Hydrogen storage behaviour of Cr- and Mn-doped Mg2Ni alloys fabricated via high-energy ball milling

This paper describes the efficient preparation of an Mg2Ni alloy for hydrogen storage via high-energy ball milling mechanical alloying for 2 h. The degree of alloy amorphisation increases with increasing ball-milling time. Ball milling for 4 h affords partially amorphous alloys exhibiting the best hydrogen storage performance. Partial substitution of Ni with Cr and Mn improves the hydrogen absorption/desorption thermodynamics, kinetics and cycling performance of the alloy. Specifically, partial Mn substitution improves the cycling performance and reduces the activation energy of the hydrogen desorption reaction, effectively improving the hydrogen desorption kinetic performance. Mg2Ni0.8Mn0.2 shows the best cycling and hydrogen absorption/desorption kinetic performances. Partial Cr substitution reduces the entropy and enthalpy changes of the hydrogen absorption/ desorption reaction and effectively reduces the temperature of the initial hydrogen ab-sorption/desorption reaction. In particular, Mg2Ni0.9Cr0.1 shows the best thermodynamic performance.(c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

This paper describes the efficient preparation of an Mg2Ni alloy for hydrogen storage via high-energy ball milling mechanical alloying. The alloy's amorphisation degree increases with ball-milling time. After 4 hours of ball milling, partially amorphous alloys show the best hydrogen storage performance. Partial substitution of Ni with Cr and Mn improves the thermodynamics, kinetics, and cycling performance of the alloy. Mg2Ni0.8Mn0.2 exhibits the best cycling and hydrogen absorption/desorption kinetics.