Hydrogen storage behavior of nanocrystalline and amorphous La-Mg-Ni-based LaMg12-type alloys synthesized by mechanical milling
(1. Key Laboratory of Integrated Exploitation of Baiyun Obo Multi-metal Resources, Inner Mongolia University of Science and Technology, Baotou 014010, China;
2. Department of Functional Material Research, Central Iron and Steel Research Institute, Beijing 100081, China;
3. School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China)
2. Department of Functional Material Research, Central Iron and Steel Research Institute, Beijing 100081, China;
3. School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China)
Abstract: Nanocrystalline and amorphous LaMg11Ni+x% Ni (x=100, 200, mass fraction) alloys were synthesized by mechanical milling. The electrochemical hydrogen storage properties of the as-milled alloys were tested by an automatic galvanostatic system. The gaseous hydrogen absorption and desorption properties were investigated by Sievert’s apparatus and differential scanning calorimeter (DSC) connected with a H2 detector. The results indicated that increasing Ni content significantly improves the gaseous and electrochemical hydrogen storage performances of the as-milled alloys. The gaseous hydrogen absorption capacities and absorption rates of the as-milled alloys have the maximum values with the variation of the milling time. But the hydrogen desorption kinetics of the alloys always increases with the extending of milling time. In addition, the electrochemical discharge capacity and high rate discharge (HRD) ability of the as-milled alloys both increase first and then decrease with milling time prolonging.
Key words: Ni-MH battery; hydrogen storage alloy; mechanical milling; discharge capacity; kinetics