儲氫合金，而100 ℃時，LaNi4.5Al0.5儲氫量雖略遜於LaNi4.75Al0.25，但因優秀的循環穩定性，反而是較佳的選擇。

In response to the lack of energy and a lot of air pollution, the use of hydrogen as a new energy option is a trend in the world. When hydrogen is used as a fuel, its transportation and application require hydrogen storage materials to store hydrogen, and the use of hydrogen storage alloys in hydrogen storage materials is a better and safer choice. Among them, LaNi5 hydrogen storage alloy is a very suitable option. LaNi5 hydrogen storage alloy can be used in normal temperature and pressure, and is an excellent material for daily transportation or vehicle use. During its application, due to the increase in the number of uses, its hydrogen storage effect will be worse and worse, and the service life will be shortened accordingly. However, when some transition elements with a larger atomic radius than Ni are doped, the service life can be effectively improved and the cycle stability of the hydrogen storage alloy can be increased.
Therefore, in this study, Al and Cu were doped into LaNi5 hydrogen storage alloy as modified materials, and five kinds of hydrogen storage alloys were made: LaNi5、LaNi4.75Al0.25、LaNi4.5Al0.5、LaNi4.75Cu0.25 and LaNi4.5Cu0.5. Through the two temperatures of 50 ℃ and 100 ℃, the hydrogen absorption and desorption are studied to observe whether the purpose is achieved. After research, it is found that the effect of Al addition is very good in cycle stability, and the performance at 50 ℃ or 100 ℃ is obviously better than that of other alloys. However, due to the addition of Al, the hydrogen storage capacity is slightly lower than that of the other alloys, and the more Al content is added, the more the hydrogen storage capacity decreases. At 50 ℃, the hydrogen storage capacities of LaNi4.75Al0.25 and LaNi4.5Al0.5 are 0.989 wt% and 0.969 wt%, respectively. At 100 ℃, the hydrogen storage capacities of LaNi4.75Al0.25 and LaNi4.5Al0.5 are 0.924 wt% and 0.902 wt%, and the cycle stability is better for LaNi4.5Al0.5. The effect of doping Cu is similar to that of Al. The increase of Cu content will increase the cycle stability, but lead to a decrease in hydrogen storage. However, the hydrogen storage performance is excellent at 50 ℃, and the hydrogen storage capacity of LaNi4.75Cu0.25 and LaNi4.5Cu0.5 reaches 1.024 wt% and 1.014 wt%, and the cycle stability performance is even better than that of Al-containing hydrogen storage alloys. At 100 ℃, the hydrogen storage performance of the alloy containing Cu is similar to that of LaNi5, which is greatly reduced, and the remaining about 0.75 wt%, while the cycle stability of LaNi4.5Cu0.5 is better.
The effect of doping Al and Cu in LaNi5 proves that the cycle stability is obviously improved when larger atoms are filled, but it will lead to a decrease in the hydrogen storage capacity. At 50 ℃, LaNi4.5Cu0.5 has the best hydrogen storage effect, and the cycle stability performance is even better than that of Al-containing hydrogen storage alloys. At 100 ℃, although the hydrogen storage capacity of LaNi4.5Al0.5 is slightly lower than that of LaNi4.75Al0.25, it is a better choice due to its excellent cycle stability.

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