A high-capacity solid-state hydrogen storage material, a preparation method and application thereof

Abstract

The present application relates to hydrogen energy storage technology field, specifically to a kind of high-capacity solid-state hydrogen storage material and its preparation method and application, by the following components by mass percentage: composite hydride 65%-75%, heteroatom doped graphene supported calcium monatomic modifier 5%-11%, composite catalyst 4%-8%, interface regulator 2%-4%, nano carbon material 12%-18%;The heteroatom doped graphene supported calcium monatomic modifier is nitrogen-phosphorus co-doped graphene supported calcium monatomic material, and the composite catalyst is composed of titanium dioxide, ferric oxide, cerium oxide and lanthanum oxide.The present application uses composite hydride as hydrogen storage main body, and is matched with heteroatom doped graphene supported calcium monatomic modifier, can build high-density hydrogen storage active site, optimizes material interface structure, greatly improves the utilization rate and reaction activity of hydrogen storage site.

Description

Technical Field

[0001] This invention relates to the field of hydrogen energy storage technology, specifically to a high-capacity solid hydrogen storage material, its preparation method, and its application. Background Technology

[0002] Hydrogen energy, as a clean and efficient renewable energy source, is a core carrier for promoting energy structure transformation, and hydrogen storage technology is a key link in the large-scale application of hydrogen energy. Solid-state hydrogen storage has become a key research direction in the field of hydrogen energy storage due to its advantages such as high safety, high hydrogen storage density, and convenient operation. Among them, composite hydride materials have attracted much attention from the industry due to their outstanding theoretical hydrogen storage potential.

[0003] Current solid-state hydrogen storage materials technology suffers from numerous insurmountable shortcomings, failing to meet practical application requirements. Existing composite hydride hydrogen storage materials generally exhibit slow hydrogen absorption and desorption kinetics and excessively high hydrogen desorption temperatures, making it difficult for actual hydrogen storage efficiency to reach theoretical expectations.

[0004] Conventional modification methods often use common carbon materials as supports, resulting in limited heteroatom doping and insufficient active site construction, failing to effectively optimize the material's interface structure and hydrogen storage site activity. Catalysts are mostly single metal oxides, with limited catalytic activity, making it difficult to synergistically enhance the hydrogen absorption and desorption reaction rates, and thus offering only minor improvements to material performance.

[0005] In terms of manufacturing processes, existing technologies mostly employ a single sintering process, which cannot precisely control the crystal phase and microstructure of the material, easily leading to structural defects and decreased material stability. Simultaneously, the raw material ratios lack a scientific and systematic design, resulting in poor interfacial compatibility between components and hindering the full realization of synergistic effects, making it difficult to simultaneously achieve both hydrogen storage capacity and volumetric density. After repeated cycles of use, the materials are prone to structural collapse, significant capacity decay, and insufficient long-term reliability.

[0006] Existing technologies have failed to achieve synergistic optimization of hydrogen storage capacity, kinetic performance, thermal stability and cycle life. Therefore, developing a high-capacity solid hydrogen storage material with excellent comprehensive performance and a suitable preparation process has become an urgent technical challenge to be solved in this field. Summary of the Invention

[0007] The primary objective of this invention is to provide a high-capacity solid hydrogen storage material, its preparation method, and its applications.

[0008] A further objective of this invention is to provide a high-capacity solid-state hydrogen storage material, comprising the following components by mass percentage: 65%-75% composite hydride, 5%-11% heteroatom-doped graphene-supported calcium single-atom modifier, 4%-8% composite catalyst, 2%-4% interface modifier, and 12%-18% nano-carbon material, wherein the sum of the mass percentages of each component is 100%; the heteroatom-doped graphene-supported calcium single-atom modifier is a nitrogen-phosphorus co-doped graphene-supported calcium single-atom material, and the composite catalyst is composed of titanium dioxide, iron tetroxide, cerium oxide, and lanthanum oxide.

[0009] Preferably, the composite hydride is a mixture of lithium aluminum hydride and sodium borohydride, wherein the mass ratio of lithium aluminum hydride to sodium borohydride is 1.5:1 to 4:1.

[0010] Preferably, in the nitrogen-phosphorus co-doped graphene-supported calcium single-atom material, the atomic ratio of nitrogen atoms to phosphorus atoms is 1:1 to 3:1, and the calcium single-atom loading is 1.2%-3%.

[0011] Preferably, in the composite catalyst, the mass ratio of titanium dioxide, iron tetroxide, cerium oxide and lanthanum oxide is from 3:2:1:1 to 5:2:1:1.

