Nano nickel molybdate as well as preparation method and application thereof

Abstract

The invention discloses nano nickel molybdate and a preparation method and application thereof, and belongs to the technical field of capacitor materials. The preparation method of the nano nickel molybdate comprises the following steps: mixing a molybdenum source and a nickel source according to a molar ratio of Mo to Ni of 3: 8 to 9: 8 to obtain a mixture; wherein the molybdenum source is nano molybdenum oxide, and the nickel source comprises at least one of nickel oxide and nickel carbonate; the mixture is preheated for 60 min to 80 min under the condition that the temperature ranges from 150 DEG C to 180 DEG C; and the preheated mixture is subjected to a reaction for 100 min to 150 min under the condition of 450 DEG C to 490 DEG C, and the nano nickel molybdate is obtained. The preparation method is simple in process, convenient to operate, capable of achieving large-scale production and high in practicability. The nanometer nickel molybdate obtained by the method is in a nanometer level, and a super capacitor with high energy density can be further prepared.

Description

Technical Field

[0001] The present invention relates to the technical field of capacitor materials, and in particular to nano nickel molybdate and a preparation method and application thereof. Background Art

[0002] Nickel molybdate is an inorganic compound with the chemical formula NiMoO 4 .

[0003] Currently, the preparation of nickel molybdate is usually carried out by hydrothermal reaction under high temperature and high pressure conditions, which has high requirements on equipment, long reaction time, low production efficiency, limited output each time, and is difficult to mass produce.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The purpose of the present invention is to provide a nano nickel molybdate and a preparation method and application thereof, so as to solve or improve the above technical problems.

[0006] The present invention can be implemented like this:

[0007] In a first aspect, the present invention provides a method for preparing nano nickel molybdate, comprising the following steps:

[0008] Mixing a molybdenum source and a nickel source in a molar ratio of Mo to Ni of 3:8 to 9:8 to obtain a mixture; wherein the molybdenum source is nano molybdenum oxide, and the nickel source includes at least one of nickel oxide and nickel carbonate;

[0009] Preheat the mixture at 150°C to 180°C for 60min to 80min;

[0010] The preheated mixture is reacted at 450° C. to 490° C. for 100 min to 150 min to obtain nano nickel molybdate.

[0011] In an alternative embodiment, the molybdenum source and the nickel source are mixed in a molar ratio of Mo to Ni of 9:8.

[0012] In an optional embodiment, the particle size of the nano-molybdenum oxide is 30nm to 100nm.

[0013] In an optional embodiment, the preheating temperature is 150° C. and the preset time is 1 hour.

[0014] In an optional embodiment, the reaction temperature is 450° C. and the reaction time is 2 h.

[0015] In an optional embodiment, after preheating, the temperature is increased to 450° C. to 490° C. at a heating rate of 1° C. / min to 3° C. / min.

[0016] In a second aspect, the present invention provides a nano nickel molybdate, which is prepared by the preparation method of any one of the aforementioned embodiments.

[0017] In a third aspect, the present invention provides a positive electrode plate, the active material of which includes the nano nickel molybdate as described in the above embodiment.

[0018] In a fourth aspect, the present invention provides a supercapacitor, which includes the positive electrode plate of the aforementioned embodiment.

[0019] In an optional embodiment, the supercapacitor is an asymmetric supercapacitor, and the energy density of the asymmetric supercapacitor is not less than 112Wh / Kg.

[0020] In an optional embodiment, the energy density of the asymmetric supercapacitor is 112Wh / Kg to 127Wh / Kg.

[0021] The beneficial effects of the present invention include:

[0022] The preparation method of nano nickel molybdate provided by the present invention has simple process, easy operation, easily controllable conditions, low requirements on reaction equipment, short reaction time, high production efficiency, high single batch output, large-scale production, and strong practicality. The nano nickel molybdate obtained by the method is nanometer-level and has high capacitance, and can be further used to prepare supercapacitors with high energy density. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 This is a SEM image of the nano nickel molybdate prepared in Example 1;

[0025] Figure 2 This is the XRD pattern of nano nickel molybdate prepared in Example 1. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0027] The nano nickel molybdate and its preparation method and application provided by the present invention are specifically described below.

