Enhanced Hydrogen Storage Properties Research Articles

Hydrogen storage properties of MgH2 + Mg2NiH4–Co/C ternary nanocomposite

The application of ternary nanocomposite synergetic catalysis has proven to be an effective modification strategy for enhancing MgH2 hydrogen storage performance. The ternary magnesium-based hydrogen storage alloy, composed of MgH2+Mg2NiH4–Co/C, is successfully prepared and characterized. Through the optimized preparation process and the optimal ratio, it is observed that the catalyst Mg2NiH4–Co/C significantly reduces the reaction activation energy, resulting in a the initial hydrogen desorption temperature is approximately 60 °C lower than that of pure MgH2. The enhanced hydrogen storage properties are attributed to the synergistic catalytic effect of carbon (C) combined with the formation of Mg2Ni and Mg2Co facilitated by Ni and Co elements. Furthermore, the reversible phase transitions of Mg2Co/Mg2CoH5 and Mg2Ni/Mg2NiH4 serve as "hydrogen pumps" further aiding in hydrogen storage. This study extends the investigation of the synergistic catalytic effect of ternary nanocomposites to enhance the hydrogen storage performance of alloys.

Ball Milling Innovations Advance Mg-Based Hydrogen Storage Materials Towards Practical Applications

Mg-based materials have been widely studied as potential hydrogen storage media due to their high theoretical hydrogen capacity, low cost, and abundant reserves. However, the sluggish hydrogen absorption/desorption kinetics and high thermodynamic stability of Mg-based hydrides have hindered their practical application. Ball milling has emerged as a versatile and effective technique to synthesize and modify nanostructured Mg-based hydrides with enhanced hydrogen storage properties. This review provides a comprehensive summary of the state-of-the-art progress in the ball milling of Mg-based hydrogen storage materials. The synthesis mechanisms, microstructural evolution, and hydrogen storage properties of nanocrystalline and amorphous Mg-based hydrides prepared via ball milling are systematically reviewed. The effects of various catalytic additives, including transition metals, metal oxides, carbon materials, and metal halides, on the kinetics and thermodynamics of Mg-based hydrides are discussed in detail. Furthermore, the strategies for synthesizing nanocomposite Mg-based hydrides via ball milling with other hydrides, MOFs, and carbon scaffolds are highlighted, with an emphasis on the importance of nanoconfinement and interfacial effects. Finally, the challenges and future perspectives of ball-milled Mg-based hydrides for practical on-board hydrogen storage applications are outlined. This review aims to provide valuable insights and guidance for the development of advanced Mg-based hydrogen storage materials with superior performance.

Sodium alanate in-situ doped with Ti2C MXene with enhanced hydrogen storage properties

NaAlH4 is a reversible hydrogen storage material and has attracted great attention recently. However, the application of NaAlH4 in hydrogen storage still has great difficulties. In this study, 2D MXene Ti2C-doped NaAlH4 samples were prepared in-situ by reaction ball milling of NaH under moderate condition. TPD measurement results show that all the as-prepared samples exhibit good thermodynamic performance except for the sample doped with 1 wt% Ti2C. And DSC analysis results show that at the heating rate of 5 K/min, the first and second dehydrogenation peak temperatures of the sample doped with 7 wt% Ti2C were 127.1 °C and 150.6 °C respectively, which are 57.4 °C and 123.6 °C lower than those of pure NaAlH4 (after ball milling), respectively. Meanwhile, NaH/Al-7 wt.% Ti2C sample displays a superior kinetics behavior. Isothermal hydrogen evolution curves show that NaH/Al-7 wt.%Ti2C released 5.21 wt% H2 within 30 min at 150 °C and then absorbs 5.2 wt% H2 in 90 s at 120 °C. Even at a lower temperature of 80 °C, the sample still absorbed 4.71 wt% H2 within 60 min. In addition, almost no release capacity attenuation was observed for NaH/Al-7 wt.%Ti2C after 10 hydrogen absorption/desorption cycles. The improvement of the hydrogen storage properties can be ascribed to the high reactivity of NaAlH4 produced in situ and catalysis of lamellar Ti3+/0 species formed by the reduction of high valent Ti in Ti2C during ball milling.

