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<p>As a typical reactive composite hydrogen storage system, 2LiBH<sub>4</sub>–MgH<sub>2</sub> holds an ultrahigh hydrogen storage capacity of 11.5&#xa0;wt%. However, it suffers from sluggish hydrogen storage kinetics due to the difficult nucleation of MgB<sub>2</sub>. Herein, amorphous VB<sub>2</sub> nanoparticles with an average size of approximately 32&#xa0;nm are synthesized to enhance the hydrogen storage performance of 2LiBH<sub>4</sub>–MgH<sub>2</sub> composite. VB<sub>2</sub>, sharing the same hexagonal structure with MgB<sub>2</sub> with a <i>d</i>-value mismatch ratio of only 2.28%, could serve as effective nucleation sites for promoting the formation of MgB<sub>2</sub>. Theoretical calculations reveal that the introduction of VB<sub>2</sub> significantly reduces the binding energies of B and Mg, facilitating in situ nucleation of MgB<sub>2</sub>. As a result, after the introduction of VB<sub>2</sub> nanoparticles, complete hydrogen desorption of 9.23&#xa0;wt% is achieved for 2LiBH<sub>4</sub>-MgH<sub>2</sub> within 2&#xa0;h at 400&#xa0;°C, which is 4 times shorter than the time required for pure 2LiBH<sub>4</sub>-MgH<sub>2</sub>, and no nucleation incubation period for hydrogen desorption is observed even at a low temperature of 380&#xa0;°C. More importantly, a reversible capacity of 9.3&#xa0;wt%, corresponding to a capacity retention of 100%, could be preserved after 10 cycles of hydrogen storage, demonstrating stable reversible hydrogen storage performance. This study provides a novel technological pathway for improving the reversible hydrogen storage performance of composite metal hydrides and offers significant insights into the development of high-performance hydrogen storage materials.</p> Graphical Abstract <p></p>

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Amorphous VB2 nanoparticles for stable hydrogen storage of 2LiBH4–MgH2

  • 期刊论文

  • 发表日期：

    2025年4月22日

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  • Yu-Kun Liu,
  • Yu-Chen Pang,
  • Chao-Qun Li,
  • Xiao-Yue Zhang,
  • Xue-Chun Hu,
  • Wei Chen,
  • Xue-Bin Yu,
  • Guang-Lin Xia

摘要

As a typical reactive composite hydrogen storage system, 2LiBH4–MgH2 holds an ultrahigh hydrogen storage capacity of 11.5 wt%. However, it suffers from sluggish hydrogen storage kinetics due to the difficult nucleation of MgB2. Herein, amorphous VB2 nanoparticles with an average size of approximately 32 nm are synthesized to enhance the hydrogen storage performance of 2LiBH4–MgH2 composite. VB2, sharing the same hexagonal structure with MgB2 with a d-value mismatch ratio of only 2.28%, could serve as effective nucleation sites for promoting the formation of MgB2. Theoretical calculations reveal that the introduction of VB2 significantly reduces the binding energies of B and Mg, facilitating in situ nucleation of MgB2. As a result, after the introduction of VB2 nanoparticles, complete hydrogen desorption of 9.23 wt% is achieved for 2LiBH4-MgH2 within 2 h at 400 °C, which is 4 times shorter than the time required for pure 2LiBH4-MgH2, and no nucleation incubation period for hydrogen desorption is observed even at a low temperature of 380 °C. More importantly, a reversible capacity of 9.3 wt%, corresponding to a capacity retention of 100%, could be preserved after 10 cycles of hydrogen storage, demonstrating stable reversible hydrogen storage performance. This study provides a novel technological pathway for improving the reversible hydrogen storage performance of composite metal hydrides and offers significant insights into the development of high-performance hydrogen storage materials.

Graphical Abstract