Improved Hydrogen Storage Properties Research Articles

Influence of carbon catalysts on the improvement of hydrogen storage properties in a body-centered cubic solid solution alloy

Body-centered cubic (BCC) alloys are considered as promising materials for hydrogen storage with high theoretical storage capacity (H/M ratio of 2). Nonetheless, they often suffer from sluggish kinetics of hydrogen absorption and high hydrogen desorption temperature. Carbon materials are efficient hydrogenation catalysts, however, their influence on the hydrogen storage properties of BCC alloy has not been comprehensively studied. Therefore, in this paper, composites obtained by milling of carbon catalysts (carbon nanotubes, mesoporous carbon, carbon nanofibers, diamond powder, graphite, fullerene) and BCC alloy (Ti1.5V0.5) were extensively studied in the non-hydrogenated and hydrogenated state. The structure and microstructure of the obtained materials were studied by scanning and transmission electron microscopes, X-ray diffraction (XRD), and Raman spectroscopy. XRD and Raman measurements showed that BCC alloy and carbon structures were in most cases intact after the composite synthesis. The hydrogenation/dehydrogenation studies showed that all of the used carbon catalysts significantly improve the hydrogenation kinetics, reduce the activation energy of the dehydrogenation process and decrease the dehydrogenation temperature (by nearly 100 K). The superior kinetic properties were measured for the composite with 5 wt % of fullerene that absorbs 3.3 wt % of hydrogen within 1 min at room temperature.

Enhancement of hydrogen storage properties of metal-organic framework-5 by substitution (Zn, Cd and Mg) and decoration (Li, Be and Na)

Two strategies of decoration by three elements Z = Li, Be and Na in cyclic site, and substitution of Zn by Mg and Cd in unit cell were used in the framework of functional density theory to tune the hydrogen storage properties of metal-organic framework-5 (MOF-5) based on Zn whose decomposition temperature and initial gravimetric capacity are 300 K and 1.57 wt% respectively.Based on the adsorption of hydrogen molecules in the crystal surface at three different adsorption sites with three orientations of H2, we show that our system may reach a maximum gravimetric storage capacity of 4.09 wt% for multiple hydrogen molecules. Moreover, the functionalization of Z combined to the substitution, shows an exceptional improvement of hydrogen storage properties. For example, Mg-MOF-5 decorated with Li2 has a capacity up to 5.41 wt% and 513 K as desorption temperature.

Recent Development of Lithium Borohydride‐Based Materials for Hydrogen Storage

Lithium borohydride (LiBH4) has been attracting extensive attention as an exemplary high‐capacity complex hydride for solid‐state hydrogen storage applications because of its high hydrogen capacities (18.5 wt% and 121 kg H2 m−3). However, the strong and highly directional covalent and ionic bonds within LiBH4 structure induce high desorption temperatures, slow kinetics, and poor reversibility, which make large‐scale application impractical. To improve its hydrogen cycling performance, several strategies including cation/anion substitution, catalyst doping, reactive compositing, and nanoengineering, have been developed to tailor the thermodynamics and kinetics of hydrogen storage process. For example, largely reduced operation temperatures and remarkably improved hydrogen storage reversibility under moderate conditions have been achieved by the synergistic effect of nanostructuring and nanocatalysis. Herein, the state‐of‐the‐art development of LiBH4‐based hydrogen storage materials is summarized, including the basic physical and chemical properties, the principles of thermodynamic and kinetic manipulation and the strategies to improve hydrogen storage properties. The remaining challenges and the main directions of future research are also discussed.

Bonding effects for hydrogen storage improvement in Li-based hydrides

The aim of this work is to study the effects of bonding in Li-based hydrides in order to improve hydrogen storage properties. The tendency of (Li, H) atoms to form covalent bonding with (C, Si, Ge) atoms results in an improved reversibility of hydrogen in Li7XH8 (where X = C, Si, and Ge) compared to the LiH hydride. This bonding is considered to be stronger than the ionic bonding along Li-H. The structural and electronic properties of the hydrides Li7XH8 (X = C, Si, Ge) were investigated using the density functional theory and the full-potential linearised augmented plane wave. The covalent bonding tendency along Li-(C, Si, Ge) and along H-(C, Si, Ge) lowers formation energy values and leads to a decrease in desorption temperatures and stability of the hydrides Li7XH8 compared to the LiH hydride. The most hydrogen reversible compound having high gravimetric hydrogen storage was found to be Li7CH8 among all studied hydrides. In addition, the Li7CH8 hydride has smaller lattice parameters and smaller desorption temperature than the others. The calculated electronic densities of states and electron spatial distributions support this picture.