Enhanced Hydrogen-Storage Properties of MgH2 Catalyzed via a Cerium Doped TiCrV BCC Alloy

Enhanced Hydrogen-Storage Properties of MgH2 Catalyzed via a Cerium Doped TiCrV BCC Alloy

Magnesium based multi-metallic hybrids with soot for hydrogen storage

Magnesium hydride is one of the most sought-after materials for solid state hydrogen storage due to its low cost and high gravimetric capacity (7.6 wt% hydrogen). However, high temperature of desorption (>350 °C) and slow kinetics limit its use for commercial on-board applications. In this work, accumulative roll bonding (ARB) technique has been utilized to synthesise Mg–LaNi5–Mg2Ni-soot hybrid with enhanced hydrogen storage properties. It is seen that the hybrid absorbs ∼6.2 wt% hydrogen at a plateau pressure of ∼2 bar at 300 °C and exhibits fast kinetics with ∼6.6 wt% hydrogen absorption within ∼30 min at 300 °C and 20 bar hydrogen pressure. The role of Mg2Ni as a catalyst as well as hydrogen absorbing medium provides an effect akin to ‘hydrogen pump’, thus enhancing the rate of hydrogen absorption. Presence of carbon in various forms such as aciniform, carbonaceous microgel and cenospheres (derived from soot) plays a vital role by providing channels for diffusion of hydrogen through the hybrid. The ARB technique provides an inexpensive and scalable method of synthesis of Mg based hybrids with large number of interfaces and high amount of strain leading to enhanced hydrogen storage properties.

Enhanced hydrogen storage properties of Ti40-xV45Zr15Crx alloys by dual-phase nanostructures of eutectic and spinodal decomposition

Multi-principal elements alloys (MPEAs) with body center cubic (BCC) structure have shown great potential in hydrogen storage. However, the multi-cycle activation process and the high desorption temperature have inhibited their applications. In this study, the Ti40-xV45Zr15Crx (x = 1, 2, 3 at. %) alloys with three different BCC phases are synergized, and high hydrogenation capacities of over 2 wt% are achieved in the first hydrogen absorption. Owing to the formation of spinodal decomposition nanostructure in Ti38V45Zr15Cr2 alloy, 90 % of total hydrogen capacity is reached in 30s at 250 °C under 1 MPa H2, which indicates no incubation time is needed for activation. The Ti38V45Zr15Cr2 alloy also shows the highest reversible hydrogen storage capacity with fastest kinetics at 200 °C. The hydrogenation reaction is controlled by the 1D diffusion process of H atoms according to JMAK model. The spinodal decomposition structure can accelerate the decomposition of H2 molecules and the diffusion of H atoms by providing extra energy from large lattice distortion. The high-density interfaces in nano-eutectic structure can serve as active sites for the nucleation of hydrides and fast paths for the diffusion of H atoms.

Enhanced hydrogen storage properties of MgH2 with the co-addition of LiBH4 and YNi5 alloy

MgH2, as one of the typical solid-state hydrogen storage materials, has attracted extensive attention. However, the slow kinetics and poor cycle stability limit its application. In this work, LiBH4 and YNi5 alloy were co-added as additives to MgH2 via ball milling, thereby realizing an excellent dehydrogenation performance and good cycle stability at 300 °C. The MgH2-0.04LiBH4-0.01YNi5 composite can release 7 wt.% of hydrogen in around 10 min at 300 °C and still have a reversible hydrogen storage capacity of 6.42 wt.% after 110 cycles, with a capacity retention rate as high as 90.3 % based on the second dehydrogenation capacity. The FTIR results show that LiBH4 can reversibly absorb and desorb hydrogen throughout the hydrogen ab/desorption process, which contributes a portion of the reversible hydrogen storage capacity to the MgH2-0.04LiBH4-0.01YNi5 composite. Due to the small amount of LiBH4 and YNi5, the dehydrogenation activation energy of MgH2 did not decrease significantly, nor did the dehydrogenation enthalpy (∆H) change. However, the MgNi3B2 and in-situ formed YH3 during the hydrogen absorption/desorption cycles is not only beneficial to the improvement of the kinetics performance for MgH2 but also improves its cycle stability. This work provides a straightforward method for developing high reversible hydrogen capacity on Mg-based hydrogen storage materials with moderate kinetic performance.

