Electrochemical properties of magnesium-based hydrogen storage alloys improved by transition metal boride and silicide additives

Transition metal borides and silicides prepared by mechanical alloying (MA) and chemical reduction methods (CR) were introduced to improve the corrosion resistance of magnesium-based hydrogen storage alloys. The additive of FeB prepared by MA can remarkably enhance the discharge capacity and cycling stability which has initial discharge capacity of 355.9 mA h g(-1) and keeps 224 mA h g(-1) after 100 cycles, and the exchange density I-o of MgNi-NiB(CR) electrodes is 344.80 mA g(-1) but MgNi is only 67.6 mA g(-1) which leads to the better rate capability of the composite alloys. The results of SEM characterization, cyclic charge-discharge tests, potentiodynamic polarization, linear polarization and AC impedance experiment show that the corrosion inhibition property of MgNi in alkaline is improved by transition metal boride and silicide additives. (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.