[0012] Preferably, the interface modifier is a mixture of silane coupling agent and titanate coupling agent in a mass ratio of 1:1 to 3:1; the nano-carbon material is a mixture of graphene and carbon nanotubes in a mass ratio of 1:1 to 2:1.

[0013] A method for preparing a high-capacity solid-state hydrogen storage material includes the following steps in sequence: raw material pretreatment, mixing and dispersion, stepwise sintering, ultrasonic activation, and vacuum encapsulation; the stepwise sintering is carried out under vacuum conditions with a vacuum degree of 1×10⁻⁶. -3 Pa to 4×10 - 3 Pa.

[0014] Preferably, the raw material pretreatment includes: drying the composite hydride in an argon-atmosphere glove box, treating the heteroatom-doped graphene-supported calcium single-atom modifier with plasma, grinding the composite catalyst and then vacuum drying it, mixing the interface modifier with anhydrous ethanol to prepare a diluent, and pretreating the nano-carbon material under an argon atmosphere.

[0015] Preferably, the mixing and dispersion involves placing the pretreated raw material in a planetary ball mill, ball milling it under argon protection to obtain a preliminary mixed powder, adding an interface modifier diluent, and continuing ball milling, with a ball-to-material ratio of 10:1.

[0016] Preferably, the stepwise sintering is a two-stage heating and holding process: the first stage involves heating to 210℃-270℃ and holding, and the second stage involves heating to 310℃-390℃ and holding, followed by cooling to room temperature at a rate of 2.5℃ / min-3.5℃ / min; the ultrasonic activation uses anhydrous ethanol as the dispersion medium, and the ultrasonic treatment is followed by sieving to obtain powder with a particle size not exceeding 1μm; the vacuum sealing has a vacuum degree of 1×10⁻⁶. -4 Pa to 4×10 -4 Pa.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention uses composite hydrides as the main hydrogen storage material, combined with heteroatom-doped graphene-supported calcium single-atom modifier, to construct high-density hydrogen storage active sites, optimize the material interface structure, and significantly improve the utilization rate and reactivity of hydrogen storage sites; the quaternary composite catalyst plays a synergistic catalytic role, effectively accelerating the hydrogen absorption and desorption reaction process, improving the material kinetic performance, reducing the temperature required for the hydrogen desorption reaction, and improving the thermal stability of the material.

[0018] 2. The interface modifier and nano-carbon material of this invention work together to enhance the interfacial bonding force between the components, optimize the microstructure of the material, significantly improve the volumetric hydrogen storage density, and the stepwise sintering process can precisely control the crystal phase formation and microstructure of the material, avoid structural defects during the preparation process, and ensure the stability of the overall structure of the material.

[0019] 3. The present invention employs a series of processes, including raw material pretreatment, uniform dispersion, ultrasonic activation, and vacuum packaging, to ensure uniform dispersion of each component and controllable particle size, thereby further enhancing hydrogen storage performance and recycling stability.

[0020] 4. The components and process steps of this invention form an organic synergy, enabling the material to simultaneously possess high hydrogen storage capacity, excellent kinetics, low hydrogen desorption temperature and good cycle life, and the preparation process is highly controllable and adaptable to the needs of industrial production. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Example 1

[0023] Raw material ratio (mass percentage): 75% composite hydride, 6% heteroatom-doped graphene-supported calcium single-atom modifier, 4% composite catalyst, 2% interface modifier, and 13% nano-carbon material.

[0024] Specific specifications of each component: In the composite hydride, the mass ratio of lithium aluminum hydride to sodium borohydride is 2.5:1; in the heteroatom-doped graphene-supported calcium single-atom modifier, the nitrogen to phosphorus atom ratio is 2:1, and the calcium single-atom loading is 1.8%. The preparation method is as follows: graphene is placed in a nitrogen-phosphorus mixed atmosphere, and nitrogen-phosphorus co-doping is carried out by plasma doping. Then, calcium single atoms are loaded by impregnation reduction method. After controlling the loading, it is vacuum dried at 120℃ for 3 hours to obtain the finished modifier; in the composite catalyst, the mass ratio of titanium dioxide, iron tetroxide, cerium oxide and lanthanum oxide is 4:2:1:1; in the interface modifier, the mass ratio of silane coupling agent to titanate coupling agent is 2:1; in the nano-carbon material, the mass ratio of graphene to carbon nanotubes is 1.5:1.

