Development of ZrFeV alloys for hybrid hydrogen storage system

• (Zr0.7Ti0.3)1.04Fe1.8V0.2 alloy is optimized to have the best overall properties.
• (Zr0.7Ti0.3)1.04Fe1.8V0.2 alloy shows no obvious capacity loss after 200 cycles.
• A hybrid hydrogen storage system based on (Zr0.7Ti0.3)1.04Fe1.8V0.2 is proposed.
• ZrTiFeV alloy is a potential candidate for high pressure MH tank of fuel cell.

The combination of unstable hydrogen storage materials with a high pressure tank provides a potential solution to on-board hydrogen storage system for fuel cell vehicles. However, none of the available solid-state materials can fulfill all the requirements. In this work, ZrFeV-based alloys were systematically investigated for the possible use in such kind of hybrid storage devices.Among these alloys studied here, the composition (Zr0.7Ti0.3)1.04Fe1.8V0.2 shows the best overall properties with a reversible hydrogen capacity of 1.51 wt%, and a hydrogen desorption pressure of 11.2 atm at 0 °C. Besides, this alloy also shows excellent stability without obvious capacity loss even after 200 hydrogen absorption/desorption cycles. Calculated results show that the gravimetric density of the hybrid storage system combining a 35 MPa high pressure tank with (Zr0.7Ti0.3)1.04Fe1.8V0.2 alloy is 1.95 wt% when the volumetric density reaches 40 kg/m3.