Mixed-phase lithium metavanadate micron particle negative electrode material, preparation method and lithium ion battery

Abstract

The invention discloses a mixed-phase lithium metavanadate micron particle negative electrode material, a preparation method and a lithium ion battery. The composition formula of the mixed-phase lithium metavanadate micron particle negative electrode material is Li1 + xVO3, wherein x is more than or equal to 0.05 and less than or equal to 0.5. A solid-phase sintering method is adopted for synthesis, specifically, V2O5 and lithium salt are fully mixed and ground until no obvious granular sensation exists, the mixture is poured into a corundum porcelain boat and calcined for 4 h at the temperature of 750 DEG C in the air atmosphere, then the product is fully ground until no obvious granular sensation exists, and the Li1 + xVO3 material is obtained, has a composite phase structure of LiVO3 and Li3VO4 and is micron blocky particles with the length being 5-10 microns and the width being 2-5 microns. The Li1 + xVO3 material provided by the invention solves the problem of relatively poor performance of a lithium ion battery negative electrode material in the prior art, can be applied to a lithium ion battery, has high safety and high rate performance, and has a good application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium ion batteries, in particular to a mixed phase lithium metavanadate microparticle negative electrode material, a preparation method and a lithium ion battery. BACKGROUND

[0002] Lithium ion batteries have become the mainstream power source for electric vehicles and portable electronic devices due to their high energy density and long cycle life. The market has higher requirements for the fast charging capacity of batteries, and the US Advanced Battery Consortium has explicitly required charging to 80% capacity within 15 minutes. However, the graphite that currently dominates the market for negative electrode materials has a high electrical conductivity, but a very low Li + diffusion coefficient, and a low theoretical capacity (372 mAh g -1 ) due to the solid limitations of reversible ion absorption at the graphite / electrolyte interface. In addition, the low lithium intercalation potential of 0.1 V of graphite also leads to safety problems such as lithium dendrite induced at high rates. Another mainstream negative electrode material, Li4Ti5O 12 , has a high lithium intercalation potential (1.55 V) and does not produce safety problems caused by lithium precipitation, but the low theoretical specific capacity of 175 mAh g –1 and the serious gassing behavior have severely limited its large-scale commercial use. Therefore, there is an urgent need to develop a lithium ion battery negative electrode material with high rate performance, safe potential, and high cycle stability.

[0003] Vanadium-based negative electrode materials are considered to be the next generation of lithium ion battery negative electrode materials that can replace graphite due to their numerous physical and chemical properties that are conducive to electrochemical energy storage. However, vanadium-based negative electrode materials also have some drawbacks. For example, V2O5 has poor electrical conductivity and is easily dissolved, resulting in large volume expansion during charging and discharging, which leads to electrode capacity decay; Li3VO4 has low electrical conductivity, large polarization during charging and discharging, and low initial coulombic efficiency; and LiVO3 has a low energy density. These drawbacks limit the practical application of vanadium-based negative electrode materials.

[0004] In summary, there is an urgent need for a new mixed phase structure of lithium metavanadate negative electrode material and a controllable preparation method to achieve high rate, high safety, and long life lithium ion battery applications. SUMMARY

[0005] Therefore, the present application provides a mixed phase lithium metavanadate microparticle negative electrode material, a preparation method and a lithium ion battery. The present application utilizes the mixed phase structure of the lithium metavanadate negative electrode material to improve the electrochemical performance of the negative electrode, thereby solving the problem of poor performance of the lithium ion battery negative electrode material in the prior art.

[0006] To solve the problems of the prior art, the technical scheme adopted by the present application is as follows:

[0007] A mixed phase lithium metavanadate microparticle negative material, the mixed phase lithium metavanadate microparticle negative material has a composite phase structure of LiVO3 and Li3VO4, and a microparticle block with a length of 5-10 microns and a width of 2-5 microns, and a general chemical formula of LiVO3, wherein 0.05<=x<=0.5. 1+x VO3, wherein 0.05<=x<=0.5.

[0008] Preferably, the mixed phase lithium metavanadate microparticle negative material has high rate performance and is stable in charging and discharging at a large current density of 20 Ag -1 .