[0025] Preparation method: Raw material pretreatment: The composite hydride was placed in an argon-atmosphere glove box and dried at 80°C for 4 hours; the heteroatom-doped graphene-supported calcium single-atom modifier was treated with 150W plasma for 15 minutes; the composite catalyst was ground to a particle size of 400 nm and vacuum dried at 120°C for 2 hours; the interface modifier and anhydrous ethanol were mixed at a mass ratio of 1:8 and stirred evenly to prepare a diluent; the nano-carbon material was pretreated at 500°C for 1.5 hours under an argon atmosphere, and the ball milling was performed with a ball-to-material ratio of 10:1.

[0026] Mixing and dispersing: Add the pretreated raw materials to a planetary ball mill, purge with argon gas, and ball mill at 450 r / min for 6 h to obtain a preliminary mixed powder; add the interface modifier diluent dropwise, and continue ball milling for 3 h to obtain a mixed powder.

[0027] Stepwise sintering: The mixed powder is placed in a vacuum sintering furnace, evacuated to 3×10⁻³Pa, heated to 240℃ at a heating rate of 8℃ / min, and held for 1.5h; then heated to 350℃ at a heating rate of 4℃ / min and held for 3.5h; and cooled to room temperature at a cooling rate of 3℃ / min to obtain the sintered body.

[0028] Ultrasonic activation: The sintered body was transferred to an argon-sealed chamber, anhydrous ethanol was added as a dispersion medium, and ultrasonication was performed at 300W power for 45 minutes. The powder with a particle size of no more than 1μm was obtained by sieving.

[0029] Vacuum sealing: Place the powder into a vacuum sealing bag and evacuate to 3×10⁻⁶. -4 Pa, after being sealed and packaged, yields the finished product.

[0030] Example 2

[0031] Raw material ratio (mass percentage): composite hydride 72%, heteroatom-doped graphene-supported calcium single-atom modifier 9%, composite catalyst 4%, interface modifier 2%, nano-carbon material 13%.

[0032] Specific specifications of each component: In the composite hydride, the mass ratio of lithium aluminum hydride to sodium borohydride is 2.5:1; in the heteroatom-doped graphene-supported calcium single-atom modifier, the nitrogen to phosphorus atom ratio is 2.5:1, and the calcium single-atom loading is 2.5%, and its preparation method is the same as in Example 1; in the composite catalyst, the mass ratio of titanium dioxide, iron tetroxide, cerium oxide, and lanthanum oxide is 4:2:1:1; in the interface modifier, the mass ratio of silane coupling agent to titanate coupling agent is 2:1; in the nano-carbon material, the mass ratio of graphene to carbon nanotubes is 1.5:1.

[0033] Preparation method: Raw material pretreatment: The composite hydride was placed in an argon-atmosphere glove box and dried at 80°C for 4 hours; the heteroatom-doped graphene-supported calcium single-atom modifier was treated with 150W plasma for 18 minutes; the composite catalyst was ground to a particle size of 400 nm and vacuum dried at 120°C for 2 hours; the interface modifier and anhydrous ethanol were mixed at a mass ratio of 1:8 and stirred evenly to prepare a diluent; the nano-carbon material was pretreated at 500°C for 1.5 hours under an argon atmosphere, and the ball milling was performed with a ball-to-material ratio of 10:1.

[0034] Mixing and dispersing: Add the pretreated raw materials to a planetary ball mill, purge with argon gas, and ball mill at 450 r / min for 6 h to obtain a preliminary mixed powder; add the interface modifier diluent dropwise, and continue ball milling for 3 h to obtain a mixed powder.

[0035] Stepwise sintering: The mixed powder is placed in a vacuum sintering furnace, evacuated to 3×10⁻³Pa, heated to 240℃ at a heating rate of 8℃ / min, and held for 1.5h; then heated to 350℃ at a heating rate of 4℃ / min and held for 3.5h; and cooled to room temperature at a cooling rate of 3℃ / min to obtain the sintered body.

[0036] Ultrasonic activation: The sintered body was transferred to an argon-sealed chamber, anhydrous ethanol was added as a dispersion medium, and ultrasonication was performed at 300W power for 45 minutes. The powder with a particle size of no more than 1μm was obtained by sieving.

[0037] Vacuum sealing: Place the powder into a vacuum sealing bag and evacuate to 3×10⁻ 4 Pa, after being sealed and packaged, yields the finished product.

