TiFe-based hydrogen storage alloy and method for preparing the same
By introducing Zr, Ni, and Nd elements into TiFe alloys to form the Laves phase and catalytic active sites, the problems of difficult activation, high plateau pressure, and poor kinetic performance of TiFe alloys are solved, achieving safe and efficient hydrogen storage performance suitable for fuel cell applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- INNER MONGOLIA UNIV OF SCI & TECH
- Filing Date
- 2026-01-20
- Publication Date
- 2026-04-14
AI Technical Summary
Traditional TiFe alloys suffer from difficulties in activation, high plateau pressure, poor kinetic properties, and large hysteresis effects, making it difficult to meet the requirements for safe, efficient, and low-cost hydrogen storage applications.
By introducing Zr, Ni and Nd elements into TiFe alloys, a Laves phase and catalytic active sites are formed, constructing an efficient hydrogen diffusion network to achieve room temperature activation and matching plateau pressure, thereby improving the hydrogen absorption and desorption rates.
Rapid activation at room temperature and activation under low pressure are achieved, the hydrogen storage capacity of the alloy remains above 1.6 wt%, the hydrogen absorption and desorption rates are significantly improved, and the platform pressure is matched with fuel cell applications.
Smart Images
Figure CN121538544B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of metal hydrogen storage materials technology, and more specifically, to a TiFe-based hydrogen storage alloy and its preparation method. Background Technology
[0002] With the increasing severity of the global energy crisis and environmental problems, developing a clean and renewable energy system has become a global consensus. Hydrogen energy, due to its high energy density, water as a combustion product, and lack of pollution, is considered the most promising clean energy carrier of the 21st century. However, safe, efficient, and low-cost hydrogen storage technology remains a technological bottleneck for the large-scale application of hydrogen energy. Solid-state hydrogen storage technology, which stores hydrogen in atomic form within alloy materials, offers advantages such as high hydrogen storage density, good safety, and low operating pressure, making it one of the most promising hydrogen storage methods.
[0003] Among numerous hydrogen storage alloy systems, TiFe-based intermetallic compounds are considered one of the most promising hydrogen storage materials for commercial application due to their abundant constituent elements, low cost, high theoretical hydrogen storage capacity (up to 1.9 wt%), and good reversibility of hydrogen absorption and desorption. Despite these significant advantages, traditional binary TiFe alloys suffer from a series of inherent defects that greatly limit their practical applications:
[0004] 1. Difficulty in activation: A dense passivation oxide layer (such as TiO2) easily forms on the surface of TiFe alloys, which hinders the adsorption and dissociation of hydrogen. Therefore, the initial hydrogen absorption (activation) usually requires a long-term process under harsh conditions of high temperature (e.g., 300-400°C) and high pressure (e.g., 5-10 MPa), which not only consumes a lot of energy but also requires sophisticated equipment and is complex to operate.
[0005] 2. High plateau pressure: Traditional TiFe alloys have high hydrogen absorption and desorption plateau pressures at room temperature (the desorption plateau pressure is usually greater than 0.5 MPa), which does not match the working pressure required by downstream applications such as current mainstream proton exchange membrane fuel cells (PEMFC) (usually 0.1~0.5 MPa).
[0006] 3. Poor kinetic performance: Its hydrogen absorption and desorption reaction rate is relatively slow, making it difficult to meet the application requirements of rapid hydrogen charging and desorption.
[0007] 4. Large hysteresis effect: There is a large gap between the hydrogen absorption plateau pressure and the hydrogen release plateau pressure, resulting in energy efficiency loss.
[0008] To improve the performance of TiFe alloys, the inventors of this application have conducted extensive research on existing technologies, primarily focusing on element substitution. For example, replacing Fe with elements such as Mn and Cr can effectively reduce plateau pressure; using elements such as Ni, Zr, and V can improve activation performance. However, single or simple binary substitution strategies often suffer from trade-offs, potentially sacrificing other key properties (such as hydrogen storage capacity) while improving one, or offering limited improvement effects, failing to synergistically address all the aforementioned problems.
