Recent Advances on Preparation Method of Ti-Based Hydrogen Storage Alloy
Based on the low equilibrium pressure of hydrogen adsorption, strong ability of helium fixation, stable chemical properties and high safety of the formed hydrides, pure titanium and TiZr can be studied for the long-term storage of tritium gas. The key problem to be solved is to reduce the retention. Based on the high equilibrium pressure of TiFe and TiMn hydrogen desorption systems, they can be developed and studied for hydrogen storage and pumping in the production process. The key problem to be solved is to realize the repeated recycling of materials and reduce the cost.
In order to solve the above problems, the current research direction is mainly elemental substitution, hoping to make a breakthrough in hydrogen absorption and desorption and comprehensive properties of the multi-element alloy through the study of ternary or even multi-element alloying.
1, Pure Titanium Series
Compared with other materials, titanium has very superior properties for hydrogen storage. First of all, titanium has the advantages of rapid adsorption and desorption of hydrogen. In addition, the equilibrium pressure of adsorption hydrogen of titanium at room temperature (25℃) is 10-8 Pa, which reduces the loss of hydrogen. Second, in terms of safety, titanium-hydrogen compounds are very stable and easy to handle even when exposed to air at room temperature. Hydrogen will not be released unless subjected to high temperature. Finally, titanium is a low-cost metal that is naturally abundant, five times more abundant than iron and 100 times more abundant than copper in the earth's crust. The main disadvantage of titanium hydrogen storage is that the desorption temperature of titanium hydride is too high and the retention is large. In order to reach the equilibrium hydrogen pressure of 100kPa, it must be heated to a temperature near 800℃.
2, TiFe Series
TiFe alloy is a kind of hydrogen storage material with good performance, and it is also a typical AB type hydrogen storage alloy. It was discovered by Reilly and Wiswall in the United States in 1974. As a hydrogen storage material, TiFe alloy has been gradually paid attention to by researchers and a lot of research has been done.
After activation, TiFe alloy has a better performance in hydrogen absorption and desorption. The hydrogen adsorption capacity is large and the maximum hydrogen absorption capacity is up to (mass fraction). The equilibrium hydrogen adsorption pressure of TiFe alloy is 300kPa at room temperature. TiFe alloys have many advantages as hydrogen storage materials, but there are also some problems: 1) activation difficulty; 2) Large retention.
3, TiZr Series
Zr and Ti belong to group ⅳB metal elements. Similar to Ti, Zr is also a metal material with high hydrogen absorption density. It is shown that suitable Ti/Zr ratio can improve the performance of the alloy. In addition, the addition of the third component metal M (where M is Co, Cr, V, Fe, etc.) can also improve the hydrogen storage performance of TiZr. Benvenuti C et al. 's study showed that TiZrV has good hydrogen absorption performance and has a wide application prospect in hydrogen and isotope storage, purification and other fields.