[0028] The present invention provides a method for preparing nano nickel molybdate, which comprises the following steps:

[0029] S1: mixing a molybdenum source and a nickel source in a molar ratio of Mo to Ni of 3:8 to 9:8 to obtain a mixture; wherein the molybdenum source is nano molybdenum oxide, and the nickel source includes at least one of nickel oxide and nickel carbonate;

[0030] S2: preheating the mixture at 150°C to 180°C for 60min to 80min;

[0031] S3: reacting the preheated mixture at 450° C. to 490° C. for 100 min to 150 min to obtain nano nickel molybdate.

[0032] In the above step S1, the molar ratio of Mo in the molybdenum source to Ni in the nickel source can be 3:8, 4:8, 5:8, 6:8, 7:8:8:8 or 9:8, etc., or other values ​​within the range of 3:8 to 9:8.

[0033] In some typical embodiments, the molybdenum source and the nickel source are mixed in a molar ratio of Mo to Ni of 9:8.

[0034] The particle size of the nano-molybdenum oxide used as the molybdenum source may be 30 nm to 100 nm, such as 30 nm, 50 nm, 80 nm or 100 nm.

[0035] In the above step S2, the preheating temperature can be 150°C, 155°C, 160°C, 165°C, 170°C, 175°C or 180°C, etc., or any other value within the range of 150°C to 180°C.

[0036] The preheating time may be 60 min, 65 min, 70 min, 75 min or 80 min, etc., or may be other values ​​within the range of 60 min to 80 min.

[0037] If the preheating temperature is too low, the reaction energy will be insufficient and the reaction will be difficult to proceed; if the preheating temperature is too high, it will easily cause the crystals to grow prematurely, which is not conducive to the later preparation. In addition, the above preheating treatment can also remove moisture from the raw materials and purify the materials.

[0038] In some typical implementations, the preheating temperature is 150° C. and the preset time is 1 hour.

[0039] In the above step S3, the reaction time can be 450°C, 455°C, 460°C, 465°C, 470°C, 475°C, 480°C, 485°C or 490°C, etc., or any other value within the range of 450°C to 490°C.

[0040] The reaction time can be 100 min, 105 min, 110 min, 115 min, 120 min, 125 min, 130 min, 135 min, 140 min, 145 min or 150 min, etc., or other values ​​within the range of 100 min to 150 min.

[0041] If the reaction temperature is too low, the reaction will not be complete and the yield will be low. On the other hand, the reaction time will be significantly prolonged, reducing the preparation efficiency. If the reaction temperature is too high, the grains of the reactants and products will grow rapidly, making it difficult to obtain nano-scale nickel molybdate materials.

[0042] In some typical embodiments, the reaction temperature is 450° C. and the reaction time is 2 h.

[0043] In some optional embodiments, after preheating, the temperature can be raised to the reaction temperature at a heating rate of 1°C / min to 3°C / min. The heating rate can be 1°C / min, 1.5°C / min, 2°C / min, 2.5°C / min or 3°C / min, or any other value within the range of 1°C / min to 3°C / min.

[0044] If the heating rate after preheating is slow, the production process will take a long time and the work efficiency will be low; if the heating rate after preheating is fast, it will be unfavorable to remove moisture from the raw materials and fully preheat the raw materials.

[0045] It should be noted that the nickel molybdate currently used to prepare supercapacitors is mostly prepared by hydrothermal method, and the molar ratio of molybdenum raw material to nickel raw material is basically maintained at 1:1, and the reaction process needs to be carried out under high temperature and high pressure conditions, which has high requirements for equipment, long reaction time, and low production efficiency. For example, the reaction is carried out for 48 hours at 180°C plus ten atmospheres. The preparation method of nickel molybdate provided by the present invention, taking the preferred scheme as an example, is to preheat the molybdenum source and the nickel source at a molar ratio of Mo to Ni of 9:8 at 150°C for 1h, and then increase the temperature to 450°C at a heating rate of 1°C / min to 3°C / min for 2h to obtain nano-level nickel molybdate. The whole process is simple, easy to operate, easy to control, low requirements for reaction equipment, short reaction time, high production efficiency, and about 50 kg of nano-nickel molybdate products can be prepared each time.