[0009] Therefore, there is an urgent need in this field to develop a novel TiFe-based hydrogen storage alloy that can simultaneously achieve: rapid activation without harsh conditions, platform pressure matching the application, excellent kinetic performance, and high hydrogen storage capacity. Summary of the Invention
[0010] This application provides a TiFe-based hydrogen storage alloy and its preparation method, which can be activated at room temperature, has a suitable hydrogen absorption / desorption plateau pressure, and simultaneously maintains high hydrogen storage capacity and fast hydrogen absorption / desorption rate.
[0011] This application is implemented as follows:
[0012] Firstly, this application provides a TiFe-based hydrogen storage alloy with the general chemical formula: Ti a Nd b Zr c Fe d Ni e Mn f The atomic percentages of each element satisfy the following: Ti 46~53 at%, Nd 0.1~1.5 at%, Zr 1~6.5 at%, Fe 27~40 at%, Ni 2~10 at%, and Mn 4.5~12 at%.
[0013] Among them, Ti, Nd and Zr are the first metallic elements, and Fe, Ni and Mn are the second metallic elements. The ratio of the total atomic percentage of the first metallic elements to the total atomic percentage of the second metallic elements is 1.05~1.20.
[0014] Secondly, this application provides a method for preparing a TiFe-based hydrogen storage alloy according to the first aspect, comprising the following steps:
[0015] (a) According to Ti a Nd b Zr c Fe d Ni e Mn fThe required proportions of each element are used for batching, with an excess of 3-8 wt% of Mn and Nd metals added to compensate for volatilization losses during the smelting process;
[0016] (b) The raw materials prepared in step (a) are placed in an electric arc melting furnace and melted in an inert atmosphere to obtain a molten alloy. The molten alloy is then cast to obtain an alloy ingot, and the alloy ingot is repeatedly melted and cast at least four times.
[0017] This application has at least the following beneficial effects:
[0018] The TiFe-based hydrogen storage alloy of this application, due to the synergistic effect of Ti, Nd, Zr, Fe, Ni, and Mn, can be rapidly activated within several cycles at room temperature (20-30°C) and relatively low pressure (1-3 MPa) without the need for high-temperature and high-pressure treatment. This significantly reduces the cost and operational difficulty, while maintaining a high effective hydrogen storage capacity of over 1.6 wt%. By precisely controlling the content of elements such as Mn, the hydrogen desorption plateau pressure at room temperature can be controlled within the range of 0.2-0.5 MPa, achieving good matching with applications such as fuel cells. The catalytic phase formed by the introduction of Ni, the Laves phase formed by the introduction of Zr, and the lattice distortion caused by the introduction of Nd collectively construct a highly efficient hydrogen diffusion network, resulting in a significant increase in the hydrogen absorption and desorption rates of the alloy. Attached Figure Description
[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0020] Figure 1 The images show the XRD patterns of the TiFe-based hydrogen storage alloys from Examples 1 to 6 of this application.
[0021] Figure 2 These are SEM images of the TiFe-based hydrogen storage alloys of Examples 1 to 6 of this application in BSE mode.
[0022] Figure 3 EDS image of the TiFe-based hydrogen storage alloy metallographic structure of Example 6 of this application;
[0023] Figure 4 These are SEM images of the TiFe-based hydrogen storage alloy powders from Examples 1 to 6 of this application;
[0024] Figure 5These are SEM images of the TiFe-based hydrogen storage alloy powders from Examples 1 to 6 of this application after hydrogen absorption. Detailed Implementation
[0025] The embodiments of this application will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of this application. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.
[0026] The following is a detailed description of the preparation method of the TiFe-based hydrogen storage alloy according to the embodiments of this application:
[0027] In one aspect, this application provides a TiFe-based hydrogen storage alloy with the general chemical formula: TiANdbZrcFedNieMnf, wherein the atomic percentages of each element satisfy the following: Ti 46~53 at%, Nd 0.1~1.5 at%, Zr 1~6.5 at%, Fe 27~40 at%, Ni 2~10 at%, and Mn 4.5~12 at%.
