CN110317974B

CN110317974B - Yttrium-nickel rare earth hydrogen storage alloy

Info

Publication number: CN110317974B
Application number: CN201910670769.7A
Authority: CN
Inventors: 闫慧忠; 李宝犬; 熊玮; 王利; 李金�
Original assignee: Baotou Rare Earth Research Institute; Ruike Rare Earth Metallurgy and Functional Materials National Engineering Research Center Co Ltd; Tianjin Baogang Rare Earth Research Institute Co Ltd
Current assignee: Baotou Rare Earth Research Institute; Ruike Rare Earth Metallurgy and Functional Materials National Engineering Research Center Co Ltd; Tianjin Baogang Rare Earth Research Institute Co Ltd
Priority date: 2014-08-28
Filing date: 2014-08-28
Publication date: 2021-02-05
Anticipated expiration: 2034-08-28
Also published as: CN110317974A; CN104532062A

Abstract

The invention relates to a₅B₁₉Type general formula is RE_xY_yNi_z‑a‑ _bMn_aAl_bThe rare earth-based hydrogen storage alloy of (1). The alloy has good pressure-composition-isothermal characteristics, and the maximum hydrogen storage capacity can reach more than 1.33 wt.% under the common conditions. The alloy of the invention has better electrochemical performance as a hydrogen storage electrode and gas-phase hydrogen absorption and desorption performance as a hydrogen storage material than the traditional LaNi₅A hydrogen storage alloy of type; because the composition does not contain magnesium element, the rare earth-magnesium-nickel alloy is similar to the traditional rare earth-magnesium-nickel alloy A₅B₁₉Compared with the hydrogen storage alloy, the manufacturing method is simple and safe. The alloy of the invention has good activation performance, rate discharge capability and stability of charge-discharge or hydrogen absorption-discharge circulation, can be used in a wider temperature range, and has small self-discharge.

Description

Yttrium-nickel rare earth hydrogen storage alloy

The invention relates to a divisional application of Chinese patent application 201410429187.7, the application date of the original application is 2014, 8 and 28, and the invention name is yttrium-nickel rare earth hydrogen storage alloy.

Technical Field

The invention relates to a₅B₁₉Rare earth-yttrium-nickel hydrogen storage alloy.

Background

Hydrogen storage alloys are functional materials with high hydrogen storage density found in the last 60 years of the last century, and existing hydrogen storage alloys can be roughly classified into six types from the composition: rare earth system AB₅Of the type LaNi₅(ii) a Magnesium being, e.g. Mg₂Ni、MgNi、La₂Mg₁₇(ii) a Rare earth-magnesium-nickel series AB_3-4Type as La₂MgNi₉,La₅Mg₂Ni₂₃,La₃MgNi₁₄(ii) a Titanium system AB type such as TiNi, TiFe; zirconium and titanium series Laves phase AB₂Type ZrNi₂(ii) a Vanadium-based solid solution type such as (V)_0.9Ti_0.1)_1-xFe_x。

The widely used hydrogen storage material at present is LaNi₅A hydrogen storage alloy. The alloy is mainly used as a negative electrode material of a metal hydride-nickel secondary battery (MH/Ni), and the theoretical electrochemical capacity of the alloy is 373 mAh.g^–1Practical commercial negative electrode material Mm (NiCoMnAl)₅(Mm is a misch metal) has a maximum capacity of about 350mAh g^–1. Research on magnesium-based alloys has been hot in order to develop hydrogen storage alloys having better electrochemical properties or greater hydrogen storage capacity. The magnesium-based hydrogen storage alloy material has high theoretical electrochemical capacity, in particular to the rare earth-magnesium-nickel AB series₃Type A₂B₇Type A₅B₁₉Research on hydrogen occluding alloys of the type has made an important progress and has entered the industrial application stage. Zirconium, titanium, and vanadium based hydrogen storage materials have not been widely used because of the difficulty of activation, high cost, and the like.