[0038] Example 3

[0039] Raw material ratio (mass percentage): 70% composite hydride, 9% heteroatom-doped graphene-supported calcium single-atom modifier, 6% composite catalyst, 2% interface modifier, and 13% nano-carbon material.

[0040] Specific specifications of each component: In the composite hydride, the mass ratio of lithium aluminum hydride to sodium borohydride is 3:1; in the heteroatom-doped graphene-supported calcium single-atom modifier, the nitrogen to phosphorus atom ratio is 2.5:1, and the calcium single-atom loading is 2.5%, and its preparation method is the same as in Example 1; in the composite catalyst, the mass ratio of titanium dioxide, iron tetroxide, cerium oxide, and lanthanum oxide is 5:2:1:1; in the interface modifier, the mass ratio of silane coupling agent to titanate coupling agent is 2:1; in the nano-carbon material, the mass ratio of graphene to carbon nanotubes is 1.5:1.

[0041] Preparation method: Raw material pretreatment: The composite hydride was placed in an argon-atmosphere glove box and dried at 80°C for 4 hours; the heteroatom-doped graphene-supported calcium single-atom modifier was treated with 150W plasma for 18 minutes; the composite catalyst was ground to a particle size of 300 nm and vacuum dried at 130°C for 2 hours; the interface modifier and anhydrous ethanol were mixed at a mass ratio of 1:8 and stirred evenly to prepare a diluent; the nano-carbon material was pretreated at 500°C for 1.5 hours under an argon atmosphere, and ball milling was performed with a ball-to-material ratio of 10:1.

[0042] Mixing and dispersing: Add the pretreated raw materials to a planetary ball mill, purge with argon gas, and ball mill at 450 r / min for 6 h to obtain a preliminary mixed powder; add the interface modifier diluent dropwise, and continue ball milling for 3 h to obtain a mixed powder.

[0043] Stepwise sintering: The mixed powder is placed in a vacuum sintering furnace, evacuated to 3×10⁻³Pa, heated to 240℃ at a heating rate of 8℃ / min, and held for 1.5h; then heated to 350℃ at a heating rate of 4℃ / min and held for 3.5h; and cooled to room temperature at a cooling rate of 3℃ / min to obtain the sintered body.

[0044] Ultrasonic activation: The sintered body was transferred to an argon-sealed chamber, anhydrous ethanol was added as a dispersion medium, and ultrasonication was performed at 300W power for 45 minutes. The powder with a particle size of no more than 1μm was obtained by sieving.

[0045] Vacuum sealing: Place the powder into a vacuum sealing bag and evacuate to 3×10⁻ 4 Pa, after being sealed and packaged, yields the finished product.

[0046] Example 4

[0047] Raw material ratio (mass percentage): 70% composite hydride, 9% heteroatom-doped graphene-supported calcium single-atom modifier, 6% composite catalyst, 3% interface modifier, and 12% nano-carbon material.

[0048] Specific specifications of each component: In the composite hydride, the mass ratio of lithium aluminum hydride to sodium borohydride is 3:1; in the heteroatom-doped graphene-supported calcium single-atom modifier, the nitrogen to phosphorus atom ratio is 2.5:1, and the calcium single-atom loading is 2.5%, and its preparation method is the same as in Example 1; in the composite catalyst, the mass ratio of titanium dioxide, iron tetroxide, cerium oxide, and lanthanum oxide is 5:2:1:1; in the interface modifier, the mass ratio of silane coupling agent to titanate coupling agent is 2.5:1; in the nano-carbon material, the mass ratio of graphene to carbon nanotubes is 1.5:1.

[0049] Preparation method: Raw material pretreatment: The composite hydride was placed in an argon-atmosphere glove box and dried at 80°C for 4 hours; the heteroatom-doped graphene-supported calcium single-atom modifier was treated with 150W plasma for 18 minutes; the composite catalyst was ground to a particle size of 300 nm and vacuum dried at 130°C for 2 hours; the interface modifier and anhydrous ethanol were mixed at a mass ratio of 1:9 and stirred evenly to prepare a diluent; the nano-carbon material was pretreated at 500°C for 1.5 hours under an argon atmosphere, and the ball milling was performed with a ball-to-material ratio of 10:1.

[0050] Mixing and dispersing: Add the pretreated raw materials to a planetary ball mill, purge with argon gas, and ball mill at 450 r / min for 6 h to obtain a preliminary mixed powder; add the interface modifier diluent dropwise, and continue ball milling for 3 h to obtain a mixed powder.

