Metal ion-doped dimanganese trioxide, method of preparation and use thereof

Abstract

The application discloses a kind of metal ion doped dimanganese trioxide, preparation method and application thereof, manganese salt and metal nitrate are dissolved in glycerol and isopropyl alcohol, the ratio of manganese salt, metal nitrate and glycerol is (0.5-2) mmol: (0.1-0.5) mmol: (4-8) mL, to obtain mixed solution;The mixed solution is kept at 160-200 DEG C, and then the precipitate in the obtained reaction liquid is separated and then washed, dried, to obtain metal ion doped manganese glycerate;Metal ion doped manganese glycerate is calcined at 700-800 DEG C in oxygen atmosphere, to obtain metal ion doped dimanganese trioxide, by metal ion doping, adjust the electronic structure of dimanganese trioxide, improve the conductivity and optimize the ion transmission characteristics, to realize higher specific capacity, longer cycle life and better charge-discharge performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of preparation of positive electrode materials of secondary batteries, and particularly relates to a metal ion doped dimanganese trioxide, a preparation method and application thereof. BACKGROUND

[0002] Secondary batteries, as a kind of rechargeable batteries, play a vital role in current life. With the wide application of electric vehicles, wearable devices and mobile communications, higher requirements are put forward for the performance and energy density of secondary batteries. In order to improve the performance of secondary batteries, technicians are constantly seeking new materials and application methods.

[0003] Manganese oxides are widely used in secondary batteries, among which dimanganese trioxide (Mn2O3) is a common positive electrode material. However, Mn2O3 itself has some inherent defects, which limit its large-scale application in industrial production.

[0004] Firstly, Mn2O3 has a low ionic conductivity, which will cause an increase in internal resistance of the secondary battery, thereby limiting the discharge performance of the secondary battery. This characteristic can make the secondary battery perform poorly under high discharge current, affecting its feasibility in high-power applications. Secondly, the material will undergo volume expansion and shrinkage during the charging and discharging process, resulting in a decrease in cycle stability of the secondary battery, thereby shortening the service life of the battery. SUMMARY

[0005] In view of the problems in the prior art, the application provides a metal ion doped dimanganese trioxide, a preparation method and application thereof. By doping metal ions, the electronic structure of dimanganese trioxide is adjusted, the conductivity is improved, and the ion transmission characteristics are optimized, so as to realize higher specific capacity, longer cycle life and better charging and discharging performance.

[0006] The application is achieved by the following technical solutions:

[0007] A preparation method of a metal ion doped dimanganese trioxide, comprising the following steps:

[0008] S1, dissolving manganese salt and metal nitrate salt in glycerol and isopropyl alcohol, the ratio of manganese salt, metal nitrate salt and glycerol being (0.5-2) mmol:(0.1-0.5) mmol:(4-8) mL, to obtain a mixed solution;

[0009] S2, carrying out heat preservation treatment on the mixed solution at 160-200℃, then separating the precipitate in the obtained reaction liquid, and sequentially washing and drying to obtain metal ion doped manganese glycerate;

[0010] S3, calcining the manganese glycerate doped with metal ions in an oxygen atmosphere at 700-800℃ to obtain manganese dioxide doped with metal ions.

[0011] Preferably, the volume ratio of glycerol to isopropyl alcohol in S1 is (4-8):(40-60).

[0012] Preferably, S1 disperses glycerol in isopropyl alcohol first, and then adds manganese salt and metal nitrate under stirring at a stirring rate of 500-800 rpm.

[0013] Preferably, the manganese salt in S1 is manganese nitrate, manganese acetate or manganese sulfate, and the metal nitrate is cobalt nitrate, nickel nitrate, iron nitrate, copper nitrate or zinc nitrate.

[0014] Preferably, the mixed solution in S2 is kept at 160-200℃ for 6-12h.

[0015] Preferably, S2 centrifuges the reaction solution first, then collects the precipitate, and then washes the precipitate with water, methanol and ethanol in sequence, and then dries.

[0016] Further, the drying in S2 is performed at 60-80℃ for 10-14h to obtain manganese glycerate doped with metal ions.

[0017] Preferably, S3 heats the manganese glycerate doped with metal ions from room temperature to 700-800℃ at a heating rate of 5-10℃ / min.

[0018] Manganese dioxide doped with metal ions prepared by the preparation method of any one of the above.

[0019] The application of manganese dioxide doped with metal ions in lithium ion battery cathode material, sodium ion battery cathode material, magnesium ion battery cathode material or zinc ion battery cathode material.

