High-efficiency AB2 type solid hydrogen storage material and preparation method thereof

Abstract

This invention discloses a high-efficiency solid-state hydrogen storage material and its preparation method, belonging to the technical field of solid-state hydrogen storage materials. The solid-state hydrogen storage material is a multi-element alloy composed of Ti, Zr, Mn, V, Cr, and Mg, with the general chemical formula: Ti = ZrbMncVdCrMgf, where a + b = 1, c + d + e ≈ 2, and 0 < f ≤ 0.03. The advantages of this invention are: the obtained hydrogen storage material has high reversible hydrogen storage capacity at room temperature, fast initial activation response, and long cycle life, effectively solving the problems of difficult initial activation, large compositional deviation, and rapid performance degradation of traditional titanium-manganese alloys. This material operates under mild conditions, has a mature and stable preparation process, controllable production costs, and high safety, showing broad application prospects in hydrogen energy fields such as on-board hydrogen energy storage and supply, distributed power generation, stationary energy storage, and portable hydrogen sources.

Description

Technical Field

[0001] This invention relates to the field of solid-state hydrogen storage materials technology, and particularly to a high-efficiency... Solid-state hydrogen storage materials and their preparation methods. Background Technology

[0002] Hydrogen energy, as a clean, efficient, and renewable secondary energy source, is considered one of the important ways to solve the global energy crisis and environmental pollution. The core bottleneck for its large-scale application lies in efficient, safe, and economical hydrogen storage technology. Currently, hydrogen storage methods mainly include high-pressure gaseous hydrogen storage, cryogenic liquid hydrogen storage, and solid-state hydrogen storage. Among them, high-pressure gaseous hydrogen storage has problems such as low hydrogen storage density, high high-pressure safety risks, and high energy consumption; while cryogenic liquid hydrogen storage faces defects such as high refrigeration energy consumption, expensive equipment costs, and serious hydrogen evaporation losses, which limit its large-scale engineering application.

[0003] Solid-state hydrogen storage has become a research hotspot in the field of hydrogen energy storage due to its advantages such as high hydrogen storage density, good safety, and mild operating conditions. Laves phase hydrogen storage alloys are widely studied and used in solid-state hydrogen storage systems due to their high hydrogen storage capacity, excellent hydrogen absorption and desorption kinetics, and good cycle stability. Among them, titanium-manganese alloys... Hydrogen storage alloys have become one of the most promising hydrogen storage materials for engineering applications due to their low raw material costs and strong environmental adaptability.

[0004] However, existing titanium-manganese systems Hydrogen storage alloys still have many shortcomings: First, the hydrogen storage density needs to be improved. Most alloys have low reversible hydrogen storage density under normal temperature (25℃) and medium and low pressure conditions, which cannot meet the high density requirements of scenarios such as on-board hydrogen storage. Secondly, the alloys have shortcomings in activation performance and cycle stability. Some alloys require high temperature and high pressure conditions to complete activation, and their hydrogen storage capacity decays significantly after long-term hydrogen charging and discharging cycles. Third, Mg is volatile during the preparation process, which causes the alloy composition to deviate from the designed ratio and affects the stability of hydrogen storage performance; Fourth, the preparation process is difficult to balance performance uniformity and the needs of large-scale production, which limits its engineering application.

[0005] Therefore, it is necessary to design an efficient Solid-state hydrogen storage materials and their preparation methods. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a highly efficient... The invention relates to a solid-state hydrogen storage material and its preparation method, which solves the problems mentioned in the background section.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A high efficiency Solid-state hydrogen storage materials are alloys composed of Ti, Zr, Mn, V, Cr, and Mg, with the general chemical formula: Ti = ZrbMnVdCrMgf Where: a+b=1; c+d+e≈2; 0<f≤0.03; The molar ratios of each element are as follows: Ti: 0.75–0.90; Zr: 0.10–0.25; Mn: 1.00–1.30; V: 0.20–0.60; Cr: 0.20–0.60; Mg: 0.005–0.03.

[0008] Furthermore, the main phase of the alloy is a C14 hexagonal Laves phase structure.

