Mg-based hydrogen storage nanocomposites added with carbon nanotubes(CNTs) were prepared by mechanical milling under the atmosphere of hydrogen. The results show that because of their own excellent heat conductivity a...Mg-based hydrogen storage nanocomposites added with carbon nanotubes(CNTs) were prepared by mechanical milling under the atmosphere of hydrogen. The results show that because of their own excellent heat conductivity and good hydrogen storage ability, the carbon nanotubes improve the mass transfer and heat transfer properties of the Mg-based nanocomponents, thus enhancing the kinetic property of hydrogen absorption and desorption of the hydrogen storage nanocomposites, and raising the hydrogen storage capacity. Due to the addition of the carbon nanotubes, the milling stress in the process of preparing the Mg-based nanocomposites is reduced, the components can be closely bonded easily, and the additives can play better catalytic roles.展开更多
In this paper, the effects of Si and Ce on the microstructure and hydrogen storage property of Ti26.5 Cr20V45Fe8.5Ce0.5 alloy were studied, respectively. First of all, effects of Si on the microstructure and hydrogen ...In this paper, the effects of Si and Ce on the microstructure and hydrogen storage property of Ti26.5 Cr20V45Fe8.5Ce0.5 alloy were studied, respectively. First of all, effects of Si on the microstructure and hydrogen storage properties of Ti26.5Cr20(V45Fe8.5)1?xSixCe0.5 (x = 0, 0.5, 1.0, 1.5 and 2.0 at%) alloys were studied by X-ray diffraction, scanning electron microscopy and P-C isotherm measurements. As the Si addition increases, the hydrogen absorption capacities of alloys decrease but the equilibrium pressure increases, due to the formation of Laves phase. Secondly, the effect of Ce on Ti26.5Cr20 (V45Fe8.5)0.98Si2 alloy was studied. It was found that Ce addition is an effective way to eliminate the effect of Si on the hydrogen storage properties of the alloy.展开更多
As typical high-capacity complex hydrides,lightweight hydrides have attracted intensive attention due to their high gravimetric and volumetric energy densities of hydrogen storage.However,lightweight hydrides also hav...As typical high-capacity complex hydrides,lightweight hydrides have attracted intensive attention due to their high gravimetric and volumetric energy densities of hydrogen storage.However,lightweight hydrides also have high thermodynamic stability and poor kinetics,so they ususally require high hydrogen desorption temperature and show inferior reversibility under mild conditions.This review summarizes recent progresses on the endeavor of overcoming thermodynamic and kinetic challenges for Mg based hydrides,lightweight metal borohydrides and alanates.First,the current state,advantages and challenges for Mg-based hydrides and lightweight metal hydrides are introduced.Then,alloying,nanoscaling and appropriate doping techniques are demonstrated to decrease the hydrogen desorption temperature and promote the reversibility behavior in lightweight hydrides.Selected scaffolds materials,approaches for synthesis of nanoconfined systems and hydriding-dehydriding properties are reviewed.In addition,the evolution of various dopants and their effects on the hydrogen storage properties of lightweight hydrides are investigated,and the relevant catalytic mechanisms are summarized.Finally,the remaining challenges and the sustainable research efforts are discussed.展开更多
LaMg8.52Ni2.23M0.15 （M=Ni, Cu, Cr） alloys were prepared by induction melting. X-ray diffraction showed that all the three alloys had a multiphase structure, consisting of La2Mg17, LaMg2Ni and Mg2Ni phases. Energy di...LaMg8.52Ni2.23M0.15 （M=Ni, Cu, Cr） alloys were prepared by induction melting. X-ray diffraction showed that all the three alloys had a multiphase structure, consisting of La2Mg17, LaMg2Ni and Mg2Ni phases. Energy dispersive X-ray spectrometer results revealed that most of Cu and Cr distributed in MgzNi phase. La2Mg17 and LaMg2Ni phases decomposed into MgHz, Mg2NiH4 and LaH3 phases during the hydrogenation process. Hydriding/dehydriding measurements indicated that the reversible hydrogen storage capacities of Mg2Ni phase in LaMgs.52Ni2.23M0.15 （M=Cu, Cr） alloys increased to 1.05 wt.% and 0.97 wt.% from 0.79 wt.% of Mg2Ni phase in LaMgs.52Ni2.38 alloy at 523 K. Partial substitution of Cu and Cr for Ni decreased the onset dehydrogenation temperature of the alloy hydrides and the temperature lowered by 18.20 and 5.50 K, respectively. The improvement in the dehydrogenation property of the alloys was attributed to that Cu and Cr decreased the stability of Mg2NiH4 phase.展开更多
文摘Mg-based hydrogen storage nanocomposites added with carbon nanotubes(CNTs) were prepared by mechanical milling under the atmosphere of hydrogen. The results show that because of their own excellent heat conductivity and good hydrogen storage ability, the carbon nanotubes improve the mass transfer and heat transfer properties of the Mg-based nanocomponents, thus enhancing the kinetic property of hydrogen absorption and desorption of the hydrogen storage nanocomposites, and raising the hydrogen storage capacity. Due to the addition of the carbon nanotubes, the milling stress in the process of preparing the Mg-based nanocomposites is reduced, the components can be closely bonded easily, and the additives can play better catalytic roles.
