熔炼掺杂对AB5型贮氢合金的结构和性能影响

为了探索一种新的掺杂方式对AB5型贮氢合金性能的影响，采用熔炼掺杂方法，研究了掺杂适量TiMn1.5合金（掺杂量为4％、8％的TiMn1.5）对成分为‰．La0.7Ni2.65Co0.75Mn0.1的AB5型贮氢合金的结构及性能影响。XRD测试结果证实：掺杂后合金的主相仍为LaNi5相，生成了少量（NiCo）2Ti相。（NiCo）3Ti相的出现对贮氢合金的气态和电化学贮氢性能都有不同程度的降低。合金电极的动力学测试结果表明（线性扫描法和交流阻抗法）：在0．5～2．5C的放电电流密度，掺杂前后的合金电极的反应速率均由电极表面电荷转移速率决定，掺杂4％TiMn1.5的合金样品电极的高倍率放电性能有一定的改善。在3C放电电流密度以上，电极反应速率均由氢扩散速率来控制，随着TiMn1.5的掺杂的增加，其合金电极的高倍率性能降低。

Structure and properties of melting-doped AB5 hydrogen storage alloys

To Search the affection of a new way doping on ABs-type hydrogen storage alloys, La0.7 Ni2.65 Coo. 7s Mn0.1 （AB5 type） hydrogen storage alloys, melting-clopped with TiMnl.s alloy （4 %, 8 %）, have been investigated to illus- trate the effects of doping on its structure and properties. XRD analysis indicated that the dopped alloy samples con- sist of a main LaNis phase and small （NiCo）3 Ti phase, the formation of （NiCo）3 Ti phase will result in the decrease of hydrogenation and high-rate dischargeabilities. Further analysis of electrode kinetics were measured by linear po- larization and Electrochemical impedance spectroscopy （EIS）, the results presented that the electrode reaction was determined by charge-transfer reaction, and the electrode melting-dolaped with 4 % TiMnl. 5 alloy, shown better high- rate dischargeabilities, when discharged at the rate from 0.5 to 2.5 C. While, the electrode reaction was determined by hydrogen-diffusion reaction, and the high-rate disehargeabilities have been decreased with the increase of TiMn1.5 content, when discharged at the rate from 3.0 to 4.0 C.