Enhanced hydrogen storage properties of Ti–Cr–Nb alloys by melt-spin and Mo-doping

Ti–Cr–Nb hydrogen storage alloys with a body centered cubic (BCC) structure have been successfully prepared by melt-spin and Mo-doping. The crystalline structure, solidification microstructural evolution, and hydrogen storage properties of the corresponding alloys were characterized in details. The results showed that the hydrogen storage capacity of Ti–Cr–Nb ingot alloys increased from 2.2 wt% up to around 3.5 wt% under the treatment of melt-spin and Mo-doping. It is ascribed that the single BCC phase of Ti–Cr–Nb alloys was stabilized after melt-spin and Mo-doping, which has a higher theoretical hydrogen storage site than the Laves phase. Furthermore, the melt-spin alloy after Mo doping can further effectively increase the de-/absorption plateau pressure. The hydrogen desorption enthalpy change ΔH of the melt-spin alloy decreased from 48.94 kJ/mol to 43.93 kJ/mol after Mo-doping. The short terms cycling test also manifests that Mo-doping was effective in improving the cycle durability of the Ti–Cr–Nb alloys. And the BCC phase of the Ti–Cr–Nb alloys could form body centered tetragonal (BCT) or face center cubic (FCC) hydride phase after hydrogen absorption and transform to the original BCC phase after desorption process. This study might provide reference for developing reversible metal hydrides with favorable cost and acceptable hydrogen storage characteristics.

Dual tuning of the de-/hydrogenation thermodynamics and kinetics of the Mg–Ni alloy by introducing the Ag–H bond: enhanced hydrogen storage properties at moderate temperatures

The onset dehydrogenation temperature of Mg85Ni14.8Ag0.2 reduces to 178 °C due to the enhanced hydrogen pumping effect of Mg2NiH4 by adjusting the Ni–H bond.

Enhanced hydrogen storage properties of NaAlH4 with the addition of CoTiO3 synthesised via a solid-state method

CoTiO3 that was synthesised via the solid-state method was effective in ameliorating the desorption behaviour of NaAlH4. The initial desorption temperature of NaAlH4 catalysed by different weight percentage of CoTiO3 (5 wt%, 10 wt%, 15 wt% and 20 wt%) was dramatically decreased to around 130–160 °C for the first desorption stage and decreased to around 182–198 °C for the second desorption stage, which is lower than milled NaAlH4. The composite sample also exhibits 15–18 times faster desorption kinetics at 150 °C where the NaAlH4-CoTiO3 composite could release 3.0–3.7 wt% of H2 in 60 min but milled NaAlH4 only could release 0.2 wt% H2 in the same time duration. The activation energies for the two-desorption stage of NaAlH4 was downshifted to 85.5 and 91.6 kJ/mol, lowered by 30.7 and 35.5 kJ/mol than milled NaAlH4, respectively. The beneficial catalytic effect of CoTiO3 can be attributed to the in-situ formation of Al-Co and Al-Ti alloys after the desorption process of the NaAlH4-CoTiO3 system. These findings pave the way for the development of highly effective catalysts for NaAlH4 as a favourable material for hydrogen storage.

Striking enhanced effect of PrF3 particles on Ti3C2 MXene for hydrogen storage properties of MgH2

The enhanced effect of metal catalysts is crucial to achieve advanced performance of hydrogen storage system. Rational design of catalysts with superior catalytic activity is significant to regulate the re-/hydrogenation kinetics of MgH2. Herein, Ti3C2-supported praseodymium(III) fluoride (PrF3) nanoparticles (PrF3/Ti3C2) composite was prepared by hydrothermal method, which exhibited superior catalytic activity toward hydrogen storage of MgH2. The onset temperature of dehydrogenation was reduced to 180 °C after adding 5 wt% PrF3/Ti3C2, corresponding to a reduction of 107 °C compared with pristine MgH2. About 7.0 wt% hydrogen was rapidly desorbed within 3 min at 260 °C and 6.6 wt% hydrogen was absorbed within 36 s at 200 °C for MgH2-5 wt% PrF3/Ti3C2. Moreover, MgH2-5 wt% PrF3/Ti3C2 exhibited an excellent capacity retention of 92.5% even after 10 cycles. Experimental results reveal that the electron transfer among Ti-species (Ti0, Ti2+, and Ti3+) occurred due to the striking enhanced effect of PrF3 on Ti3C2 MXene during the reaction process, and the synergistic action between Ti-species and PrF3 are responsible for the markedly enhanced hydrogen storage properties of MgH2. This study is helpful to the design and optimization of hydrogen storage materials for mobile application.

