Development of V-Free BCC Structured Alloys for Hydrogen Storage

Abstract

V-free body-centered cubic (BCC) structured hydrogen storage alloys have gained significant attention for their low cost and high theoretical hydrogen storage capacity (3.8 wt %). However, before practical application, critical challenges, such as low dehydriding capacity, activation difficulty, and poor cyclic stability, need to be solved. In this work, an easily activated and high-performance V-free BCC-type alloy (Ti40Cr50Mo10Ce1) was successfully synthesized by heat treatment and Ce doping. The heat treatment significantly increased its dehydriding capacity to 2.5 wt %, attributed to a reduced slope factor (0.76–0.17), making it comparable to V-based BCC-type alloys. And the V-free BCC-type alloy, after Ce doping, enabled room-temperature hydrogen absorption, eliminating the need for high-temperature activation. Ce doping did not significantly affect the activation energy, enthalpy change, or hysteresis factor of the alloy during de/hydrogenation. Additionally, the V-free BCC-type alloy, after heat treatment and Ce doping, exhibited excellent cyclic stability, with a capacity retention rate of 90% after 100 cycles. This study provides valuable guidance for designing innovative and cost-effective hydrogen storage alloys.