A_(2)B_(7)-type La-Mg-Ni alloys prepared by Mg thermal diffusion for improved hydrogen storage performance  

作　　者：Yong-Xi Zhang Guan-Jiu Wu Jing Gu Hong-Xing Kang Yuan Li Di Zhou Wen-Feng Wang Lu Zhang Shu-Min Han 

机构地区：[1]Hebei Key Laboratory of Applied Chemistry,School of Environmental and Chemical Engineering,Yanshan University,Qinhuangdao 066004,China [2]Department of Chemistry and Biochemistry,San Diego State University,San Diego,CA92182-1030,USA [3]State Key Laboratory of Metastable Materials Science and Technology,Yanshan University,Qinhuangdao 066004,China

出　　处：《Rare Metals》2024年第7期3260-3272,共13页稀有金属（英文版）

基　　金：financially supported by the National Key Research and Development Program of China(2022YFB3803804);the National Natural Science Foundation of China(Nos.51971197,52071281 and 52201282);Basic Innovation Research Project in Yanshan University(No.2022LGZD004);China Postdoctoral Science Foundation(2023M742945);Postdoctoral research project of Hebei Province(B2023003023);Subsidy for Hebei Key Laboratory of Applied Chemistry after Operation Performance(No.22567616H)。

摘　　要：A novel approach based on thermal diffusion was used to achieve controllable Mg content in A_(2)B_(7)-type La-Mg-Ni-based alloys.The formation mechanism of the A_(2)B_(7)-type phase as a result of the thermal diffusion process and the effect of Mg content on hydrogen storage performance were investigated.X-ray diffraction(XRD)patterns and Rietveld refinement results showed that increased Mg transformed the LaNi_(5)phase in the La_(0.74)Sm_(0.03)Y_(0.23)Ni_(4.32)Al_(0.04)precursor alloy into a superlattice structure.Scanning electron microscopy(SEM)images showed that Mg was evenly distributed in the alloy bulk.Mg in the superlattice significantly inhibited the phase decomposition of the superlattice structure during the hydrogen absorption/desorption cycles.An A_(2)B_(7)-type La_(0.57)Sm_(0.02)Y_(0.18)Mg_(0.23)Ni_(3.38)Al_(0.03)alloy composed of Gd_(2)Co_(7)and Ce_(2)Ni_(7)phases was successfully synthesized.The pressure-composition isotherm profiles showed that the alloy had a hydrogen storage capacity as high as 1.73 wt%,with good cycling stability.After 50 cycles of hydrogen absorption/desorption,the alloy retained a hydrogen storage capacity of 1.45 wt%,with a capacity retention rate of up to 84.28%.The Mg thermal diffusion process thus provides a new approach for the controlled preparation of La-Mg-Ni-based alloys.

关 键 词：La-Mg-Ni-based hydrogen storage alloy A_(2)B_(7)-type superlattice alloy Mg thermal diffusion process Phase transformation Hydrogen storage property 

分 类 号：TG139.7[一般工业技术—材料科学与工程]