|Improved reversible dehydrogenation of 2LiBH(4)-MgH2 composite by the controlled formation of transition metal boride|
|K. K. Wang; X. D. Kang; Q. Kang; Y. J. Zhong; C. H. Hu; P. Wang
|Source Publication||Journal of Materials Chemistry A
|Abstract||In this paper, we report a careful study of the properties and mechanisms of a 2LiBH(4)-MgH2 composite with a niobium oxide (Nb2O5) additive. It was found that directly milling with a small amount of the Nb2O5 additive exerted a negligible effect on the dehydrogenation kinetics of the 2LiBH(4)-MgH2 composite in the first cycle. However the recycled sample showed notable property advantages over the neat 2LiBH(4)-MgH2 composite. Phase/chemical state analyses and control experiments were conducted to gain insight into the chemical transformation of the Nb-containing species. It was found that the Nb2O5 additive reacted with LiBH4 to form a niobium boride (NbB2) heterogeneous nucleation agent, via a niobium hydride (NbH2) intermediate, in the dehydrogenation process of the composite sample. The retarded formation of the NbB2 is a major mechanistic reason for the observed drastic property change of the composite upon cycling. As a solution, we employed a novel three-step method to controllably promote the formation of the targeted NbB2 species and improve its dispersion state. As expected, the 2LiBH(4)-MgH2-0.08Nb(2)O(5) composite sample, prepared using the new method, exhibits rapid dehydrogenation kinetics and high cyclic stability, which compare favorably with the literature results of the 2LiBH(4)-MgH2 composites with transition metal additives.|
|description.department||[wang, kuikui] univ sci & technol china, hefei 230026, peoples r china. [wang, kuikui
; kang, xiangdong
; zhong, yujie
; wang, ping] chinese acad sci, inst met res, shenyang natl lab mat sci, shenyang 110016, peoples r china. [kang, qiang] chinese acad sci, inst met res, anal & testing div, shenyang 110016, peoples r china. [hu, chaohao] guilin univ elect technol, guangxi key lab informat mat, guilin 541004, peoples r china.
; kang, xd (reprint author), chinese acad sci, inst met res, shenyang natl lab mat sci, shenyang 110016, peoples r china.
|Keyword||Reactive Hydride Composite
K. K. Wang,X. D. Kang,Q. Kang,et al. Improved reversible dehydrogenation of 2LiBH(4)-MgH2 composite by the controlled formation of transition metal boride[J]. Journal of Materials Chemistry A,2014,2(7):2146-2151.
K. K. Wang,X. D. Kang,Q. Kang,Y. J. Zhong,C. H. Hu,&P. Wang.(2014).Improved reversible dehydrogenation of 2LiBH(4)-MgH2 composite by the controlled formation of transition metal boride.Journal of Materials Chemistry A,2(7),2146-2151.
K. K. Wang,et al."Improved reversible dehydrogenation of 2LiBH(4)-MgH2 composite by the controlled formation of transition metal boride".Journal of Materials Chemistry A 2.7(2014):2146-2151.
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