[0020] Compared with the prior art, the application has the following beneficial technical effects:

[0021] The application provides a preparation method of metal ion doped manganese sesquioxide, which is prepared by a two-step method. First, manganese glycerate doped with different metal ions is generated by a hydrothermal method, and then the manganese sesquioxide doped with metal ions is obtained by high-temperature calcination in an oxygen atmosphere. The method is simple, controllable and low in cost, and can realize the doping of different metal ions in the manganese sesquioxide. Through metal ion doping, defects are provided in the crystal structure of the manganese sesquioxide, the reversible capacity and the conductivity of the manganese sesquioxide are improved, the internal resistance of the battery is reduced when the manganese sesquioxide is applied to a lithium ion battery positive electrode material, a sodium ion battery positive electrode material, a magnesium ion battery positive electrode material or a zinc ion battery positive electrode material, the cycle stability and the rate performance of the manganese sesquioxide are improved, and the structural stability of the manganese sesquioxide is improved. The introduction of metal ions can stabilize the structure of the manganese sesquioxide, slow down the volume change of the manganese sesquioxide, reduce the mechanical stress of the manganese sesquioxide, and improve the cycle life of the battery. The metal ion doped manganese sesquioxide also has a high specific capacity, and the specific capacity can be further improved by optimizing the doping amount and type of metal ions, so that the energy density of the battery is improved. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is the X-ray diffraction (XRD) pattern of the cobalt ion doped manganese sesquioxide prepared in Example 1 of the application.

[0023] Figure 2 is the scanning electron microscope (SEM) pattern of the cobalt ion doped manganese sesquioxide prepared in Example 1 of the application.

[0024] Figure 3 is the charge-discharge curve of the cobalt ion doped manganese sesquioxide prepared in Example 1 of the application in a zinc ion battery. DETAILED DESCRIPTION

[0025] In order to more clearly illustrate the application, further description will be made through implementation cases. The following examples do not limit the scope of the application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the application shall be included in the protection scope of the application.

[0026] Metal ion doping is an effective way to improve the performance of secondary battery materials. By introducing different metal ions, the conductivity of the material can be effectively improved, thereby improving the electrical conductivity and charge transfer rate of the battery. Secondly, the introduction of metal ions can regulate the crystal structure and electronic band structure of the material, thereby enhancing the cycle stability and structural stability of the material. In addition, metal ion doping also helps to improve the ion storage capacity of the material and improve the energy density of the battery.

[0027] The application provides a preparation method of metal ion doped manganese sesquioxide, which comprises the following steps:

[0028] S1, disperse 4-8 mL of glycerol in 40-60 mL of isopropanol, and add 0.5-2 mmol of manganese salt and 0.1-0.5 mmol of metal nitrate while stirring at 500-800 rpm. The manganese salt can be manganese nitrate, manganese acetate, or manganese sulfate, and the metal nitrate can be cobalt nitrate, nickel nitrate, ferric nitrate, copper nitrate, or zinc nitrate. Then, transfer the resulting mixture to a PTFE-lined stainless steel autoclave and maintain it at 160-200 °C for 6-12 h.

[0029] S2, then the reaction solution was centrifuged, and the precipitate was collected and washed successively with 30-50 mL of water, 30-50 mL of methanol and 30-50 mL of ethanol, and dried at 60-80 °C for 10-14 h to obtain metal ion-doped manganese glycerate.

[0030] S3. Finally, manganese glycerate is calcined (i.e. pyrolyzed) at 700-800℃ in an oxygen atmosphere for 2-4 hours with a heating rate of 5-10℃ / min to obtain metal ion-doped manganese trioxide.

[0031] The aforementioned metal ion-doped manganese trioxide can be used in lithium-ion battery cathode materials, sodium-ion battery cathode materials, magnesium-ion battery cathode materials, or zinc-ion battery cathode materials, respectively.

[0032] Example 1:

[0033] 8 mL of glycerol was dispersed in 52 mL of isopropanol, and 1 mmol of manganese nitrate and 0.1 mmol of cobalt nitrate were added while stirring at 600 rpm. The resulting mixture was then transferred to a stainless steel autoclave lined with polytetrafluoroethylene and maintained at 200 °C for 7 h.

[0034] The reaction solution was then centrifuged, and the precipitate was collected and washed sequentially with 40 mL of water, 40 mL of methanol, and 40 mL of ethanol. The precipitate was then dried at 60 °C for 14 h to obtain cobalt ion-doped manganese glycerate.

[0035] Finally, cobalt ion-doped manganese glycerate was calcined at 800℃ in an oxygen atmosphere for 2 hours with a heating rate of 8℃ / min to obtain cobalt ion-doped manganese trioxide.

[0036] See Figure 1 , Figure 1 This is the X-ray diffraction (XRD) pattern of cobalt ion-doped manganese trioxide obtained in Example 1. Its diffraction characteristic peaks correspond to manganese trioxide (JCPDS: 97-000-9091), indicating the successful preparation of cobalt ion-doped manganese trioxide.

[0037] See Figure 2 , Figure 2is a scanning electron microscope (SEM) image of the cobalt ion-doped manganese sesquioxide prepared in Example 1. It can be seen that the cobalt ion-doped manganese sesquioxide exhibits a porous micrometer cage structure. Figure 2

[0038] Referring to Figure 3 , Figure 3 is a charge-discharge curve of the cobalt ion-doped manganese sesquioxide prepared in Example 1 in a zinc ion battery. A water-based zinc ion battery was assembled using a CR2032 button cell, the positive electrode was the cobalt ion-doped manganese sesquioxide obtained by the present application, the zinc foil was the negative electrode, and the 2M ZnS04+0.2M MnS04aqueous solution (i.e. in the mixed solution of ZnS04and MnS04, the former was 2M and the latter was 0.2M) was the electrolyte. The discharge capacity at a charge-discharge rate of 0.2Ag -1 -1 , which indicates that the cobalt ion-doped manganese sesquioxide obtained by the present application has a high specific capacity.

