A negative electrode material for a lithium-ion battery, a preparation method thereof, and an application thereof
The Li2+4xTi1-x(MoO4)3 material was synthesized by the sol-gel method, which solved the problems of poor conductivity and circulation performance of the negative electrode materials of traditional lithium-ion batteries, and achieved the preparation of the negative electrode materials of lithium-ion batteries with high capacity and excellent circulation performance.
Patent Information
- Application Number
- CN202111523824.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-12-14
- Publication Date
- 2025-07-29
- Estimated Expiration
- 2041-12-14
AI Technical Summary
Traditional lithium-ion battery negative electrode materials have problems such as poor conductivity, large volume changes during charging and discharging, and poor circulation performance, which limits its commercial application prospects.
The Li2+4xTi1-x(MoO4)3 material was synthesized by the sol-gel method, and a stable transparent sol system was formed by mixing lithium salts, titanium-containing compounds, molybdenum-containing compounds and chelating agents. The negative electrode material of the lithium-ion battery was prepared after drying and sintering. The component diffusion characteristics within the nano-range of the sol-gel method were used to reduce the reaction temperature and ensure a single material structure.
The synthetic Li2+4xTi1-x(MoO4)3 has a single material structure, good conductivity, excellent cycle performance, and high reversible capacity. It is suitable for lithium-ion batteries. The first discharge specific capacity reaches 1375mAh/g, and the capacity retention rate still reaches 99% after 100 weeks of circulation.
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Figure CN114361432B_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of negative electrode materials for lithium-ion batteries, and particularly relates to a negative electrode material for lithium-ion batteries, a preparation method thereof, and an application thereof. Background Art
[0002] With the aggravation of global environmental pollution and the gradual depletion of traditional fossil energy, searching for and developing sustainable clean energy has become a common problem faced by the world. Due to excellent electrochemical performance, lithium-ion batteries have become one of the most mature energy storage devices currently developed. While lithium-ion batteries are widely used, they also need to meet higher requirements. Therefore, developing new negative electrode materials with low working voltage, high capacity, and good cycle stability is of great significance in the practical application of lithium-ion batteries.
[0003] Traditional commercial graphite anodes not only have a relatively low theoretical specific capacity (372 mAh g -1 ), but also have poor rate performance, and gradually cannot meet the growing market demand. Transition metal oxides provide high specific capacity based on multi-electron transfer of transition metals during charge and discharge, and are considered to have the potential to become substitutes for the next-generation commercial graphite anode materials. Molybdenum-based negative electrode materials have high specific capacity as negative electrodes for lithium-ion batteries because molybdenum can undergo multi-electron transfer at low voltages (<1V), such as molybdenum trioxide (MoO3) having a theoretical capacity of 1117 mAh g -1 as a negative electrode material for lithium-ion batteries.
[0004] However, transition metal oxide anodes have problems such as poor conductivity, large volume change during charge and discharge, and poor cycle performance, which limit their commercial application prospects. Therefore, exploring transition metal oxide anode materials with good conductivity and cycle stability is of great significance for their practical application. Summary of the Invention
[0005] The first technical problem to be solved by the present invention is:
[0006] To provide a negative electrode material for lithium-ion batteries. When the negative electrode material for lithium-ion batteries is used to prepare a lithium-ion battery, the lithium-ion battery has excellent cycle performance and high reversible capacity.
[0007] The second technical problem to be solved by the present invention is:
[0008] To provide a preparation method of the negative electrode material for lithium-ion batteries.
[0009] The third technical problem to be solved by the present invention is:
[0010] The application of the negative electrode material for lithium-ion batteries.
[0011] To solve the first technical problem, the technical solution adopted by the present invention is as follows:
[0012] An anode material for a lithium-ion battery, comprising a material with the chemical formula Li 2+4x Ti 1-x (MoO4)3;
[0013] wherein, 0.2 < x < 0.3.
[0014] According to an embodiment of the present invention, 0.23 ≤ x ≤ 0.26.
[0015] According to an embodiment of the present invention, the particle size of the anode material for the lithium-ion battery is 100 nm - 2 μm.
[0016] The anode material for the lithium-ion battery is a compound of AMM’(XO4)3 with a Nasicon-like crystal structure.