Enhanced hydrogen storage properties of ball-milled Mg with C<sub>60</sub> and Fe

Enhanced hydrogen storage properties of ball-milled Mg with C<sub>60</sub> and Fe

Enhanced Hydrogen Storage Properties of Li-RHC System with In-House Synthesized AlTi3 Nanoparticles

In recent years, the use of selected additives for improving the kinetic behavior of the system 2LiH + MgB2 (Li-RHC) has been investigated. As a result, it has been reported that some additives (e.g., 3TiCl3·AlCl3), by reacting with the Li-RHC components, form nanostructured phases (e.g., AlTi3) possessing peculiar microstructural properties capable of enhancing the system’s kinetic behavior. The effect of in-house-produced AlTi3 nanoparticles on the hydrogenation/dehydrogenation kinetics of the 2LiH + MgB2 (Li-RHC) system is explored in this work, with the aim of reaching high hydrogen storage performance. Experimental results show that the AlTi3 nanoparticles significantly improve the reaction rate of the Li-RHC system, mainly for the dehydrogenation process. The observed improvement is most likely due to the similar structural properties between AlTi3 and MgB2 phases which provide an energetically favored path for the nucleation of MgB2. In comparison with the pristine material, the Li-RHC doped with AlTi3 nanoparticles has about a nine times faster dehydrogenation rate. The results obtained from the kinetic modeling indicate a change in the Li-RHC hydrogenation reaction mechanism in the presence of AlTi3 nanoparticles.

Synthesis of silicon-based nanosheets decorated with Pd/Li particles with enhanced hydrogen storage properties

Synthesis of silicon-based nanosheets decorated with Pd/Li particles with enhanced hydrogen storage properties

Enhanced hydrogen storage properties of NaBH4–Mg(BH4)2 composites by NdF3 addition

As two important members of complex hydrides, Mg(BH4)2 and NaBH4 have a high gravimetric capacity (14.9 and 10.8 ​wt%, respectively). In this study, the Mg(BH4)2 was synthesized by the ion exchange method. Afterwards, the Mg(BH4)2 and NaBH4 composites with different amounts (30, 40 and 50 ​wt%) of NdF3 were prepared by mechanical milling. Effects of the NdF3 on the microstructural evolution and hydrogen storage properties were investigated. The results show that NdF3 catalyst can significantly improve the dehydrogenation kinetics of the eutectic composites of NaBH4–Mg(BH4)2. The onset hydrogen desorption temperature of the composites is about 88.6 ​°C, which is about 110 ​°C lower than that of Mg(BH4)2 and NaBH4 composites. Mg(BH4)2–NaBH4-0.5NdF3 composites can released 5.2 ​wt% H2 at 250 ​°C within 30 ​min, and the dehydrogenation capacity is significantly higher than that of Mg(BH4)2–NaBH4 composites. The analysis of the dehydrogenation mechanism reveals that NdF3 takes participate in the reaction to generate NaMgF3 to promote the dehydrogenation reaction process of the composites.

Enhanced hydrogen storage properties of Mg by the synergistic effect of grain refinement and NiTiO3 nanoparticles

As a promising hydrogen storage material, the practical application of magnesium is obstructed by the stable thermodynamics and sluggish kinetics. In this paper, three kinds of NiTiO 3 catalysts with different mole ratio of Ni to Ti were successfully synthesized and doped into nanocrystalline Mg to improve its hydrogen storage properties. Experimental results indicated that all the Mg-NiTiO 3 composites showed prominent hydrogen storage performance. Especially, the Mg-NiTiO 3 /TiO 2 composite could take up hydrogen at room temperature and the apparent activation energy for hydrogen absorption was dramatically decreased from 69.8 ± 1.2 (nanocrystalline Mg) kJ/mol to 34.2 ± 0.2 kJ/mol. In addition, the hydrogenated sample began to release hydrogen at about 193.2 °C and eventually desorbed 6.6 wt% H 2 . The desorption enthalpy of the hydrogenated Mg-NiTiO 3 -C was estimated to be 78.6 ± 0.8 kJ/mol, 5.3 kJ/mol lower compared to 83.9 ± 0.7 kJ/mol of nanocrystalline Mg. Besides, the sample revealed splendid cyclic stability during 20 cycles. No obvious recession occurred in the absorption and desorption kinetics and only 0.3 wt% hydrogen capacity degradation was observed. Further structural analysis demonstrates that nanosizing and catalyst doping led to a synergistic effect on the enhanced hydrogen storage performance of Mg-NiTiO 3 -C composite, which might serve as a reference for future design of highly effective hydrogen storage materials.