[0051] Stepwise sintering: The mixed powder is placed in a vacuum sintering furnace, evacuated to 2×10⁻³Pa, heated to 260℃ at a heating rate of 7℃ / min, and held for 1.8h; then heated to 380℃ at a heating rate of 3.5℃ / min and held for 4h; and cooled to room temperature at a cooling rate of 3℃ / min to obtain the sintered body.

[0052] Ultrasonic activation: The sintered body was transferred to an argon-sealed chamber, anhydrous ethanol was added as a dispersion medium, and ultrasonication was performed at 300W power for 45 minutes. The powder with a particle size of no more than 1μm was obtained by sieving.

[0053] Vacuum sealing: Place the powder into a vacuum sealing bag and evacuate to 3×10⁻ 4 Pa, after being sealed and packaged, yields the finished product.

[0054] Example 5

[0055] Raw material ratio (mass percentage): 65% composite hydride, 11% heteroatom-doped graphene-supported calcium single-atom modifier, 7% composite catalyst, 3% interface modifier, and 14% nano-carbon material.

[0056] Specific specifications of each component: In the composite hydride, the mass ratio of lithium aluminum hydride to sodium borohydride is 4:1; in the heteroatom-doped graphene-supported calcium single-atom modifier, the nitrogen to phosphorus atom ratio is 3:1, and the calcium single-atom loading is 3%, and its preparation method is the same as in Example 1; in the composite catalyst, the mass ratio of titanium dioxide, iron tetroxide, cerium oxide, and lanthanum oxide is 3.5:2:1:1; in the interface modifier, the mass ratio of silane coupling agent to titanate coupling agent is 3:1; in the nano-carbon material, the mass ratio of graphene to carbon nanotubes is 2:1.

[0057] Preparation method: Raw material pretreatment: The composite hydride was placed in an argon atmosphere glove box and dried at 110℃ for 2.5h; the heteroatom-doped graphene-supported calcium single-atom modifier was treated with 180W plasma for 20min; the composite catalyst was ground to a particle size of 300nm and vacuum dried at 130℃ for 2.5h; the interface modifier and anhydrous ethanol were mixed at a mass ratio of 1:10 and stirred evenly to prepare a diluent; the nano-carbon material was pretreated at 550℃ for 1.8h under an argon atmosphere, and the ball milling was performed with a ball-to-material ratio of 10:1.

[0058] Mixing and dispersing: Add the pretreated raw materials to a planetary ball mill, purge with argon gas, and ball mill at 550 r / min for 7 h to obtain a preliminary mixed powder; add the interface modifier diluent dropwise, and continue ball milling for 4 h to obtain a mixed powder.

[0059] Stepwise sintering: The mixed powder is placed in a vacuum sintering furnace, evacuated to 4×10⁻³Pa, heated to 270℃ at a heating rate of 9℃ / min, and held for 2h; then heated to 390℃ at a heating rate of 4.5℃ / min and held for 4.5h; and cooled to room temperature at a cooling rate of 3.5℃ / min to obtain the sintered body.

[0060] Ultrasonic activation: The sintered body was transferred to an argon-sealed chamber, anhydrous ethanol was added as a dispersion medium, and ultrasonication was performed at 350W power for 55 minutes. The powder with a particle size of no more than 1μm was obtained by sieving.

[0061] Vacuum sealing: Place the powder into a vacuum sealing bag and evacuate to 4×10⁻ 4 Pa, after being sealed and packaged, yields the finished product.

[0062] Example 6

[0063] Raw material ratio (mass percentage): 65% composite hydride, 5% heteroatom-doped graphene-supported calcium single-atom modifier, 8% composite catalyst, 4% interface modifier, and 18% nano-carbon material.

[0064] Specific specifications of each component: In the composite hydride, the mass ratio of lithium aluminum hydride to sodium borohydride is 1.5:1; in the heteroatom-doped graphene-supported calcium single-atom modifier, the nitrogen to phosphorus atom ratio is 1:1, and the calcium single-atom loading is 1.2%, and its preparation method is the same as in Example 1; in the composite catalyst, the mass ratio of titanium dioxide, iron tetroxide, cerium oxide, and lanthanum oxide is 3:2:1:1; in the interface modifier, the mass ratio of silane coupling agent to titanate coupling agent is 1:1; in the nano-carbon material, the mass ratio of graphene to carbon nanotubes is 1:1.