[0017] To solve the second technical problem, the technical solution adopted by the present invention is as follows:
[0018] A method for preparing the anode material for the lithium-ion battery, comprising the following steps:
[0019] Mix a lithium salt, a titanium-containing compound, a molybdenum-containing compound and a chelating agent in a solvent to obtain a mixed solution;
[0020] Heat the mixed solution to obtain a wet gel;
[0021] After drying and sintering, the anode material for the lithium-ion battery is obtained.
[0022] Mix a lithium salt, a titanium-containing compound, a molybdenum-containing compound and a chelating agent in a solvent to obtain a mixed solution, forming a stable transparent sol system. The sol is aged after being heated in a water bath, and the colloidal particles slowly polymerize to form a gel with a three-dimensional network structure. The solvent that has lost fluidity fills the space between the gel networks to form a wet gel. The wet gel is dried and sintered to prepare the anode material for the lithium-ion battery.
[0023] The diffusion of components in the sol-gel system is in the nanometer range, making the subsequent reaction easy to carry out and requiring a lower temperature. Compared with solid-phase reaction, the diffusion of components in solid-phase reaction is in the micrometer range, making the requirements for subsequent reaction conditions higher.
[0024] The Li 2+4x Ti 1-x (MoO4)3 material synthesized by the sol-gel method has a single structure and no impurity phase. The structure of the Li 2+4x Ti 1-x (MoO4)3 material is an orthorhombic crystal system with a space group of Pnma.
[0025] According to an embodiment of the present invention, the lithium salt includes at least one of lithium carbonate and lithium acetate.
[0026] According to an embodiment of the present invention, the titanium-containing compound includes at least one of diammonium bis(2-hydroxypropionate) dihydroxytitanium and tetrabutyl titanate.
[0027] According to an embodiment of the present invention, the molybdenum-containing compound includes at least one of molybdate and molybdenum trioxide.
[0028] According to an embodiment of the present invention, the chelating agent includes at least one of citric acid, ascorbic acid, oxalic acid, and ethylenediaminetetraacetic acid; preferably citric acid. During subsequent sintering, self-combustion of citric acid can reduce the sintering reaction time and the residual carbon content.
[0029] During sintering, carbon dioxide and water are generated by the decomposition of citric acid, generating pores.
[0030] The amount of the chelating agent is 100%-300% of the sum of the amounts of titanium and molybdenum elements in the mixed solution.
[0031] According to an embodiment of the present invention, in the mixed solution, the molar ratio of lithium, titanium, and molybdenum elements is 1-1.1:0.5-1:2-4; preferably 1.05:0.75:3.
[0032] According to an embodiment of the present invention, both the drying and sintering are carried out in an air atmosphere.
[0033] According to an embodiment of the present invention, the temperature for drying the wet gel is 150°C.
[0034] According to an embodiment of the present invention, the sintering is divided into two steps. First, sinter at a temperature of 300-400°C for 2-6 hours, grind after natural cooling; then sinter at a temperature of 500-600°C for 8-16 hours.
[0035] In another aspect of the present invention, a lithium-ion battery is further provided, including a positive electrode, a negative electrode, and a separator, and the negative electrode includes the negative electrode material of the lithium-ion battery described above.
[0036] According to an embodiment of the present invention, the negative electrode material of the lithium-ion battery and a lithium metal sheet form a battery, the electrolyte is a solution of ethylene carbonate / diethyl carbonate (EC / DME, volume ratio 1:1) with 1 mol / L LiClO4. When charging and discharging at a rate of 100 mA / g and the charging voltage is 0.01 - 3.0 V, the initial discharge specific capacity reaches 1375 mAh / g, the reversible specific capacity reaches 950 mAh / g, and after 100 cycles, the capacity retention rate still reaches 99%.
[0037] One of the technical solutions in the above technical solutions has at least one of the following advantages or beneficial effects:
[0038] 1. The Li 2+4x Ti 1-x (MoO4)3 material synthesized by using the method has a single structure and does not contain impurity phases;
[0039] 2. The Li 2+4x Ti 1-x (MoO4)3 material synthesized by using the method has good crystallization. When applied to a lithium-ion battery, the lithium-ion battery has excellent cycling performance and high reversible capacity. BRIEF DESCRIPTION OF THE DRAWINGS
[0040] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation of the present invention.
[0041] Figure 1 It is the X-ray diffraction pattern of the negative electrode material of the lithium-ion battery for the product of Example 1.