[0009] A preparation method of the mixed phase lithium metavanadate microparticle negative material, V2O5 and lithium salt are fully mixed, ground until no obvious particles are felt, poured into a corundum porcelain boat, burned at 750 DEG C for 4 hours in an air atmosphere, and then the product is fully ground until no obvious particles are felt, to obtain Li 1+x VO3 powder.

[0010] Preferably, the lithium salt is lithium carbonate.

[0011] A Li 1+x VO3 material electrode sheet, containing the mixed phase lithium metavanadate microparticle negative material.

[0012] Preferably, the Li 1+x VO3 material electrode sheet has a lithium intercalation potential of 0.5-1 V. 1+x VO3 as an active material, acetylene black and polyvinylidene fluoride are mixed uniformly to obtain a mixture, then N-methyl pyrrolidone is added dropwise into the mixture to form a slurry, the slurry is uniformly coated on a copper foil current collector, and then dried to obtain a Li 1+x VO3 material electrode sheet.

[0013] Preferably, the Li 1+x VO3 material electrode has a lithium intercalation potential of 0.5-1 V.

[0014] The mixed phase lithium metavanadate microparticle negative material or the Li 1+x VO3 material electrode sheet is applied to a lithium battery.

[0015] Advantages:

[0016] Compared with the prior art, the mixed phase lithium metavanadate microparticle negative material, the preparation method and the lithium ion battery have the following advantages:

[0017] (1) The Li 1+x VO3 negative material has a maximum specific capacitance of 552 mAh g –1 -1. –1At that time, the specific capacity was 552 mAh g. –1 When the current density is 20Ag –1 At that time, the specific capacity was 104 mAh g. –1 It has excellent specific capacity and rate performance.

[0018] (2) The present invention Li 1+x VO3 negative electrode material, Li + The reversibility of insertion and extraction is good. Based on the GCD curve, the lithium insertion potential is mainly between 0.5-1V, indicating high safety. Attached Figure Description

[0019] Figure 1 These are X-ray diffraction patterns of Embodiments 2, 5, 10 and the comparative example of the present invention;

[0020] Figure 2 The SEM images are those of Embodiments 2, 5, 10 and the comparative example of the present invention;

[0021] Figure 3 The Raman spectra of Embodiments 2, 5, 10 and the comparative example of the present invention are shown below;

[0022] Figure 4 The constant current charge-discharge curves of Embodiments 2, 5, 10 and the comparative example of the present invention under different current densities are shown.

[0023] Figure 5 Examples 2, 5, 10 and the comparative example of the present invention are in 0.1 Ag. –1 Below is a comparison chart of specific capacities;

[0024] Figure 6 The negative electrode materials of Examples 2, 5, 10 and the comparative examples of the present invention are in 1Ag –1 The loop performance is as follows. Detailed Implementation

[0025] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0026] A mixed-phase lithium metavanadate micron-sized particle anode material, wherein the mixed-phase lithium metavanadate micron-sized particle anode material has a composite phase structure of LiVO3 and Li3VO4, and consists of micron-sized bulk particles with a length of 5-10 μm and a width of 2-5 μm, and its general chemical formula is Li. 1+x VO3, where 0.05 ≤ x ≤ 0.5.

[0027] Preferably, the mixed-phase lithium metavanadate micron-sized particle anode material exhibits high rate performance at 20Ag. -1 Stable charging and discharging under high current density.

[0028] The preparation method of the mixed phase lithium metavanadate microparticle negative electrode material is as follows: V2O5 and lithium salt are fully mixed, ground until no obvious particles are felt, poured into a corundum porcelain boat, calcined at 750 DEG C for 4 hours in an air atmosphere, and then the product is fully ground until no obvious particles are felt, and then Li 1+x VO3 powder.

[0029] Preferably, the lithium salt is lithium carbonate.

[0030] A Li 1+x VO3 material electrode sheet contains the mixed phase lithium metavanadate microparticle negative electrode material described above.

