Abstract

AB 5-type intermetallic compounds were prepared by arc-melting in argon atmosphere. The composition of a stoichiometric compound LaNi 3.6Al 0.4Co 0.7Mn 0.3 with a hexagonal CaCu 5 structure was varied by stoichiometric and nonstoichiometric addition of Ti. With the increase of the Ti y⩽0.05 content in LaNi 3.6Al 0.4Co 0.7Mn 0.3Ti y , the hydrogen storage capacity is enhanced, whereas when y=0.1–0.3, it is decreased. The discharge capacity and cyclability are increased considerably by addition of titanium in the range of 0.02–0.1 with a maximum value at about 0.1%. The highest maximum capacity is achieved for a nonstoichiometric addition of 0.05% Ti. The kinetic properties are also additionally improved by the formation of a titanium-rich second phase. This can explain the improvement of the capacity for alloys with low Ti content. The decrease in capacity for high Ti content was also correlated with the amount of the Ti-rich phase. Therefore, the improvement of kinetics are due to the catalytic effect, grain boundary diffusion effect or more pronounced alloy pulverization upon cycling. This study has been aimed to improve the electrode properties of a series of multicomponent LaNi 3.6Al 0.4Co 0.7Mn 0.3Ti y ( y=0.0, 0.02, 0.05, 0.1, 0.2, 0.3) alloys which have mutual complementary properties. All the prepared alloys have been subjected to analyses by EDS, SEM and XRD. In order to determine the hydrogen storage capacity, the pressure composition isotherms ( P– C– T curves) have been used. The metal hydride electrodes were characterized by galvanostatic cycling test.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.