[0042] Figure 2 It is a schematic diagram of the charge-discharge curve of the negative electrode material of the lithium-ion battery prepared in Example 1, the charge-discharge rate is 100 mA / g, and the charge-discharge voltage is 0.01 - 3.0 V.
[0043] Figure 3 It is a schematic diagram of the long charge-discharge cycle of the lithium-ion battery assembled with the negative electrode material of the lithium-ion battery prepared in Example 1, the charge-discharge current density is 100 mA / g, and the charge-discharge voltage is 0.01 - 3.0 V.
[0044] Figure 4 It is the X-ray diffraction pattern of the negative electrode material of the lithium-ion battery for the product of Example 2.
[0045] Figure 5 It is a scanning electron microscope photograph of the negative electrode material of the lithium-ion battery for the product of Example 2.
[0046] Figure 6Schematic diagram of charge and discharge long cycle of a lithium-ion battery assembled with the product lithium-ion battery anode material prepared in Example 2. The charge and discharge current density is 1 A / g, and the charge and discharge voltage is 0.01 - 3.0 V.
[0047] Figure 7 Schematic diagram of the rate performance of a lithium-ion battery assembled with the product lithium-ion battery anode material prepared in Example 2. The charge and discharge rates are 0.1, 0.2, 0.5, 1, 2, and 0.1 A / g, and the charge and discharge voltage is 0.01 - 3.0 V.
[0048] Figure 8 X-ray diffraction pattern of the lithium-ion battery anode material of the product in Example 3.
[0049] Figure 9 Schematic diagram of the charge and discharge curve of a lithium-ion battery assembled with the product lithium-ion battery anode material prepared in Example 3. The charge and discharge current density is 200 mA / g, and the charge and discharge voltage is 0.01 - 3.0 V. Detailed implementation manners
[0050] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of the present invention.
[0051] In the embodiment, LiCH3COO is lithium acetate;
[0052] In the embodiment, (CH3CH(O-)CO2NH4)2Ti(OH)2 is diammonium titanium dihydroxide bis(2-hydroxypropionate);
[0053] In the embodiment, (NH4)2MoO4 is ammonium molybdate.
[0054] Example 1
[0055] Weigh the following raw materials in 60 mL of deionized water:
[0056] 2.1 mmol of LiCH3COO;
[0057] 1.5 mmol of (CH3CH(O-)CO2NH4)2Ti(OH)2;
[0058] 6 mmol of (NH4)2MoO4;
[0059] 15 mmol of citric acid monohydrate;
[0060] Constant temperature magnetic stirring and drying were carried out at 80 °C, and a wet gel was obtained after 12 hours.
[0061] The wet gel was placed in an oven at 150 °C and dried for 12 h to obtain a dry gel, which was ground to obtain a powder.
[0062] The above product was pre-calcined at 300 °C for 4 h in an air atmosphere, cooled naturally and then ground. After grinding evenly, a powdery material was obtained; after grinding evenly again, it was calcined at 500 °C for 12 h in an air atmosphere to obtain Li3Ti 0.75 (MoO4)3.
[0063] Take Li3Ti 0.75 (MoO4)3 to prepare a lithium-ion battery, and the button cell mold is CR2032.
[0064] Li3Ti 0.75 (MoO4)3 lithium-ion battery anode material, acetylene black, and polyvinylidene fluoride were uniformly mixed in an N-methylpyrrolidone solution in a mass ratio of 7:2:1, coated on a copper foil, fully dried, and then cut into battery electrode sheets as the anode. A lithium metal sheet was used as the counter electrode, and the electrolyte was a 1 mol / L LiClO4 ethylene carbonate / diethyl carbonate (EC / DME, volume ratio 1:1) solution. The above battery electrode sheets and other materials were encapsulated into a button lithium-ion battery in a glove box filled with high-purity argon.
[0065] The XRD pattern of the product obtained in this example is shown in Figure 1 , as can be seen from the figure, through the above preparation method, a pure-phase orthorhombic Li3Ti 0.75 (MoO4)3 material was synthesized, and there are no impurity peaks in the spectrum, and the product purity is high.
[0066] The first three charge-discharge curves of the Li3Ti 0.75 (MoO4)3 anode material are shown in Figure 2 , its charge-discharge rate is 100 mA / g, and the charge-discharge voltage is 0.01 - 3.0 V.
