In situ formed ultrafine metallic Ni from nickel(Ⅱ) acetylacetonate precursor to realize an exceptional hydrogen storage performance of MgH_(2)-Ni-EG nanocomposite  

作　　者：Shaoyang Shen Liuzhang Ouyang Jiangwen Liu Hui Wang Xu-Sheng Yang Min Zhu 

机构地区：[1]School of Materials Science and Engineering and Key Laboratory of Advanced Energy Storage Materials of Guangdong Province,South China University of Technology,Guangzhou,510641,China [2]China-Australia Joint Laboratory for Energy&Environmental Materials,Key Laboratory of Fuel Cell Technology of Guangdong Province,Guangzhou,Guangzhou,510641,China [3]Advanced Manufacturing Technology Research Centre,Department of Industrial and Systems Engineering,The Hong Kong Polytechnic University,Hung Hom,Kowloon,Hong Kong,China [4]Research Institute for Smart Energy,The Hong Kong Polytechnic University,Hung Hom,Kowloon,Hong Kong,China

出　　处：《Journal of Magnesium and Alloys》2023年第9期3174-3185,共12页镁合金学报（英文）

基　　金：financial support from the National Basic Research Program of China (2018YFB1502100);the support from the PolyU grant (No.G-YW5N)。

摘　　要：It has been well known that doping nano-scale catalysts can significantly improve both the kinetics and reversible hydrogen storage capacity of MgH_(2) . However, so far it is still a challenge to directly synthesize ultrafine catalysts(e.g., < 5 nm), mainly because of the complicated chemical reaction processes. Here, a facile one-step high-energy ball milling process is developed to in situ form ultrafine Ni nanoparticles from the nickel acetylacetonate precursor in the MgH_(2) matrix. With the combined action of ultrafine metallic Ni and expanded graphite(EG), the formed MgH_(2)-Ni-EG nanocomposite with the optimized doping amounts of Ni and EG can still release 7.03 wt.% H_(2) within 8.5 min at 300 ℃ after 10 cycles. At a temperature close to room temperature(50 ℃), it can also absorb 2.42 wt.% H_(2) within 1 h. It can be confirmed from the microstructural characterization analysis that the in situ formed ultrafine metallic Ni is transformed into Mg_(2)Ni/Mg_(2)NiH_4 in the subsequent hydrogen absorption and desorption cycles. It is calculated that the dehydrogenation activation energy of the MgH_(2)-Ni-EG nanocomposite is also reduced obviously in comparison with the pure MgH_(2) . Our work provides a methodology to significantly improve the hydrogen storage performance of MgH_(2) by combining the in situ formed and uniformly dispersed ultrafine metallic catalyst from the precursor and EG.

关 键 词：Hydrogen storage Magnesium hydride Nickel precursor Size effect Expanded graphite 

分 类 号：TB33[一般工业技术—材料科学与工程]