Improved Hydrogen Storage Performance of MgH₂–LiAlH₄ Composite by Addition of MnFe₂O₄

Abstract

The catalytic effects of MnFe 2 O 4 nanoparticles on the hydrogen storage properties of MgH 2 −LiAlH 4 , prepared by ball milling, are studied for the first time. The hydrogen storage properties and reaction mechanism are investigated by pressure−composition−temperature (PCT), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The nonisothermal desorption results show that MgH 2 −LiAlH 4 + 5 mol % MnFe 2 O 4 has a lower onset dehydrogenation temperature, 85, 50, and 40°C lower than these of ball-milled MgH 2 −LiAlH 4 sample for each stage in the dehydrogenation process. The isothermal dehydriding kinetics and isothermal rehydrogenation kinetics results indicate that adding MnFe 2 O 4 to MgH 2 −LiAlH 4 could significantly enhance the absorption/desorption kinetics of MgH 2 −LiAlH 4 . From the differential scanning calorimetry and Kissinger analysis, the apparent activation energy of the 5 mol % MnFe 2 O 4 -doped sample for the three decomposition stage is 55.8, 70.8, and 96.5 kJ/mol, resulting in a 45.7, 85.5, and 99.6 kJ/mol decrease, respectively, compared with the MgH 2 −LiAlH 4 sample. These improvements are mainly attributed to in situ formed Fe 0.872 O phase and the amorphous Mn-containing phase during the dehydrogenation process, which act as the real catalyst in the MgH 2 −LiAlH 4 + 5 mol % MnFe 2 O 4 composite.

Enhanced hydrogen storage performance of destabilized 4MgH2–Li3AlH6 system doped with Co2NiO nanopowder

“…Meanwhile, many studies have shown that oxide nanopowder is a good catalyst for mixed-metal hydride system [39e41]. For example, Wan et al [41] showed that the sorption performance of MgH 2 eLiAlH 4 system are significantly improved by adding MnFe 2 O 4 nanoparticles. They claimed that the catalytic activity of MnFe 2 O 4 was due to the in situ formation of the Fe oxide phase and the amorphous Mn-containing phase during the dehydrogenation process.…”

Alanates, a Comprehensive Review

“…Along the last decade, several LiAlH 4 -MgH 2 composites have been studied for hydrogen storage [90,91,92,93,94,95]. The main results coincide in that the dehydrogenation pathway is marked by three steps, the usual two of LiAlH 4 and one of MgH 2 .…”

“…The temperature of these dehydrogenation steps is somewhat reduced compared to the pure components. Even more, the use of additives, such as TiH 2 [96], TiF 3 [90], MnFe 2 O 4 [91], or HfCl 4 [93], reduced approximately up to 60 °C the dehydrogenation temperatures as compared to the mixture without additives. The role of the additives is to reduce the activation energy of dehydrogenation [93].…”

Enhanced the hydrogen storage properties and reaction mechanisms of 4MgH 2 + LiAlH 4 composite system by addition with TiO 2

“…Up to now, just a few studies have been published regarding the function of a catalyst in the efficiency of hydrogen storage for the MgH 2 + LiAlH 4 composite 31‐36 . Currently, Sulaiman et al 37 revealed the de/rehydrogenation efficiency improvement of the 4MgH 2 + LiAlH 4 sample with the inclusion of metal oxide, SrFe 12 O 19 .…”