CN101210294A discloses a₅B₁₉A type alloy having a composition corresponding to the general formula X_5-aY_aZ_bWherein X is one or more of rare earth metals, Y is one or more of alkaline earth metals, and Z is Mn, Al, V, Fe, Si, Mn, Al, V, Y,One or more of Sn, Ni, Co, Cr, Cu, Mo, Zn and B, a is more than 0 and less than or equal to 2, and B is more than or equal to 17.5 and less than or equal to 22.5. CN102195041A discloses a hydrogen storage alloy for alkaline storage batteries, the composition formula is La_xRe_yMg_1-x-yNi_n-m-vAl_mT_vWherein Re is at least one element selected from rare earth elements (except La) including Y, and T is at least one element selected from Co, Mn and Zn; x is more than or equal to 0.17 and less than or equal to 0.64, n is more than or equal to 3.5 and less than or equal to 3.8, m is more than or equal to 0.06 and less than or equal to 0.22, and v is more than or equal to 0, the crystal structure of the main phase is A₅B₁₉And (4) a mold structure. CN101238231A discloses a hydrogen storage alloy with a general formula A_(4-w)B_(1+w)C₁₉Represented by containing Pr₅Co₁₉A phase of a crystal structure of a type in which A is 1 or 2 or more elements selected from rare earth elements including Y (yttrium), B is Mg, C is 1 or 2 or more elements selected from Ni, Co, Mn and Al, and w represents a number in the range of-0.1 to 0.8; and, the composition of the alloy as a whole is represented by the general formula: r1_xR2_yR3_zWherein 15.8. ltoreq. x.ltoreq.17.8, 3.4. ltoreq. y.ltoreq.5.0, 78.8. ltoreq. z.ltoreq.79.6, x + Y + z 100, R1 is 1 or 2 or more elements selected from rare earth elements including Y (yttrium), R2 is Mg, R3 is 1 or 2 or more elements selected from Ni, Co, Mn and Al, and z represents that Mn + Al is 0.5 or more and Al is 4.1 or less. The alloy composition of the above patent necessarily contains an alkaline earth metal or magnesium element. Because the steam pressure of the active metal element magnesium is high, the manufacturing difficulty is increased, the alloy components are difficult to control, and meanwhile, the volatilized superfine magnesium powder is flammable and explosive and has potential safety hazards.

Disclosure of Invention

The invention aims to provide a rare earth hydrogen storage alloy without Mg element to overcome the defects in the prior art.

The invention relates to a compound of general formula RE_xY_yNi_z-a-bMn_aAl_bThe novel rare earth hydrogen storage alloy of (1), wherein RE is one or more elements selected from La, Ce, Pr, Nd, Sm and Gd, x is more than 0, y is more than or equal to 0.5, and x + y is 3; z is more than or equal to 12.5 and more than or equal to 11 (when z is 11.4, the stoichiometric ratio A is₅B₁₉Molding; when z ≠ 11.4, it is non-activatedStoichiometric ratio A₅B₁₉Type); 5.5 is more than or equal to a + b and more than 0.

Further, the preferable content range of RE element is 0.5-2.0;

further, the preferable content range of the Mn element is 0.5-3.0;

further, the preferable content range of the Al element is 0.3-1.5;

the alloy can be prepared by adopting a high-temperature smelting-rapid quenching method, and the technological process comprises the following steps: the purity of each simple substance metal or intermediate alloy raw material in the composition is uniform>99.0 percent, calculating and accurately weighing each raw material according to the chemical molecular formula ratio, and sequentially adding the raw materials into Al₂O₃The crucible is vacuumized to 3.0Pa, and inert gas Ar is filled to 0.055 MPa. Heating and smelting, and quickly solidifying after heat preservation for about 6 min. The linear speed of the rapid-hardening copper roller is 3.4 m/s. The copper roller is always filled with cooling water, and the temperature of the cooling water is 25 ℃. The proportion of easily burnt raw materials needs to be increased in a proper amount, and the increase ratio is as follows:

raw materials	RE	Y	Mn	Al
					Increase the ratio	2％	1％	5％	3％

In addition to the above preparation methods, the RE of the present invention_xY_yNi_z-a-bMn_aAl_bThe hydrogen storage alloy may also be prepared using other hydrogen storage alloy preparation methods known in the art, such as: high-temperature melting casting method, Mechanical Alloying (MA) method, powder sintering method, high-temperature melting-gas atomization method, reduction diffusion method, displacement diffusion method, Combustion Synthesis (CS) method, self-propagating high-temperature synthesis (SHS) method, and the like.

The invention also provides a method for preparing the RE_xY_yNi_z-a-bMn_aAl_bThe secondary battery is prepared from the hydrogen storage alloy.

RE described in the present invention_xY_yNi_z-a-bMn_aAl_bThe hydrogen storage alloy can also be compounded with other hydrogen storage materials according to different proportions to prepare a new hydrogen storage material.

RE described in the present invention_xY_yNi_z-a-bMn_aAl_bThe hydrogen storage alloy can be improved in the structure and properties by heat treatment, such as: eliminating alloy structural stress and component segregation, improving alloy hydrogen absorption/desorption platform characteristics or alloy electrode charge/discharge platform characteristics, improving hydrogen absorption amount, prolonging cycle life and the like; various surface treatments may also be used to improve their properties, such as: improve the hydrogen absorption/desorption or charge/discharge kinetic performance of the alloy, enhance the oxidation resistance of the alloy, improve the electric conduction and heat conduction performance of the alloy and the like.

