Electrochemical Properties of Sn Doped AB_5 Non-Stoichiometric Hydrogen Absorbing Alloys-Ⅱ

摘要

The effects of some substituting elements on the specific discharge capacity, activation and cycling life of AB 5 non stoichiometric hydrogen absorbing alloys were studied electrochemically. Results show that the characteristics of hydrogen absorbing alloys under low current density are greatly improved through the substitution of Ni by Sn, Co, and Mn. Three hydrogen storage alloys, i.e., La(NiSn) 5.14 , La(NiSnCo) 5.12 and La(NiSnMn) 5.12 have the higher specific capacity and easy activation. However, Al in the alloy shows the opposite effect on the electrochemical properties. Under high current density, the discharge capacity and potential of La(NiSn) 5.14 is superior to La(NiSnCo) 5.12 and La(NiSnMn) 5.12 , but the cycling life of La(NiSn) 5.14 is very short. The addition of Mn, Co and Al to the alloys improves the cycling characteristics. In all these alloys, La(NiSnCo) 5.12 is considered as an ideal hydrogen storage alloy.