The Influence Of Alkaline Treating And Y Doping On Hydrogen Stroage Alloy

Focused on solving technical problems exsited in Chinese enterprises, this paper studied the modification of negative hydrogen-storage alloy of Ni-MH in order to extend Ni-MH’s cycle life and improve its storage capacity. On the basis of this study, Chinese enterprises will bridge the gap between SANYO and Yuasa--the two leading enterprises in Japan in this field so that Chinese enterprises will enter into the field of HEV one day. The study object being La0.63Ce0.26Pr0.03Nd0.08Ni3.68Co0.72Mn0.4Al0.3negative hydrogen-storage alloy which is used commonly in Chinese enterprises, this paper studied alkali treatment and the modification of doped yttrium metal (Y) respectively.By the Alkaline treatment of30%KOH solutions on La0.63Ce0.26Pr0.03Nd0.08Ni3.68Co0.72Mn0.4Al0.3, this paper discovered the parameters of termperature and time. By the analysis of physical and chemical differences between the treated and untreated, this paper discovered that alkaline treatment doesn’t change the structures of alloy. However, the treated alloy had rougher surface and larger surface area which reduced the alloy’s electrochemical impedance spectroscopy and improved its performance. By applying the treated alloy into Ni-MH, Ni-MH obtained extended cycle life, increased internal pressure, and higher activation speed.After the modification of doped yttrium metal (Y), the alloy had smaller grain size with its structure unchanged. The modified alloy obtained improved corrosion resistance and extended cycle life with its internal pressure and activation speed slightly decreased. By applying the modified alloy into Ni-MH, Ni-MH obtained extended cycle life and better storage capacity at room temperature, thanks to the the formation of a surface layer of yttrium oxide which reduced the corrosion of the alloy.Although both the two treatment can achieve the desired purpose on extending the cycle life and improving the storage capacity of Ni-MH, the modification of doped yttrium metal (Y) meets enterprises’practical production needs better, in consideration of feasibility. Based on the study, the latter modification method is finally chosen to be applied into mass production.