A hydrogen storage material additive, a composite hydrogen storage material and a preparation method thereof

Abstract

A hydrogen storage material additive, a composite hydrogen storage material, and a preparation method thereof, relate to the technical field of hydrogen storage materials and solve the problem of slow low-temperature hydrogen release kinetics in existing hydrogen storage systems. The additive is a CeO2@TiO2 nanorod core-shell heterostructure with Co metal loaded on the surface, with a Co loading of 2 wt.%. CeCl3·7H2O and NaOH solution are used as raw materials for hydrothermal reaction, centrifuged, washed, and dried to obtain CeO2 powder, which is added to anhydrous ethanol, stirred, and then C 16 H 36 O4Ti and deionized water are reacted in an oil bath, centrifuged, washed, and dried to obtain a precursor. This precursor is then calcined to obtain CeO2@TiO2 powder, which is then added to deionized water and stirred. Co(NO3)2·3H2O is then added, stirred for reaction, filtered, dried, and then calcined in reducing gas to obtain the additive. This additive can be used in LiAlH4-AlH3 composite hydrogen storage systems and has broad application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen storage materials, and in particular to a hydrogen storage material additive, a composite hydrogen storage material and a preparation method thereof. Background Art

[0002] As a clean, high-energy-density renewable energy source, hydrogen is crucial for building a clean, low-carbon, safe, and efficient energy system. To achieve widespread commercial application of hydrogen, it is necessary to overcome barriers to its production, storage, transportation, and application. High-density, low-cost, and safe storage and transportation of hydrogen are key components of its utilization.

[0003] Hydrogen storage methods are primarily categorized as gaseous, cryogenic liquid, organic liquid, and solid-state, each with its own advantages and disadvantages. Light metal compound solid-state hydrogen storage materials, with their high volumetric hydrogen storage capacity and ability to rapidly dehydrogenate at relatively low pressures, are a promising hydrogen storage method.

[0004] LiAlH4 boasts the highest theoretical hydrogen storage density (10.5 wt.%) and a relatively low dehydrogenation temperature. However, its sluggish dehydrogenation kinetics, wide dehydrogenation temperature range, and lack of catalyst mechanism research hinder its practical application. Forming a composite system of LiAlH4 and AlH3 reduces the thermal stability of the hydride, significantly improving the dehydrogenation kinetics of this composite hydrogen storage system. However, its dehydrogenation kinetics are relatively slow at low temperatures, and further improvement is needed.

[0005] In this regard, Chinese patent document CN117899884A discloses a Ni@CeO2 catalyst that can reduce the onset temperature of LiAlH4 dehydrogenation from 159.5°C to 72.9°C and increase the hydrogen release rate to 4.34 wt.% within 2 hours. However, this approach has many limitations. First, Ni particles are prone to agglomeration during the hydrogen release reaction, resulting in a reduction in active sites and a decrease in catalytic activity. Second, the CeO2 support, due to its inherent defects such as low oxygen vacancy density, uneven distribution, poor electronic conductivity, and weak interfacial interactions, cannot fully exert its catalytic activity as a catalyst support. Moreover, the CeO2 support is prone to sintering at high temperatures, further reducing the oxygen vacancy concentration and weakening the catalytic activity. Furthermore, the structural stability of a single CeO2 support is insufficient, and the nanorod morphology tends to collapse over long-term use, further limiting the catalyst lifespan.

[0006] Based on the above problems, it is urgent to develop new catalyst systems to break through the existing technological bottlenecks. Summary of the Invention

[0007] In order to solve the problem of slow low-temperature hydrogen release kinetics in the existing composite hydrogen storage system LiAlH4-AlH3, the present invention proposes a hydrogen storage material additive, a composite hydrogen storage material and a preparation method thereof.

[0008] The technical solutions of the present invention are as follows:

[0009] A hydrogen storage material additive is a CeO2@TiO2 nanorod core-shell heterostructure with Co metal loaded on the surface, wherein the loading amount of the Co metal is 2 wt.%.

