Abstract:
This work investigated the crystal structure, hydrogen storage, and electrochemical properties of the Ti
0.2Zr
0.8(V
0.2Mn
0.8)
1–xM
xNi
1.0 (M = Al, Fe;
x = 0, 0.05, 0.1) Zr-rich AB
2 alloys. Rietveld refinement of X-ray diffraction (XRD) revealed that C14 phase abundance increased with Al content, while Fe promoted C15 phase formation, accompanied by a variation in the lattice constants. Hydrogen storage experiments showed C15 phase abundance positively correlated with maximum adsorption capacity, while plateau pressures were negatively correlated with lattice constants. The Fe
0.1 alloy exhibited the largest adsorption capacity and the highest plateau pressure, whereas the Al
0.1 alloy displayed opposite characteristics. All alloys demonstrated rapid hydrogen adsorption kinetics, reaching 98% capacity within 1 min after 5 activation cycles, retaining no obvious capacity decay after 20 cycles. Electrochemical studies indicated that Fe doping enhanced discharge capacity and high-rate discharge (HRD) performance due to increased C15 phase abundance. Electrochemical kinetics revealed that the improved HRD performance can be attributed to the enhanced electrocatalytic performance and hydrogen diffusion rate in Fe-doped alloys. This work provides a systematic analysis of how Al and Fe doping influences the AB
2-type Laves phase alloys, offering theoretical and experimental evidence for alloy design and optimization.