Rapid and reversible hydrogen sorption in Mg–Fe–Ti thin films

Abstract

This study focused on hydrogen sorption properties of 1.5 μm thick Mg–10 at. % Fe–10 Ti, Mg–15 at. % Fe–15 Ti, and Mg–20 at. % Fe–20 Ti films. We show that the alloys display remarkable sorption behavior: At 200 °C the films are capable of absorbing nearly 5 wt % hydrogen in seconds and desorbing in minutes. Furthermore this sorption behavior is stable over cycling. In the Mg–15 at. % Fe–15 Ti alloy there is no kinetic or capacity degradation even after 100 absorption/desorption cycles. Pressure–composition isotherm data for Mg–10 at. % Fe–10 Ti indicates that the sorption enhancement is due to improved kinetics rather than any altered thermodynamics. We envision these alloys as becoming the material of choice for a variety of sensing and storage applications.