MOFs structure lithium ion battery negative electrode material MIL-53(Al-Fe) and preparation method thereof
Technical Field
The invention relates to a lithium ion battery cathode material MIL-53(Al-Fe) with an MOFs structure and a preparation method thereof, belonging to the field of lithium ion battery materials.
Background
Metal-Organic Frameworks (MOFs) are a new porous framework material formed by self-assembling Metal ions and Organic ligands, and can form one-dimensional, two-dimensional or three-dimensional periodic network structures. Compared with the traditional porous material, the porous material has the advantages of large surface area, high pore volume, adjustable pore diameter, variable functional groups, high redox activity and the like. The open three-dimensional framework structure of the crystalline porous coordination polymers is derived from the molecular bonding of metal ions and multifunctional organic matters, the number and the direction of ligands which can be combined with metals are mainly determined by the coordination preference of central metal ions and the symmetry of organic connecting groups, so that the size and the shape of generated pores can be controlled by a specific method, and MOFs (metal-organic frameworks) are widely applied to various lithium ion batteries as a promising material.
As MOFs materials belonging to MIL-53(MIII) series, MIL-53(Al) and MIL-53(Fe) are aluminum-based or iron-based metal organic framework materials, and have the advantages of three-dimensional porous structure, large specific surface area, low cost, no toxicity, no harm and the like. However, when the material is used as a lithium ion battery material, the material is an organic electrode material with poor conductivity and has certain solubility in an electrolyte, so that the cycle performance and specific capacity of the material are not ideal. It is reported that MIL-53(Al) is prepared by Huangzong (Huangzong, research on terephthalate anode material of sodium ion battery [ D ]. Sichuan: university of electronic technology, 2014), and the specific capacity is 84mAh/g after the battery is cycled 51 times at a rate of 0.5C. While Chuan hui Zhuang (Zhuang C, Hu W, Jiang H, et al. electrochemical performance of MIL-53(Fe) @ RGO as an Organic Material for Li-ion Batteries [ J ]. Electrochimica Acta,2017,246:528-535) reported that MIL-53(Fe) @ RGO was prepared, and the reversible capacity of MIL-53(Fe) was 310mAh/g at a current density of 100mA/g, indicating that the advantages of the specific capacity and the cycling stability of the two are not outstanding.
The invention uses FeCl3·6H2O and Al (NO)3)3·9H2O is used as a metal ion raw material, and terephthalic acid is used as an organic ligand to prepare the MIL-53(Al-Fe) material with the bimetallic MOFs structure with different Al/Fe ratios. The provided MIL-53(Al-Fe) material has the advantages of rich raw materials, various structures, low cost, environmental friendliness, simple and convenient synthesis process, mild preparation conditions and easiness in operation. The MIL-53(Al-Fe) material with the bimetallic MOFs structure has the advantages that the structure is adjustable in a certain range due to the discrete matching centers of two metal ions, sufficient lithium ion storage sites are provided, and Li is used as the storage sites+The rapid diffusion channel is provided, and has a large specific surface and a large porosity, so that the rapid diffusion channel is beneficial to full infiltration of electrolyte when being used as a lithium ion battery material, and can bring good structural stability of lithium ion desorption and insertion through coordination of two metal ion centers, and realize good capacity and cycle performance.
Disclosure of Invention
The invention aims to provide a lithium ion battery cathode material MIL-53(Al-Fe) with an MOFs structure and a preparation method thereof. Due to the fact that the metal alloy has a bimetal MOFs structure, and synergistic effects exist between different metals, the specific capacity of MIL-53(Al-Fe) is superior to that of MIL-53(Al) and MIL-53(Fe) which are single-metal MOFs materials. And the method has the advantages of low cost, mild preparation conditions, easy operation and the like, and is relatively suitable for large-scale production.
