Search

CN-121990524-A - N@C-coated Mg-Ni-Nd antitoxic alloy and preparation method and application thereof

CN121990524ACN 121990524 ACN121990524 ACN 121990524ACN-121990524-A

Abstract

The invention discloses N@C-coated Mg-Ni-Nd anti-poisoning alloy which is prepared by mixing N@C-I and Mg-Ni-Nd alloy and ball milling, and is simply called MNN/N@C-I, wherein the content of Mg is 85-90 wt percent, the content of Ni is 12-18 wt percent, the content of Nd is 15-20 wt percent, the content of N@C-I is 1-5 wt percent, C phase, mg 2 Ni phase, nd 4 Mg 80 Ni 8 phase and NdH 2.61 phase exist, polyacrylonitrile PAN is prepared by taking isopropanol as a solvent, graphite carbon is obtained, the microstructure is a leaf-shaped nanostructure with edges, the size is 400-500nm, the specific surface area is 250-260 m 2 /g, and the pore volume is 0.15-0.20 cm 3 /g. The preparation method comprises the following steps of 1, preparing nitrogen-doped carbon nanoflower N@C and preparing 2, N@C coated Mg-Ni-Nd alloy. When the hydrogen storage alloy is used, the maximum hydrogen absorption amount is more than 4.4 wt percent under the condition of hydrogen, the maximum hydrogen absorption amount is more than 4.4 wt percent under the condition of toxic atmosphere, the toxic atmosphere is mixed gas of CO 2 and H 2 , and the volume fraction of CO 2 is 1-5 percent.

Inventors

  • LU YANGFAN
  • YANG JINGSONG
  • LI JIE
  • TANG ZHENGJIE
  • LI HUI
  • LI QIAN

Assignees

  • 重庆新型储能材料与装备研究院
  • 重庆大学

Dates

Publication Date
20260508
Application Date
20260203

Claims (9)

  1. 1. The N@C-coated Mg-Ni-Nd anti-poisoning alloy is characterized in that the alloy is obtained by mixing and ball milling N@C-I and Mg-Ni-Nd alloy, and is simply called MNN/N@C-I, wherein the content of Mg is 85-90 wt percent, the content of Ni is 12-18 wt percent, the content of Nd is 15-20 wt percent, and the content of N@C-I is 1-5 wt percent; The phase composition of the obtained MNN/N@C-I has a C phase, a Mg 2 Ni phase, a Nd 4 Mg 80 Ni 8 phase and a NdH 2.61 phase; the N@C-I is obtained by carbonizing polyacrylonitrile PAN prepared by taking isopropanol as a solvent.
  2. 2. The N@C-coated Mg-Ni-Nd anti-poisoning alloy according to claim 1, wherein N@C-I is graphite carbon, the microstructure is a leaf-shaped nano structure with sharp edges, the size is 400-500nm, the specific surface area is 250-260 m 2 /g, and the pore volume is 0.15-0.20 cm 3 /g.
  3. 3. A preparation method of N@C-coated Mg-Ni-Nd anti-poisoning alloy is characterized by comprising the following steps: Step 1, preparing nitrogen-doped carbon nanoflower N@C, namely firstly, under the condition of nitrogen, taking azo tertiary butyl nitrile as an initiator and isopropanol as a solvent, carrying out polymerization reaction on free radical polymerization acrylonitrile, after the reaction is finished, drying at the drying temperature of 60-70 ℃ to obtain polyacrylonitrile PAN, and then carbonizing the PAN by adopting a two-step carbonization method to obtain nitrogen-doped carbon nanoflower N@C; And 2, preparing the N@C coated Mg-Ni-Nd alloy, firstly, performing mixed ball milling on N@C obtained in the step 1 and the Mg-Ni-Nd alloy by adopting a gap ball milling method to obtain MNN-NCI, and then performing activation treatment on the MNN-NCI to obtain N@C coated Mg-Ni-Nd anti-poisoning alloy MNN/N@C.
  4. 4. The method of claim 3, wherein in the step 1, the polymerization reaction is carried out at a temperature of 70-90 ℃ for a time of 2-3 h; In the step 1, the two-step carbonization method is characterized in that the first step is that the temperature rising rate is 0.1-0.5 ℃ for min -1 under the air condition, the pre-oxidation temperature is 230-250 ℃ and the pre-oxidation time is 2-2.5 h, and the second step is that the temperature rising rate is 2-5 ℃ under the nitrogen condition.
  5. 5. The method of claim 3, wherein in step 2, the condition of the gap ball milling method is that zirconia balls are ball milling balls under argon gas condition, the ball material ratio is 40:1-80:1, the ball milling revolution is 450-500 rpm, the forward and reverse rotation gap ball milling is carried out, the single forward ball milling time is 10-15 min, the pause time is 10-20min, then the single reverse rotation ball milling is 10-15 min, and the total ball milling time is 1200-2000 min.
  6. 6. The method of claim 3, wherein in step 2, the activation treatment is performed under the conditions of sequentially performing hydrogen absorption activation and hydrogen desorption activation, and the number of times of activation treatment is 3-5 times; the specific conditions of the hydrogen absorption and activation are that the hydrogen absorption temperature is 300-350 ℃, the hydrogen absorption pressure is 1-3 MPa, and the hydrogen absorption time is 0.5-2h; The specific condition of the hydrogen release activation is that the hydrogen release temperature is 300-350 ℃, the hydrogen release pressure is 0.001-0.005MPa, and the hydrogen release time is 0.5-1h.
  7. 7. A simulated poisoning treatment method for hydrogen storage alloy is characterized by comprising the steps of firstly, carrying out hydrogen absorption test on MNN/N@C under the poisoning atmosphere condition, and then, carrying out hydrogen release test under the vacuum condition to complete one-time simulated poisoning treatment, wherein the poisoning atmosphere is mixed gas of CO 2 and H 2 , and the volume fraction of CO 2 is 1-5%; The hydrogen absorption test is carried out under the conditions that the hydrogen absorption temperature is 280-300 ℃, the hydrogen absorption pressure is 1-3 MPa, and the hydrogen absorption time is 30-120 min.
  8. 8. The N@C-clad Mg-Ni-Nd anti-poisoning alloy of claim 1, wherein when applied as a hydrogen storage alloy, the maximum hydrogen absorption is greater than 4.4 wt% under hydrogen conditions at a hydrogen absorption temperature of 280-300 ℃ and a hydrogen absorption pressure of 1-3 MPa for a hydrogen absorption time of 10-15 min.
  9. 9. The N@C-clad Mg-Ni-Nd anti-poisoning alloy of claim 1, wherein when applied as an anti-poisoning hydrogen storage alloy, MNN/N@C has a maximum hydrogen absorption of greater than 4.4 wt% under P atmosphere conditions at a hydrogen absorption temperature of 280-300 ℃ and a hydrogen absorption pressure of 1-3 MPa for a hydrogen absorption time of 10-15 min.