基金Supported by the National Hi-Tech Research and Development Program of China ("863" Project) (Grant No. 2006AA05Z144)
文摘In this paper, the effects of Si and Ce on the microstructure and hydrogen storage property of Ti26.5 Cr20V45Fe8.5Ce0.5 alloy were studied, respectively. First of all, effects of Si on the microstructure and hydrogen storage properties of Ti26.5Cr20(V45Fe8.5)1?xSixCe0.5 (x = 0, 0.5, 1.0, 1.5 and 2.0 at%) alloys were studied by X-ray diffraction, scanning electron microscopy and P-C isotherm measurements. As the Si addition increases, the hydrogen absorption capacities of alloys decrease but the equilibrium pressure increases, due to the formation of Laves phase. Secondly, the effect of Ce on Ti26.5Cr20 (V45Fe8.5)0.98Si2 alloy was studied. It was found that Ce addition is an effective way to eliminate the effect of Si on the hydrogen storage properties of the alloy.
基金supported by the National Key R&D Program of China (2018YFB1502102)the National Natural Science Foundation of China (51571124, 51571125, 51871123 and 51501072)+1 种基金111 Project (B12015)MOE (IRT13R30)
文摘As typical high-capacity complex hydrides,lightweight hydrides have attracted intensive attention due to their high gravimetric and volumetric energy densities of hydrogen storage.However,lightweight hydrides also have high thermodynamic stability and poor kinetics,so they ususally require high hydrogen desorption temperature and show inferior reversibility under mild conditions.This review summarizes recent progresses on the endeavor of overcoming thermodynamic and kinetic challenges for Mg based hydrides,lightweight metal borohydrides and alanates.First,the current state,advantages and challenges for Mg-based hydrides and lightweight metal hydrides are introduced.Then,alloying,nanoscaling and appropriate doping techniques are demonstrated to decrease the hydrogen desorption temperature and promote the reversibility behavior in lightweight hydrides.Selected scaffolds materials,approaches for synthesis of nanoconfined systems and hydriding-dehydriding properties are reviewed.In addition,the evolution of various dopants and their effects on the hydrogen storage properties of lightweight hydrides are investigated,and the relevant catalytic mechanisms are summarized.Finally,the remaining challenges and the sustainable research efforts are discussed.
基金Project supported by High-Tech Research and Development(863)Program of China(2007AA05Z117)National Natural Science Foundation of China(50971112,51171165)the Natural Science Foundation of Hebei Province(E201001170)
文摘LaMg8.52Ni2.23M0.15 （M=Ni, Cu, Cr） alloys were prepared by induction melting. X-ray diffraction showed that all the three alloys had a multiphase structure, consisting of La2Mg17, LaMg2Ni and Mg2Ni phases. Energy dispersive X-ray spectrometer results revealed that most of Cu and Cr distributed in MgzNi phase. La2Mg17 and LaMg2Ni phases decomposed into MgHz, Mg2NiH4 and LaH3 phases during the hydrogenation process. Hydriding/dehydriding measurements indicated that the reversible hydrogen storage capacities of Mg2Ni phase in LaMgs.52Ni2.23M0.15 （M=Cu, Cr） alloys increased to 1.05 wt.% and 0.97 wt.% from 0.79 wt.% of Mg2Ni phase in LaMgs.52Ni2.38 alloy at 523 K. Partial substitution of Cu and Cr for Ni decreased the onset dehydrogenation temperature of the alloy hydrides and the temperature lowered by 18.20 and 5.50 K, respectively. The improvement in the dehydrogenation property of the alloys was attributed to that Cu and Cr decreased the stability of Mg2NiH4 phase.