[0028] Ti, Nd, and Zr are the first metallic elements, and Fe, Ni, and Mn are the second metallic elements. The ratio of the total atomic percentage of the first metallic element to the total atomic percentage of the second metallic element is 1.05 to 1.20, for example, 1.05, 1.10, 1.15, or 1.20.
[0029] In some implementations, the atomic percentages of each element are: Ti 47~52 at%, Nd 0.2~1.0 at%, Zr 1.5~6.0 at%, Fe 23~38 at%, Ni 2~9.5 at%, and Mn 4.5~11.7 at%.
[0030] The mechanisms of action and synergistic effects of the elements in this application are as follows:
[0031] Ni exhibits high catalytic activity, effectively catalyzing the decomposition of hydrogen molecules (H2) and the recombination of hydrogen atoms (H). In alloys, the presence of Ni can disrupt the integrity of the surface oxide layer or form Ni-rich catalytic active sites on the surface, providing a "fast channel" for hydrogen atoms to enter the alloy interior. Some Ni may combine with Ti to form the TiNi phase. The TiNi phase itself has excellent hydrogen adsorption and desorption capabilities and is easily activated, serving as a "hydrogen pump" or "gateway" for hydrogen to enter the TiFe main phase, greatly reducing the activation difficulty.
[0032] Mn has a larger atomic radius than Fe. When Mn replaces Fe in the TiFe crystal lattice, it causes lattice distortion and expands the cell volume. Based on the empirical rule that "the larger the cell volume, the more stable the hydride and the lower the plateau pressure," the addition of Mn can effectively reduce the hydrogen absorption / desorption plateau pressure of the TiFe alloy, making it closer to the requirements of room temperature and atmospheric pressure applications. For example, it can match the 0.1~0.5 MPa operating pressure of proton exchange membrane fuel cells.
[0033] During alloy solidification, Zr tends to segregate at grain boundaries, forming Zr-rich second phases, such as C14 or C15 type Laves phases (e.g., ZrFe2, Zr(Fe,Mn)2, etc.). These Laves phases readily absorb hydrogen and undergo significant volume expansion after hydrogen absorption, leading to microcracks in the alloy matrix. This "self-powdering" effect greatly increases the specific surface area of the alloy in contact with hydrogen, thereby significantly reducing activation difficulty and improving hydrogen absorption and desorption kinetics. The Zr-rich phase can act as a "highway" for hydrogen diffusion, accelerating hydrogen transport throughout the alloy.
[0034] Nd is a rare earth element with extremely high chemical reactivity, especially a very strong affinity for oxygen. During alloy smelting, trace amounts of Nd can act as a "purifier" or "oxygen absorber," combining with residual oxygen in the alloy to form stable oxides (such as Nd₂O₃), thereby purifying the grain boundaries of the TiFe main phase and reducing the formation of harmful oxide phases.
[0035] Similar to Zr, Nd also tends to segregate at grain boundaries, forming an Nd-rich second phase. These rare earth phases also exhibit good catalytic activity, serving as "gateways" for hydrogen to enter the alloy and aiding in activation. Nd is an element with a very large atomic radius, and its solid solution causes severe lattice distortion, which is conducive to the formation of amorphous or nanocrystalline structures, and is also very beneficial for improving hydrogen storage kinetics.
[0036] This application introduces appropriate proportions of Zr, Ni, and Nd into a TiFe-based hydrogen storage alloy. Through the combined action of Zr, Ni, and Nd, activation difficulties are reduced from different mechanisms (formation of the Laves phase, catalytic active sites, and matrix purification). Activation can be rapidly completed within several cycles at room temperature (20–30 °C) and relatively low pressure (1–3 MPa), without requiring high-temperature and high-pressure treatment. The alloy's effective hydrogen storage capacity remains at a high level of over 1.6 wt%. The catalytic phase formed by the introduction of Ni, the Laves phase formed by the introduction of Zr, and the lattice distortion caused by the introduction of Nd collectively construct a highly efficient hydrogen diffusion network, significantly improving the alloy's hydrogen absorption and desorption rates. By precisely controlling the Mn content, the hydrogen desorption plateau pressure at room temperature can be controlled within the range of 0.2–0.5 MPa, achieving good matching with applications such as fuel cells.
