LmNi4.78Mn0.22 alloy modified with Si used as anodic materials in borohydride fuel cells

Fuel cells using borohydride as the fuel have received much attention because of high potential and power density. LMNi4.78Mn0.22 alloy used as the anodic material instead of noble metal shows high catalytic activity both in the electrochemical oxidation reaction and the hydrolysis of fuel. In this work, Si has been added to modify LmNi(4.78)Mn(0.22) alloy by ball-milling and heat-treatment methods. It is found that the surface of the alloy particles is covered with Si by ball-milling treatment, and then, the Si on the surface diffuses into the bulk of the alloy particles after heat treatment. Experimental results show that the electrochemical catalytic activity of the alloy after modification with Si decreases; at the same time, the H-2 generation rate also decreases in the discharge process. The utilization of the fuel increases from 21.37% for the parent alloy to 95.27% for the modified alloy at a small current density. (c) 2004 Published by Elsevier B.V.