化学计量比和放氢背压对LiBH_4+xMg_2NiH_4体系放氢性能的影响  

Effects of Stoichiometry and Dehydrogenation Back-pressure on the Dehydrogenation Behavior of LiBH_4+xMg_2NiH_4 Composites

作　　者：邓帅帅[1] 肖学章[1] 陈立新[1] 韩乐园[1] 李寿权[1] 葛红卫[1] 王启东[1] 

机构地区：[1]浙江大学材料科学与工程学系,杭州310027

出　　处：《高等学校化学学报》2012年第9期2030-2034,共5页Chemical Journal of Chinese Universities

基　　金：国家"九七三"计划项目(批准号:2010CB631300);国家自然科学基金(批准号:51171173;51001090)资助

摘　　要：研究了不同化学计量比(x=0.25,0.5,0.75,1.0,1.25)和放氢背压(1×10-4和0.4 MPa)对LiBH4+xMg2NiH4复合体系吸放氢性能的影响.结果表明,随着化学计量比(x)的增加,复合体系的放氢温度逐渐降低,放氢动力学性能得到提高,但放氢容量逐渐降低;其中,在1×10-4和0.4 MPa初始放氢背压下,LiBH4+0.75Mg2NiH4体系具有最佳放氢动力学性能和较高的储氢容量.结果表明,放氢背压和化学计量比均会对高温下液相LiBH4与固态Mg2NiH4的润湿性产生影响,进而影响复合体系的放氢路径和放氢动力学性能.The effects of stoichiometry（x =0. 25,0. 5,0. 75, 1.0, 1.25） and hydrogen back pressure on the dehydrogenation behavior of LiBH4 ＋xMg2 NiH4 composites were investigated systematically by methods of X-ray diffraction（XRD） and temperature programmed desorption（TPD） analysis. The results show that the stoichiometry x has a great effect on the dehydriding kinetics of LiBH4＋xMg2NiH4 composites. With the increase of x value for the LiBH4 ＋xMgzNiH4 composites, the decrease of the dehydrogenation temperature and the improvement of the dehydriding kinetics are observed but with a loss of dehydrogenation capacity. Thereinto, LiBH4 ＋ 0. 75Mg2NiH4 composite has the best dehydriding kinetics and a relatively high hydrogen storage capacity under initial hydrogen back pressure of 1 xl0-4 or 0. 4 MPa. The analysis shows that both the stoichiometry x of the LiBH4＋xMg2NiH4 mixtures and hydrogen back pressure can influence the wetting between liquid LiBH4 and solid MgzNiH4 , and have a great effect on the dehydrogenation path and kinetics furthermore.

关 键 词：储氢材料 储氢性能 化学计量比 LiBH4 MG2NIH4 

分 类 号：O643[理学—物理化学]