[0046] Correspondingly, the present invention also provides a nano nickel molybdate, which is prepared by the above preparation method.

[0047] In addition, the present invention also provides a positive electrode plate, the active material of which includes the above-mentioned nano nickel molybdate.

[0048] In addition, the present invention also provides a supercapacitor, which includes the above-mentioned positive electrode plate.

[0049] The supercapacitor may be a symmetrical supercapacitor or an asymmetrical supercapacitor.

[0050] In some embodiments, taking an asymmetric supercapacitor as an example, the preparation process of the supercapacitor includes: cleaning the nickel foam substrate (such as cleaning with dilute hydrochloric acid, acetone, and anhydrous ethanol in sequence), and drying it for standby use. Nickel molybdate, polytetrafluoroethylene and acetylene black are mixed evenly, and then methyl pyrrolidone is added, and the positive electrode active layer material is prepared after sufficient mixing, and then the mixed active layer material is applied to the cleaned nickel foam substrate, and after vacuum drying at 80°C, the positive electrode coated with the active material is obtained. After the positive electrode coated with the active material is placed in a clean battery shell, KOH solution is added to fully wet the electrode. After the ion exchange membrane is covered on the nickel foam electrode coated with the active material, the nickel foam electrode coated with commercial activated carbon is placed opposite to the electrode coated with the active substance below, and the electrolyte is dripped into the activated carbon electrode to fully and fully wet the activated carbon electrode, and the capacitor is assembled.

[0051] The energy density of the asymmetric supercapacitor is not less than 120Wh / Kg. In some preferred embodiments, the energy density of the asymmetric supercapacitor is 120Wh / Kg to 127Wh / Kg.

[0052] This shows that the nano nickel molybdate obtained by the method provided by the present invention can be further prepared into an asymmetric supercapacitor with high energy density and excellent performance.

[0053] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0054] Example 1

[0055] This embodiment provides a nano nickel molybdate, which is prepared by the following method:

[0056] S1: mixing a molybdenum source and a nickel source at a molar ratio of Mo to Ni of 9:8 to obtain a mixture; wherein the molybdenum source is nano-molybdenum oxide with a particle size of 50nm to 80nm, and the nickel source is nickel carbonate.

[0057] S2: preheat the mixture at 150°C for 1 h;

[0058] S3: heating the mixture to 450° C. at a heating rate of 2° C. / min, so that the preheated mixture is reacted at 450° C. for 2 h to obtain nano nickel molybdate.

[0059] Example 2

[0060] This embodiment provides a nano nickel molybdate, which is prepared by the following method:

[0061] S1: mixing a molybdenum source and a nickel source at a molar ratio of Mo to Ni of 3:8 to obtain a mixture; wherein the molybdenum source is nano molybdenum oxide with a particle size of 30nm to 80nm, and the nickel source is nickel carbonate powder.

[0062] S2: preheat the mixture at 150°C for 80 min;

[0063] S3: heating the mixture to 470° C. at a heating rate of 1° C. / min, so that the preheated mixture is reacted at 470° C. for 150 min to obtain nano nickel molybdate.

[0064] Example 3

[0065] This embodiment provides a nano nickel molybdate, which is prepared by the following method:

[0066] S1: mixing a molybdenum source and a nickel source at a molar ratio of Mo to Ni of 8:8 to obtain a mixture; wherein the molybdenum source is nano molybdenum oxide with a particle size of 80nm to 100nm, and the nickel source is nickel oxide powder.

[0067] S2: preheat the mixture at 180°C for 70 min;

[0068] S3: heating the mixture to 490° C. at a heating rate of 3° C. / min, so that the preheated mixture is reacted at 490° C. for 100 min to obtain nano nickel molybdate.

