Crystal Structure and Hydrogen Storage Properties of novel Mg-Zr-(Li, Na, K) Hydrides Prepared by Gigapascal Hydrogen Pressure Method

2011 ◽  
Vol 1334 ◽  
Author(s):  
Nobuhiko Takeichi ◽  
Kenji Shida ◽  
Xiao Yang ◽  
Tetsuo Sakai
Keyword(s):  
Crystal Structure ◽  
Hydrogen Pressure ◽  
Hydrogen Desorption ◽  
X Ray Diffraction ◽  
Hydrogen Storage Properties ◽  
X Ray ◽  
Pressure Method ◽  
Xrd Patterns ◽  
Storage Properties ◽  
Fcc Structure

ABSTRACTNovel Mg-Zr-A (A=Na, Li and K) hydrides have been synthesized by the gigapascal hydrogen pressure method. Their crystal structures were analyzed based on synchrotron X-ray diffraction (XRD) patterns. In the Mg-Zr-H system, the Mg-Zr hydride with FCC structure was formed under 8 GPa and 873 K. In the case of Mg-Zr-Li and Mg-Zr-K systems, the quaternary hydrides were formed and these retained the same crystal structure, FCC structure, up to x = 1.0 While in the Mg-Zr-Na system, the quaternary hydrides were formed and these retained the FCC structure, up to x = 0.3. With the addition of 0.5 NaH, a hydride with the Ca7Ge type structure was formed instead of the FCC structure. The Mg-Zr-(Li, Na, K) hydrides can reversibly absorb and desorb hydrogen. The hydrogen desorption temperatures of those hydrides decrease with the increasing ionic radius of the alkali metal.

scholarly journals Dehydrogenation/rehydrogenation mechanism in aluminum destabilized lithium borohydride

2009 ◽  
Vol 24 (8) ◽  
pp. 2720-2727 ◽  
Author(s):  
Xuebin Yu ◽  
Guanglin Xia ◽  
Zaiping Guo ◽  
Huakun Liu
Keyword(s):  
Photoelectron Spectroscopy ◽  
Hydrogen Desorption ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Lithium Borohydride ◽  
Hydrogen Storage Properties ◽  
X Ray ◽  
Before And After ◽  
Storage Properties ◽  
Desorption Cycle

LiBH4/Al mixtures with various mol ratios were prepared by ball milling. The hydrogen storage properties of the mixtures were evaluated by differential scanning calorimetry/thermogravimetry analyses coupled with mass spectrometry measurements. The phase compositions and chemical state of elements for the LiBH4/Al mixtures before and after hydrogen desorption and absorption reactions were assessed via powder x-ray diffraction, infrared spectroscopy, and x-ray photoelectron spectroscopy. Dehydrogenation results revealed that LiBH4 could react with Al to form AlB2 and AlLi compounds with a two-step decomposition, resulting in improved dehydrogenation. The rehydrogenation experiments were investigated at 600 °C with various H2 pressure. It was found that intermediate hydride was formed firstly at a low H2 pressure of 30 atm, while LiBH4 could be reformed completely after increasing the pressure to 100 atm. Absorption/desorption cycle results showed that the dehydrogenation temperature increased and the hydrogen capacity degraded with the increase of cycle numbers.

Magnetic Properties of Tb(Ni0.95Fe0.05)3 Crystalline Compound and Powder

2013 ◽  
Vol 203-204 ◽  
pp. 292-295 ◽  
Author(s):  
Krzysztof Ociepka ◽  
Ania Bajorek ◽  
Artur Chrobak ◽  
Grażyna Chełkowska
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Magnetocaloric Effect ◽  
Milling Time ◽  
Crystalline Compound ◽  
X Ray Diffraction ◽  
X Ray ◽  
Arc Melting ◽  
Melting Technique ◽  
Xrd Patterns

The magnetic properties and the crystal structure of the ball-milled Tb(Ni0.95Fe0.05)3compound have been studied by using magnetization measurements and X-ray diffraction (XRD). The results were compared with those obtained for the bulk compound prepared by arc-melting technique. The investigated sample is polycrystalline and crystallizes in the rhombohedral PuNi3type of crystal structure (space group R-3m). With the increase of the time milling (i.e. 1 h, 24 h and 48 h) a for-mation of grains less than 1μm and a reduction of magnetocaloric effect have been observed. The analysis of XRD patterns for ball-milled powders shows that after 48h milling time there is still visible a crystalline structure.