[0009] Furthermore, the preferred chemical formula is Ti0.84Zr0.16Mn1.14V0.40Cr0.44Mg0.020.

[0010] Furthermore, the alloy has a maximum hydrogen storage capacity of 3.6 wt% at 25°C and 3 MPa.

[0011] Furthermore, the alloy retains up to 95.3% of its hydrogen storage capacity after 1000 charge-discharge hydrogen cycles.

[0012] A high efficiency The preparation method of solid hydrogen storage material includes the following steps: (a) Raw material pretreatment and weighing: Weigh Ti, Zr, Mn, V, Cr and Mg pure metal raw materials according to the target molar ratio. The purity of all raw materials is ≥99.5%. Dry the pure metal raw materials for later use. (b) Vacuum induction melting: The pretreated Ti, Zr, Mn, V, and Cr pure metal raw materials are placed in a vacuum induction melting furnace. The furnace is evacuated to a vacuum degree ≤5×10 Pa, and an inert protective gas argon / helium is introduced until the furnace pressure is 0.01-0.1 MPa. A covering agent is added, and induction heating is started to raise the furnace temperature to 1400–1600°C. The temperature is held for 15–30 min to ensure complete melting and uniform mixing of the raw materials. Then, metallic magnesium is quickly added and held for 2–10 min to reduce Mg volatilization loss. Finally, heating is stopped, and the furnace is cooled to room temperature to obtain an ingot. (c) Homogenization annealing: The ingot is placed in a tube annealing furnace, and an inert protective gas (argon / helium) is introduced. After the air in the furnace is removed, the furnace temperature is raised to 850-1050°C and held for 6-10 hours. Then, the ingot is slowly cooled to room temperature in the furnace to eliminate internal stress and compositional segregation. (d) Crushing process: The annealed ingot is crushed mechanically under an inert protective gas and then screened to obtain alloy powder of 50-200 mesh; the finished hydrogen storage alloy powder is obtained.

[0013] Furthermore, in step (b), the presence of the covering agent can effectively control the Mg volatilization loss rate to ≤5%, ensuring that the alloy composition is consistent with the design ratio; electromagnetic stirring is used during the smelting process to further improve the uniformity of the alloy composition.

[0014] Compared with existing technologies, the advantages of this invention are: 1. This invention constructs a highly stable C14 hexagonal Laves phase pure phase structure through A-site Ti-Zr-Mg composite doping modification and B-site Mn-V-Cr synergistic regulation. At room temperature of 25℃ and conventional hydrogen pressure of 3 MPa, the reversible hydrogen storage density can reach 3.6wt%, which far exceeds that of traditional titanium-manganese hydrogen storage alloys. It has high plateau flatness, small hysteresis, moderate hydride formation enthalpy, and excellent reversibility of hydrogen absorption and desorption.

[0015] 2: The alloy of this invention has abundant interstitial sites in the crystal lattice and controllable crystal defects. It does not require high temperature and high pressure pretreatment and has a fast hydrogen absorption response speed, which solves the technical problems of difficult activation and initial hydrogen absorption lag of traditional titanium-manganese alloys.

[0016] 3: This invention optimizes the homogenization annealing process, regulates the grain structure, eliminates internal stress, and achieves a capacity retention rate of up to 95.3% after 1000 cycles. The cycle life is superior to existing similar materials, significantly reducing equipment replacement costs.

[0017] 4. This invention employs a process of adding a covering agent, which effectively suppresses the high-temperature volatilization of low-melting-point Mg elements, controls the Mg loss rate to within 5%, ensures that the alloy composition accurately matches the design ratio, and effectively reduces the problems of large composition deviation and unstable performance in traditional processes.

[0018] 5. This invention adopts a mature vacuum induction melting + high-temperature homogenization annealing process. The process parameters are stable and highly repeatable. No complicated post-processing is required, the production cost is controllable, and large-scale industrial production can be achieved. It has good promotion value.

[0019] 6. The material of this invention has high safety, mild working conditions, and excellent hydrogen storage performance, and can be widely used in many fields such as on-board hydrogen energy storage systems, distributed hydrogen supply for fuel cells, stationary hydrogen energy storage, and portable hydrogen source equipment.