[0069] Example 4

[0070] This embodiment provides a nano nickel molybdate, which is prepared by the following method:

[0071] S1: Mix a molybdenum source and a nickel source in a molar ratio of Mo to Ni of 4:8 to obtain a mixture; wherein the molybdenum source and the nickel source are the same as those in Example 1.

[0072] S2: preheat the mixture at 160°C for 75 min;

[0073] S3: heating the mixture to 460° C. at a heating rate of 1.5° C. / min, so that the preheated mixture reacts at 460° C. for 150 min to obtain nano nickel molybdate.

[0074] Example 5

[0075] This embodiment provides a nano nickel molybdate, which is prepared by the following method:

[0076] S1: Mix a molybdenum source and a nickel source in a molar ratio of Mo to Ni of 5:8 to obtain a mixture; wherein the molybdenum source and the nickel source are the same as those in Example 1.

[0077] S2: preheat the mixture at 170°C for 70 min;

[0078] S3: heating the mixture to 470° C. at a heating rate of 2.5° C. / min, so that the preheated mixture reacts at 470° C. for 140 min to obtain nano nickel molybdate.

[0079] Example 6

[0080] This embodiment provides a nano nickel molybdate, which is prepared by the following method:

[0081] S1: Mix a molybdenum source and a nickel source in a molar ratio of Mo to Ni of 6:8 to obtain a mixture; wherein the molybdenum source and the nickel source are the same as those in Example 1.

[0082] S2: preheat the mixture at 155°C for 65 min;

[0083] S3: heating the mixture to 480° C. at a heating rate of 3° C. / min, so that the preheated mixture is reacted at 480° C. for 130 min to obtain nano nickel molybdate.

[0084] Example 7

[0085] This embodiment provides a nano nickel molybdate, which is prepared by the following method:

[0086] S1: Mix a molybdenum source and a nickel source in a molar ratio of Mo to Ni of 7:8 to obtain a mixture; wherein the molybdenum source and the nickel source are the same as those in Example 1.

[0087] S2: preheat the mixture at 165°C for 60 min;

[0088] S3: heating the mixture to 490° C. at a heating rate of 3° C. / min, so that the preheated mixture is reacted at 490° C. for 110 min to obtain nano nickel molybdate.

[0089] Example 8

[0090] This embodiment provides a nano nickel molybdate, which is prepared by the following method:

[0091] S1: Mix a molybdenum source and a nickel source in a molar ratio of Mo to Ni of 9:8 to obtain a mixture; wherein the molybdenum source and the nickel source are the same as those in Example 1.

[0092] S2: preheat the mixture at 175°C for 60 min;

[0093] S3: heating the mixture to 460° C. at a heating rate of 3° C. / min, so that the preheated mixture is reacted at 460° C. for 120 min to obtain nano nickel molybdate.

[0094] Comparative Example 1

[0095] The difference between this comparative example and Example 1 is that the preheating step of S2 is not performed, and the mixture is directly heated to 450° C. for reaction.

[0096] Comparative Example 2

[0097] The difference between this comparative example and Example 1 is that the preheating temperature is 100°C.

[0098] Comparative Example 3

[0099] The difference between this comparative example and Example 1 is that the preheating temperature is 200°C.

[0100] Comparative Example 4

[0101] The difference between this comparative example and Example 1 is that the reaction temperature is 420°C.

[0102] Comparative Example 5

[0103] The difference between this comparative example and Example 1 is that the reaction temperature is 520°C.

[0104] Comparative Example 6

[0105] The difference between this comparative example and Example 1 is that the heating rate is 1° C. / min.

[0106] Comparative Example 7

[0107] The difference between this comparative example and Example 1 is that the heating rate is 5° C. / min.

[0108] Test example

[0109] ①, taking the nano nickel molybdate prepared in Example 1 as an example, its structure was characterized, and its SEM and XRD patterns were as follows: Figure 1 and Figure 2 shown.

[0110] Depend on Figure 1 It can be seen that the nickel molybdate material is a cluster of nanoparticles.

[0111] Depend on Figure 2It can be seen that compared with the XRD pattern of standard nickel molybdate (JCPDS 45-0142), the product prepared in this embodiment is β-phase nickel molybdate, containing a small amount of MoO 3 .