The synthesis and hydrogen storage properties of Mg2Ni substituted with Cu, Co

2009 ◽  
Vol 24 (4) ◽  
pp. 1311-1316 ◽  
Author(s):  
Yu’an Chen ◽  
Hua Huang ◽  
Jie Fu ◽  
Qing Guo ◽  
Fusheng Pan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Hydrogen Absorption ◽  
Energy Dispersive Spectrometry ◽  
Induction Melting ◽  
X Ray Diffraction ◽  
Hydrogen Storage Properties ◽  
X Ray ◽  
Storage Properties ◽  
Scanning Electron

Mg2Ni1-xCux (x = 0, 0.2, 0.4) and Mg2Ni1-yCoy (y = 0, 0.2, 0.4) were successfully synthesized via two steps: induction melting and then ball milling. The component and microstructure of the alloys were determined with x-ray diffraction (XRD) and scanning electron microscopy/x-ray energy-dispersive spectrometry (SEM/XEDS). Mg2Ni phase was observed in all 5 alloys. When the amount of Cu was increased, it led to the formation of phase from Mg2Cu to Cu11Mg10Ni9. Co2Mg was detected in the Co-containing alloys. The hydrogen absorption/desorption properties were tested with p-C-T measurement apparatus, and the results showed that the gaseous storage properties of the alloys were improved by the addition of Cu or Co.

Effect of Li3N additive on the hydrogen storage properties of Li-Mg-N-H system

2009 ◽  
Vol 24 (6) ◽  
pp. 1936-1942 ◽  
Author(s):  
Lai-Peng Ma ◽  
Zhan-Zhao Fang ◽  
Hong-Bin Dai ◽  
Xiang-Dong Kang ◽  
Yan Liang ◽  
...  
Keyword(s):  
Hydrogen Desorption ◽  
Structure Property ◽  
X Ray Diffraction ◽  
Hydrogen Storage Properties ◽  
Capacity Enhancement ◽  
Ammonia Release ◽  
Screening Study ◽  
Practical Capacity ◽  
Combined Structure ◽  
Storage Properties

The effect of Li3N additive on the Li-Mg-N-H system was examined with respect to the reversible dehydrogenation performance. Screening study with varying Li3N additions (5, 10, 20, and 30 mol%) demonstrates that all are effective for improving the hydrogen desorption capacity. Optimally, incorporation of 10 mol% Li3N improves the practical capacity from 3.9 wt% to approximately 4.7 wt% hydrogen at 200 °C, which drives the dehydrogenation reaction toward completion. Moreover, the capacity enhancement persists well over 10 de-/rehydrogenation cycles. Systematic x-ray diffraction examinations indicate that Li3N additive transforms into LiNH2 and LiH phases and remains during hydrogen cycling. Combined structure/property investigations suggest that the LiNH2 “seeding” should be responsible for the capacity enhancement, which reduces the kinetic barrier associated with the nucleation of intermediate LiNH2. In addition, the concurrent incorporation of LiH is effective for mitigating the ammonia release.