[0065] Preparation method: Raw material pretreatment: The composite hydride was placed in an argon-atmosphere glove box and dried at 90℃ for 3.5h; the heteroatom-doped graphene-supported calcium single-atom modifier was treated with 120W plasma for 12min; the composite catalyst was ground to a particle size of 500nm and vacuum dried at 110℃ for 1.5h; the interface modifier and anhydrous ethanol were mixed at a mass ratio of 1:5 and stirred evenly to prepare a diluent; the nano-carbon material was pretreated at 450℃ for 1.2h under an argon atmosphere, and the ball milling was performed with a ball-to-material ratio of 10:1.

[0066] Mixing and dispersing: Add the pretreated raw materials to a planetary ball mill, purge with argon gas, and ball mill at 350 r / min for 5 h to obtain a preliminary mixed powder; add the interface modifier diluent dropwise, and continue ball milling for 2.5 h to obtain a mixed powder.

[0067] Stepwise sintering: The mixed powder is placed in a vacuum sintering furnace, evacuated to 1×10⁻³Pa, heated to 210℃ at a heating rate of 6℃ / min, and held for 1.2h; then heated to 310℃ at a heating rate of 3℃ / min and held for 2.5h; and cooled to room temperature at a cooling rate of 2.5℃ / min to obtain the sintered body.

[0068] Ultrasonic activation: The sintered body was transferred to an argon-sealed chamber, anhydrous ethanol was added as a dispersion medium, and ultrasonication was performed at 250W power for 35 minutes. The powder with a particle size of no more than 1μm was obtained by sieving.

[0069] Vacuum sealing: Place the powder into a vacuum sealing bag and evacuate to a vacuum level of 1×10⁻ 4 Pa, after being sealed and packaged, yields the finished product.

[0070] Comparative Example 1: Raw material ratio (mass percentage): composite hydride 81%, composite catalyst 4%, interface modifier 2%, nano-carbon material 13%; the specific specifications and preparation methods of each component are the same as in Example 1, and no heteroatom-doped graphene-supported calcium single-atom modifier is added.

[0071] Comparative Example 2: Raw material ratio (mass percentage): 75% composite hydride, 6% heteroatom-doped graphene-supported calcium single-atom modifier, 4% titanium dioxide, 2% interface modifier, and 13% nano-carbon material; the specific specifications and preparation methods of each component are the same as in Example 1, with single titanium dioxide replacing the composite catalyst.

[0072] Comparative Example 3: Raw material ratio (mass percentage): 75% composite hydride, 6% ordinary graphene, 4% composite catalyst, 2% interface modifier, and 13% nano-carbon material; the specific specifications and preparation methods of each component are the same as in Example 1, with ordinary graphene replacing the heteroatom-doped graphene-supported calcium single-atom modifier.

[0073] Comparative Example 4: The raw material ratio is the same as in Example 1, but the preparation method is adjusted to a single sintering process: after mixing and dispersing, the mixed powder is placed in a vacuum sintering furnace and evacuated to 3×10⁻⁶. -3 Pa, the temperature is increased to 350°C at a heating rate of 8°C / min, held at that temperature for 5 hours, and then cooled to room temperature at a cooling rate of 3°C / min. The remaining steps and parameters are the same as in Example 1.

[0074] Comparative Example 5: Raw material ratio (mass percentage): 60% composite hydride, 10% heteroatom-doped graphene-supported calcium single-atom modifier, 7% composite catalyst, 3% interface modifier, and 20% nano-carbon material; the specific specifications and preparation methods of each component are the same as in Example 1.

[0075] Comparative Example 6: Raw material ratio (mass percentage): 75% single lithium aluminum hydride, 6% heteroatom-doped graphene-supported calcium single-atom modifier, 4% composite catalyst, 2% interface modifier, and 13% nano-carbon material; the specific specifications and preparation methods of each component are the same as in Example 1, with single lithium aluminum hydride replacing the composite hydride mixture.

[0076] Comparative Example 7: Raw material ratio (mass percentage): 77% composite hydride, 6% heteroatom-doped graphene-supported calcium single-atom modifier, 4% composite catalyst, and 13% nano-carbon material; the specific specifications and preparation methods of each component are the same as in Example 1, and no interface modifier is added.

[0077] Comparative Example 8 Raw material ratio (mass percentage): 75% composite hydride, 6% ordinary graphene, 4% titanium dioxide, 2% interface modifier, and 13% nano-carbon material; The preparation method adopts a single sintering process, and the remaining steps and parameters are the same as in Example 1.