[0020] In summary, this invention provides a highly efficient This invention relates to a novel solid-state hydrogen storage material and its preparation method. Through multi-element synergistic doping modification and phase structure optimization, combined with loss control by a covering agent and high-temperature homogenization annealing, precise control of alloy composition and regularization of microstructure are achieved. Compared with existing technologies, the obtained material exhibits high room-temperature reversible hydrogen storage capacity, fast activation response, and long cycle life, effectively solving the problems of difficult initial activation, large compositional deviation, and rapid performance degradation of traditional titanium-manganese alloys. This material operates under mild conditions, has a mature and stable preparation process, controllable production costs, and high safety, showing broad application prospects in hydrogen energy fields such as on-board hydrogen energy storage and supply, distributed power generation, stationary energy storage, and portable hydrogen sources. Attached Figure Description

[0021] Figure 1 This invention proposes a highly efficient Flowchart of the preparation method of solid hydrogen storage materials; Figure 2 The samples prepared in Examples 1-4 and Comparative Example 1 of this invention A bar chart showing the test results of solid hydrogen storage materials. Detailed Implementation

[0022] Reference Figures 1-2 The present invention will be further described in detail below with reference to specific embodiments, but the present invention is not limited to the following embodiments. Without departing from the core technical solution of the present invention, those skilled in the art can make reasonable fine-tuning of the parameters, all of which fall within the protection scope of the present invention.

[0023] Example 1 This embodiment provides a high efficiency The solid hydrogen storage material has the chemical formula Ti0.84Zr0.16Mn1.14V0.40Cr0.44Mg0.020.

[0024] The preparation steps are as follows: (1) Raw material pretreatment: Select pure metal raw materials of Ti, Zr, Mn, V, Cr and Mg with a purity of ≥99.5% and weigh them accurately according to the target molar ratio (among which, volatile metals are kept in a certain excess to take into account the loss). All raw materials were placed in a 90℃ vacuum oven and dried for 3 hours to remove adsorbed moisture and volatile impurities.

[0025] (2) Vacuum melting: Put Ti, Zr, Mn, V and Cr elemental raw materials into the melting furnace, evacuate to 4×10 Pa, and fill with argon gas to 0.05 MPa inside the furnace; Add the covering agent, heat to 1500℃, keep at that temperature for 20 minutes, and turn on the electromagnetic stirrer to mix the melt evenly. Then, metallic magnesium is quickly added, the mixture is kept at a constant temperature for 3 minutes, and then cooled to room temperature in the furnace to obtain an alloy ingot.

[0026] (3) Homogenization annealing: The ingot is placed in a tube annealing furnace, heated to 1000℃ under argon protection, kept at a constant temperature for 8 hours, and then slowly cooled to room temperature with the furnace.

[0027] (4) Crushing and screening: Mechanical crushing under an inert atmosphere, followed by screening to obtain 50-200 mesh alloy powder, which is the finished product.

[0028] Example 2 This embodiment provides a high efficiency The solid hydrogen storage material has the general chemical formula Ti0.80Zr0.20Mn1.10V0.45Cr0.45Mg0.015.

[0029] The preparation steps are as follows: (1) Raw material pretreatment: Select pure metal raw materials of Ti, Zr, Mn, V, Cr and Mg with a purity of ≥99.5% and weigh them accurately according to the target molar ratio (among which, volatile metals are kept in a certain excess to take into account the loss). All raw materials were placed in a 90℃ vacuum oven and dried for 3 hours to remove adsorbed moisture and volatile impurities.

[0030] (2) Vacuum melting: Put Ti, Zr, Mn, V and Cr elemental raw materials into the melting furnace, evacuate to 4×10 Pa, and fill with argon gas to 0.05 MPa inside the furnace; Add the covering agent, heat to 1500℃, keep at that temperature for 20 minutes, and turn on the electromagnetic stirrer to mix the melt evenly. Then, metallic magnesium is quickly added, the mixture is kept at a constant temperature for 3 minutes, and then cooled to room temperature in the furnace to obtain an alloy ingot.