The Effect of Heat-Treatment on the Phase Transformation of Hard Clam Shell

2013 ◽  
Vol 770 ◽  
pp. 76-79
Author(s):  
Kulnicha Poch-Chongdach ◽  
Jakrapong Kaewkhao ◽  
Wichian Siriprom ◽  
Kanyakorn Teanchai ◽  
Pichet Limsuwan ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Heat Treatment ◽  
Trace Element ◽  
Hard Clam ◽  
Meretrix Meretrix ◽  
X Ray Diffraction ◽  
Clam Shell ◽  
X Ray ◽  
Specific Temperature ◽  
Xrd Patterns

The aim of this work is to a systematic study of trace element, crystal structure and structural transformation upon heat treatment. The hard clam (Meretrix meretrix) shells was ground and characterized as powder throughout this work. Trace element of the hard clam shells was determination easiest and fasts by energy dispersive x-ray fluorescence (EDXRF) techniques, while the crystal structure was identifications by x-ray diffraction (XRD). The result showed that, the element content are Calcium (Ca), Aluminum (Al), Titanium (Ti), Ferrum (Fe), Copper (Cu) and Strontium (Sr), along with the crystal structure of the hard clam shells from the XRD patterns is shown aragonite phase. Another that, the consequence of heat treatment was annealed the hard clam shell samples at specific temperature over the range 300 1200 °C were studied.

scholarly journals Solid gas and electrochemical hydrogenation properties of the R1-xR’xMgNi4-yCoy (R, R’ = Y, La, Ce) alloys

2020 ◽  
Vol 21 (3) ◽  
pp. 503-509
Author(s):  
Yu. V. Verbovytskyy ◽  
I. Yu. Zavaliy ◽  
V. V. Berezovets ◽  
P. Ya. Lyutyy
Keyword(s):  
Room Temperature ◽  
Electrode Materials ◽  
High Rate ◽  
X Ray Diffraction ◽  
Hydrogen Storage Properties ◽  
X Ray ◽  
Powder Sintering ◽  
Related Compounds ◽  
Sintering Method ◽  
Storage Properties

New R1-xR’xMgNi4-yCoy (R, R’ = Y, La, Ce; x = 0.5; y = 0, 1, 2) alloys have been synthesized by powder sintering method, and their crystal structure and hydrogen storage properties have been studied. X-ray diffraction analysis showed that R1-xR’xMgNi4-yCo alloys belong to the MgCu4Sn-type structure. The synthesized alloys absorb hydrogen at room temperature and hydrogen pressure 0.1-10 bar. For some of the studied compounds, the formation of hydrides with cubic and orthorhombic structures was found. Highest hydrogen content is found for the Co-rich compounds: La0.5Y0.5MgNi2Co2H5.18 and La0.5Ce0.5MgNi2Co2H6.48. Electrochemical studies showed that Y-based electrode materials exhibit better electrochemical performance comparing with Ce-doped ones. Highest discharge capacity of 292 mА∙h/g was observed for La0.5Y0.5MgNi3Co, but the best cyclic stability after 50th cycle of 92% was seen for La0.5Y0.5MgNi2Co2. Additionally, obtained results of the electrochemical properties were compared with related compounds. High rate dischargeability of Co-free alloys at I = 1 A/g were twice higher than ones containing cobalt.

Hydrogen storage properties of mechanically alloyedMg–8 mol% LaNi0.5 composite

2004 ◽  
Vol 19 (10) ◽  
pp. 2871-2876 ◽  
Author(s):  
Qian Li ◽  
Qin Lin ◽  
Kuo-Chih Chou ◽  
Li-Jun Jiang ◽  
Feng Zhan
Keyword(s):  
Hydrogen Storage ◽  
Mechanical Alloying ◽  
X Ray Diffraction ◽  
Equilibrium Pressure ◽  
Hydrogen Storage Properties ◽  
X Ray ◽  
Transmission Electron ◽  
Lower Temperature ◽  
Material Preparation ◽  
Storage Properties