Hydrogen storage performance of methyl-substituted mesoporous silica with tailored textural characteristics

The present study reports a systematic analysis of morphology and hydrogen sorption capacity of mesoporous organic-inorganic silica prepared by varying the silica synthesis parameters. Cationic surfactants of different chain lengths and different proportions of functionalised precursors were introduced in the synthesis mixture. Improved hydrogen storage properties have been obtained, already below 20 bar, reaching a maximum storage capacity around 4.75 wt% at 80 bar. The textural characteristics were analysed by nitrogen sorption and small angle X-ray scattering, and the thermal stability has been characterized by thermogravimetric analysis. The materials show specific surface area between 400 and 700 m2/g and a weakly ordered mesoporosity induced by the short chain surfactant template.

Synergetic effect of multiple phases on hydrogen desorption kinetics and cycle durability in ball milled MgH2–PrF3–Al–Ni composite

A new MgH2–PrF3–Al–Ni composite was prepared by ball milling under hydrogen atmosphere. After initial dehydrogenation and rehydrogenation, Pr3Al11, MgF2, PrH3 and Mg2NiH4 nanoparticles formed accompanying the main phase MgH2. The hydrogen absorption-desorption properties were measured by using a Sieverts-type apparatus. The results showed that the MgH2–PrF3–Al–Ni composite improved cycle stability and enhanced hydrogen desorption kinetics. The improvement of hydrogen absorption-desorption properties is ascribed to the synergetic effect of the in situ formed Pr3Al11, MgF2, PrH3 and Mg2NiH4 nanoparticles. This work provides an important inspiration for the improvement of hydrogen storage properties in Mg-based materials.

MOF-derived Ni nanoparticles dispersed on monolayer MXene as catalyst for improved hydrogen storage kinetics of MgH

We designed a state-of-art catalyst Ni@C-MXene, which provides ample Ni and Ti active sites to significantly promote the hydrogen storage performance of MgH 2 . Experimental methods and theoretical calculations reveal that the in-situ formed Ti 0 facilitates the mutual transformation of Mg 2 Ni/Mg 2 NiH 4 , which is called “facilitated hydrogen pump” effect in this work. • Monolayer MXene was used as the functional carrier to undertake Ni nanoparticles derived from Ni-MOFs. • Striking improvements in hydrogen storage properties were achieved for MgH 2 when the catalyst was added. • DFT calculations revealed the effect of in-situ formed Ti 0 on the Mg 2 Ni/Mg 2 NiH 4 mutual transformation. • A concept of “facilitated hydrogen pump” effect was proposed. A novel catalyst—MOFs derived Ni nanoparticles dispersed on exfoliated monolayered MXene functional carrier was prepared and introduced into MgH 2 in this work. Striking improvements in hydrogen storage properties were achieved for MgH 2 when the catalyst was added. Concisely, the hydrogen releasing peak temperature of the MgH 2 + 10 wt% Ni@C-MXene is 241.1 °C, about 120.2 °C lower than that of the additive-free MgH 2 . According to Kissinger method, the dehydrogenation activation energy of the MgH 2 + 10 wt% Ni@C-MXene composite is calculated to be 54.79 kJ mol −1 , over 60% lower when compared with the pristine MgH 2 (145.08 kJ mol −1 ). At 300 °C, the MgH 2 + 10 wt% Ni@C-MXene composite releases about 5.6 wt% hydrogen within 2 min, while only 2 wt% hydrogen is desorbed even the dehydriding time prolongs to 60 min for the pure MgH 2 . In addition, the completely dehydrogenated MgH 2 + 10 wt% Ni@C-MXene exhibits eminent hydrogen absorption performance, with approximate 5 wt% hydrogen uptaken within 2 min under 3.2 MPa hydrogen pressure at 150 °C. Moreover, an excellent hydrogen cycling stability is achieved in the MgH 2 + 10 wt% Ni@C-MXene without decay for both capacity and kinetics after 10 cycles. Beside the regular XRD, XPS and TEM techniques to clarify the evolution of Ni and Ti during hydrogen de/absorption cycling, more importantly we performed the first principle based calculations to reveal how the in-situ formed Ti 0 would affect the Mg 2 Ni/Mg 2 NiH 4 mutual transformation. Apart from the nano confinement effect of MXene for Ni/Mg 2 Ni/Mg 2 NiH 4 , the in-situ formed Ti 0 from MXene also favors the “hydrogen pump” effect of Mg 2 NiH 4 due to the decreased formation energy E f under the assistance of Ti 0 . Through such a synergistic “nano-confinement and facilitated hydrogen pump” effect, the hydrogen de-/absorption kinetics of MgH 2 is significantly accelerated.

