Hydrogen Storage Performance of C14 Type Ti 0.24 V 0.17 Zr 0.17 Mn 0.17 Co 0.17 Fe 0.08 High Entropy Intermetallics

In this present investigation, we discussed the synthesis, microstructure, and hydrogen storage behavior in C14 type high entropy intermetallic Laves phase in a hexanary Ti 0.24 V 0.17 Zr 0.17 Mn 0.17 Co 0.17 Fe 0.08 high entropy alloy (HEA). In this HEA, three elements are hydride-forming elements (Ti, V, Zr), whereas other three are non-hydride-forming elements (Fe, Mn, Co). The thermodynamic parameter like enthalpy of mixing was calculated using the Miedma’s model. The mixing enthalpy (∆H mix ) of Ti 0.24 V 0.17 Zr 0.17 Mn 0.17 Co 0.17 Fe 0.08 HEA system was evaluated to be − 23.3472 kJ/mole, and atomic radius mismatch turned out to be = 7.441%. This alloy was synthesized using 35 kW radio frequency induction furnace under argon atmosphere. X-ray diffraction technique (XRD) revealed that this system belongs to the C14 type Laves phase with unit cell parameters, a = b = 5.0158 Å, c = 8.1790 Å, α = β = 90˚, γ = 120˚ under space group: P6 3 /mmc. Microstructural analysis was carried out with the help of a transmission electron microscope (TEM). The SEM–EDX data confirmed the elemental composition. Hydrogen absorption and desorption of this high entropy intermetallic were carried out using the PCI apparatus. The hydrogen storage of this system was observed around ~ 0.53 wt% within 15 s but the maximum storage capacity was evaluated to be about 0.72 wt% in 150 min. However, it exhibited better hydrogen ab/desorption kinetics. With the help of the Van’t Hoff plot, calculated experimental change in enthalpy of Ti 0.24 V 0.17 Zr 0.17 Co 0.17 Fe 0.08 Mn 0.17 HEA for hydrogen absorption and desorption was found out to be ~ − 19.06 ± 1.12 kJ/mol and -34.10 ± 1.32 kJ /mol, respectively. The possibility of developing high entropy Laves phase-based hydrogen storage materials was advocated.