[0037] For example, the chemical formula of the TiFe-based hydrogen storage alloy of this application is Ti 1.05 Nd 0.02 Zr 0.08 Fe 0.7 5Ni 0.10 Mn 0.15 Ti 1.10 Nd 0.01 Zr 0.04 Fe 0.85 Ni 0.05 Mn 0.10 Ti 1.00 Nd 0.02 Zr 0.13 Fe 0.65 Ni 0.10 Mn 0.25 Ti 1.03 Nd 0.02 Zr 0.10 Fe 0.70 Ni 0.15 Mn 0.15 Ti 1.12 Nd 0.005 Zr 0.025 Fe 0.80 Ni 0.05 Mn 0.15 or Ti 1.05 Nd 0.02 Zr 0.08 Fe 0.60 Ni 0.20 Mn 0.20 .
[0038] Secondly, this application provides a method for preparing the above-mentioned TiFe-based hydrogen storage alloy, comprising the following steps:
[0039] (a) According to Ti a Nd b Zr c Fe d Ni e Mn f The required proportions of each element are used for batching, with an excess of 3-8 wt% of Mn and Nd metals added to compensate for volatilization losses during the smelting process.
[0040] For example, the raw materials for each element are: titanium ingots with a purity greater than 99.5%, sponge zirconium, pure iron, nickel electrolytic plates, electrolytic manganese, and bulk neodymium metal ingots. In addition, considering that manganese (Mn) and neodymium (Nd) have relatively low melting and boiling points and are easily volatilized and lost during the smelting process, an excess of 5 wt% of electrolytic manganese and bulk neodymium metal ingots is added to the original atomic percentage mass of each element during the batching process.
[0041] (b) The raw materials prepared in step (a) are placed in an electric arc melting furnace and melted in an inert atmosphere to obtain a molten alloy. The molten alloy is then cast to obtain an alloy ingot, and the alloy ingot is repeatedly melted and cast at least four times.
[0042] For example, after placing the raw materials in the electric arc melting furnace, the vacuum level inside the furnace is first evacuated to 1×10⁻⁶. -3 Below 0.04 MPa, an inert atmosphere (e.g., high-purity helium) is then introduced and maintained to effectively suppress the volatilization of the various metal components. In addition, to ensure the uniform composition of the final alloy ingot, the alloy ingot is repeatedly melted at least four times, and the alloy ingot is turned over in the furnace after each melting.
[0043] (c) Anneal the alloy ingot at 850~950℃ for 10~24h. This is beneficial to further improve the uniformity of the microstructure.
[0044] The preparation method of the TiFe-based hydrogen storage alloy in this application is simple. It mainly relies on the proportion design of each element in the TiFe-based hydrogen storage alloy, and can achieve effects such as room temperature activation and hydrogen absorption / desorption rate in the as-cast state.
[0045] The preparation method of the TiFe-based hydrogen storage alloy of this application will be further described in detail below with reference to the embodiments. Example 1
[0046] This embodiment provides a TiFe-based hydrogen storage alloy with the chemical formula Ti 1.05 Nd 0.02 Zr 0.08 Fe 0.75 Ni 0.10 Mn 0.15 . Example 2
[0047] This embodiment provides a TiFe-based hydrogen storage alloy with the chemical formula Ti 1.10 Nd 0.01 Zr 0.04 Fe 0.85 Ni 0.05 Mn 0.10 . Example 3
[0048] This embodiment provides a TiFe-based hydrogen storage alloy with the chemical formula Ti 1.00 Nd 0.02 Zr 0.13 Fe 0.65 Ni 0.1 0Mn 0.25 . Example 4
[0049] This embodiment provides a TiFe-based hydrogen storage alloy with the chemical formula Ti 1.03 Nd 0.02 Zr 0.10 Fe 0.70 Ni 0.15 Mn 0.15 . Example 5
[0050] This embodiment provides a TiFe-based hydrogen storage alloy with the chemical formula Ti 1.12 Nd 0.005 Zr 0.025 Fe 0.80 Ni 0.05 Mn 0.15 . Example 6
[0051] This embodiment provides a TiFe-based hydrogen storage alloy with the chemical formula Ti 1.05 Nd 0.02 Zr 0.08 Fe 0.60 Ni 0.20 Mn 0.20 .
