Enhancing reversible hydrogen storage performance of 2LiBH_(4)–MgH_(2)via in-situ building heterogeneous nucleation sites  

作　　者：Wei Chen Ya-Hui Sun Tian Xu Xue-Bin Yu Guang-Lin Xia 

机构地区：[1]Department of Materials Science,Fudan University,Shanghai 200433,China

出　　处：《Rare Metals》2024年第9期4367-4376,共10页稀有金属（英文版）

基　　金：financially supported by the National Key R&D Program of China(No.2020YFA0406204);the National Natural Science Foundation of China(Nos.U2130208,22279020,22109026,51971065,51901045 and 52071156);the Science and Technology Commission of Shanghai Municipality(Nos.21ZR1407500 and 23ZR1406500);the Programs for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning。

摘　　要：2LiBH_(4)-MgH_(2)composite is one of the most attractive reactive hydride composites with a theoretic hydrogen capacity of 10.8 wt%.However,the large nucleation restriction of MgB_(2)during the second step of dehydrogenation results in sluggish hydrogen storage kinetics and high operating temperature,which hinders its practical application as on-board hydrogen storage materials.Herein,Al3Ti doped Al nanoparticles(AT NPs)are prepared by a facile chemical reduction reaction to improve the hydrogen storage performance of 2LiBH_(4)-MgH_(2)composite.During the initial H_(2)desorption process,MgAlB_(4)and TiB_(2)that have identical crystal structure and low d-value mismatch with MgB_(2)resulting from the reaction between AT NPs and 2LiBH_(4)-MgH_(2)composite serve as effective nucleation sites for the formation of MgB_(2).As a result,the apparent activation energy of the two-step H_(2)desorption of AT NPs doped 2LiBH_(4)-MgH_(2)composite are notably decreased to(110.0±5.9)and(119.6±1.4)kJ·mol^(-1),which is 55.5 and 33.5 kJ·mol^(-1)lower than that of the undoped sample.More importantly,a reversible hydrogen storage capacity of 9.2 wt%after 10cycles of H_(2)desorption and adsorption could be achieved,corresponding to a capacity retention rate of 99%.The building of reactive bimetallic catalyst towards in situ formation of heterogeneous nucleation sites provides a new strategy for improving the hydrogen storage performance of reactive hydride composites.

关 键 词：Reversible hydrogen storage Reactive hydride composites Catalytic effects Heterogeneous nucleation 

分 类 号：TB332[一般工业技术—材料科学与工程]