Gas phase hydrogen absorption and electrochemical performance of La-2(Ni,Co,Mg,M)(10) based alloys

作者：Drulis H^*; Hackemer A; Gluchowski P; Giza K; Adamczyk L; Bala H

来源：International Journal of Hydrogen Energy, 2014, 39(5): 2423-2429.

DOI：10.1016/j.ijhydene.2013.11.092

• Intermetallic hydrides
• Pressure-composition isotherms
• Electrochemical charge/discharge
• Hydrogen capacity

The effect of M = In or Al on the hydrogenation behavior of the La-2(Ni,Co,Mg,M)(10) alloys at room temperature is presented. The ceramic like samples have been prepared by powder metallurgy route using pure Mg- and the La2Ni9-xMx alloy powder precursors. XRD analysis revealed predominantly the CaCu5-type structure for all final alloys. Partial substitution of Co by In in La2Ni8MgCo causes a slight decrease of hydrogen concentration whereas Al addition increases this parameter. The highest hydrogen concentration of 1.87 wt.% has been reached for La-2(Ni8Co0.8Al0.2)Mg composition at hydrogen pressure of 10 bar. Indium addition dramatically decreases the middle-plateau hydrogen equilibrium pressure from p(eq) = 0.37 bar (In-free alloy) to p(eq) = 0.06 bar (1.7 at.% In). The electrochemical performance of the studied materials has been characterized using chronoamperometric and chronopotentiometric techniques. The galvanostatic hydrogenation experiments at 185 mA/g discharge rate revealed the largest discharge current capacity of 355 mAh/g for La-2(Ni8Co0.8Al0.2)Mg alloy. The relative diffusivity factor of hydrogen ((D) over bar (H)/a(2)) varies for the tested materials in the range of (2.0-5.4).10(-5) s(-1).

• 出版日期2014-2-4