Hydrogen storage alloy is an important functional material. Of all the hydrogen storage alloys studied previously, AB~5-type mischmetal- based hydrogen storage alloy is used most widely. In this paper, positron-annihilation technique (PAT) is used to study the defect of the alloys. At the same time, X-ray diffraction (XRD), cyclic voltammetry (CV) and electrochemical capacities of the alloys are investigated to characterize the structure and properties of the alloys. Experimental results show that the microdefect in the alloys can improve the properties of the alloys apparently.

Key words: HYDROGEN STORAGE ALLOY, DEFECTS, X-RAY DIFFRACTION ANALYSIS