[0112] ②. Taking the nickel molybdate materials prepared in Examples 1 to 8 and Comparative Examples 1 to 7 as examples, each nickel molybdate material was prepared into a supercapacitor according to the following method, and the energy density of each supercapacitor was tested. The results are shown in Table 1.

[0113] The preparation method is as follows: the nickel foam substrate is cleaned with dilute hydrochloric acid, acetone and anhydrous ethanol in turn, and then dried for use. Nickel molybdate, polytetrafluoroethylene and acetylene black are mixed evenly, and then methyl pyrrolidone is added, and the positive electrode active layer material is prepared after sufficient mixing, and then the mixed active layer material is coated on the clean nickel foam substrate, and after vacuum drying at 80°C for 6 to 8 hours, the positive electrode coated with the active material is obtained. After the positive electrode coated with the active material is placed in a clean battery shell, KOH solution is added to fully wet the electrode. After the ion exchange membrane is covered on the nickel foam electrode coated with the active material, the nickel foam electrode coated with commercial activated carbon is placed opposite to the electrode coated with the active material below, and the electrolyte is dripped into the activated carbon electrode to fully and fully wet the activated carbon electrode, and the capacitor is assembled.

[0114] Table 1 Test results

[0115] Energy density (Wh / Kg) Example 1 127 Example 2 123 Example 3 122 Example 4 121 Example 5 125 Example 6 121 Example 7 120 Example 8 120 Comparative Example 1 91 Comparative Example 2 83 Comparative Example 3 109 Comparative Example 4 80 Comparative Example 5 72 Comparative Example 6 115 Comparative Example 7 107

[0116] It can be seen from Table 1 that the nano nickel molybdate provided in the embodiment of the present invention can be used to prepare a supercapacitor with a higher energy density than the nickel molybdate provided in the comparative example.

[0117] In summary, the preparation method of nano nickel molybdate provided by the present invention has simple process, easy operation, easy controllable conditions, low requirements on reaction equipment, short reaction time, high production efficiency, and can prepare about 50 kilograms of nano nickel molybdate products each time, which can be mass-produced and has strong practicality. The nano nickel molybdate obtained by the method is nano-level and has a high capacitance, and can be further used to prepare supercapacitors with a high energy density.

[0118] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing nano nickel molybdate, characterized in that: The following steps are involved: A molybdenum source and a nickel source are mixed in a ratio of Mo to Ni of 3:8 to 9:8 to obtain a mixture; wherein the molybdenum source is nano molybdenum oxide, and the nickel source includes at least one of nickel oxide and nickel carbonate; Preheating the mixture at 150°C to 180°C for 60min to 80min; The preheated mixture is reacted at 450° C. to 490° C. for 100 min to 150 min to obtain nano nickel molybdate.

2. The preparation method according to claim 1, characterized in that: The molybdenum source and the nickel source are mixed at a molar ratio of Mo to Ni of 9:

8.

3. The preparation method according to claim 1, characterized in that: The particle size of the nano molybdenum oxide is 30nm-100nm.

4. The preparation method according to claim 1, characterized in that: The preheating temperature is 150℃ and the preset time is 1h.

5. The preparation method according to claim 1, characterized in that: The reaction temperature is 450°C and the reaction time is 2h.

6. The preparation method according to claim 1, characterized in that: After preheating, the temperature is increased to 450°C to 490°C at a heating rate of 1°C / min to 3°C / min.

7. A nano nickel molybdate, characterized in that: The nano nickel molybdate is prepared by the preparation method described in any one of claims 1 to 6.

8. A positive electrode sheet, characterized in that: The active material of the positive electrode plate includes the nano nickel molybdate described in claim 7.

9. A supercapacitor, characterized in that: The supercapacitor comprises the positive electrode sheet according to claim 8.

10. The supercapacitor according to claim 9, characterized in that: The supercapacitor is an asymmetric supercapacitor, and the energy density of the asymmetric supercapacitor is not less than 120Wh / Kg; preferably, the energy density of the asymmetric supercapacitor is 120Wh / Kg to 127Wh / Kg.

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