The technical scheme adopted by the invention is as follows:
an MOFs structure lithium ion battery cathode material MIL-53(Al-Fe) is prepared from Al3+、Fe3+Is a metal ion raw material, takes terephthalic acid as an organic ligand,MIL-53(Al-Fe) material forming a bimetallic MOFs structure.
The molar ratio is terephthalic acid to Al3+:Fe3+1: Y, wherein X is 3-9, and Y is 1-5.
Further, a preparation method of the MOFs structure lithium ion battery negative electrode material MIL-53(Al-Fe), which comprises the following steps:
(1) weighing 0.85-2.54 g of terephthalic acid, measuring 54.94-156.56 ml of dimethylformamide according to the molar ratio of the terephthalic acid to the dimethylformamide of 1:140, adding the terephthalic acid into the dimethylformamide, and stirring at room temperature at the rotating speed of 30-60 r/min for 30-60 min to obtain a solution A with the concentration of 0.09 mol/L;
(2) according to Al (NO)3)3·9H2O and FeCl3·6H20.64g of Al (NO) is weighed out respectively according to the molar ratio of O of 1: 1-53)3·9H2O and 0.46-2.30 g FeCl3·6H2O;
(3) Al (NO) weighed in the step (2)3)3·9H2O and FeCl3·6H2O, by adding Al (NO) first3)3·9H2Adding FeCl after O3·6H2Adding O into the solution A in the step (1), stirring at a rotating speed of 30-60 r/min for 4-6 h at room temperature, transferring to a 100ml reaction kettle with a polytetrafluoroethylene lining, reacting at 180-220 ℃ for 24-72 h, cooling to room temperature, washing with dimethylformamide and absolute ethyl alcohol respectively for 3 times, and performing centrifugal separation to obtain a reddish brown precipitate;
(4) and (4) placing the product obtained in the step (3) in a vacuum drying oven, and drying for 6-12 hours under the condition that the vacuum degree is 0.1MPa and the temperature is 60-80 ℃ to obtain MIL-53 (Al-Fe).
The material prepared by the method has the advantages of uniform phase, high purity, good crystallization and good electrochemical performance, and can be used as a lithium ion battery cathode material.
The invention has the following beneficial effects:
(1) terephthalic acid is selected as an organic ligand, FeCl3·6H2O and Al (NO)3)3·9H2O is a metal ionThe sub-raw materials can synthesize MIL-53(Al-Fe) materials with bimetal MOFs structures with different Al/Fe ratios, and the materials are rich in raw materials, various in structure, low in cost and environment-friendly.
(2) The two metal ion separated matching centers of the MIL-53(Al-Fe) of the bimetallic MOFs structure enable the structure to be adjustable in a certain range, have sufficient lithium ion storage sites and are Li+The rapid diffusion channel is provided, the specific surface and the porosity are large, the electrolyte is favorably fully infiltrated, the good structural stability of the lithium ions which are de-intercalated is brought through the coordination of the centers of the two metal ions, and the good capacity and the cycle performance can be realized.
(3) The synthesis process of the MIL-53(Al-Fe) with the bimetal MOFs structure is simple and convenient, the preparation condition is mild, the operation is easy, and the industrialization is convenient to realize.
Description of the drawings:
FIG. 1 is an XRD pattern of an MIL-53(Al-Fe) material prepared in example 1 of the present invention;
FIG. 2 is a graph showing the cycle performance of the MIL-53(Al-Fe) material obtained in example 1 of the present invention.
The specific implementation mode is as follows:
the invention is further illustrated with reference to the following figures and examples.