[0067] The charge-discharge long cycle schematic diagram of the lithium-ion battery assembled with the Li3Ti 0.75 (MoO4)3 anode material is as shown in Figure 3 , as can be seen from Figure 3 , when the charge-discharge voltage is 0.01 - 3.0 V and the charge-discharge rate is 100 mA / g, the first discharge specific capacity of the battery reaches 1375 mAh / g, and after 100 cycles, the capacity is still 954 mAh / g, showing good cycle performance.
[0068] Example 2
[0069] Weigh the following raw materials in 60 mL of deionized water:
[0070] 2.1 mmol of LiCH3COO;
[0071] 1.5 mmol of (CH3CH(O-)CO2NH4)2Ti(OH)2;
[0072] 6 mmol of (NH4)2MoO4;
[0073] 15 mmol of citric acid monohydrate;
[0074] Stir magnetically at a constant temperature of 80 °C and dry. After 12 hours, a wet gel is obtained;
[0075] Place the wet gel in an oven at 150 °C and dry for 12 h to obtain a dry gel, and grind it to obtain a powder.
[0076] Pre-calcine the above product in an air atmosphere at 350 °C for 4 h, cool naturally and then grind. After grinding evenly, a powdery material is obtained; After grinding evenly again, calcine in an air atmosphere at 550 °C for 12 h to obtain Li3Ti 0.75 (MoO4)3.
[0077] Take Li3Ti 0.75 (MoO4)3 to prepare a lithium-ion battery, and the button cell mold is CR2032.
[0078] Mix the Li3Ti 0.75 (MoO4)3 lithium-ion battery anode material, acetylene black, and polyvinylidene fluoride evenly in an N-methylpyrrolidone solution according to a mass ratio of 7:2:1, coat it on a copper foil, fully dry it, and then cut it into a battery electrode sheet as the anode. Use a lithium metal sheet as the counter electrode, and the electrolyte is a 1 mol / L LiClO4 ethylene carbonate / diethyl carbonate (EC / DME, volume ratio 1:1) solution. Package the above battery electrode sheet and other materials into a button lithium-ion battery in a glove box filled with high-purity argon.
[0079] The XRD pattern of the sample is shown in Figure 4 As shown, it can be seen from the figure that there are no impurities in this sample, and it is a pure-phase Li3Ti 0.75 (MoO4)3 material.
[0080] Figure 5 This is the SEM (scanning electron microscope) image of the lithium-ion battery anode material of the product of Example 2.
[0081] Figure 6 This is a schematic diagram of the cycling performance at a charge-discharge voltage of 0.01 - 3.0 V and a charge-discharge rate of 1 A / g. After 350 cycles, the capacity remains at 640 mAh / g, and the cycling performance is excellent.
[0082] Figure 7 For the Li3Ti 0.75 (MoO4)3 anode material, the rate performance at current densities of 0.1, 0.2, 0.5, 1, 2, and 0.1 A / g within a voltage window of 0.01 - 3.0 V is shown. It can be seen from the figure that the Li3Ti 0.75 (MoO4)3 anode material has excellent rate performance and still has a specific capacity of approximately 500 mAh / g at a current density of 2 A / g.
[0083] Example 3
[0084] Weigh the following raw materials into 60 mL of deionized water:
[0085] 2.1 mmol of LiCH3COO;
[0086] 1.5 mmol of (CH3CH(O-)CO2NH4)2Ti(OH)2;
[0087] 6 mmol of (NH4)2MoO4;
[0088] 15 mmol of citric acid monohydrate;
[0089] Stir magnetically at a constant temperature of 80 °C and dry. After 12 hours, a wet gel is obtained;
[0090] Place the wet gel in an oven at 150 °C and dry for 12 h to obtain a dry gel, and grind it to obtain a powder.
[0091] Pre-calcine the above product in an air atmosphere at 400 °C for 4 h, cool naturally and then grind. After grinding evenly, a powdered material is obtained; after grinding evenly again, calcine in an air atmosphere at 600 °C for 12 h to obtain Li3Ti 0.75 (MoO4)3.
[0092] Take Li3Ti 0.75 (MoO4)3 to prepare a lithium-ion battery, and the button cell mold is CR2032.
