La_(1-x)Y_xNi_(4.8)Mn_(0.2)合金的储氢性能

Hydrogen Storage Properties of La_(1-x)Y_xNi_(4.8)Mn_(0.2) Alloys

研究了元素Y(钇)对La_(1-x)Y_xNi_(4.8)Mn_(0.2)(x=0.6,0.7,0.8)合金储氢性能的影响,结果表明:La_(1-x)Y_xNi_(4.8)Mn_(0.2)合金为CaCu_5型六方结构;随着Y含量的增加,晶格参数a和晶胞体积V减小,而c几乎不变,c/a线性增大;随着Y含量的增加,合金的吸放氢平台压显著升高,吸氢量减少,吸放氢平台斜率S和滞后系数_f略有增加,滞后系数H_f与XRD(111)峰的半高宽(FWHM)值的变化有着很好的对应关系,抗粉化性能提高。当Y含量x=0.8时,合金的吸放氢动力学综合性能最好。

The influences of Y content on the crystal structure, hydrogen storage thermodynamics and kinetics, and pulverization resistance ofLa_1-xY_xNi_4.8Mn_0.2（x=0.6, 0.7, 0.8） alloys were investigated sys- tematically. The results show that all the alloys have CaCu5 type hexagonal structure; with increasing Y content, the lattice parameter a, crystal volume Vdecreased, while the lattice parameter c kept almost un- changed, and c/a increased linearly. With the increase of Y content, the absorption/desorption plateau pressures increased dramatically; however, the hydrogen storage capacity decreased; the slopes of hy- drogen absorption/desorption plateau declined, and the hysteresis increased lightly; A similar variation trend was presented between the hysteresis and FWHM （the full width at half maximum） of （111） XRD patterns with increasing Y content; the pulverization resistance improved. When Y content x=0.8, the al- loy showed good performance both in the hydrogen absorption and desorption;