[0039] Example 2:

[0040] 8 mL of glycerol was dispersed in 52 mL of isopropyl alcohol, and 1 mmol of manganese nitrate and 0.1 mmol of nickel nitrate were added at a stirring rate of 500 rpm. Subsequently, the obtained mixed solution was transferred to a stainless steel autoclave lined with polytetrafluoroethylene, and maintained at 200°C for 7 h.

[0041] Subsequently, the reaction solution was centrifuged, and then the precipitate was collected and washed with 40 mL of water, 40 mL of methanol and 40 mL of ethanol in sequence, and dried at 60°C for 12 h to obtain manganese glycerate doped with nickel ions.

[0042] Finally, the manganese glycerate doped with nickel ions was calcined at 750°C in an oxygen atmosphere for 2 h, with a heating rate of 5°C / min, to obtain manganese sesquioxide doped with nickel ions.

[0043] Example 3:

[0044] 8 mL of glycerol was dispersed in 52 mL of isopropyl alcohol, and 1.5 mmol of manganese nitrate and 0.1 mmol of iron nitrate were added at a stirring rate of 800 rpm. Subsequently, the obtained mixed solution was transferred to a stainless steel autoclave lined with polytetrafluoroethylene, and maintained at 190°C for 7 h.

[0045] Subsequently, the reaction solution was centrifuged, and then the precipitate was collected and washed with 40 mL of water, 40 mL of methanol and 40 mL of ethanol in sequence, and dried at 60°C for 13 h to obtain manganese glycerate doped with iron ions.

[0046] ​​Finally, the iron ion doped manganese glycerate was calcined at 700 °C for 2 h under oxygen atmosphere with a heating rate of 10 °C / min to obtain the iron ion doped manganese dioxide.

[0047] Example 4:

[0048] 7.5 mL of glycerol was dispersed in 52.5 mL of isopropanol, 2 mmol of manganese nitrate and 0.3 mmol of copper nitrate were added at a stirring rate of 700 rpm. Subsequently, the resulting mixed solution was transferred into a polytetrafluoroethylene lined stainless steel autoclave and maintained at 180 °C for 12 h.

[0049] Subsequently, the reaction solution was centrifuged, after which the precipitate was collected and washed with 40 mL of water, 40 mL of methanol and 40 mL of ethanol in sequence, and dried at 60 °C for 12 h to obtain the copper ion doped manganese glycerate.

[0050] Finally, the copper ion doped manganese glycerate was calcined at 800 °C for 2 h under oxygen atmosphere with a heating rate of 6 °C / min to obtain the copper ion doped manganese dioxide.

Claims

1. A method for preparing metal ion-doped manganese trioxide, characterized in that, Includes the following steps: S1, first disperse glycerol in isopropanol, then add manganese salt and metal nitrate at a stirring rate of 500-800 rpm. The volume ratio of glycerol to isopropanol is (4-8):(40-60). The manganese salt is manganese nitrate, manganese acetate, or manganese sulfate. The metal nitrate is cobalt nitrate, nickel nitrate, ferric nitrate, copper nitrate, or zinc nitrate. The ratio of manganese salt, metal nitrate, and glycerol is (0.5-2) mmol:(0.1-0.5) mmol:(4-8) mL, to obtain a mixed solution. S2, the mixed solution is kept at 160-200℃ for 6-12 h, and then the precipitate in the resulting reaction solution is separated, washed and dried sequentially to obtain metal ion-doped manganese glycerate; S3, metal ion-doped manganese glycerate is calcined in an oxygen atmosphere at 700-800℃ to obtain metal ion-doped manganese trioxide.

2. The method for preparing metal ion-doped manganese trioxide according to claim 1, characterized in that, S2 first centrifuges the reaction solution, then collects the precipitate, washes it sequentially with water, methanol and ethanol, and then dries it.

3. The method for preparing metal ion-doped manganese trioxide according to claim 2, characterized in that, The drying process described in S2 is carried out at 60-80℃ for 10-14 hours to obtain metal ion-doped manganese glycerate.

4. The method for preparing metal ion-doped manganese trioxide according to claim 1, characterized in that, S3 heats the metal ion-doped manganese glycerate from room temperature to 700-800℃ at a heating rate of 5-10℃ / min.

5. A metal ion-doped manganese trioxide obtained by the preparation method of metal ion-doped manganese trioxide according to any one of claims 1-4.

6. The application of metal ion-doped manganese trioxide as described in claim 5 in lithium-ion battery cathode materials, sodium-ion battery cathode materials, magnesium-ion battery cathode materials, or zinc-ion battery cathode materials.

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