[0031] (3) Homogenization annealing: The ingot is placed in a tube annealing furnace, heated to 1000℃ under argon protection, kept at a constant temperature for 8 hours, and then slowly cooled to room temperature with the furnace.

[0032] (4) Crushing and screening: Mechanical crushing under an inert atmosphere, followed by screening to obtain 50-200 mesh alloy powder, which is the finished product.

[0033] Example 3 This embodiment provides a high efficiency The solid hydrogen storage material has the general chemical formula Ti0.86Zr0.14Mn1.18V0.38Cr0.44Mg0.010.

[0034] The preparation steps are as follows: (1) Raw material pretreatment: Select pure metal raw materials of Ti, Zr, Mn, V, Cr and Mg with a purity of ≥99.5% and weigh them accurately according to the target molar ratio (among which, volatile metals are kept in a certain excess to take into account the loss). All raw materials were placed in a 90℃ vacuum oven and dried for 3 hours to remove adsorbed moisture and volatile impurities.

[0035] (2) Vacuum melting: Put Ti, Zr, Mn, V and Cr elemental raw materials into the melting furnace, evacuate to 4×10 Pa, and fill with argon gas to 0.05 MPa inside the furnace; Add the covering agent, heat to 1500℃, keep at that temperature for 20 minutes, and turn on the electromagnetic stirrer to mix the melt evenly. Then, metallic magnesium is quickly added, the mixture is kept at a constant temperature for 3 minutes, and then cooled to room temperature in the furnace to obtain an alloy ingot.

[0036] (3) Homogenization annealing: The ingot is placed in a tube annealing furnace, heated to 1000℃ under argon protection, kept at a constant temperature for 8 hours, and then slowly cooled to room temperature with the furnace.

[0037] (4) Crushing and screening: Mechanical crushing under an inert atmosphere, followed by screening to obtain 50-200 mesh alloy powder, which is the finished product.

[0038] Example 4 This embodiment provides a high efficiency A solid-state hydrogen storage material with the general chemical formula Ti0.81Zr0.19Mn1.08V0.48Cr0.44Mg0.025 The preparation steps are as follows: (1) Raw material pretreatment: Select pure metal raw materials of Ti, Zr, Mn, V, Cr and Mg with a purity of ≥99.5% and weigh them accurately according to the target molar ratio (among which, volatile metals are kept in a certain excess to take into account the loss). All raw materials were placed in a 90℃ vacuum oven and dried for 3 hours to remove adsorbed moisture and volatile impurities.

[0039] (2) Vacuum melting: Put Ti, Zr, Mn, V and Cr elemental raw materials into the melting furnace, evacuate to 4×10 Pa, and fill with argon gas to 0.05 MPa inside the furnace; Add the covering agent, heat to 1500℃, keep at that temperature for 20 minutes, and turn on the electromagnetic stirrer to mix the melt evenly. Then, metallic magnesium is quickly added, the mixture is kept at a constant temperature for 3 minutes, and then cooled to room temperature in the furnace to obtain an alloy ingot.

[0040] (3) Homogenization annealing: The ingot is placed in a tube annealing furnace, heated to 1050℃ under argon protection, kept at a constant temperature for 8 hours, and then slowly cooled to room temperature with the furnace.

[0041] (4) Crushing and screening: Mechanical crushing under an inert atmosphere, followed by screening to obtain 50-200 mesh alloy powder, which is the finished product.

[0042] Comparative Example 1 Using traditional Mg-free modified titanium-manganese system Hydrogen storage alloy with the general chemical formula Ti0.85Zr0.15Mn1.15V0.40Cr0.45.

[0043] The preparation steps are as follows: (1) Raw material pretreatment: Select pure metal raw materials of Ti, Zr, Mn, V and Cr with a purity of ≥99.5% and weigh them accurately according to the target molar ratio; All raw materials were placed in a 90℃ vacuum oven and dried for 3 hours to remove adsorbed moisture and volatile impurities.