[0093] Mix the Li3Ti 0.75 (MoO4)3 lithium-ion battery anode material, acetylene black, and polyvinylidene fluoride in a mass ratio of 7:2:1 evenly in an N-methylpyrrolidone solution, coat it on a copper foil, fully dry it, and then cut it into battery electrode sheets as the anode. Use a lithium metal sheet as the counter electrode, and the electrolyte is a 1 mol / L LiClO4 ethylene carbonate / diethyl carbonate (EC / DME, volume ratio of 1:1) solution. Package the above battery electrode sheets and other materials into a button-type lithium-ion battery in a glove box filled with high-purity argon.
[0094] The XRD pattern of the sample is shown inFigure 8 As shown, it can be seen from the figure that there are no impurities in this sample, and it is a pure-phase Li3Ti 0.75 (MoO4)3 material. The first charge-discharge curves of this Li3Ti 0.75 (MoO4)3 anode material at a rate of 200 mA / g and a charge-discharge voltage of 0.01 - 3.0 V are shown in Figure 9 , and the initial charge and discharge capacities are 1272 mAh / g and 911 mAh / g respectively.
[0095] Example 4
[0096] Weigh the following raw materials in 60 mL of deionized water:
[0097] 1.05 mmol LiCH3COO;
[0098] 0.75 mmol (CH3CH(O-)CO2NH4)2Ti(OH)2;
[0099] 3 mmol (NH4)2MoO4;
[0100] 9.6 mmol citric acid monohydrate;
[0101] Stir magnetically at a constant temperature of 80 °C and dry. After 12 hours, a wet gel is obtained;
[0102] Place the wet gel in an oven at 150 °C and dry for 12 h to obtain a dry gel, and grind it to obtain a powder;
[0103] Pre-calcine the above product in an air atmosphere at 300 °C for 4 h, cool it naturally and then grind it. After grinding evenly, a powdery material is obtained; After grinding evenly again, calcine it in an air atmosphere at 500 °C for 12 h to obtain Li3Ti 0.75 (MoO4)3.
[0104] Take Li3Ti 0.75 (MoO4)3 to prepare a lithium-ion battery, and the button battery mold is CR2032.
[0105] Mix the Li3Ti 0.75 (MoO4)3 lithium-ion battery anode material, acetylene black, and polyvinylidene fluoride evenly in an N-methylpyrrolidone solution according to a mass ratio of 7:2:1, coat it on a copper foil, fully dry it, and then cut it into battery electrode sheets as the negative electrode. Use a lithium metal sheet as the counter electrode, and the electrolyte is a 1 mol / L LiClO4 ethylene carbonate / diethyl carbonate (EC / DME, volume ratio 1:1) solution. Package the above battery electrode sheets and other materials into a button lithium-ion battery in a glove box filled with high-purity argon.
[0106] Example 5
[0107] Weigh the following raw materials in 60 mL of deionized water:
[0108] 3.15 mmol of LiCH3COO;
[0109] 2.25 mmol of (CH3CH(O-)CO2NH4)2Ti(OH)2;
[0110] 9 mmol of (NH4)2MoO4;
[0111] 28.8 mmol of citric acid monohydrate;
[0112] Stir magnetically and dry at a constant temperature of 80 °C. After 12 hours, a wet gel is obtained;
[0113] Place the wet gel in an oven at 150 °C and dry for 12 h to obtain a dry gel, and grind it to obtain a powder;
[0114] Pre-calcine the above product in an air atmosphere at 300 °C for 4 h, cool it naturally and then grind it. After grinding evenly, a powdery material is obtained; After grinding evenly again, calcine it in an air atmosphere at 500 °C for 12 h to obtain Li3Ti 0.75 (MoO4)3.
[0115] Take Li3Ti 0.75 (MoO4)3 to prepare a lithium-ion battery, and the button cell mold is CR2032.
[0116] Mix Li3Ti 0.75 (MoO4)3 lithium-ion battery anode material, acetylene black, and polyvinylidene fluoride evenly in an N-methylpyrrolidone solution according to a mass ratio of 7:2:1, coat it on a copper foil, fully dry it, and then cut it into a battery electrode sheet as the anode. Use a lithium metal sheet as the counter electrode, and the electrolyte is a solution of 1 mol / L LiClO4 in ethylene carbonate / diethyl carbonate (EC / DME, volume ratio 1:1). Package the above battery electrode sheet and other materials into a button-type lithium-ion battery in a glove box filled with high-purity argon.