A in the invention₅B₁₉Type RE_xY_yNi_z-a-bMn_aAl_bThe hydrogen storage alloy has good pressure-composition-isothermality (P-c-T) characteristics, and the maximum hydrogen storage capacity can reach 1.33 wt.% or more under normal conditions. The alloy of the invention has better electrochemical performance as a hydrogen storage electrode and gas-phase hydrogen absorption and desorption performance as a hydrogen storage material than the traditional LaNi₅A hydrogen storage alloy of type; because the composition does not contain magnesium element, the rare earth-magnesium-nickel alloy is similar to the traditional rare earth-magnesium-nickel alloy A₅B₁₉Compared with the hydrogen storage alloy, the manufacturing method is simple and safe. The alloy of the invention has good activation performance and rate discharge energyThe stability of force, charge and discharge or hydrogen absorption and discharge cycle can be used in a wider temperature range, and the self-discharge is small. In addition, the yttrium (Y) element in the hydrogen storage alloy is one of the main components, the yttrium resource in rare earth mineral reserves of China is rich, and the use of the element is favorable for balancing the comprehensive utilization of the rare earth resources of China.

Drawings

LaY in FIG. 1₂Ni_10.6Mn_0.5Al_0.3XRD pattern of hydrogen occluding alloy

LaY in FIG. 2₂Ni_10.6Mn_0.5Al_0.3P-c-T curve of hydrogen storage alloy

Detailed Description

The preparation method is adopted to prepare the A described in the embodiments 1-6 and 9-22₅B₁₉Type RE_xY_yNi_z-a-bMn_aAl_bA hydrogen storage alloy.

The alloys described in examples 13 and 14 were prepared using the same raw material ratios. The alloy of example 13 is prepared by the high temperature melting-rapid quenching method, and the process comprises: the purity of each simple substance metal or intermediate alloy raw material in the composition is uniform>99.0 percent, calculating and accurately weighing each raw material according to the chemical formula ratio (the raw material easy to burn needs to be increased by a proper amount), and sequentially adding the raw materials into Al₂O₃The crucible is vacuumized to 3.0Pa, and inert gas Ar is filled to 0.055 MPa. Heating and smelting, and quickly solidifying after heat preservation for about 6 min. The linear speed of the rapid-hardening copper roller is 3.4 m/s. The copper roller is always filled with cooling water, and the temperature of the cooling water is 25 ℃.

The alloy in example 14 can also be prepared by a high-temperature melting-rapid quenching method, and an annealing heat treatment step is added in the process, specifically: the purity of each simple substance metal or intermediate alloy raw material in the composition is uniform>99.0 percent, calculating and accurately weighing each raw material according to the chemical formula ratio (the raw material easy to burn needs to be increased by a proper amount), and sequentially adding the raw materials into Al₂O₃The crucible is vacuumized to 3.0Pa, and inert gas Ar is filled to 0.055 MPa. Heating and smelting, and quickly solidifying after heat preservation for about 6 min. The linear speed of the rapid-hardening copper roller is 3.4 m/s. The copper roller is always filled with cooling water, and the temperature of the cooling water is 25 ℃. In vacuum or inert atmosphereAnd (4) annealing and heat treating for 8h at 750 ℃ under the protection of the gas.

The Ml in example 20 is a lanthanum rich mischmetal containing about 64% La, about 25% Ce, about 3% Pr, and about 8% Nd.

The preparation method of the test electrode comprises the following steps: the alloys of examples 1 to 6 and 9 to 22 were mechanically crushed into 200-mesh 300-mesh powders, and the alloy powders and the nickel carbonyl powders were mixed at a mass ratio of 1: 4 and prepared under a pressure of 16MPa

The electrode sheet is placed between two pieces of nickel foam, a nickel strip serving as a tab is clamped at the same time, a hydrogen storage negative electrode (MH electrode) for testing is manufactured under the pressure of 16MPa again, and the electrode sheet and a nickel net are in close contact through spot welding at the periphery of the electrode sheet.

In an open type two-electrode system for testing electrochemical performance, a negative electrode is an MH electrode, and a positive electrode adopts sintered Ni (OH) with excessive capacity₂A NiOOH electrode with 6 mol.L electrolyte^–1KOH solution, the assembled battery is placed for 24 hours, a LAND battery tester is used for measuring the electrochemical properties (activation times, maximum capacity, high-rate discharge capacity HRD, circulation stability and the like) of the alloy electrode by a constant current method, and the test environment temperature is 298K. Charging current density 70mA g^–1Charging time 6h, discharge current density 70mA g^–1The discharge cut-off potential is 1.0V, and the charge and discharge pause time is 10 min.

