Development of Ti–Mn alloys with low hysteresis and high capacity by introducing Cr

Ti–Mn hydrogen storage alloys have excellent comprehensive advantages, including high reversible capacity, good cycling stability, and cost-effectiveness. However, the significant hydrogen absorption and desorption hysteresis hinders its practical applications. In this work, a systematic investigation is conducted into the effects of Cr content on the composition, structure, and hydrogen storage properties of Ti 1.25 Mn 1.75- x Cr x ( x = 0, 0.05, 0.15, and 0.25) alloys, with a particular focus on the impact of Cr introduction on the hydrogen absorption and desorption hysteresis of these alloys. The experimental results indicate that the alloy exhibits the best overall hydrogen storage properties when x = 0.15, with a maximum reversible hydrogen storage capacity of 1.96 wt%. The introduction of Cr can significantly reduce hysteresis without notably altering the hydrogen absorption and desorption properties. The hysteresis factor decreases from 0.1881 ( x = 0) to 0.0496 ( x = 0.25). Notably, a reasonable explanation for how the introduction of Cr reduces hysteresis in Ti–Mn alloys based on the material's plastic deformation properties is given. This study provides insights for the design of Ti–Mn alloys with low hysteresis and high capacity. • Cr introduction reduces hysteresis without significantly compromising capacity. • Ti 1.25 Mn 1.60 Cr 0.15 alloy shows negligible capacity decay after 100 cycles. • Underlying factors of Cr in reducing hysteresis were analyzed.