[0031] Preferably, the Li 1+x VO3 material electrode sheet is prepared by mixing the mixed phase lithium metavanadate microparticle negative electrode material Li 1+x VO3 as an active material, mixing with acetylene black and polyvinylidene fluoride to obtain a mixture, then adding N-methyl pyrrolidone dropwise into the mixture to form a slurry, uniformly coating the slurry on a copper foil current collector, and then drying to obtain a Li 1+x VO3 material electrode sheet.

[0032] Preferably, the Li 1+x VO3 material electrode has a lithium intercalation potential of 0.5-1V.

[0033] The mixed phase lithium metavanadate microparticle negative electrode material or Li 1+x VO3 material electrode sheet is applied in a lithium battery.

[0034] It should be noted that the specific content involved in the embodiments of the present application can be referred to the description of the above embodiments, and will not be described here again for brevity.

[0035] For the convenience of understanding, the technical solutions provided by the present application will be described in detail below in combination with specific embodiments.

[0036] Embodiment 1

[0037] A Li 1.05 VO3 material is prepared by a solid phase sintering method, 1.82g of V2O5 and 0.78g of Li2CO3 are weighed and fully mixed, ground until no obvious particles are felt, poured into a corundum porcelain boat, calcined at 750 DEG C for 4 hours in an air atmosphere, and then the product is fully ground until no obvious particles are felt, to obtain Li 1.05 VO3 powder.

[0038] Based on the Li 1.05 VO3 material prepared electrode sheet, specifically, Li 1.05VO3 material, acetylene black and polyvinylidene fluoride were uniformly mixed in N-methyl pyrrolidone in a mass ratio of 7:2:1 to form a slurry, which was uniformly coated on a copper foil current collector, vacuum dried at 80℃ for 12h, and the electrode sheet was obtained by cutting the piece. 1.05 VO3 electrode sheet.

[0039] In commercial secondary electrolyte LB014 (1mol L -1 LiPF6solution), the solvent was a mixed solution of ethylene carbonate (EC), diethyl carbonate (DEC) and dimethyl carbonate (DMC) in a volume ratio of 1:1:1, and the electrochemical test was carried out in the mixed solution. The test method was to use Li 1.05 VO3 electrode as the working electrode and lithium metal sheet as the counter electrode to assemble a half-cell system in a glove box.

[0040] Example 2

[0041] A Li 1.10 The preparation method of the VO3 material is prepared by solid phase sintering method. 1.82g of V2O5 and 0.81g of Li2CO3 are weighed and mixed, ground to no obvious particle feeling, poured into a corundum boat, calcined at 750℃ in air for 4h, and the product is fully ground to no obvious particle feeling to obtain Li 1.10 VO3 powder.

[0042] Figure 1 The X-ray diffraction pattern of the micron block-shaped particle Li 1.10 VO3 provided in this example is compared with the LiVO3 standard card (JCPDS #32-0606) and the Li3VO4 standard card (JCPDS #38-1247).

[0043] Figure 2 The SEM image of the micron block-shaped particle Li 1.10 VO3 provided in this example is provided. 1.10 VO3 is mainly long strip-shaped with a length of 8-10μm and a width of 2-4μm.

[0044] Figure 3 The Raman spectrum of the micron block-shaped particle Li 1.10 VO3 provided in this example.

[0045] Based on the above Li 1.10 VO3 material prepared electrode sheet, specifically Li 1.10 VO3 material, acetylene black and polyvinylidene fluoride were uniformly mixed in N-methyl pyrrolidone in a mass ratio of 7:2:1 to form a slurry, which was uniformly coated on a copper foil current collector, vacuum dried at 80℃ for 12h, and the electrode sheet was obtained by cutting the piece. 1.10 VO3 electrode sheet.

[0046] In commercial secondary electrolyte LB014, i.e. 1 mol L -1 LiPF6 solution, the solvent is a mixture of ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC) in a volume ratio of 1:1:1, and the electrochemical test is carried out. The test method is to respectively use Li 1.10 VO3 electrode as the working electrode, and metal lithium sheet as the counter electrode, and the half-cell system is tested in the glove box. The results are shown in Figures 4-6

[0047] Figure 4 The Li 1.10 VO3 electrode sheet under different current densities, and the constant current charge-discharge curve diagram is shown in the figure. Under the current density of 0.1, 0.2, 0.5, 1, 2, 5, 10, 20 Ag –1 The reversible specific capacity provided by Li 1.10 VO3 is 542, 430, 331, 262, 202, 135, 109, 78 mAh g –1 , which shows that the Li 1.10 VO3 electrode has excellent specific capacity.