[0117] Example 6
[0118] Weigh the following raw materials in 60 mL of deionized water:
[0119] 2.1 mmol of lithium carbonate (Li2CO3);
[0120] 1.5 mmol of (CH3CH(O-)CO2NH4)2Ti(OH)2;
[0121] 6 mmol of (NH4)2MoO4;
[0122] 15 mmol of citric acid monohydrate;
[0123] Constant temperature magnetic stirring and drying are carried out at 80 °C, and a wet gel is obtained after 12 hours.
[0124] The wet gel is placed in an oven at 150 °C and dried for 12 h to obtain a dry gel, which is ground to obtain a powder.
[0125] The above product is pre-calcined at 300 °C for 4 h in an air atmosphere, naturally cooled and then ground. After grinding evenly, a powdery material is obtained; after grinding evenly again, it is calcined at 500 °C for 12 h in an air atmosphere to obtain Li3Ti 0.75 (MoO4)3.
[0126] Take Li3Ti 0.75 (MoO4)3 to prepare a lithium-ion battery, and the button cell mold is CR2032.
[0127] Put Li3Ti 0.75 (MoO4)3 lithium-ion battery anode material, acetylene black, and polyvinylidene fluoride are uniformly mixed in an N-methylpyrrolidone solution according to a mass ratio of 7:2:1, coated on a copper foil, fully dried and then cut into battery electrode sheets as the anode. A metal lithium sheet is used as the counter electrode, and the electrolyte is a 1 mol / L LiClO4 ethylene carbonate / diethyl carbonate (EC / DME, volume ratio 1:1) solution. The above battery electrode sheets and other materials are encapsulated into a button lithium-ion battery in a glove box filled with high-purity argon.
[0128] Example 7
[0129] Weigh the following raw materials in 60 mL of deionized water:
[0130] 2.1 mmol LiCH3COO;
[0131] 1.5 mmol tetrabutyl titanate (C 16 H 36 O4Ti);
[0132] 6 mmol (NH4)2MoO4;
[0133] 15 mmol citric acid monohydrate;
[0134] Constant temperature magnetic stirring and drying are carried out at 80 °C, and a wet gel is obtained after 12 hours.
[0135] The wet gel is placed in an oven at 150 °C and dried for 12 h to obtain a dry gel, which is ground to obtain a powder.
[0136] The above product was pre-calcined at 300 °C for 4 h in an air atmosphere, cooled naturally, and then ground. After grinding evenly, a powdery material was obtained; after grinding evenly again, it was calcined at 500 °C for 12 h in an air atmosphere to obtain Li3Ti 0.75 (MoO4)3.
[0137] Take Li3Ti 0.75 (MoO4)3 to prepare a lithium-ion battery, and the button battery mold is CR2032.
[0138] Li3Ti 0.75 (MoO4)3, acetylene black, and polyvinylidene fluoride were uniformly mixed in an N-methylpyrrolidone solution in a mass ratio of 7:2:1, coated on a copper foil, fully dried, and then cut into battery electrode sheets as the negative electrode. A lithium metal sheet was used as the counter electrode, and the electrolyte was a solution of 1 mol / L LiClO4 in ethylene carbonate / diethyl carbonate (EC / DME, volume ratio 1:1). The above battery electrode sheets and other materials were encapsulated into a button lithium-ion battery in a glove box filled with high-purity argon.
[0139] Example 8
[0140] Weigh the following raw materials in 60 mL of deionized water:
[0141] 2.1 mmol LiCH3COO;
[0142] 1.5 mmol (CH3CH(O-)CO2NH4)2Ti(OH)2;
[0143] 6 mmol molybdenum trioxide (MoO3);
[0144] 15 mmol citric acid monohydrate;
[0145] Stir magnetically and dry at a constant temperature of 80 °C. After 12 hours, a wet gel was obtained;
[0146] The wet gel was placed in an oven at 150 °C and dried for 12 h to obtain a dry gel, which was ground to obtain a powder;
[0147] The above product was pre-calcined at 300 °C for 4 h in an air atmosphere, cooled naturally, and then ground. After grinding evenly, a powdery material was obtained; after grinding evenly again, it was calcined at 500 °C for 12 h in an air atmosphere to obtain Li3Ti 0.75 (MoO4)3.
