2020/09/07 by Junxian Zhang, Véronique Charbonnier, Nicolas Madern +3 · 23 citations
Chemical Engineering · Chemistry · Engineering · Materials Science · Physics and Astronomy · #Advanced Battery Materials and Technologies #Ammonia Synthesis and Nitrogen Reduction #Catalysis #Chemistry #Composition (language) #Crystal structure #Crystallography #Hydrogen #Hydrogen Storage and Materials #Hydrogen storage #Materials science #Metal #Metallurgy #Organic chemistry #Physical chemistry #Powder diffraction #Rietveld refinement #Sorption #Transition metal #Yttrium #cond-mat.mtrl-sci
paper · pdf · doi:10.1016/j.jallcom.2020.157008
published in Journal of Alloys and Compounds 852, 157008 (Elsevier BV)
openalex publication_date 2020/09/07 · openalex created_date 2020/09/11 · arxiv created 2021/02/08 · arxiv updated 2021/02/09 · openalex updated_date 2026/08/05
A2B7 compounds (A = rare earth or Mg, B = transition metal) are widely studied as active materials for negative electrode in Ni-MH batteries. By playing on the substitution rate of both A and B elements, it is possible to prepare various compositions. This strategy will help to improve the properties, for example get a higher reversible hydrogen capacity and a well-adapted hydrogen sorption pressure. Indeed, A can be almost all light rare earths (La to Gd), yttrium and alkaline earth metals (Mg or Ca), whereas B can contain various late transition metals (Mn to Ni). To understand the effects of composition on the physicochemical properties of La2Ni7-based compound, various pseudo-binary systems have been investigated: Gd2 xLaxNi7 (x = 0, 0.6, 1, 1.5), Sm2-xLaxNi7 (x = 0, 0.5, 1, 1.5), Y2-xLaxNi7 (x = 0, 0.4, 0.5, 0.6, 0.8, 1, 1.5, 1.75) and A0.5La1.1Mg0.4Ni7 (A = Sm, Gd and Y). To determine their crystallographic properties, X-ray diffraction analysis was performed followed by Rietveld refinement. Thermodynamic properties regarding reversible hydrogen sorption were investigated at room temperature. Quaternary compounds present drastically improved sorption properties in the frame of practical energy storage applications with reversible capacity equivalent to 400 mAh/g for the compound La1.1Sm0.5Mg0.4Ni7.