Multielement synergetic effect of NiFe2O4 and h-BN for improving the dehydrogenation properties of LiAlH4

Effective hydrogen storage is one of the main unresolved challenges towards deploying the so-called hydrogen economy. LiAlH4 is considered a promising candidate for hydrogen storage due to its high hydrogen storage capacity and the relative abundance of aluminum. However, it also has the disadvantages of slow kinetics, high dehydrogenation temperature and poor reversibility. To improve these shortcomings of LiAlH4, we made a composite material by incorporating hexagonal boron nitride supported NiFe2O4 (NiFe2O4@h-BN) into it. We then studied the effect of NiFe2O4@h-BN composites on the dehydrogenation and rehydrogenation behaviors of LiAlH4 using thermogravimetric analysis, mass spectrometry and the Sieverts-type pressure composition temperature. The results showed that the onset decomposition temperature of LiAlH4 doped with 7 wt% NiFe2O4@h-BN is 77.1 degrees C with 6.74 wt% hydrogen released. In addition, under 30 bar pressure hydrogen and at 300 degrees C constant temperature, the LiAlH4 doped with 7 wt% NiFe2O4@h-BN after dehydrogenation absorbed nearly 0.6 wt% of hydrogen in 11 hours. At the same time, Al4Ni3 and LiFeO2 were found in LiAlH4 doped with NiFe2O4@h-BN after ball milling, and Al1.1Ni0.9 was obtained during heating.