Enhancing hydrogen storage properties of MgH2 by core-shell CoNi@C

Introducing multicomponent nanoparticles can improve remarkably de/hydrogenation kinetic properties of MgH2. In this work, the original core-shell CoNi@C bimetallic nanoparticles were obtained via hydrothermal and calcination reduction technology. MgH2-8 wt% CoNi@C starts to dehydrogenate at 173 °C with the dehydrogenation capacity of 5.83 wt% within 1800 s at 275 °C. Moreover, the composite absorbs 4.83 wt% H2 within 1800 s at 100 °C with prominent advantage at low temperature. The notable improvement of hydrogen storage properties of MgH2 is attributed to the reversible phase transitions of Mg2Co/Mg2CoH5 and Mg2Ni/Mg2NiH4, and the excellent thermal conductivity and confinement effect of the carbon shell. As a result, the apparent activation energy of dehydrogenation reaction reduces to 78.5 kJ/mol. This work extends the horizon of bimetallic nanoparticles with especial microstructure for enhancing the hydrogen storage properties of metal hydrides.

Graphene-induced growth of N-doped niobium pentaoxide nanorods with high catalytic activity for hydrogen storage in MgH2

High operation temperatures and slow kinetics remain big challenges for using magnesium (Mg) as a practical hydrogen storage medium. In this work, a novel graphene-guided nucleation and growth process was developed for the preparation of N-doped Nb2O5 nanorods that enable remarkably improved hydrogen storage properties of MgH2. The nanorods were measured to be 10–20 nm in diameter. MgH2 doped with 10 wt% of the nanorods released 6.2 wt% H2 from 170 °C, which is 130 °C lower than additive-free MgH2, thanks to a 40% reduction in the kinetic barriers. About 5.5 wt% of H2 was desorbed in isothermal dehydrogenation test at 175 °C. Reloading of hydrogen was notably completed at 25 °C under 50 atm of hydrogen pressure, which has not been reported before. Density functional theory (DFT) calculations demonstrate the extended bond lengths and weakened bond strengths of Mg-H or H-H when MgH2/H2 adsorbs on the Nb-N-O/graphene model, consequently favouring lower operating temperatures and improved kinetics for hydrogen storage in MgH2 catalyzed by the graphene-guided N-Nb2O5 nanorods. Our findings provide useful insights in the design and preparation of high-performance catalysts of transition metals and rare metals for on-board hydrogen storage.

Formation and hydrogen storage behavior of nanostructured Mg2FeH6 in a compressed 2MgH2–Fe composite

The present study focuses on enhancing the yield of Mg2FeH6 and its hydrogen storage performances through a novel high-pressure compression approach. For which, MgH2 and Fe powders are first mechanically milled in a molar ratio of 2:1 and subsequently compressed to a cylindrical pellet. Due to the compression, the yield of Mg2FeH6 in the compressed 2MgH2–Fe pellet (90%) has been increased by 24% as compared to the reference ball-milled powder (66%). The thermodynamic destabilization of Mg2FeH6 in the pelletized sample is observed through measuring the pressure-composition isotherms, resulting in the reduced ab/desorption enthalpy for the pellet sample (−68.34 and 75.61 kJ/mol H2, respectively). The hydrogen uptake and release kinetics of Mg2FeH6 is remarkably fast, and it can store/release about 5 wt% H in less than 2.5 min at 400 °C. The faster hydrogen ab/desorption kinetics corresponds to the lower activation energies (36 and 95 kJ/mol H2, respectively). The excellent yield of Mg2FeH6 and its improved hydrogen storage properties for the compressed pellet are primarily attributed to the microstructural modifications upon high-pressure compression, and also the obtained results for Mg2FeH6 ternary hydride are linked to the literature data based on theoretical calculations.