Fabrication of Multiple-Phase Magnesium-Based Hydrides with Enhanced Hydrogen Storage Properties by Activating NiS@C and Mg Powder

Magnesium hydride is considered as a promising candidate for hydrogen storage; however, the sluggish kinetics and thermodynamic stability seriously obstruct its industrial applications. Hence, in o...

Hydrogen Absorption/Desorption Behavior of a Cold-Rolled TiFe Intermetallic Compound

The (de)hydrogenation properties of a TiFe intermetallic compound (IMC) alloy activated by cold rolling inside a glovebox at ambient temperature were investigated by kinetic measurements, x-ray powder diffraction (XRD), and transmission electron microscopy (TEM). Rate-limiting steps were identified by testing kinetic models on hydrogen absorption and desorption curves. To prevent surface poisoning during air exposure, the TiFe IMC was also cold rolled with polytetrafluoroethylene (PTFE) and ultra-high molecular weight polyethylene (UHMWPE). The addition of either PTFE or UHMWPE to nanostructured TiFe by cold rolling did not produce a polymer-metal composite with O2 poisoning resistance, regardless of the polymer-mixing way adopted. This occurred because large surfaces of the particles were not adequately coated with polymer. The results identify challenges to the TiFe IMC polymer-covered material that must be overcome before a methodology can significantly contribute to the formation of nanostructured TiFe-polymer composites with enhanced hydrogen storage properties. The diffusion-controlled reactions in the cold-rolled TiFe IMC without polymer were prevalent in all cases, as predicted by the Jander three-dimensional diffusion model. The main contribution of this work regards estimation of the amount of hydrogen released, which was 0.60% after 6 min and reproducible for the three subsequent cycles.

Enhanced hydrogen storage properties of high-loading nanoconfined LiBH4–Mg(BH4)2 composites with porous hollow carbon nanospheres

Novel porous hollow carbon nanospheres (HCNS) have been synthesized and utilized as scaffold for LiBH4–Mg(BH4)2 eutectic borohydride (LMBH). Large loading amounts of LMBH (33, 50 and 67 wt%) have been melt-infiltrated into HCNS, and the significantly improved dehydrogenation properties have been discovered. The LMBH@HCNS composites not only exhibit high actual dehydrogenation amounts and fast hydrogen desorption rates, but also an increased reversible hydrogen storage capacities after three cycles without obvious degradation. Further structural tests have revealed that the over-infiltrated LMBH covering the spherical surface of HCNS could also contribute to the improved hydrogen storage behaviors, due to a strong interfacial adhesion effect that avoid LMBH from aggregation during de/rehydrogenation cycles.

Enhanced Hydrogen Storage Properties of MgH2 Using a Ni and TiO2 Co-Doped Reduced Graphene Oxide Nanocomposite as a Catalyst.

To improve the hydrogen storage properties of Mg/MgH2, a Ni and TiO2 co-doped reduced graphene oxide [(Ni-TiO2)@rGO] nanocomposite is synthesized by a facile impregnation method and introduced into Mg via ball milling. The results demonstrated that the dispersive distribution of Ni and TiO2 with a particle size of 20–200 nm in the reduced graphene oxide matrix led to superior catalytic effects on the hydrogen storage properties of Mg-(Ni-TiO2)@rGO. The initial hydrogenation/dehydrogenation temperature for Mg-(Ni-TiO2)@rGO decreased to 323/479 K, 75/84 K lower than that of the additive-free sample. The hydrogen desorption capacity of the Mg-(Ni-TiO2)@rGO composite released 1.47 wt.% within 120 min at 498 K. When the temperature was increased to 523 K, the hydrogen desorption capacity increased to 4.30 wt.% within 30 min. A hydrogenation/dehydrogenation apparent activation energy of 47.0/99.3 kJ·mol−1 was obtained for the Mg-(Ni-TiO2)@rGO composite. The improvement in hydrogenation and dehydrogenation for the Mg-(Ni-TiO2)@rGO composite was due to the reduction of the apparent activation energy by the catalytic action of (Ni-TiO2)@rGO.