Enhanced Hydrogen Storage Properties of LiAlH4 by Excellent Catalytic Activity of XTiO3@h‐BN (X = Co, Ni)

• Published in: Advanced functional materials 2022-03, Vol.32 (13), p.n/a
• Main Authors: Wei, Sheng, Liu, Jiaxi, Xia, Yongpeng, Zhang, Huanzhi, Cheng, Riguang, Sun, Lixian, Xu, Fen, Bu, Yiting, Liu, Zhaoyu, Huang, Pengru, Zhang, Kexiang, Rosei, Federico, Pimerzin, Aleskey A., Seifert, Hans Jürgen
• Format: Article
• Language: English
• Subjects: Ball milling; Catalytic activity; Charge transfer; Coordination compounds; Dehydrogenation; Density functional theory; Desorption; hexagonal boron nitride; Hydrogen; Hydrogen storage; ilmenite cobalt titanate; ilmenite nickel titanate; Intermetallic compounds; lithium aluminum; Lithium aluminum hydrides; Materials science; Nanoparticles; Nickel compounds; Nickel titanides; Titanates
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202110180

The high desorption temperature and slow kinetics still restrict the applications of LiAlH4 in hydrogen storage. To solve the above problems, NiTiO3@h‐BN and CoTiO3@h‐BN prepared for the first time are introduced into LiAlH4 by ball milling. LiAlH4 doped with 7 wt% NiTiO3@h‐BN, selected as an optimal doping sample, starts to release hydrogen at 68.1 °C, and the total amount of hydrogen released is 7.11 wt% below 300 °C. The activation energies (Ea) of the two‐step hydrogen release reactions are 55.93 and 59.25 kJ∙mol−1, which are 45.8% and 69.0% lower than those of as‐received LiAlH4, respectively. Under 30 bar hydrogen pressure and 300 °C constant temperature, LiAlH4 doped with 7 wt% NiTiO3@h‐BN after dehydrogenation can absorb ≈1.05 wt% hydrogen. Based on density functional theory calculations, AlNi3 and NiTi, in situ formed nanoparticles during ball milling, can decrease the desorption energy barrier of AlH bonding in LiAlH4 and accelerate the breakdown of AlH bonding due to the interfacial charge transfer and the dehybridization. Furthermore, NiTi can enhance the adsorption and splitting of H2, promoting the activation of H2 molecules during the rehydrogenation process. The in situ formed NiTi and AlNi3 in NiTiO3@h‐BN doped‐LiAlH4 after ball milling facilitate the surface adsorption and hydrogen dissociation due to the interfacial charge transfer and the dehybridization of the AlH cluster. In addition, the NiTi catalyst can promote the activation of H2 molecules, which is beneficial to the rehydrogenation performance of LiAlH4.