A new nano-ternary Mg–8 mol% LaNi0.5 was prepared by melted and subsequent mechanical alloying technique for hydrogen storage. It was found from our experiments that, this kind of alloy had superior hydriding/dehydriding characteristics in comparison with conventional materials for hydrogen storage. It possessed large hydrogen capacity at a lower temperature, which could absorb 4.55–7.01 mass% H under 3 MPa hydrogen pressure and desorb 4.40–6.90 mass% H under 0.0133 MPa in 600 s above 423 K without any activation requirement drawn from our pressure-composition isotherm and kinetic experiments. Through the x-ray diffraction and transmission electron microscopy experiments, we further found that these superior characteristics could be attributed to the multiphase structure and a catalytic effect of LaH3 and Mg2Ni that were formed in the material preparation of mechanical alloying process. Finally, based on these data the relationships between equilibrium pressure of hydrogen and temperature were obtained, they were lgp(0.1 MPa) = −3985/T + 7.188(553 K ⩽ T ⩽ 573K) for hydriding and lgp(0.1 MPa) = −3804/T + 6.770 (553 K ⩽ T ⩽ 573 K) for dehydriding.

Structural and Textural of Marine Mollusc Shell

2012 ◽  
Vol 506 ◽  
pp. 363-366 ◽  
Author(s):  
Wichian Siriprom ◽  
K. Kirdsiri ◽  
Jakrapong Kaewkhao ◽  
N. Chumnanvej ◽  
A. Choeysuppaket ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Esr Spectroscopy ◽  
Rietveld Method ◽  
X Ray Diffraction ◽  
Mollusc Shell ◽  
X Ray ◽  
Marine Mollusc ◽  
Mixture Phase ◽  
Mussel Shells ◽  
Xrd Patterns

The Anadaragranosa and Pernaviridis shell sample were prepared in powder and plate form has been studied. The crystal structure of the shells was studied by x-ray diffraction (XRD). The identification and quantitative analysis were performed by the XRD patterns and the Rietveld method. It found that the crystal structure of Anadaragranosa shells is a pure aragonite phase, and the Pernaviridis shells is a mixture phase of aragonite and calcite. Also we used the scanning electron microscope (SEM) to study the Morphology of the Anadaragranosa and Pernaviridis shell sample. The results on SEM micrographs agree well with those of XRD. The results from SEM can be described the textural information and used to determine of the mollusc shell. In addition, the metals in the shells were determined by ESR spectroscopy. The metals in all samples reveals that Mn were found in all mussel shells, and then the ESR spectrum agree well with those of XRD and SEM result, then it can be used to indentification of structural of mollusc shell.

Hydrogen Storage Properties of Mg76Ti12Ni12-xCrX(x=0,3,6,9) Alloys by Mechanical Alloying

2010 ◽  
Vol 156-157 ◽  
pp. 1146-1150
Author(s):  
Zhi Qiang Lan ◽  
Shu Bo Li ◽  
Zhao Lu ◽  
Jin Guo
Keyword(s):  
Hydrogen Storage ◽  
Mechanical Alloying ◽  
Storage Capacity ◽  
X Ray Diffraction ◽  
Hydrogen Storage Capacity ◽  
Hydrogen Storage Properties ◽  
X Ray ◽  
Cr Content ◽  
Ti2ni Phase ◽  
Storage Properties

Mg76Ti12Ni12-xCrx(x=0,3,6,9) alloys were synthesized by mechanical alloying(MA) approach and hydrogen storage properties of the alloys were investigated by X-ray diffraction, thermal analysis and pressure-composition isotherm measurement. It is found that Ti2Ni phase and Mg2Ni phase exist as the main phases in Mg76Ti12Ni12-xCrx(x=0,3,6,9) alloys. The Mg76Ti12Ni12-xCrx(x=0,3,6,9) alloys exhibit the hydrogen storage capacity of 4.61,4.30,4.21 and 4.12wt%, and the decomposition enthalpies of the alloy hydrides are 928.4, 898.3, 831.2 and 851.4J/g H2, respectively. Mg76Ti12Ni6Cr6 alloy shows small hysteresis and fast hydrogen absorption rate. Proper Cr content can improve the performance of the Mg76Ti12Ni12-xCrx(x =0,3,6,9) alloys.

Sign in / Sign up

Export Citation Format

Share Document