The following table lists A for examples 1-6, 9-22₅B₁₉Type RE_xY_yNi_z-a-bMn_aAl_bHydrogen storage alloys and their electrochemical properties.

TABLE 1A₅B₁₉Type RE_xY_yNi_z-a-bMn_aAl_bHydrogen storage alloy and electrochemical properties thereof

Note: a is the number of cycles required for electrode activation; b is the maximum discharge capacity; c is the capacity retention for 100 cycles; d is discharge current density I_dIs 350mA · g^–1Rate discharge capability; e is the discharge capacity retention at low temperature 243K; f is the capacity retention (self-discharge characteristic) after 72 hours of storage.

As can be seen from Table 1, the alloy LaY of examples 13 and 14₂Ni_9.9MnAl_0.5Compared with the electrochemical performance of the alloy electrode in the example 14 after annealing heat treatment, the electrochemical capacity of the alloy electrode is improved, and the cycle life, the rate discharge capability, the low-temperature discharge characteristic and the self-discharge performance are all improved.

FIG. 1 shows analysis LaY using an X-ray diffractometer₂Ni_10.6Mn_0.5Al_0.3Structure of alloy (example 2) containing YNi₃Phase, Y₂Ni₇Phase or LaY₂Ni₉Phase, LaNi₅Phase, Pr₅Co₁₉Phase or Ce₅Co₁₉Are equal.

FIG. 2 shows LaY measured at 313K using the Sievert's method₂Ni_10.6Mn_0.5Al_0.3Pressure-composition isotherms (P-c-T curves) for the alloys (example 2). As can be seen from the figure, the maximum hydrogen storage capacity of the alloy can reach 1.33 wt.%, and the pressure of a hydrogen discharge platform is about 0.1 MPa.

Claims

1. A method for preparing rare earth hydrogen storage alloy is characterized in that: the general formula of the rare earth hydrogen storage alloy is RE_xY_yNi_z-a-bMn_aAl_bWherein RE is one or more elements of La, Ce, Pr, Nd, Sm and Gd; x is more than or equal to 1 and more than or equal to 0.5, y>1.5，x+y＝3；12.5≥z≥11；5.5≥a+b＞0；

The preparation method comprises calculating and accurately weighing each simple substance metal raw material according to the chemical molecular formula ratio, wherein the purity of the raw material is more than 99.0%, and adding Al into the raw material₂O₃Vacuumizing a crucible to 3.0Pa, filling inert gas Ar to 0.055MPa, heating and smelting, keeping the temperature for 6min, and then quickly solidifying, wherein the linear speed of a quickly solidified copper roller is 3.4m/s, the copper roller is always filled with cooling water, the temperature of the cooling water is 25 ℃, and annealing heat treatment is carried out at 750 ℃ after the quick solidifying step is finished.

2. The method for producing a rare-earth hydrogen storage alloy according to claim 1, wherein: a is more than or equal to 3.0 and more than or equal to 0.5.

3. The method for producing a rare-earth-based hydrogen storage alloy according to claim 1 or 2, wherein: b is more than or equal to 1.5 and more than or equal to 0.3.

4. The method for producing a rare-earth-based hydrogen storage alloy according to claim 1 or 2, wherein: and z is 11.4.

5. The method for producing a rare-earth hydrogen storage alloy according to claim 1, wherein: y is more than or equal to 2, a is more than or equal to 3.0 and more than or equal to 0.5, b is more than or equal to 1.5 and more than or equal to 0.3, and z is more than or equal to 11.4.

6. The method for producing a rare-earth hydrogen storage alloy according to claim 1, wherein: after the rapid hardening step is finished, the alloy is annealed and heat-treated for 8 hours at 750 ℃ under the protection of vacuum or inert gas.

7. A rare earth-based hydrogen storage alloy characterized by: obtained by the preparation process according to any one of claims 1 to 6.

8. The rare earth-based hydrogen storage alloy according to claim 7, wherein: it comprises YNi₃Phase, Y₂Ni₇Phase or LaY₂Ni₉Phase, LaNi₅Phase, Pr₅Co₁₉Phase or Ce₅Co₁₉And (4) phase(s).

9. The rare earth-based hydrogen storage alloy according to claim 7, wherein: the maximum hydrogen storage amount reaches 1.33 wt.%, and the pressure of the hydrogen discharging platform is 0.1 MPa.

10. A hydrogen storage alloy electrode, characterized in that: the rare earth-based hydrogen storage alloy according to any one of claims 7 to 9 as a hydrogen storage medium.

11. A secondary battery, characterized in that: comprising the hydrogen occluding alloy electrode as recited in claim 10.