Example 1
Weighing 1.70g of terephthalic acid, measuring 109.86ml of dimethylformamide according to the molar ratio of the terephthalic acid to the dimethylformamide of 1:140, adding the terephthalic acid into the dimethylformamide, and stirring at room temperature at the rotating speed of 60r/min for 60min to obtain the solution A with the concentration of 0.09 mol/L. According to Al (NO)3)3·9H2O and FeCl3·6H20.64g of Al (NO) was weighed out in a molar ratio of O1: 33)3·9H2O and 1.38gFeCl3·6H2And O. Weighing Al (NO)3)3·9H2O and FeCl3·6H2O, by adding Al (NO) first3)3·9H2Adding FeCl after O3·6H2Sequentially adding O into the solution A, stirring at room temperature at 60r/min for 6h, transferring into a 100ml reaction kettle with polytetrafluoroethylene lining, reacting at 180 deg.C for 72h, and cooling toAfter room temperature, washing with dimethylformamide and absolute ethyl alcohol respectively for 3 times, and centrifuging to obtain a reddish brown precipitate. And (3) placing the product after centrifugal separation into a vacuum drying oven, and drying for 6h under the condition that the vacuum degree is 0.1MPa and the temperature is 80 ℃ to obtain MIL-53 (Al-Fe).
The CR2032 button cell is used as a model for assembling the cell, the first discharge/charge specific capacity is 1577mAh/g and 1114mAh/g respectively under the current density of 100mA/g, and the discharge specific capacity can still keep 892mAh/g after 100 times of circulation.
Example 2
Weighing 0.85g of terephthalic acid, measuring 54.94ml of dimethylformamide according to the molar ratio of the terephthalic acid to the dimethylformamide of 1:140, adding the terephthalic acid into the dimethylformamide, and stirring at room temperature at the rotating speed of 30r/min for 30min to obtain the solution A with the concentration of 0.09 mol/L. According to Al (NO)3)3·9H2O and FeCl3·6H20.64gAl (NO) was weighed out in a molar ratio of O1: 13)3·9H2O and 0.46gFeCl3·6H2And O. Weighing Al (NO)3)3·9H2O and FeCl3·6H2O, by adding Al (NO) first3)3·9H2Adding FeCl after O3·6H2And sequentially adding the O into the solution A, stirring at the room temperature for 4h at the rotating speed of 30r/min, transferring to a 100ml reaction kettle with a polytetrafluoroethylene lining, reacting for 60h at the temperature of 180 ℃, cooling to the room temperature, respectively washing for 3 times by using dimethylformamide and absolute ethyl alcohol, and performing centrifugal separation to obtain a reddish brown precipitate. And (3) placing the product after centrifugal separation into a vacuum drying oven, and drying for 12h at the temperature of 60 ℃ under the vacuum degree of 0.1MPa to obtain MIL-53 (Al-Fe).
Example 3
Weighing 2.54g of terephthalic acid, measuring 164.80ml of dimethylformamide according to the molar ratio of the terephthalic acid to the dimethylformamide of 1:140, adding the terephthalic acid into the dimethylformamide, and stirring at room temperature at the rotating speed of 30r/min for 30min to obtain the solution A with the concentration of 0.09 mol/L. According to Al (NO)3)3·9H2O and FeCl3·6H20.64gAl (NO) was weighed out in a molar ratio of O1: 53)3·9H2O and 2.30gFeCl3·6H2And O. Weighing Al (NO)3)3·9H2O and FeCl3·6H2O, by adding Al (NO) first3)3·9H2Adding FeCl after O3·6H2And sequentially adding the O into the solution A, stirring at the room temperature for 4h at the rotating speed of 30r/min, transferring to a 100ml reaction kettle with a polytetrafluoroethylene lining, reacting for 48h at the temperature of 200 ℃, cooling to the room temperature, respectively washing for 3 times by using dimethylformamide and absolute ethyl alcohol, and performing centrifugal separation to obtain a reddish brown precipitate. And (3) placing the product after centrifugal separation into a vacuum drying oven, and drying for 12h at the temperature of 80 ℃ and the vacuum degree of 0.1MPa to obtain MIL-53 (Al-Fe).
