Mechanochemical Synthesis and Hydrogen Sorption Properties of a V-Ni Alloy

Hydrogen

Oriele Palumbo¹  Sergio Brutti¹  Annalisa Paolone¹  Nicholas Carboni¹  Francesco Trequattrini² 

[1] Consiglio Nazionale delle Ricerche, Istituto dei Sistemi Complessi, Piazzale Aldo Moro 5, 00185 Rome, Italy;Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy;

关键词: ball milling;    vanadium alloys;    hydrogen storage;    SEM–EDX;    X-ray diffraction;    pressure-composition isotherms;   

DOI  :  10.3390/hydrogen3010009

来源: DOAJ

【 摘 要 】

Vanadium can store large quantities of hydrogen (about 4 mass%). However, only half of it can be reversibly absorbed. To avoid this issue, various partial substitutions were previously proposed, such as Ni. In this work, we explore the synthesis of a V₈₅Ni₁₅ alloy by means of ball milling, a simpler and more scalable method compared to arc or induction melting usually applied for metal alloys. After ball milling the powders of the pure metals for 15 h in argon, SEM–EDX measurements confirmed the stoichiometry of the synthesized material, which has a typical particle dimension of the order of a few microns and is composed from the coalescence of nanometric primary particles. XRD indicated a BCC crystalline structure with a typical grain size of ≈3 nm. Hydrogen can be absorbed without activation procedures at high temperatures. Up to H/M ≈ 0.08, one can observe the occurrence of a solid solution of hydrogen in the alloy, while at a higher hydrogen content, the formation of a hydride is likely to occur. The maximum hydrogen content is H/M ≈ 0.4 at the maximum investigated pressure in this study of p ≈ 45 bar. Both the hydrogenation enthalpy and entropy decrease as the hydrogen content increases, and the shape of the sorption isotherms is different from that of V₈₅Ni₁₅ produced by induction melting, possibly because of the nanometric dimensions of the particles produced by ball milling.

【 授权许可】

Unknown