[0048] Figure 5 The specific capacity comparison diagram of the Li 1.10 VO3 electrode sheet under 0.1-20 Ag –1 , the maximum specific mass capacity of the Li 1.10 VO3 electrode under 10 Ag -1 is 109 mAh·g -1 , and when the current density is 20 Ag –1 , the specific capacity is 78 mAh g –1 , and it also has excellent rate capacity.

[0049] Figure 6 The cycle performance of the Li 1.10 VO3 electrode sheet under 1 Ag –1 , the specific capacity of Li 1.10 VO3 under the current density of 1 Ag –1 decreases from 282.3 mAh g –1 to 281.7 mAh g –1 after 200 charge-discharge cycles, the capacity retention rate is 99.79%, and the cycle performance is excellent.

[0050] Example 3

[0051] A Li 1.15 ​The preparation method of VO3 material adopts solid-state sintering. 1.82g of V2O5 and 0.85g of Li2CO3 are weighed and thoroughly mixed. After grinding until no obvious particles are felt, the mixture is poured into a corundum ceramic boat and calcined at 750℃ for 4 hours in air. The product is then thoroughly ground to obtain Li. 1.15 VO3 powder.

[0052] Based on the above Li 1.15 Electrode sheets made of VO3 material, specifically Li 1.15 VO3 material, acetylene black, and polyvinylidene fluoride were uniformly mixed in N-methylpyrrolidone at a mass ratio of 7:2:1 to form a slurry. The slurry was then uniformly coated onto a copper foil current collector and vacuum dried at 80°C for 12 hours. Li was then cut into pieces to obtain the final product. 1.15 VO3 electrode sheet.

[0053] In commercial secondary electrolyte LB014 (1 mol L) -1 Electrochemical tests were conducted using a LiPF6 solution, a mixture of ethylene carbonate (EC), diethyl carbonate (DEC), and dimethyl carbonate (DMC) in a volume ratio of 1:1:1. The test method involved using LiPF6 solution... 1.15 The VO3 electrode is used as the working electrode, and the lithium metal sheet is used as the counter electrode. The half-cell system is installed in a glove box.

[0054] Example 4

[0055] A Li 1.20 The preparation method of VO3 material adopts solid-state sintering. 1.82 g of V2O5 and 0.89 g of Li2CO3 are weighed and thoroughly mixed. After grinding until no obvious particles are felt, the mixture is poured into a corundum ceramic boat and calcined at 750℃ for 4 hours in air. The product is then thoroughly ground until no obvious particles are felt, yielding Li. 1.20 VO3 powder.

[0056] Based on the above Li 1.20 Electrode sheets made of VO3 material, specifically Li 1.20 VO3 material, acetylene black, and polyvinylidene fluoride were uniformly mixed in N-methylpyrrolidone at a mass ratio of 7:2:1 to form a slurry. The slurry was then uniformly coated onto a copper foil current collector and vacuum dried at 80°C for 12 hours. Li was then cut into pieces to obtain the final product. 1.20 VO3 electrode sheet.

[0057] In commercial secondary electrolyte LB014 (1 mol L) -1 Electrochemical tests were conducted using a LiPF6 solution, a mixture of ethylene carbonate (EC), diethyl carbonate (DEC), and dimethyl carbonate (DMC) in a volume ratio of 1:1:1. The test method involved using LiPF6 solution... 1.20VO3electrode as working electrode, lithium metal as counter electrode, and the half-cell system was assembled in the glove box.

[0058] Example 5

[0059] A Li 1.25 VO3material was prepared by solid phase sintering method. 1.82g V2O5 and 0.92g Li2CO3 were weighed and mixed thoroughly, then grinded until no obvious particle feeling, poured into corundum boat, calcined at 750℃ for 4h in air atmosphere, and the product was grinded thoroughly until no obvious particle feeling. Li 1.25 VO3powder was obtained.