Remarkably improved hydrogen storage properties of carbon layers covered nanocrystalline Mg with certain air stability

Different nanocrystalline magnesium with carbon layers were successfully synthesized via a facile wet-chemical ball milling method for 20, 30 and 40 h, respectively. Based on Scherrer formula and X-ray diffraction results, the average crystallite size of all the three samples was below 30 nm. TEM observations showed that the hydrogenated Mg particles were covered with carbon layers. Moreover, the 40 h ball milled Mg sample showed outstanding hydrogen storage performance especially in the aspect of hydrogen absorption. The as-prepared sample started to take up hydrogen at nearly room temperature and eventually absorbed 6.8 wt% hydrogen at 200 °C. The apparent activation energy (Ea) of hydrogen absorption for the sample was decreased to 26.7 kJ/mol, much lower than that of other reported systems. For the dehydrogenation experiments, the hydrogenated sample could start to release hydrogen at about 275 °C and 6.5 wt% hydrogen was desorbed in 20 min at 325 °C. Interestingly, the prepared samples showed noteworthy air stability. Been placed in the air for 60 min, the dehydrogenation kinetics and hydrogen capacity of the three samples were basically unchanged, making it possible to be used in future commercial applications.

Improved hydrogen storage properties of MgH2 by the addition of KOH and graphene

Mg hydride is a competitive candidates for hydrogen storage based on its high gravimetric hydrogen capacity and accessibility. In this study, a small amount of KOH and graphene were added into MgH2 by high energy ball milling. MgH2 doped with both KOH and graphene has a greatly improved hydrogen storage performance. The existence of graphene and the in-situ formed KMgH3 and MgO decreased activation energy of MgH2 to 109.89 ± 6.03 kJ/mol. The both KOH and graphene doped sample has a reversibly capacity of 5.43 wt % H2 and can released H2 as much as 6.36 times and 1.84 times faster than those of undoped sample and only KOH doped sample at 300 °C, respectively. The addition of graphene not only can provide more “H diffusion channels”, but also can disperse the catalyst.

Synergistic catalytic effects of ZIF-67 and transition metals (Ni, Cu, Pd, and Nb) on hydrogen storage properties of magnesium

MgTM/ZIF-67 nanocomposites were prepared by the deposition-reduction method using ZIF-67, MgCl2, and TMClx (TM = Ni, Cu, Pd, Nb) as raw materials. The dehydrogenation activation energies of MgTM/ZIF-67 (TM = Ni, Cu, Pd, Nb) nanocomposites were calculated to be 115.4 kJ mol−1 H2, 115.7 kJ mol−1 H2, 113.6 kJ mol−1 H2, and 75.8 kJ mol−1 H2, respectively; hence, the MgNb/ZIF-67 nanocomposite manifested the best comprehensive hydrogen storage performance. The hydrogen storage capacity of the MgNb/ZIF-67 nanocomposite was hardly attenuated after the 100th hydrogen absorption-desorption cycle. The dehydrogenated enthalpies of MgH2 and CoMg2H5 in MgNb/ZIF-67 hydride were calculated to be 72.4 kJ mol−1 H2 and 81.0 kJ mol−1 H2, respectively, which were lower than those of additive-free MgH2 and Mg/ZIF-67. The improved hydrogen storage properties of MgNb/ZIF-67 can be ascribed to the CoMg2–Mg(Nb) core-shell structure and the catalytic effects of NbH and niobium oxide nanocrystals.

Tunable microstructure, de-/hydrogenation kinetics and thermodynamics performance of Mg–Ni–La–Ti–H systems

In the light of positive effects of rare earth and transition metals on the hydrogen absorption/desorption properties of magnesium, the Mg20La–5TiH2, Mg20Ni–5TiH2 and Mg10Ni10La–5TiH2 composites have been prepared in this work to ameliorate the de-/hydrogenation kinetics and thermodynamic performance. The results indicate that the as-prepared composites are mainly composed of Mg, Mg2Ni/LaH3 and TiH2 phases after activation, and LaH3 and TiH2 are stable during de-/hydrogenation cycles. The morphology observations give evidences that LaH3 with size about ~20 nm and Mg2Ni with size about ~1 μm are uniformly distributed in the composites. It is noted that the de-/hydriding kinetics of the as-prepared composites are significantly improved after internal and surface modification, of which the Mg10Ni10La–5TiH2 composite can desorb as high as 5.66 wt% hydrogen within 3 min at 623 K. Moreover, the thermodynamic properties of the experimental composites have also been investigated and discussed according to the pressure-composition isothermal curves and corresponding calculation by Van't Hoff equation. The improved hydrogen storage properties of the as-prepared composites are mainly attributed to the uniformly distributed LaH3, Mg2Ni and TiH2 phases, which provide a large amount of phase boundaries, diffusion paths and nucleation sites for de-/hydrogenation reactions.