[0010] The present invention also provides a method for preparing the above-mentioned hydrogen storage material additive, comprising the following steps:

[0011] S1, using CeCl3·7H2O and NaOH solution as raw materials for hydrothermal reaction treatment, after the reaction is completed, centrifugation is performed, and the precipitate is washed and dried to obtain CeO2 powder;

[0012] S2, add the CeO2 powder into anhydrous ethanol, stir thoroughly, add C 16 H 36 O4Ti and deionized water were stirred continuously in an oil bath, and after the reaction was completed, centrifugation, washing and drying were carried out in sequence to obtain CeO2@TiO2 core-shell nanoheterostructure precursor;

[0013] S3, calcining the CeO2@TiO2 core-shell nanoheterostructure precursor in a muffle furnace to obtain CeO2@TiO2 powder;

[0014] S4, adding the CeO2@TiO2 powder to deionized water, stirring, adding Co(NO3)2·3H2O, stirring for 4 hours, filtering and drying after the stirring to obtain a Co-CeO2@TiO2 precursor;

[0015] S5, calcining the Co-CeO2@TiO2 precursor in a tube furnace with reducing gas to obtain the hydrogen storage material additive;

[0016] Wherein, the usage ratio of CeCl3·7H2O and NaOH solution in step S1 is 0.67 g:30 mL, and the concentration of the NaOH solution is 9 mol / L;

[0017] The CeO2 powder, C 16 H 36 The dosage ratio of O4Ti, anhydrous ethanol and deionized water is 0.003 mol: 1 mL: 100 mL: 4 mL;

[0018] The mass ratio of CeO2@TiO2 to Co(NO3)2·3H2O in step S4 is 98:9.9.

[0019] Preferably, the hydrothermal reaction temperature in step S1 is 160° C. and the reaction time is 48 h.

[0020] Preferably, the temperature of the oil bath in step S2 is 70° C., and the stirring reaction time is 24 hours.

[0021] Preferably, the calcination temperature in step S3 is 500° C. and the calcination time is 4 hours.

[0022] Preferably, the calcination atmosphere in step S5 is Ar / H2, the temperature is 500°C, and the time is 4 hours.

[0023] The present invention also provides a composite hydrogen storage material, which is composed of LiAlH4 powder, AlH3 powder and the above-mentioned hydrogen storage material additive.

[0024] Preferably, the mass fractions of the LiAlH4 powder, AlH3 powder and hydrogen storage material additive are 47.5 wt.%, 47.5 wt.% and 5 wt.%, respectively.

[0025] The present invention also provides a method for preparing the composite hydrogen storage material, comprising uniformly mixing LiAlH4 powder, AlH3 powder and the hydrogen storage material additive, and then ball milling the mixture under a protective atmosphere to obtain the composite hydrogen storage material.

[0026] Preferably, the conditions for the ball milling treatment are:

[0027] Tungsten carbide beads were used for ball milling; the ball-to-material ratio was 50:1, the ball mill speed was 450 rpm, the single ball milling time was 10 min, the interval was 5 min, and it was repeated 4 times.

[0028] Compared with the prior art, the present invention solves the problem of slow low-temperature hydrogen release kinetics in the existing composite hydrogen storage system LiAlH4-AlH3 through the coordinated optimization of material design and defect engineering. The specific beneficial effects are as follows:

[0029] The present invention first constructs CeO2@TiO2 core-shell nanorods, and uses the TiO2 shell to protect the CeO2 core from high-temperature sintering. At the same time, the interface electronic coupling (such as d-band center offset and surface charge redistribution) significantly increases the oxygen vacancy concentration; further, the transition metal Co is introduced into the controllable oxygen vacancy O by calcination under a reducing atmosphere. vThe d-orbital electronic properties of Co (the d-band center is 0.3 eV higher than Ni) and the strong electronic interaction between Co and the core-shell interface optimize the hydrogen adsorption / dissociation pathway, while the oxygen vacancy network accelerates hydrogen diffusion kinetics. In addition, the heterogeneous structure effectively inhibits Co particle agglomeration and prolongs the catalyst life.

[0030] The present invention utilizes a LiAlH4-AlH3 composite hydrogen storage material to reduce the thermal stability of hydrogen desorption. Furthermore, Co is loaded onto a CeO2@TiO2 nanorod-like core-shell heterostructure to create a low-cost, high-catalytic-efficiency additive. Adding this additive to the LiAlH4-AlH3 composite system enables rapid low-temperature hydrogen desorption, resulting in a LiAlH4-AlH3-Co-CeO2@TiO2 hydrogen storage material with optimal hydrogen desorption performance. This composite hydrogen storage material begins desorbing hydrogen at temperatures as low as 66.9°C, with a hydrogen desorption capacity of 8.42 wt.% H2. Furthermore, at temperatures as low as 100°C, it can release 1.82 wt.% H2 within 30 minutes, representing a nearly 13-fold increase in hydrogen desorption capacity compared to the LAAH composite material.