[0060] Figure 1 The X-ray diffraction pattern of the micron-sized blocky particles of Li 1.25 VO3provided in this example was compared with the standard card of LiVO3(JCPDS #32-0606) and the standard card of Li3VO4(JCPDS #38-1247). Both the example 5 and the standard card kept the characteristic peaks of LiVO3 completely, proving the effectiveness of the solid phase synthesis, and the increase of lithium content did not cause great change in crystal structure, indicating that the material has good structural stability. With the increase of lithium content, the peak intensity of LiVO3 characteristic peaks decreased, the characteristic peaks of Li3VO4 gradually appeared and the peak intensity increased, indicating that the Li 1.25 VO3material has a composite phase structure.

[0061] Figure 2 The SEM image of the micron-sized blocky particles of Li 1.25 VO3provided in this example showed that the Li 1.25 VO3was mainly long strip flake with length of 8-10μm and width of 2-4μm.

[0062] Figure 3 The Raman spectrum of the micron-sized blocky particles of Li 1.25 VO3provided in this example showed that the peak intensity at 388cm –1 increased, indicating that the deformation vibration of VO2 bond was enhanced. In addition, a new peak appeared at 820cm –1 and the intensity gradually increased, which was caused by the distortion of vanadium oxygen structure and the change of oxidation state due to the increase of lithium content.

[0063] Based on the above Li 1.25 VO3, an electrode sheet was prepared. Specifically, Li 1.25 VO3material, acetylene black and polyvinylidene fluoride were uniformly mixed in N-methyl pyrrolidone in a mass ratio of 7:2:1 to form a slurry, and then the slurry was uniformly coated on a copper foil current collector, vacuum dried at 80℃ for 12h, and the electrode sheet was obtained by cutting. 1.25 VO3electrode sheet.

[0064] In commercial secondary electrolyte LB014 (1 mol L) -1 Electrochemical tests were conducted using a LiPF6 solution, a mixture of ethylene carbonate (EC), diethyl carbonate (DEC), and dimethyl carbonate (DMC) in a volume ratio of 1:1:1. The test method involved using LiPF6 solution... 1.25 A VO3 electrode was used as the working electrode, and a lithium metal sheet was used as the counter electrode. The half-cell system was tested in a glove box. The results are as follows: Figures 4-6 As shown.

[0065] Figure 4 For the above Li 1.25 Constant current charge-discharge curves of VO3 electrode sheet at different current densities: 0.1, 0.2, 0.5, 1, 2, 5, 10, and 20 Ag. –1 At current density, Li 1.25 The reversible specific capacities provided by VO3 are 552, 468, 397, 342, 290, 216, 158, and 104 mAh g, respectively. –1 This explains Li 1.25 The VO3 electrode exhibits excellent specific capacity.

[0066] Figure 5 For the above Li 1.25 VO3 electrode pads in 0.1-20Ag –1 The following is a comparison chart of specific capacities, Li 1.25 VO3 electrode at 10Ag -1 The maximum specific mass capacity at these values ​​is 180.0 mAh·g. -1 When the current density is 20Ag –1 At that time, the specific capacity was 116.1 mAhg. –1 It also has excellent rate capability.

[0067] Figure 6 For the above Li 1.25 VO3 electrode 1Ag –1 The cycling performance under [condition]. Li 1.25 VO3 in 1Ag –1 After undergoing 200 charge-discharge cycles at a current density, the specific capacity increased from 341.0 mAh g. –1 Reduced to 319.3 mAh g –1 It has a capacity retention rate of 93.64% and excellent cycle performance.

[0068] Example 6

[0069] A Li 1.30A preparation method of the VO3 material, prepared by a solid-phase sintering method, 1.82 g of V2O5 and 0.96 g of Li2CO3 are weighed and fully mixed, ground until no obvious particle feeling is felt, poured into a corundum ceramic boat, calcined at 750 DEG C for 4 h in an air atmosphere, and the product is fully ground until no obvious particle feeling is felt to obtain Li 1.30 VO3 powder.

