Transactions of Nonferrous Metals Society of China
JOURNAL OF RAILWAY SCIENCE AND ENGINEERING
|Vol. 13 No. 2 April 2003|
hydrogen storage alloy MlNi3.85Co0.45Mn0.4Al0.3X0.1(X=Mg,Si,Sn)
（College of Chemistry and Chemical Engineering,
Central South University, Changsha 410083, China）
Abstract:The non-stoichiometric high rate discharge hydrogen storage alloys series MlNi3.85Co0.45Mn0.4Al0.3X0.1(Ml represents the lanthanum-rich mischmetal, and X=Mg,Si,Sn) were prepared. The XRD and EDS results show that the high catalysis active miscellaneous La2Ni7phase forms except for main phase LaNi5 in the alloy body. The high rate discharge performance of hydrogen storage alloys electrode was improved because of the formation of La2Ni7 phase. The discharge capacities at 0.2C, 1C and 5C discharge rate reach 320mAh·g-1, 300mAh·g-1and 260mAh·g-1respectively when X is (Mg+Si). At the same scanning rate of circular volt—ampere testing, the surface anode oxidation peak current and peak area of the alloy containing (Mg+Si) electrode are far more larger than that of the high cobalt alloy MlNi3.55Co0.75Mn0.4Al0.3(AB5). Furthermore, the cobalt content of the hydrogen storage alloy containing (Mg+Si) decreases by 40% and the high rate discharge performance improves obviously compare to high cobalt AB5 alloys, it is promising that the hydrogen storage alloy containing (Mg+Si) becomes to an ideal dynamic battery cathode material.
Key words: low cobalt; high rate discharge; hydrogen storage alloys； (Mg+Si)； preparation