[0031] Therefore, the Co-CeO2@TiO2 additive provided by the present invention is used in the LiAlH4-AlH3 composite hydrogen storage system, which has broad scientific value and application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a transmission electron microscopy image of Co-CeO2@TiO2 prepared in Example 1;

[0033] Figure 2 XRD spectrum of Co-CeO2@TiO2 prepared in Example 1;

[0034] Figure 3 X-ray photoelectron spectra of Ce 3d, Ti 2p, and O 1s of Co-CeO2@TiO2 prepared in Example 1;

[0035] Figure 4 This is the Raman spectrum of Co-CeO2@TiO2 prepared in Example 1;

[0036] Figure 5 This is the N2 isothermal adsorption-desorption curve of Co-CeO2@TiO2 prepared in Example 1;

[0037] Figure 6 Temperature-dependent hydrogen release diagrams of LiAlH4-AlH3-Co-CeO2@TiO2 and LiAlH4-AlH3 prepared in Example 1;

[0038] Figure 7Isothermal hydrogen release diagram of LiAlH4-AlH3-Co-CeO2@TiO2 and LiAlH4-AlH3 prepared in Example 1 at 100°C;

[0039] Figure 8 Temperature-dependent hydrogen release diagrams of LiAlH4-AlH3-Ni-CeO2@TiO2 and LiAlH4-AlH3 prepared in Comparative Example 1;

[0040] Figure 9 Isothermal hydrogen release diagram of LiAlH4-AlH3-Ni-CeO2@TiO2 and LiAlH4-AlH3 prepared in Comparative Example 1 at 100°C;

[0041] Figure 10 Temperature-dependent hydrogen release diagrams of LiAlH4-AlH3-CeO2@TiO2 and LiAlH4-AlH3 prepared in Comparative Example 2;

[0042] Figure 11 Isothermal hydrogen release diagram of LiAlH4-AlH3-CeO2@TiO2 and LiAlH4-AlH3 prepared in Comparative Example 2 at 100°C;

[0043] Figure 12 Temperature-dependent hydrogen release diagrams of LiAlH4-AlH3-Co-CeO2 and LiAlH4-AlH3 prepared in Comparative Example 3;

[0044] Figure 13 Isothermal hydrogen release diagram of LiAlH4-AlH3-Co-CeO2 and LiAlH4-AlH3 prepared in Comparative Example 3 at 100°C. DETAILED DESCRIPTION

[0045] In order to make the technical solution of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the specification of the present invention. It should be noted that the following embodiments are only used to better understand the technical solution of the present invention and should not be understood as limiting the present invention.

[0046] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0047] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0048] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0049] The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, methods, and instruments used are conventional in the art and can be obtained commercially by those skilled in the art unless otherwise specified.

[0050] Example 1.

[0051] (1) Preparation of transition metal loaded core-shell heterostructure Co-CeO2@TiO2 powder:

[0052] First, 0.67 g of CeCl3·7H2O was dissolved in 30 mL of 9 mol / L NaOH solution, stirred vigorously, and transferred to an autoclave for hydrothermal reaction at 160°C for 48 h. The hydrothermal reaction solution was then centrifuged, washed, and dried (60°C) to obtain CeO2 powder. Then, 0.003 mol of CeO2 powder was placed in 100 mL of anhydrous ethanol, stirred vigorously, and 1 mL of C 16 H 36 O4Ti, 4 mL deionized water, reacted in an oil bath at 70 ° C for 24 h, then centrifuged, washed, and dried to obtain CeO2@TiO2 precursor powder, which was calcined at 500 ° C in a muffle furnace for 4 h to obtain powder. Take 98 mg of CeO2@TiO2 powder and dissolve it in 60 mL deionized water. After stirring, add 9.9 mg Co(NO3)2·6H2O, stir for 4 h, filter, wash, and dry. Collect the sample to obtain Co-CeO2@TiO2 precursor powder, place the powder in a tube furnace, and calcine at 500 ° C for 4 h in an Ar / H2 atmosphere to obtain Co-CeO2@TiO2 powder.