Example 4
Weighing 0.85g of terephthalic acid, measuring 54.94ml of dimethylformamide according to the molar ratio of the terephthalic acid to the dimethylformamide of 1:140, adding the terephthalic acid into the dimethylformamide, and stirring at room temperature at the rotating speed of 60r/min for 30min to obtain the solution A with the concentration of 0.09 mol/L. According to Al (NO)3)3·9H2O and FeCl3·6H20.64gAl (NO) was weighed out in a molar ratio of O1: 13)3·9H2O and 0.46gFeCl3·6H2And O. Weighing Al (NO)3)3·9H2O and FeCl3·6H2O, by adding Al (NO) first3)3·9H2Adding FeCl after O3·6H2And sequentially adding the O into the solution A, stirring at the room temperature for 6h at the rotating speed of 30r/min, transferring to a 100ml reaction kettle with a polytetrafluoroethylene lining, reacting for 36h at the temperature of 220 ℃, cooling to the room temperature, respectively washing for 3 times by using dimethylformamide and absolute ethyl alcohol, and performing centrifugal separation to obtain a reddish brown precipitate. And (3) placing the product after centrifugal separation into a vacuum drying oven, and drying for 9h at the temperature of 60 ℃ and the vacuum degree of 0.1MPa to obtain MIL-53 (Al-Fe).
Example 5
Weighing 1.70g of terephthalic acid, measuring 109.86ml of dimethylformamide according to the molar ratio of the terephthalic acid to the dimethylformamide of 1:140, adding the terephthalic acid into the dimethylformamide, and stirring at room temperature at the rotating speed of 60r/minAfter 60min, the solution A with the concentration of 0.09mol/L is obtained. According to Al (NO)3)3·9H2O and FeCl3·6H20.64g of Al (NO) was weighed out in a molar ratio of O1: 33)3·9H2O and 1.38gFeCl3·6H2And O. Weighing Al (NO)3)3·9H2O and FeCl3·6H2O, by adding Al (NO) first3)3·9H2Adding FeCl after O3·6H2And sequentially adding the O into the solution A, stirring at the room temperature at the rotating speed of 60r/min for 6h, transferring to a 100ml reaction kettle with a polytetrafluoroethylene lining, reacting at 180 ℃ for 24h, cooling to the room temperature, respectively washing with dimethylformamide and absolute ethyl alcohol for 3 times, and performing centrifugal separation to obtain a reddish brown precipitate. And (3) placing the product after centrifugal separation into a vacuum drying oven, and drying for 6 hours at the temperature of 80 ℃ under the vacuum degree of 0.1MPa to obtain MIL-53 (Al-Fe).
Example 6
Weighing 2.54g of terephthalic acid, measuring 164.80ml of dimethylformamide according to the molar ratio of the terephthalic acid to the dimethylformamide of 1:140, adding the terephthalic acid into the dimethylformamide, and stirring at room temperature at the rotating speed of 30r/min for 30min to obtain the solution A with the concentration of 0.09 mol/L. According to Al (NO)3)3·9H2O and FeCl3·6H20.64gAl (NO) was weighed out in a molar ratio of O1: 53)3·9H2O and 2.30gFeCl3·6H2And O. Weighing Al (NO)3)3·9H2O and FeCl3·6H2O, by adding Al (NO) first3)3·9H2Adding FeCl after O3·6H2And sequentially adding the O into the solution A, stirring at the room temperature for 4h at the rotating speed of 30r/min, transferring to a 100ml reaction kettle with a polytetrafluoroethylene lining, reacting for 12h at the temperature of 200 ℃, cooling to the room temperature, respectively washing for 3 times by using dimethylformamide and absolute ethyl alcohol, and performing centrifugal separation to obtain a reddish brown precipitate. And (3) placing the product after centrifugal separation into a vacuum drying oven, and drying for 12h at the temperature of 80 ℃ and the vacuum degree of 0.1MPa to obtain MIL-53 (Al-Fe).
The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes performed by the present specification and drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.