Preparation of ZrMn2 hydrogen storage alloy by electro-deoxidation in molten calcium chloride
(1. College of Chemical Engineering, Hebei United University, Tangshan 063009, China;
2. State Key Laboratory of Metastable Materials Science and Technology,
Yanshan University, Qinhuangdao 066004, China)
2. State Key Laboratory of Metastable Materials Science and Technology,
Yanshan University, Qinhuangdao 066004, China)
Abstract: ZrMn2 alloy was electro-synthesized directly from cathode pellets compacted with powdered mixture of MnO2 and ZrO2 in molten calcium chloride. Sintering temperature, cell voltage and electrolysis time were the dominant factors that affected the characteristics of the final product. The results confirmed the formation of pure ZrMn2 alloy through the electro-deoxidation of the mixed oxide pellets at 3.1 V for 12 h in 900 °C CaCl2 melt. The X-ray diffraction (XRD) and cyclic voltammetry analysis suggested that the electro-deoxidation proceeded from the reduction of manganese oxides to Mn, followed by ZrO2 or CaZrO3 reduction on the pre-formed Mn to ZrMn2 alloy. The cyclic voltammetry measurements using powder microelectrode showed that the prepared ZrMn2 alloy has a good electrochemical hydrogen storage property.
Key words: electro-deoxidation; ZrMn2 alloy; CaCl2 melt; oxides; hydrogen storage property