Improved hydrogen storage properties of MgH2 by nickel@nitrogen-doped carbon spheres.

Magnesium hydride is considered to be one of the most desirable hydrogen storage materials due to its high weight capacity (7.6 wt% H2) and low price. However, its relatively high operating temperatures and slow dynamics have always hampered its commercial applications. In this paper, nano-nickel particle coated nitrogen-doped carbon spheres (Ni@NCS) were synthesized by a chemical reduction method and then introduced into Mg to form an MgH2-Ni@NCS composite via hydriding combustion and subsequent high-energy ball milling processes. The results showed that the MgH2-Ni@NCS composite possessed high hydrogen storage capacity and fast absorbing/desorbing kinetics, absorbing 5.7 wt% H2 and desorbing 4.3 wt% H2 within 8 min at 623 K. Moreover, the capacity shows negligible degradation after 10 cycles, indicating that the MgH2-Ni@NCS composite has good cycling stability. Even at relatively low temperature (373 K), the MgH2-Ni@NCS composite still absorbed 4.2 wt% H2 within 60 min compared to 0.9 wt% H2 for milled MgH2. The improvement in hydrogen storage properties is ascribed to the in situ formed Mg2NiH4 induced dehydrogenation of MgH2 and effective prevention of the agglomeration of magnesium during the hydriding/dehydriding reaction by the carbon material.

Polymer-Based Shaping Strategy for Zeolite Templated Carbons (ZTC) and Their Metal Organic Framework (MOF) Composites for Improved Hydrogen Storage Properties.

Porous materials such as metal organic frameworks (MOFs), zeolite templated carbons (ZTC), and some porous polymers have endeared the research community for their attractiveness for hydrogen (H2) storage applications. This is due to their remarkable properties, which among others include high surface areas, high porosity, tunability, high thermal, and chemical stability. However, despite their extraordinary properties, their lack of processability due to their inherent powdery nature presents a constraining factor for their full potential for applications in hydrogen storage systems. Additionally, the poor thermal conductivity in some of these materials also contributes to the limitations for their use in this type of application. Therefore, there is a need to develop strategies for producing functional porous composites that are easy-to-handle and with enhanced heat transfer properties while still retaining their high hydrogen adsorption capacities. Herein, we present a simple shaping approach for ZTCs and their MOFs composite using a polymer of intrinsic microporosity (PIM-1). The intrinsic characteristics of the individual porous materials are transferred to the resulting composites leading to improved processability without adversely altering their porous nature. The surface area and hydrogen uptake capacity for the obtained shaped composites were found to be within the range of 1,054–2,433 m2g−1 and 1.22–1.87 H2 wt. %, respectively at 1 bar and 77 K. In summary, the synergistic performance of the obtained materials is comparative to their powder counterparts with additional complementing properties.

Improved hydrogen storage properties of Mg/MgH2 thanks to the addition of nickel hydride complex precursors

In order to improve the hydrogenation/dehydrogenation properties of the Mg/MgH2 system, the nickel hydride complex NiHCl(P(C6H11)3)2 has been added in different amounts to MgH2 by planetary ball milling. The hydrogen storage properties of the formed composites were studied by different thermal analyses methods (temperature programmed desorption, calorimetric and pressure-composition-temperature analyses). The optimal amount of the nickel complex precursor was found to be of 20 wt%. It allows to homogeneously disperse 1.8 wt% of nickel active species at the surface of the Mg/MgH2 particles. After the decomposition of the complex during MgH2 dehydrogenation, the formed composite is stable upon cycling at low temperature. It can release hydrogen at 200 °C and absorb 6.3 wt% of H2 at 100 °C in less than 1 h. The significantly enhanced H2 storage properties are due to the impact of the highly dispersed nickel on both the kinetics and thermodynamics of the Mg/MgH2 system. The hydrogenation and dehydrogenation enthalpies were found to be of −65 and 63 kJ/mol H2 respectively (±75 kJ/mol H2 for pure Mg/MgH2) and the calculated apparent activation energies of the hydrogen uptake and release processes are of 22 and 127 kJ/mol H2 respectively (88 and 176 kJ/mol H2 for pure Mg/MgH2). The change in the thermodynamics observed in the formed composite is likely to be due to the formation of a Mg0.992Ni0.008 phase during dehydrogenation/hydrogenation cycling. The impact of another hydride nickel precursor in which chloride has been replaced by a borohydride ligand, namely NiH(BH4)(P(C6H11)3)2, is also reported.

