Improvement on hydrogen storage performance of MgH ₂ by THF‐promoted nano‐crystallization under low‐speed ball milling

Abstract MgH 2 is a promising solid‐state hydrogen storage material; one of the limitations of its scale‐application is the slow rate of hydrogen uptake and release. The addition of catalyst to improve the kinetics of MgH 2 has achieved remarkable results. However, these studies require high‐speed ball milling (400–500 rpm) to achieve the combination of MgH 2 and catalyst, and such harsh processing conditions are difficult to achieve in industrial production. In this work, the catalyst and MgH 2 were efficiently combined at lower milling speed (300 rpm) by introducing tetrahydrofuran C 4 H 8 O (THF) as an auxiliary agent. Moreover, milling with THF promotes the nano‐crystallization of MgH 2 , which further improves its performance. Results show that THF‐assisted MgH 2 absorbed 6.1 wt% at 90 °C and desorbed 6.1 wt% at 275 °C, while the MgH 2 milling under the same speed without THF cannot absorb hydrogen and only desorbed 3.3 wt%. It reveals that the synergistic effect produced by nano‐crystallization and nano‐hydrogen pump is the key mechanism of improving the performance of MgH 2 after introducing THF. This work proposes a novel synergistic strategy for modifying MgH 2 , offering practical insights for enhancing its hydrogen storage performance under low‐speed ball milling.