[0070] Based on the above Li 1.30 An electrode sheet prepared from the Li 1.30 VO3 material, acetylene black and polyvinylidene fluoride are uniformly mixed in N-methyl pyrrolidone at a mass ratio of 7:2:1 to form a slurry, the slurry is uniformly coated on a copper foil current collector, vacuum dried at 80 DEG C for 12 h, and the sheet is cut to obtain a Li 1.30 VO3 electrode sheet.

[0071] In a commercial secondary electrolyte LB014 (1 mol / L -1 LiPF6 solution), the solvent is a mixed solution of ethylene carbonate (EC), diethyl carbonate (DEC) and dimethyl carbonate (DMC) in a volume ratio of 1:1:1, and the test method is to use Li 1.30 VO3 electrode as the working electrode and a lithium sheet as the counter electrode to assemble a half-cell system in a glove box.

[0072] Example 7

[0073] A Li 1.35 A preparation method of the VO3 material, prepared by a solid-phase sintering method, 1.82 g of V2O5 and 0.96 g of Li2CO3 are weighed and fully mixed, ground until no obvious particle feeling is felt, poured into a corundum ceramic boat, calcined at 750 DEG C for 4 h in an air atmosphere, and the product is fully ground until no obvious particle feeling is felt to obtain Li 1.35 VO3 powder.

[0074] Based on the above Li 1.35 An electrode sheet prepared from the Li 1.35 VO3 material, acetylene black and polyvinylidene fluoride are uniformly mixed in N-methyl pyrrolidone at a mass ratio of 7:2:1 to form a slurry, the slurry is uniformly coated on a copper foil current collector, vacuum dried at 80 DEG C for 12 h, and the sheet is cut to obtain a Li 1.35 VO3 electrode sheet.

[0075] In a commercial secondary electrolyte LB014 (1 mol / L -1 LiPF6 solution), the solvent is a mixed solution of ethylene carbonate (EC), diethyl carbonate (DEC) and dimethyl carbonate (DMC) in a volume ratio of 1:1:1, and the test method is to use Li 1.35The VO3 electrode is used as the working electrode, and the lithium metal sheet is used as the counter electrode. The half-cell system is installed in a glove box.

[0076] Example 8

[0077] A Li 1.40 The preparation method of VO3 material adopts solid-state sintering. 1.82g of V2O5 and 1.03g of Li2CO3 are weighed and thoroughly mixed. After grinding until no obvious particles are felt, the mixture is poured into a corundum ceramic boat and calcined at 750℃ for 4 hours in air. The product is then thoroughly ground to obtain Li. 1.40 VO3 powder.

[0078] Based on the above Li 1.40 Electrode sheets made of VO3 material, specifically Li 1.40 VO3 material, acetylene black, and polyvinylidene fluoride were uniformly mixed in N-methylpyrrolidone at a mass ratio of 7:2:1 to form a slurry. The slurry was then uniformly coated onto a copper foil current collector and vacuum dried at 80°C for 12 hours. Li was then cut into pieces to obtain the final product. 1.40 VO3 electrode sheet.

[0079] In commercial secondary electrolyte LB014 (1 mol L) -1 Electrochemical tests were conducted using a LiPF6 solution, a mixture of ethylene carbonate (EC), diethyl carbonate (DEC), and dimethyl carbonate (DMC) in a volume ratio of 1:1:1. The test method involved using LiPF6 solution... 1.40 The VO3 electrode is used as the working electrode, and the lithium metal sheet is used as the counter electrode. The half-cell system is installed in a glove box.

[0080] Example 9

[0081] A Li 1.45 The preparation method of VO3 material adopts solid-state sintering. 1.82 g of V2O5 and 1.07 g of Li2CO3 are weighed and thoroughly mixed. After grinding until no obvious particles are felt, the mixture is poured into a corundum ceramic boat and calcined at 750℃ for 4 hours in air. The product is then thoroughly ground until no obvious particles are felt, yielding Li. 1.45 VO3 powder.

