铸态及退火La_(1.9)Ti_(0.1)MgNi_9合金的贮氢性能(英文)

Hydrogen Storage Properties of As-Cast and Annealed La_(1.9)Ti_(0.1)MgNi_9 Alloys

采用磁悬浮感应熔炼及退火处理的方法,制备La1.9Ti0.1MgNi9合金。对合金样品的XRD、PCT和电化学测试表明,所有样品均由多相组成,LaNi5相为主相。当退火温度达到1173K时,合金中LaMg2Ni9相消失,Ti2Ni相出现。退火处理能提高合金的晶化程度、降低吸放氢平台压。退火1073K合金的有效吸氢量较高,在303K时达到1.25%(质量分数)。La1.9Ti0.1MgNi9合金退火后,放电容量、循环稳定性以及高倍率放电性能得到极大改善,以1173K退火合金电化学性能较好,其最大放电容量为377mAh/g,1100mA/g电流密度下的高倍率放电性能为0.839,经112次充放电循环后放电容量保持率为60%。

La1.9Ti0.1MgNi9 alloys were prepared by magnetic levitation melting followed by annealing treatments. The results of XRD, PCT and electrochemical measurements show that all samples possess a multiphase structure, and LaNi5 phase is the main phase. LaMg2Ni9 phase disappears and Ti2Ni phase appears at 1173 K. Annealed alloys exhibit higher compositional homogeneity and lower absorption/desorption plateau pressures compared to as-cast alloy. The effective hydrogen storage capacity of the alloy annealed at 1073 K is the highest, and it reaches 1.25% (mass fraction) at 303 K. Annealing not only enhances the discharge capacity, but also improves the cyclic stability and the high rate dischargeability markedly. La1.9Ti0.1MgNi9 alloy annealed at 1173 K presents good electrochemical performance with the maximum discharge capacity of 377 mAh/g, the HRD1100 of 0.839 and the retention of discharge capacity of 60% after 112 charge/discharge cycles.