KF掺杂量对MgH_2-2LiNH_2体系储氢性能影响的研究

Effects of Doping Content of Potassium Fluoride on Hydrogen Storage Properties of MgH_2-2LiNH_2

采用高能球磨制备了不同摩尔量KF掺杂的MgH2-2LiNH2-xKF(x=0,0.015,0.025,0.050,0.100)储氢材料,采用XRD,DSC-MS和Sieverts方法研究了材料物相与储氢性能。结果表明,KF的掺杂促进了球磨过程中MgH2-2LiNH2向Mg(NH2)2-2LiH的转变,KF掺杂的样品放氢后出现KH的衍射峰。KF的掺杂显著提高了MgH2-2LiNH2材料放氢动力学性能,降低了放氢反应起始温度和激活能,且放氢过程有效抑制了NH3的释放,其中0.05 mol KF掺杂MgH2-2LiNH2体系放氢性能最优。

MgH2-2LiNH2-xKF（x = 0, 0.015, 0.025, 0.050, 0. 100）samples were prepared by high energy ball milling. The pha- ses and hydrogen desorption characteristics of the samples were analyzed by using X-ray diffraction（ XRD）, differential scanning calo- rimetry-mass spectrometry（DSC-MS） and Sievert＇s type apparatus. The experimental results showed that the transformation from （ MgH2-2LiNH~ ） to （ Mg（ NH2 ）2-2LiH） was improved efficiently by KF dopant after ball-milling, the diffraction peaks of KH were ob- served after dehydrogenation for the KF doped sample. The onset dehydrogenation temperature and activation energy of KF doped MgH2-2LiNH2 samples were greatly decreased, and the level of NH3 desorbed during the hydrogen desorption process was also effec- tively decreased. The optimal doping content of the KF dopant for the MgH2-2LiNH2 system was 0.05 mol.