[0082] Based on the above Li 1.45 Electrode sheets made of VO3 material, specifically Li 1.45 VO3 material, acetylene black, and polyvinylidene fluoride were uniformly mixed in N-methylpyrrolidone at a mass ratio of 7:2:1 to form a slurry. The slurry was then uniformly coated onto a copper foil current collector and vacuum dried at 80°C for 12 hours. Li was then cut into pieces to obtain the final product. 1.45 VO3 electrode sheet.

[0083] In commercial secondary electrolyte LB014 (1 mol L)-1 LiPF6solution) in a glove box. The test method was to use Li 1.45 VO3electrode as the working electrode and lithium sheet as the counter electrode to assemble a half-cell system in the glove box.

[0084] Example 10

[0085] A Li 1.50 VO3material was prepared by a solid phase sintering method. 1.82 g of V2O5and 1.11 g of Li2CO3were weighed and mixed thoroughly, ground until no obvious particles were felt, and then poured into a corundum boat. The product was fully ground after calcination at 750°C for 4 h in an air atmosphere until no obvious particles were felt, to obtain Li 1.50 VO3powder.

[0086] Figure 1 The X-ray diffraction pattern of the micron-sized blocky particles of Li 1.50 VO3provided in this example was compared with the LiVO3standard card (JCPDS #32-0606) and the Li3VO4standard card (JCPDS #38-1247). Both the material of Example 10 and the standard card completely maintained the characteristic peaks of LiVO3, proving the effectiveness of the solid phase synthesis, and the increase in lithium content did not cause a large change in the crystal structure, indicating that the material has good structural stability. With the increase in lithium content, the peak intensity of the LiVO3characteristic peaks decreased; the characteristic peaks of Li3VO4gradually appeared and the peak intensity increased, indicating that the Li 1.50 VO3material has a composite phase structure.

[0087] Figure 2 The SEM image of the micron-sized blocky particles of Li 1.50 VO3provided in this example showed that the Li 1.50 VO3was mainly a cubic block with a length of 6 μm and a width of 3-5 μm.

[0088] Figure 3 The Raman spectrum of the micron-sized blocky particles of Li 1.50 VO3provided in this example showed that the peak intensity at 388 cm –1 increased, indicating that the deformation vibration of the VO2bond was enhanced. In addition, a new peak appeared at 820 cm –1 and the intensity gradually increased, which was caused by the distortion of the vanadium oxygen structure and the change in oxidation state due to the increase in lithium content.

[0089] Based on the Li 1.50 VO3material prepared above, an electrode sheet was prepared. Specifically, the Li 1.50VO3 material, acetylene black, and polyvinylidene fluoride were uniformly mixed in N-methylpyrrolidone at a mass ratio of 7:2:1 to form a slurry. The slurry was then uniformly coated onto a copper foil current collector and vacuum dried at 80°C for 12 hours. Li was then cut into pieces to obtain the final product. 1.50 VO3 electrode sheet.

[0090] In commercial secondary electrolyte LB014 (1 mol L) -1 Electrochemical tests were conducted using a LiPF6 solution, a mixture of ethylene carbonate (EC), diethyl carbonate (DEC), and dimethyl carbonate (DMC) in a volume ratio of 1:1:1. The test method involved using LiPF6 solution... 1.50 The VO3 electrode serves as the working electrode, and the lithium metal sheet serves as the counter electrode. The half-cell system is housed in a glove box.

[0091] Figure 4 For the above Li 1.25 Constant current charge-discharge curves of VO3 electrode sheet at different current densities: 0.1, 0.2, 0.5, 1, 2, 5, 10, and 20 Ag. –1 At current density, Li 1.50 The reversible specific capacities offered by VO3 are 514, 371, 307, 256, 213, 156, 119, and 89 mAh g. –1 This explains Li 1.50 The VO3 electrode exhibits excellent specific capacity.

[0092] Figure 5 For the above Li 1.50 VO3 electrode pads in 0.1-20Ag –1 The following is a comparison chart of specific capacities, Li 1.50 VO3 electrode at 10Ag -1 The maximum specific mass capacity at these values ​​is 129.6 mAh·g. -1 When the current density is 20Ag –1 At that time, the specific capacity was 99.9 mAh g. –1 It also has excellent rate capability.