[0148] Take Li3Ti 0.75 (MoO4)3 to prepare a lithium-ion battery, and the button battery mold is CR2032.
[0149] Li3Ti 0.75(MoO4)3 negative electrode material for lithium-ion batteries, acetylene black, and polyvinylidene fluoride are uniformly mixed in an N-methylpyrrolidone solution at a mass ratio of 7:2:1, then coated on a copper foil, fully dried, and cut into battery electrode sheets to serve as the negative electrode. A metal lithium sheet is used as the counter electrode, and the electrolyte is a solution of 1 mol / L LiClO4 in ethylene carbonate / diethyl carbonate (EC / DME, volume ratio 1:1). The above battery electrode sheets and other materials are encapsulated into a button-type lithium-ion battery in a glove box filled with high-purity argon.
[0150] Comparative example
[0151] Weigh the following raw materials in 60 mL of deionized water:
[0152] 2.1 mmol LiCH3COO;
[0153] 1.5 mmol (CH3CH(O-)CO2NH4)2Ti(OH)2;
[0154] 6 mmol (NH4)2MoO4;
[0155] 15 mmol citric acid monohydrate;
[0156] A mixed solution is obtained;
[0157] The above mixed solution is pre-calcined at 300 °C for 4 h in an air atmosphere, naturally cooled, ground, and after being ground evenly, a powdery material is obtained; after being ground evenly again, it is calcined at 500 °C for 12 h in an air atmosphere to obtain the negative electrode material.
[0158] Take the negative electrode material to prepare a lithium-ion battery, and the button battery mold is CR2032.
[0159] (MoO4)3 negative electrode material for lithium-ion batteries, acetylene black, and polyvinylidene fluoride are uniformly mixed in an N-methylpyrrolidone solution at a mass ratio of 7:2:1, then coated on a copper foil, fully dried, and cut into battery electrode sheets to serve as the negative electrode. A metal lithium sheet is used as the counter electrode, and the electrolyte is a solution of 1 mol / L LiClO4 in ethylene carbonate / diethyl carbonate (EC / DME, volume ratio 1:1). The above battery electrode sheets and other materials are encapsulated into a button-type lithium-ion battery in a glove box filled with high-purity argon.
[0160] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent transformation made using the content of the specification of the present invention, or directly or indirectly applied in the relevant technical fields, shall be equally included in the patent protection scope of the present invention.
Claims
1. A method for preparing a negative electrode material for a lithium-ion battery, characterized in that: It includes the following steps: Mix a lithium salt, a titanium-containing compound, a molybdenum-containing compound and a chelating agent in a solvent to obtain a mixed solution; Heat the mixed solution to obtain a wet gel; The wet gel is dried and sintered to obtain the negative electrode material of the lithium-ion battery; The titanium-containing compound includes at least one of diammonium titanium di(2-hydroxypropionate) and tetrabutyl titanate; The molybdenum-containing compound includes at least one of molybdate and molybdenum trioxide; The chelating agent is citric acid; The negative electrode material of the lithium ion battery includes a material with the chemical formula Li 2+4x Ti 1-x (MoO4)3; Wherein, 0.2 < x < 0.3; The sintering is divided into two steps. First, sinter at a temperature of 300 - 400 °C for 2 - 6 hours; then sinter at a temperature of 500 - 600 °C for 8 - 16 hours.
2. The method according to claim 1, wherein: Among them, 0.23≤x≤0.26。 3. The method according to claim 1, wherein: The particle size of the negative electrode material of the lithium-ion battery is 100 nm - 2 μm.
4. The method according to claim 1, wherein: The amount of substance of the chelating agent is 100% - 300% of the sum of the amounts of substance of titanium element and molybdenum element in the mixed solution.
5. The method according to claim 1, wherein: In the mixed solution, the molar ratio of lithium element, titanium element, and molybdenum element is 1 - 1.1:0.5 - 1:2 - 4.
6. The method according to claim 5, wherein: In the mixed solution, the molar ratio of lithium element, titanium element, and molybdenum element is 1.05:0.75:
3.
7. A lithium-ion battery, characterized in that: It includes a positive electrode, a negative electrode and a separator, and the negative electrode includes the negative electrode material of the lithium-ion battery prepared by the method according to any one of claims 1 - 3.