Amorphous TiCu-Based Additives for Improving Hydrogen Storage Properties of Magnesium Hydride.

Magnesium hydride has long been regarded as a promising candidate material for hydrogen and heat storage due to its high hydrogen capacity, reversibility, and low cost. Catalytic doping has been demonstrated as one of the most effective methods to improve hydrogen storage properties of MgH2. In this study, amorphous Ti45Cu41Ni9Zr5 and Ti40Cu47Zr10Sn3 alloys are used as additives for MgH2. Nanostructured MgH2 doped with amorphous or crystalline TiCu-based alloys are prepared by using a high-energy mechanochemical synthesis method. Results show that the amorphous TiCu additives provide enhanced catalytic effects compared to crystalline alloys of the same composition. Doping MgH2 using an amorphous Ti45Cu41Ni9Zr5 alloy yielded improved dehydrogenation kinetics compared to using crystalline Ti40Cu47Zr10Sn3 alloy. The analysis using transmission electron microscopy reveals that there are nanostructured catalytic particles uniformly distributed in the amorphous TiCu-catalyzed MgH2. The MgH2 system catalyzed by amorphous TiCu-based alloy shows little degradation during hydrogenation and dehydrogenation cycling at 300 °C. The amorphous TiCu-based catalysts are thermally stable at temperatures up to 360 °C. Heating the amorphous Ti45Cu41Ni9Zr5-catalyzed MgH2 to temperatures above 360 °C led to disproportionation of the catalyst alloy and the formation of MgCu2 and Ti2Cu. In addition, PCI analysis of the amorphous Ti45Cu41Ni9Zr5-catalyzed MgH2 shows a slight increase in hydrogen equilibrium pressure, resulting in a reaction enthalpy of -78.7 kJ/mol·H2 and an entropy of 145.0 J/K·mol·H2. The entropy calculated from this study is approximately 10 J/K·mol·H2 higher than values previously reported for undoped and catalyzed Mg-H systems.

Improved hydrogen storage properties of TiFe alloy by doping (Zr+2V) additive and using mechanical deformation

In this paper, the effects of doping, cold rolling and forging on the microstructure and hydrogen storage properties of air exposed TiFe + x wt.% (Zr+2V) (x = 0, 4, 5 and 6) alloys were studied. The results showed that all doped samples had similar crystal structure: bcc TiFe main phase and hcp secondary phase. Doping (Zr+2V) can improve obviously the first hydrogenation kinetics of TiFe alloy due to the presence of hcp secondary phase. Further study, we found that the process of cold rolling and forging could reduce the crystallite size of x = 4 sample but forged sample showed a smaller crystallite size. Then it also should be noted that x = 4 forged sample showed the fastest hydrogenation kinetics, highest hydrogen capacity and good cycling stability. By analyzing the kinetic model, all handled x = 4 samples agreed with GB3D model, which meant 3D growth, diffusion controlled with decreasing interface velocity.

Microstructure and improved hydrogen storage properties of Mg85Zn5Ni10 alloy catalyzed by Cr2O3 nanoparticles

The influences of catalyst Cr2O3 on the microstructure and hydrogen storage performances of Mg85Zn5Ni10 have been studied. The Mg85Zn5Ni10 - x wt.% Cr2O3 (x = 0, 4, 8) alloys prepared via ball milling consist of the major phase Mg, the secondary phase Mg2Ni, a little MgZn2 and Cr2O3. X-ray diffraction and high resolution transmission electron microscope results show that MgZn2 and Cr2O3 do not react with hydrogen. The Cr2O3 nanoparticles are conducive to the formation of phase interfaces, hydrogen diffusion channels, grain boundaries and nucleation sites. The hydrogen storage kinetics of Mg85Zn5Ni10 alloy has been improved by reducing the total potential barrier caused by the microstructures after ball milling with Cr2O3. The dehydrogenation activation energy has been reduced to 82.867 ± 0.21 kJ/mol from 109.83 ± 0.55 kJ/mol by adding 8 wt% Cr2O3. The dehydrogenation enthalpy values (ΔH) and entropy values (ΔS) show a downward trend with the increase of Cr2O3 contents. The catalyst Cr2O3 enhances the hydrogen storage kinetics significantly.