Titanium-iron-manganese (TiFe_(0.85)Mn_(0.15)) alloy for hydrogen storage: Reactivation upon oxidation

摘要

Titanium-iron (TiFe) is known to be a low-cost alloy that can be reactivated to nearly full hydrogen storage capacity after oxidation. However, this reactivation requires multiple heat treatments at high temperatures under vacuum even upon partial substitution of Fe with a small amount of manganese to form TiFe0.85Mn0.15. This process is cumbersome in the context of practical applications, and better strategies for the facile activation of TiFe are required. Herein, we report on an improvement in the reactivation strategy of TiFe0.85Mn0.15 by using a single heat treatment process after air oxidation of the alloy. After full oxidation of the material under air for 2 h, reactivation was achieved in a single step by heating the alloy to 300 degrees C under hydrogen pressure. During that process, the reduction of Fe was believed to lead to new reactive paths at the surface of the alloy facilitating the permeation of hydrogen. As a result, full cycling capability of the material was quickly regained, and the hydrogen capacity loss was of only 0.1 mass%. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.