[0044] (2) Vacuum melting: Put Ti, Zr, Mn, V and Cr elemental raw materials into the melting furnace, evacuate to 4×10 Pa, and fill with argon gas to 0.05 MPa inside the furnace; Add the covering agent, heat to 1500℃, keep at that temperature for 20 minutes, and turn on the electromagnetic stirrer to mix the melt evenly. The alloy ingot was obtained by cooling it to room temperature in the furnace.

[0045] (3) Homogenization annealing: The ingot is placed in a tube annealing furnace, heated to 1000℃ under argon protection, kept at a constant temperature for 8 hours, and then slowly cooled to room temperature with the furnace.

[0046] (4) Crushing and screening: Mechanical crushing under an inert atmosphere, followed by screening to obtain 50-200 mesh alloy powder, which is the finished product.

[0047] Performance testing: The maximum hydrogen storage capacity and cycle capacity retention of the solid hydrogen storage alloy materials involved in Examples 1-4 and Comparative Example 1 were tested using the following specific steps and methods: 1. Activation treatment of alloys The alloy powder samples (weighing about 3-5 g) prepared in each embodiment and comparative example were loaded into a high-pressure stainless steel reactor and connected to a Sieverts gas volume method hydrogen storage performance test device (PCT tester). First, the reaction vessel system is evacuated to a vacuum level below 1×10 Pa. At the same time, the reaction vessel is heated to 60-80℃ and held for 1.5 h to completely remove impurity gases adsorbed on the system pipelines and the surface of the alloy sample. Subsequently, high-purity hydrogen gas (purity ≥99.999%) was introduced into the reactor to bring the hydrogen pressure in the system to 3.5 MPa and maintain hydrogen absorption for 40 min. The system was then evacuated again to below 10 Pa to release hydrogen and remove hydrogen.

[0048] Repeat the above hydrogen absorption and desorption cycle three times to fully activate the internal lattice of the alloy until the amount of hydrogen absorbed and desorbed by the alloy tends to stabilize.

[0049] 2. Maximum hydrogen storage capacity test The fully activated alloy sample was placed in a sealed high-pressure reactor under a constant temperature water bath environment of 25℃. The testing device was turned on, and high-purity hydrogen was gradually introduced into the reactor through the computer control system. The final hydrogen absorption equilibrium pressure was set to 3 MPa. The testing system used the pressure drop method principle and a high-precision pressure sensor to monitor and record the pressure change curve of the reactor over time in real time. Once the pressure inside the reactor has reached complete equilibrium (i.e., the pressure no longer changes within 15 minutes), the system automatically calculates the maximum hydrogen storage capacity (mass percentage, wt%) of the alloy at 25℃ and 3 MPa based on the pressure difference before and after hydrogen absorption, the known dead volume of the test system, and the actual gas state equation.

[0050] 3. Cyclic stability test The activated alloy sample was subjected to 1000 consecutive hydrogen charge-discharge cycles using a fully automated high-pressure hydrogen charge-discharge cycle tester. The specific cycle steps are as follows: (1) Hydrogen absorption (charging) stage: Under constant temperature of 25℃, high-purity hydrogen gas with a pressure of 3 MPa is introduced into the reactor and the hydrogen absorption time is maintained for 30 min, so that the alloy sample can fully absorb hydrogen to reach saturation. The system automatically records and stores the saturated hydrogen storage capacity of the first hydrogen absorption cycle, which is denoted as C1. (2) Hydrogen release (discharge) stage: The reactor is rapidly heated to 90°C, and the vacuum pump is started to evacuate the reactor system to below 10 Pa. The hydrogen release and dehydrogenation time is maintained for 30 min to completely release the hydrogen adsorbed inside the alloy. (3) Repeat the hydrogen absorption and desorption steps in (1) and (2) above, and the instrument will run continuously for 1000 cycles. Record the saturated hydrogen storage capacity at the 1000th hydrogen absorption cycle as C1000. (4) Cyclic capacity retention rate calculation: The hydrogen storage capacity retention rate (%) of each alloy sample after 1000 charge-discharge hydrogen cycles is calculated by using the formula: Cyclic capacity retention rate = (C1000 / C1) × 100%.