[0053] The microstructure and phase characterization of the obtained Co-CeO2@TiO2 powder were carried out, and the TEM images, XRD patterns, XPS spectra, Raman spectra and BET curves were shown in Figure 2. Figures 1 to 5 As shown. Figure 1 As shown in the figure, TiO2 is loaded on the surface of CeO2 nanorods to form a core-shell nanostructure, and Co metal is evenly loaded on the CeO2@TiO2 nanorods, providing a morphological basis for a highly active interface. Figure 2As shown in Figure 2, the XRD diffraction peaks of the synthesized Co-CeO2@TiO2 material coincide with the diffraction peaks of cubic fluorite CeO2 (JCPDS card 81-0792) and anatase TiO2 standard card (JCPDS card 71-1166). Due to the low content of Co and its high dispersion on the CeO2@TiO2 nanorods, no diffraction peaks related to Co species are observed in the XRD diffraction peaks. Figure 3 XPS photoelectron spectroscopy shows that Ce atoms in Co-CeO2@TiO2 are composed of Ce 3+ With Ce 4+ The coexistence of multiple valence states is beneficial to electron transfer and accelerates the hydrogen release reaction. Ti 2p has two main characteristic peaks, the characteristic peaks at 458.79 eV and 464.45 eV correspond to Ti 4+ 2p 1 / 2 With 2p 3 / 2 electron layer, indicating that Ti atoms are mainly Ti 4+ O 1s has three peaks: defect oxygen at ~531 eV, lattice oxygen at ~529 eV, and adsorbed oxygen at ~533 eV. The presence of defect oxygen and Ce3+ proves that more oxygen vacancies are formed during the calcination process, confirming the high density of oxygen vacancies and the electronic interaction at the Co-Ti-Ce interface, which enhances the catalytic activity. Raman spectrum ( Figure 4 ) corresponds to the XRD pattern, which is mainly composed of CeO2 at ~459 cm -1 F 2g Peak and TiO2 at ~144 cm -1 E g Peak composition, the slight shift of CeO2 peak position reflects the heterogeneous interface stress, which has a promoting effect on the stability of oxygen vacancies. BET isotherm adsorption curve ( Figure 5 ) indicates that the specific surface area of Co-CeO2@TiO2 is 17.79 m 2 g -1 .

[0054] (2) Preparation of LiAlH4-AlH3-Co-CeO2@TiO2 composite hydrogen storage material:

[0055] Under an inert atmosphere, Co-CeO2@TiO2, LiAlH4 powder, and AlH3 powder were weighed at mass fractions of 5 wt.%, 47.5 wt.%, and 47.5 wt.%, respectively, and placed in a ball mill. Tungsten carbide beads were added at a ball-to-powder ratio of 50:1 and milled at 450 rpm for 40 minutes. To minimize the effects of high temperatures on sample performance during milling, the mill was rested for 5 minutes every 10 minutes. After milling, the sample was removed from the inert atmosphere to yield the LiAlH4-AlH3-Co-CeO2@TiO2 composite hydrogen storage material.

[0056] The LiAlH4-AlH3-Co-CeO2@TiO2 obtained in (2) and the original LiAlH4-AlH3 were subjected to variable temperature / constant temperature hydrogen desorption tests. The specific variable temperature hydrogen desorption curves are shown in the figure. Figure 6 As shown in the figure, the initial dehydrogenation temperature of LiAlH4-AlH3-Co-CeO2@TiO2 is reduced to 66.9℃, which is about 13℃ lower than the initial dehydrogenation temperature of LiAlH4-AlH3 (79.2℃), and the hydrogen desorption capacity reaches 8.42 wt.% H2.

[0057] The isothermal hydrogen release diagram of LiAlH4-AlH3-Co-CeO2@TiO2 and original LiAlH4-AlH3 at 100℃ is shown in Figure 2. Figure 7 As shown by Figure 7 It can be seen that the low-temperature kinetic performance of LiAlH4-AlH3-Co-CeO2@TiO2 is significantly improved compared with the original LiAlH4-AlH3, and it can release 1.82 wt.% H2 within 30 min at 100℃, which is a significant increase compared to the 0.142 wt.% H2 released by LiAlH4-AlH3 under the same conditions.

[0058] Comparative Example 1.

[0059] The difference between this comparative example and Example 1 is that the Co(NO3)2·6H2O added in step (1) is replaced by Ni(NO3)2·6H2O. Specifically, the obtained transition metal-loaded core-shell heterostructure is Ni-CeO2@TiO2 powder. The remaining process steps and parameter settings are the same as those in Example 1. A composite hydrogen storage material is prepared and named LiAlH4-AlH3-Ni-CeO2@TiO2.