[0093] Figure 6 For the above Li 1.50 VO3 electrode 1Ag –1 The cycling performance under [condition]. Li 1.50 VO3 in 1Ag –1 After undergoing 200 charge-discharge cycles at a current density, the specific capacity increased from 236.1 mAh g. –1 Increased to 245.6 mAh g –1 Side reactions may occur, but the overall cycle performance is stable.

[0094] Comparative Example

[0095] 1.82 g of V2O5 and 0.74 g of Li2CO3 were weighed and mixed thoroughly, ground until no obvious particles were felt, and then poured into a corundum boat. After calcination at 750°C for 4 h in an air atmosphere, the product was ground thoroughly until no obvious particles were felt to obtain a LiVO3 negative electrode material. The electrode sheet was prepared in the same manner as in Example 1.

[0096] Figure 6 The cycle performance of the LiVO3 electrode sheet 1 Ag –1 under the above conditions was as follows: LiVO3 experienced 200 charge-discharge cycles at a current density of 1 Ag –1 , and the specific capacity increased from 232.1 mAh g –1 to 267.8 mAh g –1 . This was due to distortion of the crystal structure, particle breakage, and an increase in side reactions, resulting in poor cycle stability.

[0097] Table 1. Performance data of electrode materials prepared under different formulations

[0098]

[0099] As can be seen from Table 1, the mixed-phase lithium metavanadate microparticles Li 1+x VO3 electrode material of the examples had excellent specific capacity and rate performance.

[0100] The above-described examples are merely specific embodiments of the present application, and those of ordinary skill in the art can make several modifications and improvements within the technical scope of the present application, which are all encompassed within the scope of the present application. The scope of protection of the present application should be subject to the claims.

Claims

1. A mixed-phase lithium vanadate microparticle negative material, characterized in that, The mixed-phase lithium vanadate microparticle negative electrode material has a composite phase structure of LiVO3 and Li3VO4, and a microparticle block with a length of 5-10 μm and a width of 2-5 μm, and a general chemical formula of LiVO3, wherein 0.05≤x≤0.

5. 1+x VO3, wherein 0.05≤x≤0.

5.

2. The mixed-phase lithium vanadium oxide microparticle negative electrode material of claim 1, wherein, The mixed-phase lithium vanadate microparticle negative electrode material has high rate performance and stable charge and discharge at a large current density of 20 Ag -1 .

3. The method of producing a mixed-phase lithium vanadium oxide microparticle negative electrode material according to any one of claims 1 to 2, characterized by, V2O5 and lithium salt were mixed thoroughly, ground until no obvious particle feeling was felt, then poured into a corundum porcelain boat, burned at 750°C for 4h under air atmosphere, then the product was ground thoroughly until no obvious particle feeling was felt, to obtain LiVO3 powder. 1+x VO3 powder.

4. The method of claim 3, wherein the mixed-phase lithium vanadium oxide microparticle negative electrode material is prepared by the steps of: preparing a mixed-phase lithium vanadium oxide precursor by mixing a lithium source, a vanadium source, and a phosphorus source; and performing a heat treatment on the mixed-phase lithium vanadium oxide precursor. The lithium salt is lithium carbonate. The lithium salt is lithium carbonate.

5. A Li 1+x VO3 material electrode sheet comprising the mixed phase lithium metavanadate microparticle negative material of any one of claims 1-2.

6. The Li 1+x VO3 material electrode sheet characterized by, The electrode sheet is prepared by mixing the lithium metavanadate microparticle negative material Li 1+x VO3 as an active material, mixing uniformly with acetylene black and polyvinylidene fluoride to obtain a mixture, then adding N-methylpyrrolidone dropwise into the mixture to form a slurry, uniformly coating the slurry on a copper foil current collector, and performing drying treatment to obtain a Li 1+x VO3 material electrode sheet.

7. The Li of claim 5 1+x VO3 material electrode sheet, characterized by, The Li 1+x The Li The Li The Li The Li The Li The Li The Li The Li The Li The Li The Li The Li The Li The Li The Li The Li The Li 8. The mixed-phase lithium vanadate microparticle anode material or Li 1+x Use of the VO3 material electrode sheet in a lithium battery.

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