Description

N@C-coated Mg-Ni-Nd antitoxic alloy and preparation method and application thereof Technical Field The invention relates to the technical field of hydrogen storage materials, in particular to N@C-coated Mg-Ni-Nd antitoxic alloy and a preparation method and application thereof. Background The magnesium-based hydrogen storage material has a theoretical hydrogen storage capacity of up to 7.6 wt% and lower cost, but has a problem of being easily poisoned by impurity gas CO 2、O2、H2 O, CO in practical application, resulting in a drastic drop in cycle stability. The poisoning mechanism mainly comprises two aspects, namely that impurity gas occupies surface hydrogen dissociation active sites to inhibit adsorption and dissociation of hydrogen molecules, and the surface of the alloy is subjected to oxidation/carbonization reaction to form a compact passivation layer to reduce the hydrogen storage phase content of the alloy. For example, prior document 1,（"The storage of industrially pure hydrogen in magnesium."International Journal of Hydrogen Energy, 1993, 18(4): 297-300.）,MgH2 completely loses hydrogen absorption capacity in an atmosphere of H 2 containing 2% CO 2. This document shows that conventional magnesium-based hydrogen storage is highly sensitive to impurity gases, i.e. does not possess antitoxic properties. At present, two solutions for improving the CO 2 poisoning resistance of magnesium-based hydrogen storage materials are respectively an alloying modification method and a surface coating protection method. The basic principle of the alloying modification method is that the surface property of the material is regulated and controlled by introducing specific alloy elements so as to relieve the toxic effect. For example, the inventors of the present invention have studied earlier, and have found that prior document 1 (Li Qian, li Jie, hu, etc.) an Mg-Ni-Nd hydrogen storage alloy having anti-poisoning and regenerating properties, and its use and regenerating method, CN120210618A [ P ] 2025-04-09 ], can obtain an Mg-Ni-Nd alloy having both anti-poisoning and regenerating capabilities by an alloying method. The technical proposal improves the antitoxic performance by enabling the magnesium-based hydrogen storage material to obtain the regeneration performance. However, the technical scheme still has the condition of further improving the antitoxic performance, and the reason is that the alloying modification method and the surface coating protection method can be simultaneously applied to the magnesium-based hydrogen storage alloy, but the technical scheme is not further combined with the surface coating protection method due to the limit of a research plan, so that the antitoxic performance is improved. The basic principle of the surface coating protection method is that an alloy substrate is protected by physical barrier action. Depending on the coating material, it can be classified into a metal coating, a carbon coating and a polymer coating. The class 1 metal coating has the function of improving the anti-poisoning performance, but has the problems of higher cost and easy cracking and falling of the coating, and is not suitable for the long-term anti-poisoning requirement of the hydrogen storage material. The class 2 carbon coating has the advantages of high temperature stability, simple process and low cost. For example, graphite coated AB 2 alloy prepared by ball milling method of prior document 2（"Improving oxygen resistance of hydrogen storage alloys with graphite or nickel coating"International Journal of Hydrogen Energy, 2025, 103, 228-238） achieves resistance to oxygen poisoning under air exposure conditions. However, the technical proposal still has 25 percent of loss of hydrogen storage capacity even under the weak poisoning condition. The reasons for this are 3: 1. the graphite layer used as the protective coating has the characteristics of small specific surface area and few pore channels, so that a compact insulating layer cannot be formed, and toxic gas invasion cannot be effectively insulated; 2. the graphite layer used as the protective coating has the problems of weak combination and incomplete coverage with the alloy matrix; 3. the alloy matrix has agglomeration problem. A common method for solving the problem that a dense carbon coating cannot be formed is to adopt carbon coatings prepared from different carbon sources so as to realize different poisoning-resistant effects. For example, the prior literature 3（"Carbon coating with different carbon sources on rare earth hydrogen storage alloy"International Journal of Hydrogen Energy, 2025, 104, 30868-30876） prepares carbon coatings on the surfaces of hydrogen storage alloys by using different small carbon-containing molecules, specifically sucrose, glucose, asphalt and chitosan, as carbon sources to improve the antitoxic performance of the alloys. However, the capacity retention of the uncoated alloy at 500 cycles was about 63%, and the c