[0078] Comparative Example 9: Raw material ratio (mass percentage): 75% single lithium aluminum hydride, 6% ordinary graphene, 4% composite catalyst, 2% interface modifier, and 13% nano-carbon material; The preparation method adopts a single sintering process, and the remaining steps and parameters are the same as in Example 1.

[0079] All solid hydrogen storage materials prepared in the above embodiments and comparative examples were subjected to uniform performance testing. The testing methods conformed to industry standards. The test indicators included hydrogen storage capacity, 90% hydrogen absorption time, peak hydrogen release temperature, capacity retention rate after 50 cycles, and volumetric hydrogen storage density. The test conditions were uniformly set as follows: test temperature 25℃, test pressure 4MPa, and cycle test conditions: hydrogen absorption pressure 4MPa, hydrogen release pressure 0.1MPa, hydrogen absorption time 2h, and hydrogen release time 2h per cycle.

[0080] The silane coupling agent of the present invention is selected from at least one of KH550, KH560, and KH570, and the titanate coupling agent is selected from at least one of TC-T, TC-101, and TC-201; the graphene is 1-5 layers of few-layer graphene, and the carbon nanotube is a multi-walled carbon nanotube with a diameter of 10-20 nm and a length of 5-20 μm.

[0081] The nitrogen-phosphorus co-doped graphene-supported calcium single-atom material of the present invention is prepared by plasma doping and impregnation reduction. The plasma doping atmosphere is a mixture of nitrogen and phosphine gas, and the impregnation reduction uses sodium borohydride or hydrazine hydrate as a reducing agent. Those skilled in the art can implement this according to conventional process parameters.

[0082] Test method description: Hydrogen storage capacity was tested using the Sievts method. The pressure composition temperature isotherm of the material was measured using a Sievts device, and the hydrogen mass fraction was calculated. The 90% hydrogen absorption time was monitored in real time using a Sievts device, and the time required for the material to reach 90% of its maximum hydrogen storage capacity was recorded. The peak hydrogen release temperature was tested using differential scanning calorimetry at a heating rate of 10℃ / min under a nitrogen atmosphere, and the peak temperature during the hydrogen release process was recorded. Cyclic stability was tested by repeated hydrogen absorption and release cycles, and the hydrogen storage capacity of the material was recorded after 50 cycles, and the capacity retention rate was calculated. The volumetric hydrogen storage density was calculated from the material's bulk density and hydrogen storage capacity.

[0083] The test results are shown in Table 1 below: Table 1:

[0084] Results analysis: The test results above show that the high-capacity solid hydrogen storage materials prepared in all embodiments of this invention exhibit excellent comprehensive performance, far superior to the corresponding existing technologies. The hydrogen storage capacity of all embodiments reaches over 6.0 wt%, with a maximum of 7.0 wt%. The 90% hydrogen absorption time is less than 35 seconds, the peak hydrogen release temperature is below 135℃, the capacity retention rate after 50 cycles is above 89.7%, and the volumetric hydrogen storage density is above 76.8 kg / m³. 3 It can effectively meet the practical application needs of hydrogen energy storage, and the values ​​are all within the conventional technical range in this field and can be stably achieved.

[0085] The performance of each embodiment shows a clear trend of optimization. Example 2, by optimizing the ratio of heteroatom-doped graphene supported on calcium single-atom modifier, compared to Example 1, shows increased hydrogen storage capacity, a 90% reduction in hydrogen absorption time, a lower peak hydrogen desorption temperature, and improved cycle retention, demonstrating the significant improvement in hydrogen storage performance through modifier ratio optimization. Example 3, based on Example 2, optimizes the ratio of composite catalyst to composite hydride, further improving hydrogen storage capacity and hydrogen absorption / desorption kinetics, proving that the synergistic effect of composite catalyst and composite hydride can effectively improve the kinetic characteristics of the material. Example 4 optimizes the stepwise sintering parameters and the ratio of interface modifier, achieving optimal hydrogen storage capacity and cycle stability, indicating that the synergistic regulation of process parameters and interface modifier can effectively improve the structural stability of the material. Examples 5 and 6 are examples with different ratios; although their overall performance is slightly lower than Example 4, it is still far superior to the comparative examples, proving that the raw material ratio of the present invention is reasonable and can be flexibly adjusted according to actual application requirements.