[0060] The obtained LiAlH4-AlH3-Ni-CeO2@TiO2 and LiAlH4-AlH3 were subjected to variable temperature / constant temperature hydrogen desorption tests. The specific variable temperature hydrogen desorption curves are shown in the figure. Figure 8 As shown by Figure 8It can be seen that the initial hydrogen desorption temperature of LiAlH4-AlH3-Ni-CeO2@TiO2 is 68.8℃ and the capacity reaches 8.68 wt.%.

[0061] The hydrogen desorption curves of LiAlH4-AlH3-Ni-CeO2@TiO2 and LiAlH4-AlH3 at 100℃ are as follows: Figure 9 As shown by Figure 9 LiAlH4-AlH3-Ni-CeO2@TiO2 releases 1.21 wt.% H2 at 100°C for 30 min, significantly improving the hydrogen release kinetics compared to LiAlH4-AlH3. This demonstrates that the Co metal-supported CeO2@TiO2 core-shell nanostructure outperforms Ni metal. This is primarily due to the difference in electronic structure between Co and Ni. Co's d-band center is closer to the Fermi level, resulting in stronger electron transfer and a stronger coupling with oxygen vacancies. Ni, on the other hand, has a deeper d-orbital and weaker electronic interaction with oxygen vacancies, leading to lower oxygen vacancy stability.

[0062] Comparative Example 2.

[0063] The difference between this comparative example and Example 1 is that Co(NO3)2·6H2O powder is not added in step (1). Specifically, the core-shell heterostructure obtained is CeO2@TiO2 powder. The remaining process steps and parameter settings are the same as those in Example 1. A composite hydrogen storage material is prepared and named LiAlH4-AlH3-CeO2@TiO2.

[0064] The obtained LiAlH4-AlH3-CeO2@TiO2 and LiAlH4-AlH3 were subjected to variable temperature / constant temperature hydrogen desorption tests. The specific variable temperature hydrogen desorption curves are shown in the figure. Figure 10 As shown by Figure 10 It can be seen that the initial dehydrogenation temperature of LiAlH4-AlH3-CeO2@TiO2 is 74.0℃ and the hydrogen desorption capacity is 8.44 wt.% H2.

[0065] The 100℃ constant temperature hydrogen release curves of LiAlH4-AlH3-CeO2@TiO2 and LiAlH4-AlH3 are as follows: Figure 11 As shown by Figure 11It can be seen that LiAlH4-AlH3-CeO2@TiO2 releases only 0.05 wt.% H2 at 100°C for 30 min. By comparison with the data of Example 1, it can be proved that the CeO2@TiO2 core-shell heterostructure alone cannot achieve the improvement of hydrogen desorption kinetics. However, the loading of Co can produce a synergistic effect with the CeO2@TiO2 core-shell heterostructure. The strong electronic interaction between Co and the core-shell interface optimizes the hydrogen adsorption / dissociation path. In turn, the heterostructure can effectively inhibit the agglomeration of Co particles. The synergistic effect of the two significantly improves the low-temperature hydrogen desorption kinetics.

[0066] Comparative Example 3.

[0067] The difference between this comparative example and Example 1 is that C is not added in step (1). 16 H 36 O4Ti liquid, no CeO2@TiO2 core-shell structure was formed, and the specific transition metal loaded oxide additive obtained was Co-CeO2 powder. The remaining process steps and parameter settings were the same as those in Example 1 to prepare a composite hydrogen storage material named LiAlH4-AlH3-Co-CeO2.

[0068] The obtained LiAlH4-AlH3-Co-CeO2 and LiAlH4-AlH3 were subjected to variable temperature / constant temperature hydrogen desorption test. The specific variable temperature hydrogen desorption curves are shown in the figure. Figure 12 As shown by Figure 12 It can be seen that the initial dehydrogenation temperature of LiAlH4-AlH3-Co-CeO2 is 73.6℃ and the hydrogen desorption capacity is 7.98 wt.% H2.

[0069] The 100℃ constant temperature hydrogen release curves of LiAlH4-AlH3-Co-CeO2 and LiAlH4-AlH3 are as follows: Figure 13 As shown by Figure 13 It can be seen that LiAlH4-AlH3-Co-CeO2 releases only 0.796 wt.% H2 at 100℃ for 30 min.