[0051] Table 1 Test Results ; Data Analysis: The results above show that the maximum hydrogen storage capacity of Examples 1-4 of the present invention is all above 3.5 wt%, with the optimal Example 1 reaching 3.6 wt%, which is much higher than the 1.72 wt% of Comparative Example 1, demonstrating a significant advantage in hydrogen storage capacity. After 1000 charge-discharge hydrogen cycles, the capacity retention rate of the embodiments of the present invention is ≥92.5%, with the optimal Example 1 reaching 95.3%, which is also significantly better than the 88% of the comparative example, and the cycle life is longer.

[0052] By employing the A-site composite doping of Ti-Zr-Mg and the synergistic regulation of the B-site in Mn-V-Cr, combined with the preparation process of this invention, it is possible to... The titanium-manganese hydrogen storage alloy achieves both high hydrogen storage density and excellent cycle stability, with all performance characteristics significantly superior to traditional Mg-free modified systems, demonstrating outstanding technical effectiveness.

[0053] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Those skilled in the art can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A highly efficient Type solid hydrogen storage material, characterized in that, It is an alloy composed of Ti, Zr, Mn, V, Cr and Mg, with the general chemical formula: Ti = ZrbMnVdCrMgf Where: a+b=1; c+d+e≈2; 0<f≤0.03; The molar ratios of each element are as follows: Ti: 0.75–0.90; Zr: 0.10–0.25; Mn: 1.00–1.30; V: 0.20–0.60; Cr: 0.20–0.60; Mg: 0.005–0.

03.

2. A high-efficiency method according to claim 1 Type solid hydrogen storage material, characterized in that, The main phase of the alloy is a C14 hexagonal Laves phase structure.

3. A high-efficiency method according to claim 1 Type solid hydrogen storage material, characterized in that, The preferred chemical formula is Ti0.84Zr0.16Mn1.14V0.40Cr0.44Mg0.

020.

4. A high-efficiency method according to claim 1 Type solid hydrogen storage material, characterized in that, The alloy has a maximum hydrogen storage capacity of 3.6 wt% at 25°C and 3 MPa.

5. A high-efficiency method according to claim 1 Type solid hydrogen storage material, characterized in that, The alloy retains up to 95.3% of its hydrogen storage capacity after 1000 charge-discharge cycles.

6. A highly efficient The method for preparing solid hydrogen storage materials is characterized by, Includes the following steps: (a) Raw material pretreatment and weighing: Weigh Ti, Zr, Mn, V, Cr and Mg pure metal raw materials according to the target molar ratio. The purity of all raw materials is ≥99.5%. Dry the pure metal raw materials for later use. (b) Vacuum induction melting: The pretreated Ti, Zr, Mn, V, and Cr pure metal raw materials are placed in a vacuum induction melting furnace. The furnace is evacuated to a vacuum degree ≤5×10 Pa, and an inert protective gas argon / helium is introduced until the furnace pressure is 0.01-0.1 MPa. A covering agent is added, and induction heating is started to raise the furnace temperature to 1400–1600°C. The temperature is held for 15–30 min to ensure that the raw materials are completely melted and uniformly mixed. Then, metallic magnesium is quickly added and held for 2–10 min to reduce Mg volatilization loss. Finally, heating is stopped, and the furnace is cooled to room temperature to obtain an ingot. (c) Homogenization annealing: The ingot is placed in a tube annealing furnace, and an inert protective gas (argon / helium) is introduced. After the air in the furnace is removed, the furnace temperature is raised to 850-1050°C and held for 6-10 hours. Then, the ingot is slowly cooled to room temperature in the furnace to eliminate internal stress and compositional segregation. (d) Crushing process: The annealed ingot is crushed mechanically under an inert protective gas and then screened to obtain alloy powder of 50-200 mesh; the finished hydrogen storage alloy powder is obtained.

7. A high-efficiency method according to claim 1 The method for preparing solid hydrogen storage materials is characterized by, In step (b), the presence of the covering agent can effectively control the Mg volatilization loss rate to ≤5%, ensuring that the alloy composition is consistent with the design ratio; electromagnetic stirring is used during the smelting process to further improve the uniformity of the alloy composition.

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