[0052] Comparative Example 1
[0053] Comparative Example 1 provides a TiFe-based hydrogen storage alloy with the chemical formula Ti 1.1 Fe 0.8 Mn 0.2 .
[0054] Comparative Example 2
[0055] Comparative Example 2 provides a TiFe-based hydrogen storage alloy with the chemical formula Ti 1.05 Nd 0.02 Zr 0.08 Fe 0.75 Mn 0.15 .
[0056] Comparative Example 3
[0057] Comparative Example 3 provides a TiFe-based hydrogen storage alloy with the chemical formula Ti 1.05 Nd 0.02 Zr 0.08 Fe 0.60 Ni 0.25 Mn 0.10 .
[0058] Experimental Example 1
[0059] The hydrogen absorption activation performance, hydrogen storage capacity, and hydrogen absorption / desorption kinetics of the TiFe-based hydrogen storage alloy powders in Examples 1-6 and Comparative Examples 1-3 were tested using a fully automated Sieverts system, and the results are recorded in Table 1. The hydrogen absorption temperature was 25°C, and the initial hydrogen pressure was 3 MPa; the hydrogen desorption temperature was 25°C, and hydrogen desorption was carried out at a pressure of 1×10⁻⁴ MPa.
[0060] Table 1. Hydrogen absorption activation performance, hydrogen storage capacity and hydrogen absorption / desorption kinetics of TiFe-based hydrogen storage alloy powder
[0061]
[0062] As shown in Table 1, the TiFe-based hydrogen storage alloys of Examples 1 to 6 of this application can be rapidly activated within 3 cycles at room temperature (25°C) and a low pressure of 2 MPa. In contrast, the TiFe-based hydrogen storage alloy of Comparative Example 1, which does not incorporate Zr, Ni, and Nd, requires 8 cycles at a high temperature of 300°C and a high pressure of 5 MPa to complete activation, indicating harsher activation conditions. The TiFe-based hydrogen storage alloy of Comparative Example 2, which also does not incorporate Ni, has similarly harsh activation conditions, requiring 5 cycles at a high temperature of 200°C and a high pressure of 5 MPa to complete activation, demonstrating extremely poor kinetics. This demonstrates that the introduction of Zr, Ni, and Nd into the TiFe-based hydrogen storage alloys in this application reduces the activation difficulty, eliminating the need for high-temperature and high-pressure treatment, and enabling rapid activation within several cycles at room temperature (20-30°C) and a low pressure of 1-3 MPa. Furthermore, the introduced Ni element is essential for achieving room-temperature activation.
[0063] Furthermore, the TiFe-based hydrogen storage alloys of Examples 1 to 6 of this application all exhibit high hydrogen storage capacities, exceeding 1.6 wt%. In contrast, the TiFe-based hydrogen storage alloy of Comparative Example 3 has an atomic percentage of Ni of 11.9 at%, exceeding the range (2-10 at%) defined in this application. Although its kinetic performance is not significantly different from that of the TiFe-based hydrogen storage alloys of Examples 1 to 6, its hydrogen storage capacity of 1.45 wt% is significantly lower than that of the TiFe-based hydrogen storage alloys of the examples in this application. This indicates that the amount of Ni introduced into the TiFe-based hydrogen storage alloy must meet the range (2-10 at%) defined in this application to ensure a high hydrogen storage capacity.
[0064] Experimental Example 2
[0065] The TiFe-based hydrogen storage alloy samples (already activated) from Examples 1 to 6 and Comparative Examples 1 to 3 were placed in a fully automated Sieverts instrument, and the test temperature was set to 25°C. The hydrogen absorption pressure was set to 3 MPa, and the hydrogen release pressure was set to 1 × 10⁻⁶ MPa. -4MPa. Under these conditions, automatic hydrogen absorption and desorption cycles were performed for a total of 500 cycles. The hydrogen storage capacity of the alloy after 500 cycles was tested, and its capacity retention rate was calculated. The results are shown in Table 2.
