•Effects of Ce on the hydriding properties of TiFe0.9Mn0.1 alloy were studied.•The added Ce remarkably improved the activation properties of TiFe0.9Mn0.1 alloy.•Ce dispersing in TiFe matrix contributes for improving the activation properties.•The degraded H2 capacity after cycling was recovered by a heat treatment at 623 K.The hydrogenation properties and the microstructures of TiFe0.9Mn0.1Cex (x = 0, 0.02, 0.04, 0.06) alloys were investigated by PCT, XRD and SEM/EDX. The results showed that the addition of small amount of Ce remarkably improved the activation properties of TiFe0.9Mn0.1 alloys. The alloys could start to absorb hydrogen at 353 K under the initial hydrogen pressure of 4.0 MPa without noticeable incubation time. XRD profiles and SEM observation indicated that Ce dispersing in TiFe matrix played an important role for the improvement of activation properties. The addition of Ce didn't affect the thermodynamics and the cycling properties of TiFe0.9Mn0.1 alloy. The degradation of hydrogen capacity after cycles of hydrogenation was recovered by a heat treatment at 623 K.

•The kinetics of hydrogen sorption of Li–N–H system was improved by LiBH4 addition.•The improvement of the hydrogen sorption may attribute to (LiNH2)x(LiBH4)(1−x).•Melted (LiNH2)x(LiBH4)(1−x) could transfer LiNH2 from solid state to molten state.Remarkable improvement of hydrogen sorption properties of Li–N–H system has been obtained by doping with a small amount of LiBH4. The starting and ending temperatures of hydrogen desorption shift to lower temperatures and the release of NH3 is obviously restrained by 10 mol% LiBH4 doping. The kinetics of hydrogen desorption and absorption of Li–N–H system became faster by the addition of LiBH4. About 4 wt.% H2 can be released within 30 min and ∼4.8 wt.% H2 can be reabsorbed within 2 min by LiBH4 doped sample at 250 °C, while only 1.44 wt.% H2 is released and 2.1 wt.% is reabsorbed for pure Li–N–H system. The quaternary hydride (LiNH2)x(LiBH4)(1−x) formed by the reaction between LiBH4 and LiNH2 may contribute to the enhancement of the hydrogen sorption performances by yielding a ionic liquid phase and transferring LiNH2 from solid state to molten state with a weakened N–H bond.

•Mg–La–Ni hydrogen storage alloy was successfully prepared by microwave sintering.•70 Mg–9.72 La–20.28 Ni (wt pct) has the best comprehensive H/D properties.•Chou model was used to analyze the reaction kinetic mechanism.It is a challenge to prepare a material meeting two conflicting criteria – absorbing hydrogen strongly enough to reach a stable thermodynamic state and desorbing hydrogen at moderate temperature with a fast reaction rate. With the guide of the Mg–La–Ni phase diagram, microwave sintering (MS) was successfully applied to preparing Mg–La–Ni ternary hydrogen storage alloys from the powder mixture of Mg, La and Ni. Their phase structures, morphologies and hydrogen absorption and desorption (A/D) properties have been studied by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), pressure-composition-isotherm (PCI) and differential scanning calorimetry (DSC). The metal hydride of 70 Mg–9.72 La–20.28 Ni (wt pct) has the best comprehensive hydriding and dehydriding (H/D) properties, which can absorb 4.1 wt.% H2 in 600 s and desorb 3.9 wt.% H2 in 1500 s at 573 K. The DSC results reveal its onset temperatures of hydrogen A/D are the lowest among all the samples, which are 671.4 and 600.9 K. Its activation energy of dehydriding reaction is 113.5 kJ/mol H2, which is the smallest among all the samples. Also, Chou model was used to analyze the reaction kinetic mechanism.

•Effect of LiBH4 on the H-sorption properties of MgH2 was investigated.•We observed two kinds of effects of LiBH4 on the H-desorption property of MgH2.•Positive effect of LiBH4 was due to making the finer structure during ball milling.•Negative effect of LiBH4 might be due to the H–H exchange between LiBH4 and MgH2.The effect of lithium borohydride (LiBH4) on the hydriding/dehydriding kinetics and thermodynamics of magnesium hydride (MgH2) was investigated. It was found that LiBH4 played both positive and negative effects on the hydrogen sorption of MgH2. With 10 mol.% LiBH4 content, MgH2–10 mol.% LiBH4 had superior hydrogen absorption/desorption properties, which could absorb 6.8 wt.% H within 1300 s at 200 °C under 3 MPa H2 and completed desorption within 740 s at 350 °C. However, with the increasing amount of LiBH4, the hydrogenation/dehydrogenation kinetics deteriorated, and the starting desorption temperature increased and the hysteresis of the pressure-composition isotherm (PCI) became larger. Our results showed that the positive effect of LiBH4 was mainly attributed to the more uniform powder mixture with smaller particle size, while the negative effect of LiBH4 might be caused by the H–H exchange between LiBH4 and MgH2.