Charge storage in 40/60 TiFe alloy electrodes

Charge storage in 40/60 TiFe alloy has been investigated using electrode fabrication powder material, either of true alloy or of alloy precursor grades. The true alloy activated very reluctantly in that its maximum charge (i.e., hydrogen) capacity remained below 100 mA h g– 1. In contrast, the alloy precursor could be activated to an intrinsic capacity of ~300 mA h g–1. Charge storage of the 40/60 TiFe alloy precursor was certainly affected by the redox reactions of surface Fe, but a large amount was stored as hydrogen absorbed by the material, as indicated by a dialometric test and the poison effect. X-ray and EDAX analyses of the two materials can account for their differing abilities to store charge.