[0066] Table 2. Results of hydrogen absorption / desorption cycle stability experiments As can be seen from the results in Table 2, the hydrogen storage capacity retention rates of the TiFe-based hydrogen storage alloys in Examples 1 to 6 of this application are all greater than 95%, indicating good cycle stability. In contrast, the hydrogen storage capacity retention rates of the TiFe-based hydrogen storage alloys in Comparative Examples 1 to 3 are 72.0%, 75.1%, and 90.3%, respectively. This demonstrates that simultaneously introducing Zr, Ni, and Nd into the TiFe-based hydrogen storage alloy, with the atomic percentages of Zr, Ni, and Nd within the range defined in this application, can effectively improve the hydrogen storage capacity retention rate of the TiFe-based hydrogen storage alloy.
[0067] Experimental Example 3
[0068] The TiFe-based hydrogen storage alloy samples (activated) from Examples 1-6 and Comparative Examples 1-3 were placed in a fully automated Sieverts system for hydrogen absorption and desorption kinetics tests. The hydrogen absorption kinetics test involved rapidly applying hydrogen pressure to 3 MPa at a constant temperature of 25°C and recording the time required for the alloy to absorb 90% of its maximum hydrogen storage capacity. The desorption kinetics test involved rapidly evacuating the system pressure to 1 × 10⁻⁶ MPa at a constant temperature of 25°C. -4 MPa was used to record the time required for the alloy to release 90% of its maximum hydrogen storage capacity. The results are shown in Table 3.
[0069] Table 3. Results of hydrogen absorption and desorption kinetics tests The results in Table 3 show that the TiFe-based hydrogen storage alloys of Examples 1 to 6 of this application have a faster hydrogen absorption and desorption rate, while the hydrogen absorption and desorption rates of the TiFe-based hydrogen storage alloys of Comparative Examples 1 and 2 are much smaller than those of Examples 1 to 6 of this application. This indicates that introducing Ni and Nd into the TiFe-based hydrogen storage alloy, and further introducing Ni element and controlling it within the ratio range defined in this application, can effectively improve the hydrogen absorption and desorption rate of the TiFe-based hydrogen storage alloy.
[0070] Test Example 4
[0071] X-ray diffraction analysis was performed on the TiFe-based hydrogen storage alloys of Examples 1 to 6, and their XRD patterns are shown below. Figure 1 As shown.
[0072] from Figure 1As can be seen from the XRD patterns of Examples 1 to 6 of this application, obvious diffraction peaks of the TiFe main phase (CsCl structure) and C14-type Laves phase (ZrMn2 type) are observed. This proves that the introduction of Zr successfully formed a Zr-rich second phase that serves as a 'hydrogen diffusion highway'.
[0073] Experimental Example 5
[0074] The TiFe-based hydrogen storage alloys from Examples 1 to 6 were observed using a scanning electron microscope in backscattered electron (BSE) mode, and SEM images of the metallographic structure of the TiFe-based hydrogen storage alloys were obtained, as shown below. Figure 2 As shown. The TiFe-based hydrogen storage alloy of Example 6 was observed under an X-ray energy dispersive spectroscopy (EDS) instrument, and the resulting EDS image is shown below. Figure 3 As shown.
[0075] from Figure 2 As can be seen, the TiFe-based hydrogen storage alloys of Examples 1 to 6 all exhibit typical cast dendritic structures. Analysis using EDS elemental distribution maps confirmed that the gray matrix phase is the TiFe main phase, while the light gray phase distributed between the dendrites is a Zr / Mn-rich Laves phase. The observed dispersed white bright spots are identified as Nd-rich phases. This confirms that Zr and Nd elements tend to segregate at grain boundaries, forming catalytic phases that aid in activation.
[0076] Experimental Example 6
[0077] The TiFe-based hydrogen storage alloy powders from Examples 1 to 6 were observed using scanning electron microscopy before and after hydrogen absorption. The SEM images are shown below. Figure 4 and Figure 5 As shown.
