Entity

Time filter

Source Type


Wang H.,Key Laboratory of Advanced Energy Storage Materials of Guangdong Province | Zhang J.,Key Laboratory of Advanced Energy Storage Materials of Guangdong Province | Liu J.W.,Key Laboratory of Advanced Energy Storage Materials of Guangdong Province | Ouyang L.Z.,Key Laboratory of Advanced Energy Storage Materials of Guangdong Province | Zhu M.,South China University of Technology
Journal of Alloys and Compounds | Year: 2013

The addition of NaH by ball milling is shown to greatly improve the hydrogen storage properties and the hydrolysis properties of MgH2, which is related to the formation of ternary hydride NaMgH3 with specific perovskite structure. The MgH2-10%NaH mixture exhibits better hydriding and dehydriding kinetics than the MgH2-10%LiH mixture, in which the LiMgH3 with perovskite structure could not be formed. The catalytic role of NaMgH3 is attributed to fast hydrogen mobility in the perovskite structure, which provides fast hydrogen diffusion pathways for the hydriding and dehydriding of MgH2. The NaMgH 3 also shows fast hydrolysis reaction kinetics without any passivation. Our work shows that such perovskite-type hydride demonstrates great potential as efficient catalysts for the high-capacity hydrides for whether reversible or irreversible hydrogen storage. © 2013 Elsevier B.V. All rights reserved.


Wang H.,South China University of Technology | Zhong H.,Xiamen University of Technology | Ouyang L.,South China University of Technology | Liu J.,Key Laboratory of Advanced Energy Storage Materials of Guangdong Province | And 3 more authors.
Journal of Physical Chemistry C | Year: 2014

This paper presents a new approach to tune the de/hydriding thermodynamic properties of Mg via forming reversible Mg base solid solutions in the Mg-In and Mg-In-Al systems by mechanical milling. The effect of solubility of In and Al on the reversible formation of solid solution structure and hydrogen storage properties were investigated. It is found that although the solute atoms unavoidably are rejected upon hydriding, the hydrogenated products of MgH 2 and intermediate MgIn compound could fully transform back to solid solution after dehydrogenation. In the hydriding of Mg(In, Al) ternary solid solution, Al would get dissolved into MgIn compound rather than forming free Al like the Mg(Al) binary solid solution. Therefore, the presence of In improves the dehydriding reversibility of Mg(Al) solid solution, and the reversible Al concentration could be increased up to the 8 at. %, which is just the solubility limit of Al in Mg by mechanical milling. The reversible phase transformation is responsible for the reduction in the desorption enthalpy of MgH2, being 12 kJ/(mol·H2) reduction for the alloy Mg 0.9In0.1 relative to the desorption enthalpy of pure MgH2. Further, the hydrogen sorption kinetics of Mg(In) solid solutions are enhanced. Comparatively, both the thermodynamic destabilizing effect and the kinetic enhancing effect due to the Al dissolving are inferior to those due to the In dissolving. This work demonstrates a feasible way to improve the thermodynamics and kinetics of Mg base hydrogen storage alloys through traditional metallurgical method. © 2014 American Chemical Society.


Fan Q.H.,South China University of Technology | Zhao Y.M.,South China University of Technology | Zhao Y.M.,Key Laboratory of Advanced Energy Storage Materials of Guangdong Province | Li D.D.,South China University of Technology
Ceramics International | Year: 2013

Lanthanum hexaboride (LaB6) nanowires have been successfully fabricated by the facile catalytic reaction of lanthanum (La) powders, and gas mixture of boron trichloride (BCl3), hydrogen and argon, where Au was used as the catalyst. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected-area electron diffraction (SAED) were used to characterize the composition, morphology and structure of the samples. Single crystal column-shape LaB6 nanowires were obtained. It is expected that LaB6 nanowires can provide thermionic emission, field-induced emission, and thermal field-induced emission of electrons for TEM, SEM, flat panel displays, as well as many electronic devices that require high-performance electron source. © 2013 Elsevier Ltd and Techna Group S.r.l.


Cai W.,South China University of Technology | Cai W.,Key Laboratory of Advanced Energy Storage Materials of Guangdong Province | Wang H.,South China University of Technology | Wang H.,Key Laboratory of Advanced Energy Storage Materials of Guangdong Province | And 3 more authors.
Journal of Physical Chemistry C | Year: 2013

A reversible reaction, 4LiBH4 + NdH2NdB4 + 4LiH + 7H2, which destabilizes the dehydrogenation thermodynamics of LiBH4, has been found in the present work. Significantly, we prove that the reversibility only exists when NdH2+x is in size of less than about 10 nm. With this reaction, the estimated dehydrogenation enthalpy change is reduced from 74 kJ mol-1 H2 for pristine LiBH4 to 64 kJ mol-1 H2; the theoretical hydrogen capacity is 6.0 wt %, and there is no emission of deleterious BH 3 and B2H6. Moreover, the dehydrogenation kinetics of this reaction are fast - 6.0 wt % hydrogen was released within 1.5 h at 370 C. When the NdH2+x becomes stable owing to its significant growth, the thermodynamic destabilization effect does not occur after several hydrogenation/dehydrogenation cycles. However, the presence of NdH2+x also has a positive effect upon the dehydrogenation kinetics of LiBH 4. This novel finding is beneficial for modifying the reversibility of the reactive hydride composite systems through nanosize controlling. © 2013 American Chemical Society.


Cai W.,South China University of Technology | Cai W.,Key Laboratory of Advanced Energy Storage Materials of Guangdong Province | Wang H.,South China University of Technology | Wang H.,Key Laboratory of Advanced Energy Storage Materials of Guangdong Province | And 5 more authors.
RSC Advances | Year: 2014

Destabilization by the alkali metal hydroxides LiOH, NaOH, and KOH in the solid-state dehydrogenation of LiBH4 is reported. 6.5 wt% of hydrogen was liberated within 10 minutes at 250 °C. Destabilization originated from the interaction between H+ in [OH]- and H- in [BH4]-. A larger Pauling's electronegativity of the alkali metal (Li > Na > K) led to a greater acidity of the proton donor [OH]- site, and thus enhanced destabilization. The temperature of the predominant dehydrogenation was reduced to 207, 221, and 230 °C, for ball milled LiBH4-LiOH, 2LiBH4-NaOH, and 2LiBH4-KOH, respectively. The LiBH4: LiOH stoichiometry greatly affected the destabilization, by providing differing reaction pathways in LiBH 4-xLiOH (x = 1, 1.36, 4). The incremental increase in the LiOH content of LiBH4-xLiOH increased the dehydrogenation rate, but the temperature increased from 207 °C (x = 1) to 250 °C (x = 4). 4.1 and 6.5 wt% of hydrogen was liberated within 10 minutes by LiBH4-LiOH and LiBH4-4LiOH, respectively. The incremental increase in dehydrogenation temperature was attributed to differing [BH4] -⋯[OH]- interactions, formed by the differing stoichiometric ratios. © 2014 The Royal Society of Chemistry.

Discover hidden collaborations