[0070] Comparison with the data from Example 1 demonstrates that the core-shell CeO2@TiO2 structure of the present invention significantly outperforms a single CeO2 support. The TiO2 shell inhibits CeO2 sintering and maintains oxygen vacancy density. This demonstrates that the CeO2@TiO2 core-shell nanostructure significantly enhances low-temperature hydrogen desorption kinetics.

[0071] In summary, the LiAlH4-AlH3-Co-CeO2@TiO2 provided by the present invention solves the limitations of a single component through a metal-support-defect ternary collaborative design. Experimental data show that the present invention achieves significant performance improvements compared with Ni-based catalysts, Co loaded on pure CeO2 carriers, and transition metal-free cases. The performance improvement is non-obvious and provides an innovative paradigm for the development of highly active hydrogen storage catalysts.

[0072] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for preparing a hydrogen storage material additive, characterized in that: The hydrogen storage material additive is a CeO2@TiO2 nanorod core-shell heterostructure with Co metal loaded on the surface, and the loading amount of the Co metal is 2wt.%; The preparation method comprises the following steps: S1, using CeCl3·7H2O and NaOH solution as raw materials for hydrothermal reaction treatment, after the reaction is completed, centrifugation is performed, and the precipitate is washed and dried to obtain CeO2 powder; S2, add the CeO2 powder into anhydrous ethanol, stir thoroughly, add C 16 H 36 O4Ti and deionized water were stirred continuously in an oil bath, and after the reaction was completed, centrifugation, washing and drying were carried out in sequence to obtain CeO2@TiO2 core-shell nanoheterostructure precursor; S3, calcining the CeO2@TiO2 core-shell nanoheterostructure precursor in a muffle furnace to obtain CeO2@TiO2 powder; S4, adding the CeO2@TiO2 powder to deionized water, stirring, adding Co(NO3)2·3H2O, stirring for 4 hours, filtering and drying after the stirring to obtain a Co-CeO2@TiO2 precursor; S5, calcining the Co-CeO2@TiO2 precursor in a tube furnace with reducing gas to obtain the hydrogen storage material additive; Wherein, the usage ratio of CeCl3·7H2O and NaOH solution in step S1 is 0.67 g:30 mL, and the concentration of the NaOH solution is 9 mol / L; The CeO2 powder, C 16 H 36 The dosage ratio of O4Ti, anhydrous ethanol and deionized water is 0.003 mol: 1 mL: 100 mL: 4 mL; The mass ratio of CeO2@TiO2 to Co(NO3)2·3H2O in step S4 is 98:9.

9.

2. The method for preparing the hydrogen storage material additive according to claim 1, characterized in that: The hydrothermal reaction temperature in step S1 is 160° C. and the reaction time is 48 h.

3. The method for preparing the hydrogen storage material additive according to claim 1, characterized in that: The temperature of the oil bath in step S2 is 70° C., and the stirring reaction time is 24 h.

4. The method for preparing the hydrogen storage material additive according to claim 1, characterized in that: The calcination temperature in step S3 is 500° C. and the calcination time is 4 h.

5. The method for preparing the hydrogen storage material additive according to claim 1, characterized in that: The calcination in step S5 is carried out in an atmosphere of Ar / H2, at a temperature of 500°C, and for 4 hours.

6. A composite hydrogen storage material, characterized in that The composite hydrogen storage material is composited by LiAlH4 powder, AlH3 powder and the hydrogen storage material additive prepared by the preparation method according to claim 1.

7. The composite hydrogen storage material according to claim 6, characterized in that The mass fractions of the LiAlH 4 powder, AlH 3 powder and hydrogen storage material additive are 47.5 wt.%, 47.5 wt.% and 5 wt.%, respectively.

8. A method for preparing the composite hydrogen storage material according to claim 6 or 7, characterized in that: The LiAlH4 powder, AlH3 powder and the hydrogen storage material additive are mixed evenly, and then ball milled under a protective atmosphere to obtain the composite hydrogen storage material.

9. The method for preparing a composite hydrogen storage material according to claim 8, characterized in that: The conditions of the ball milling process are: Tungsten carbide beads were used for ball milling; the ball-to-material ratio was 50:1, the ball mill speed was 450 rpm, the single ball milling time was 10 min, the interval was 5 min, and it was repeated 4 times.

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