[0078] Figure 4 The initial powder morphology of TiFe-based hydrogen storage alloy powder after mechanical crushing before activation is shown. Figure 4 As shown, the initial powder was in irregular lumps, exhibiting typical characteristics of brittle fracture. This figure illustrates the initial state of the material used in subsequent activation and hydrogen storage performance tests. By comparison... Figure 4 and Figure 5 It can be clearly observed that the TiFe-based hydrogen storage alloy powder underwent significant refinement and fragmentation after hydrogen absorption and desorption cycles, with a substantial reduction in particle size. This intuitively demonstrates that the TiFe-based hydrogen storage alloy of this application's embodiments experienced a 'self-pulverization' effect caused by the volume expansion of the Laves phase during hydrogen absorption, thereby continuously generating new reaction interfaces, greatly promoting the activation process and improving kinetic performance.
[0079] The above description is merely a specific embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A TiFe-based hydrogen storage alloy, characterized in that, Its general chemical formula is: Ti a Nd b Zr c Fe d Ni e Mn f The atomic percentages of each element satisfy the following: Ti 46~53 at%, Nd 0.1~1.5 at%, Zr 1~6.5 at%, Fe 27~40 at%, Ni 2~10 at%, and Mn 4.5~12 at%. Ti, Nd, and Zr are the first metallic elements, and Fe, Ni, and Mn are the second metallic elements. The ratio of the total atomic percentage of the first metallic elements to the total atomic percentage of the second metallic elements is 1.05 to 1.
20.
2. The TiFe-based hydrogen storage alloy according to claim 1, characterized in that, The atomic percentages of each element are as follows: Ti is 47~52 at, Nd is 0.2~1.0 at %, Zr is 1.5~6.0 at %, Fe is 27~38 at, Ni is 2~9.5 at %, and Mn is 4.5~11.7 at.
3. The TiFe-based hydrogen storage alloy according to claim 1, characterized in that, Its chemical formula is Ti 1.05 Nd 0.02 Zr 0.08 Fe 0.75 Ni 0.10 Mn 0.15 .
4. The TiFe-based hydrogen storage alloy according to claim 1, characterized in that, Its chemical formula is Ti 1.10 Nd 0.01 Zr 0.04 Fe 0.85 Ni 0.05 Mn 0.10 .
5. The TiFe-based hydrogen storage alloy according to claim 1, characterized in that, Its chemical formula is Ti 1.00 Nd 0.02 Zr 0.13 Fe 0.65 Ni 0.10 Mn 0.25 .
6. The TiFe-based hydrogen storage alloy according to claim 1, characterized in that, Its chemical formula is Ti 1.03 Nd 0.02 Zr 0.10 Fe 0.70 Ni 0.15 Mn 0.15 .
7. The TiFe-based hydrogen storage alloy according to claim 1, characterized in that, Its chemical formula is Ti 1.12 Nd 0.005 Zr 0.025 Fe 0.80 Ni 0.05 Mn 0.15 .
8. The TiFe-based hydrogen storage alloy according to claim 1, characterized in that, Its chemical formula is Ti 1.05 Nd 0.02 Zr 0.08 Fe 0.60 Ni 0.20 Mn 0.20 .
9. A method for preparing a TiFe-based hydrogen storage alloy as described in any one of claims 1 to 8, characterized in that, Includes the following steps: (a) According to Ti a Nd b Zr c Fe d Ni e Mn f The required proportions of each element are used for batching, with an excess of 3-8 wt% of Mn and Nd metals added to compensate for volatilization losses during the smelting process; (b) The raw materials prepared in step (a) are placed in an electric arc melting furnace and melted in an inert atmosphere to obtain a molten alloy. The molten alloy is then cast to obtain an alloy ingot, and the alloy ingot is repeatedly melted and cast at least four times.
10. The method for preparing the TiFe-based hydrogen storage alloy according to claim 9, characterized in that, It also includes step (c): annealing the alloy ingot at a temperature of 850~950℃ for 10~24h.