【摘要】 在Ar气的保护下,利用磁悬浮感应炉熔炼制备La_0.7Mg_0.3-xLi_xNi_2.8Co_0.5（x=0.00,0.05,0.10,0.15）合金,并研究Li部分取代Mg对La_0.7Mg_0.3-xLi_xNi_2.8Co_0.5（x=0.00,0.05,0.10,0.15）合金电化学性能的影响。研究结果发现,合金电极的最大放电容量依次为385mAh/g（x=0.00）、390mAh/g（x=0.05）、385mAh/g（x=0.10）和393mAh/g（x=0.15）,经过100次充放电循环后,合金电极的容量保持率S100从39.7%（x=0.00）增加到42.1%（x=0.05）,然后再下降到39.8%（x=0.10）和34.2%（x=0.15）,而合金电极在放电电流密度为1200mA/g的高倍率放电性能HRD1200则从x=0.00的80%逐渐增大到x=0.15的82.8%。这充分说明以Li局部替代Mg,对LaMg-Ni合金电极的最大放电影响较小,但能提高合金电极的动力学性能,且适量的Li有利于改善合金电极的循环稳定性。更多还原

【Abstract】 La_0.7Mg_0.3-xLi_xNi_2.8Co_0.5（x=0.00,0.05,0.10,0.15）alloys were prepared by magnetic levitation melting under an argon atmosphere,and the effects of partial substitution of Li for Mg on the electrochemical performance of La_0.7Mg_0.3-xLi_xNi_2.8Co_0.5（x=0.00,0.05,0.10,0.15）alloys were investigated.The results indicated the maximum electrochemical discharge capacity was 385mAh/g（x=0.00）,390mAh/g（x=0.05）,385mAh/g（x=0.10）and 393mAh/g（x=0.15）,respectively.Furthermore,at the discharge rate of 1200mA/g,the high rate dischargeability（HRD1200）was improved and it increased from 80%（x=0.00）to 82.8%（x=0.15）as increasing Li content.While for the cycling stability,the capacity retention ratio S100 of the alloy enhanced from 39.7%（x=0.00）to 42.1%（x=0.05）and then reduced to 39.8%（x=0.10）and 34.2%（x=0.15）,after 100charge-discharge cycles.These suggest that the impact of partial substitution of Li for Mg on discharge capacity of La-Mg-Ni alloys is not obvious,but the electrochemical performance of La-Mg-Ni-based alloys can be improved by substituting appropriate Li content for Mg.更多还原