[0086] Comparing the test results of each comparative example with those of Example 1 clearly demonstrates the performance advantages of the present invention. Comparative Example 1, without the addition of heteroatom-doped graphene-supported calcium single-atom modifier, showed a significant decrease in all performance aspects, indicating that this modifier is key to improving the hydrogen storage performance of the material. Comparative Example 2, using a single catalyst; Comparative Example 3, using ordinary graphene instead of the dedicated modifier; and Comparative Example 4, using a single sintering process, all showed performance inferior to Example 1, proving that the composite catalyst, dedicated modifier, and stepwise sintering process of the present invention can significantly improve the overall performance of the material. Comparative Example 5, with raw material ratios exceeding a reasonable range, exhibited the worst performance, proving that the raw material ratio range of the present invention is scientifically reasonable. Comparative Example 6, using a single composite hydride; Comparative Example 7, without the addition of an interface modifier; and Comparative Examples 8 and 9, combining existing technologies in a simple way, all showed performance far lower than that of Example 1, further demonstrating that the synergistic effect of the components and processes of the present invention can achieve synergistic performance improvement, rather than simple additive improvement.

[0087] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The embodiments are provided to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A high capacity solid state hydrogen storage material, characterized in that, The composite material is composed of the following components by mass percentage: 65%-75% composite hydride, 5%-11% heteroatom-doped graphene-supported calcium single-atom modifier, 4%-8% composite catalyst, 2%-4% interface modifier, and 12%-18% nano-carbon material, and the sum of the mass percentages of each component is 100%; the heteroatom-doped graphene-supported calcium single-atom modifier is a nitrogen-phosphorus co-doped graphene-supported calcium single-atom material, and the composite catalyst is composed of titanium dioxide, iron tetroxide, cerium oxide and lanthanum oxide.

2. The solid-state hydrogen storage material of claim 1, wherein, The composite hydride is a mixture of lithium aluminum hydride and sodium borohydride, with a mass ratio of lithium aluminum hydride to sodium borohydride of 1.5:1 to 4:

1.

3. The solid-state hydrogen storage material of claim 1, wherein, In the nitrogen-phosphorus co-doped graphene-supported calcium single-atom material, the atomic ratio of nitrogen atoms to phosphorus atoms is 1:1 to 3:1, and the calcium single-atom loading is 1.2%-3%.

4. The solid-state hydrogen storage material of claim 1, wherein, In the composite catalyst, the mass ratio of titanium dioxide, iron tetroxide, cerium oxide and lanthanum oxide is 3:2:1:1 to 5:2:1:

1.

5. The solid-state hydrogen storage material of claim 1, wherein, The interface modifier is a mixture of silane coupling agent and titanate coupling agent in a mass ratio of 1:1 to 3:1; the nano-carbon material is a mixture of graphene and carbon nanotubes in a mass ratio of 1:1 to 2:

1.

6. A method for the preparation of a high capacity solid state hydrogen storage material for the preparation of a solid state hydrogen storage material according to any one of claims 1 to 5, characterized in that, The method comprises the steps of raw material pretreatment, mixing and dispersing, step sintering, ultrasonic activation and vacuum packaging in sequence; the step sintering is carried out under vacuum condition, the vacuum degree is 1x10 -3 Pa to 4x10 -3 Pa.

7. The production method according to claim 6, wherein The raw material pretreatment includes: drying the composite hydride in an argon-atmosphere glove box, treating the heteroatom-doped graphene-supported calcium single-atom modifier with plasma, grinding the composite catalyst and then vacuum drying it, mixing the interface modifier with anhydrous ethanol to prepare a diluent, and pretreating the nano-carbon material under an argon atmosphere.

8. The preparation method according to claim 6, characterized in that, The mixing and dispersion process involves placing the pretreated raw materials in a planetary ball mill, ball milling them under argon protection to obtain a preliminary mixed powder, adding an interface modifier diluent, and continuing ball milling at a ball-to-material ratio of 10:

1.

9. The method of claim 6, wherein, The step sintering is two-stage temperature rising and holding, the first stage is rising to 210-270℃ and holding, the second stage is rising to 310-390℃ and holding, then lowering to room temperature at 2.5-3.5℃ / min; the ultrasonic activation uses anhydrous ethanol as the dispersion medium, and the powder with a particle size not greater than 1μm is obtained after screening; the vacuum degree of the vacuum packaging is 1×10 -4 Pa to 4×10 -4 Pa.

10. Use of a high capacity solid state hydrogen storage material, characterized in that, The high-capacity solid hydrogen storage material according to any one of claims 1 to 5 is used for hydrogen energy storage.

Images