Synthesis of nanostructured Mg2FeH6 hydride and hydrogen sorption properties of complex

Reactive mechanical alloying (RMA) was carried out in a planetary ball mill for the synthesis of ternary hydride Mg2FeH6 for hydrogen storage. The formation mechanism of Mg2FeH6 in RMA process and the sorption properties of the products were investigated. The results show that Mg2FeH6 has a yield ratio around 80%, and a grain size below 10 nm in the powder synthesized by milling 3Mg+Fe mixture for 150 h under the hydrogen pressure of 1 MPa. The synthesized powder possesses a high hydrogen capacity and good sorption kinetics, and absorbs 4.42% (mass fraction) of hydrogen within 200 s at 623 K under the hydrogen pressure of 4.0 MPa. In releasing hydrogen at 653 K under 0.1 MPa, it desorbs 4.43% (mass fraction) of hydrogen within 2 000 s. The addition of Ti increases the hydrogen desorption rate of the complex in the initial 120 s of the desorption process.