Ren Zhuanghe, Zhang Xin, Li Hai-Wen, Huang Zhenguo, Hu Jianjiang, Gao Mingxia, Pan Hongge, Liu Yongfeng
State Key Laboratory of Silicon Materials and School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China.
Hefei General Machinery Research Institute, Hefei 230031, China.
Research (Wash D C). 2021 Dec 14;2021:9819176. doi: 10.34133/2021/9819176. eCollection 2021.
Sodium alanate (NaAlH) with 5.6 wt% of hydrogen capacity suffers seriously from the sluggish kinetics for reversible hydrogen storage. Ti-based dopants such as TiCl, TiCl, TiF, and TiO are prominent in enhancing the dehydrogenation kinetics and hence reducing the operation temperature. The tradeoff, however, is a considerable decrease of the reversible hydrogen capacity, which largely lowers the practical value of NaAlH. Here, we successfully synthesized a new Ti-dopant, i.e., TiH as nanoplates with ~50 nm in lateral size and ~15 nm in thickness by an ultrasound-driven metathesis reaction between TiCl and LiH in THF with graphene as supports (denoted as NP-TiH@G). Doping of 7 wt% NP-TiH@G enables a full dehydrogenation of NaAlH at 80°C and rehydrogenation at 30°C under 100 atm H with a reversible hydrogen capacity of 5 wt%, superior to all literature results reported so far. This indicates that nanostructured TiH is much more effective than Ti-dopants in improving the hydrogen storage performance of NaAlH. Our finding not only pushes the practical application of NaAlH forward greatly but also opens up new opportunities to tailor the kinetics with the minimal capacity loss.
具有5.6 wt%储氢容量的铝氢化钠（NaAlH）在可逆储氢过程中动力学严重迟缓。诸如TiCl、TiCl、TiF和TiO等钛基掺杂剂在增强脱氢动力学从而降低操作温度方面表现突出。然而，权衡之处在于可逆储氢容量大幅下降，这在很大程度上降低了NaAlH的实际价值。在此，我们通过在四氢呋喃中以石墨烯为载体，使TiCl与LiH之间发生超声驱动复分解反应，成功合成了一种新型钛掺杂剂，即横向尺寸约为50 nm、厚度约为15 nm的纳米片状TiH（记为NP-TiH@G）。掺杂7 wt%的NP-TiH@G可使NaAlH在80°C下完全脱氢，并在100 atm氢气压力下于30°C下再氢化，可逆储氢容量为5 wt%，优于迄今报道的所有文献结果。这表明纳米结构的TiH在改善NaAlH的储氢性能方面比钛基掺杂剂有效得多。我们的发现不仅极大地推动了NaAlH的实际应用，还为以最小容量损失来调控动力学开辟了新机遇。
