Study On The Properties Of Mg-Ni-Y Hydrogen Storage Alloy Under Different Preparation Methods

Energy has always been the driving force for the development of human society.Traditional fossil energy is becoming exhausted due to its non-renewability,and it will also cause pollution to the environment.Therefore,it is urgent to develop a new renewable,clean and efficient new energy source.As a promising new energy source,hydrogen energy has the advantages of abundant raw materials,high calorific value,and no pollution.However,its storage method has always restricted its development.Magnesium-based hydrogen storage alloys have the advantages of large hydrogen storage capacity,abundant resources,low price,and convenient transportation.They have become a promising hydrogen energy carrier today.However,their excessively slow dynamic performance and excessively high thermodynamic performance limit it Practical.In this paper,8 groups of Mg₈₀Ni_xY_20-x(x=0,5,15,20)alloys were prepared by smelting+mechanical ball milling and mechanical alloying methods and adding Ni and Y elements.Using X-ray diffraction(XRD),scanning Electron microscope(SEM),observed the microscopic morphology changes of the alloy before and after hydrogen absorption,tested the performance of the alloy absorption and discharge,thermodynamics and kinetics by DSC-TG,PCT and other means,and passed JMAK(Johnson–Mehl–Avrami–Kolmogorov)The equation explores the hydrogen absorption mechanism of the alloy.The microscopic morphology and hydrogen storage performance of the alloy prepared by smelting+mechanical ball milling are studied.The results show that as the Y element increases,the Ni element decreases,the decomposition temperature of the hydrogen-absorbing phase MgH₂ in the alloy gradually decreases,and the decomposition temperature of Mg₂NiH₄ gradually increases High,showing the synergistic effect of the decomposition between Mg₂NiH₄ and MgH₂ and the promoting effect of Mg₂NiH₄ and YH₃ on the decomposition of MgH₂.Among the four combinations of gold,Mg₈₀Y₂₀ has the largest hydrogen absorption capacity,and the hydrogen absorption capacity within 150 minutes at 350°C is 5.21wt.%;Mg₈₀Ni₁₅Y₅has the fastest hydrogen absorption speed,and the hydrogen absorption capacity at 350s is 4.31wt.%for 60s.The microscopic morphology and hydrogen storage properties of the alloy prepared by mechanical alloying were studied.The results showed that the Mg₈₀Ni₁₅Y₅hydrogen absorption rate was the fastest among the four combinations of gold,and it could absorb 4.37 wt.%hydrogen at 350 s for 60 seconds,and Mg₈₀Ni₅Y₁₅ had the largest hydrogen absorption capacity.The amount of hydrogen that can be absorbed in150 min at 350? is 5.14 wt.%.The hydrogen absorption kinetics and PCT curve of the alloy under the two preparation processes are compared.Compared with smelting+mechanical ball milling,the alloy prepared by mechanical alloying has a larger hydrogen storage capacity,faster hydrogen absorption rate,and the absorption and discharge of the alloy's PCT curve.The hydrogen platform is wider and the hysteresis is smaller,and the alloy's comprehensive hydrogen storage performance is more excellent.