The Study Of Preparation And Properties Of AB₅ Type Complex Hydrogen Storage Alloys

Hydrogen has been regarded as one of the new energy sources because of its cleanliness and high energy density. But it is difficult to store and transport it. It is insecure and uneconomical to transport hydrogen in state of gas or liquid. To utilize it effectively, we must resolve the difficulty that how to store hydrogen and transport it. Because of its favorable performance for storage hydrogen and its application in Ni-MH battery, the hydrogen storage alloys which developed in 1970s are thoroughly researched by people in order to further improve their propertiesWe have prepared AB5 type complex hydrogen storage alloy by reduction-diffusion method directly. In order to make comparison, these alloys are synthesized by polymer-network gel method and coprecipitation-reduction-diffusion method at the same time. The thermo-dynamic P-C-T curve test was performed and we have made some electrodes of Ni-MH battery with the complex alloys and then examined their electrochemical properties. The primary experiment process was summarized as follows:1 The complex hydrogen storage alloy has been obtained directly by reduction-diffusion method with rare earth and other metal oxides used as raw material and CaH2 as reductant.2 The oxide precursors were obtained in a polymer-network gel process with the corresponding metal-salts as starting materials. Then the precursors were reduced by calcium hydride in a reduction-diffusion reaction to form the complex hydrogen storage alloy.3 The complex hydrogen storage alloy has been obtained by coprecipitation-reduction-difrusion method with metal-salts and oxalic acid as precipitant in ethanol solution.4 The thermo-dynamic P-C-T curve test was performed on the complex hydrogen storage alloy. The alloys have also been made into electrode of Ni-MH battery to examine their electrochemical behaviour. The result shows that there is great difference among the complex hydrogen storage alloys prepared by different methods.