Composite lithium titanate film material as well as preparation method and application thereof
By introducing nitriding treatment and nitrogen-containing organic compounds into lithium titanate materials, the material's conductivity and lithium ion transmission are improved, and the problems of low electronic conductivity and lithium ion diffusion coefficient of lithium titanate batteries are solved, achieving high efficiency and large Rate performance and safety are suitable for industrial production and extend the life of lithium-ion batteries.
Patent Information
- Application Number
- CN202411288097.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-14
- Publication Date
- 2024-12-10
AI Technical Summary
The electronic conductivity and lithium ion diffusion coefficient of lithium titanate batteries are low, which limits their large-scale charging and discharge applications. The nano- nano-translation process of material particles is complex and costly, making it difficult to achieve industrial production. At the same time, gas will be generated during recycling. The battery pack is bulging, affecting performance.
By introducing nitriding treatment into lithium titanate materials, the interface conductivity and surface electron transport of the material are improved, and nitrogen-containing organic compounds are added in the solution and grinding process to improve the smoothness of the lithium ion transmission channel and the electron transport rate, and Nitrogen doped heat treatment in a nitrogen atmosphere to prepare composite lithium titanate material.
It significantly improves the electronic conductivity and lithium ion diffusion coefficient of composite lithium titanate materials, improves the maximum performance and safety, is suitable for industrial production, extends the cycle life of lithium ion batteries, and improves the first charge and discharge efficiency and cycle performance. .
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Figure CN119100441A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of chemical power sources, and in particular relates to a composite lithium titanate material and a preparation method and application thereof. Background Art
[0002] Lithium titanate batteries have the characteristics of no memory effect, low self-discharge rate, fast charge and discharge speed, ultra-long cycle life, wide working environment temperature range, safe, stable, green and environmentally friendly, so they have very broad application prospects in the field of communication power supply. When lithium titanate is used as a negative electrode material, the potential platform is as high as 1.5V, which is more than 1V higher than the traditional graphite negative electrode material. Although some energy density is lost, it also means that the battery is safer. The battery has a relatively low demand for negative electrode voltage when charging quickly, but if it is too low, the lithium battery will easily precipitate very active metallic lithium. This lithium dendrite can easily pierce the diaphragm, making the positive and negative electrodes conductive, causing the lithium battery to short-circuit, and then release heat, generate flammable gases, and cause fires. The potential platform of lithium titanate is about 1.5V, because the higher 1V voltage avoids the situation where the negative electrode voltage is 0, and indirectly avoids the precipitation of lithium dendrites, thereby ensuring the safety of the battery. Another advantage of lithium titanate is its strong rapid charging and discharging ability and high charging rate. The charging rate of lithium titanate batteries on the market is 20C or even 50C, while the charging rate of batteries with ordinary graphite negative electrode materials is only 2C to 4C. Based on these technical characteristics of lithium titanate batteries, industry insiders believe that it meets the needs of new energy buses and large-scale energy storage equipment, but the low electronic conductivity (10-13S / cm) and lithium ion diffusion coefficient (10-10 to 10-13cm2 / S) of lithium titanate materials themselves greatly limit their application in high-rate charging and discharging. Studies have shown that nano-sizing the particle size of Li Ti O can expand the effective reaction area and reduce the diffusion distance, thereby significantly improving the rate performance of the material. However, it should be pointed out that the process of nano-sizing material particles is often difficult and requires high costs, and it is currently difficult to achieve large-scale industrial production. In addition, lithium titanate batteries will produce gas continuously during recycling, causing the battery pack to swell, which is particularly serious at high temperatures, affecting the contact between the positive and negative electrodes, increasing the battery impedance, and affecting the performance of the battery. This is also one of the main obstacles that limit the widespread application of lithium titanate, a negative electrode material, in batteries. Summary of the invention
[0003] The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art and to provide a composite lithium titanate material and a preparation method thereof, so as to solve the problems of poor electronic conductivity and low lithium ion diffusion coefficient of the existing lithium titanate electrode materials.
[0004] In order to achieve the purpose of the present invention, one aspect of the present invention provides a method for preparing a composite lithium titanate material, characterized in that it comprises the following steps: According to the molar ratio of titanium element to lithium element in lithium titanate, a lithium source and a titanium source are measured respectively, and the lithium source, the titanium source and the hypochlorite are dissolved in a solvent to prepare a mixed solution; The mixed solution is heated to 40-90° C. and kept warm, and then the mixed solution is dried and sintered to obtain a precursor; The precursor is calcined in an inert atmosphere, and then ground to obtain a sintered powder; The sintered powder is subjected to nitrogen doping heat treatment in a nitrogen-containing atmosphere to obtain a composite lithium titanate material; Wherein, in the step of preparing the mixed solution, a nitrogen-containing organic compound is further added, and the nitrogen-containing organic compound is dissolved in the mixed solution; or / and A nitrogen-containing organic compound is further added in the grinding step, and the nitrogen-containing organic compound is ground together with the precursor that has been subjected to the calcination treatment.
[0005] Another aspect of the present invention provides a composite lithium titanate material, which is prepared by the composite lithium titanate material preparation method of the present invention.
[0006] In another aspect of the present invention, a negative electrode is provided, wherein the negative electrode comprises a current collector and an active layer bonded to the current collector, wherein the active layer comprises the composite lithium titanate material of the present invention.
[0007] In another aspect of the present invention, a lithium ion battery is provided, wherein the lithium ion battery comprises a negative electrode, and the negative electrode is the negative electrode described in the present invention.
[0008] Compared with the prior art, the preparation method of the composite lithium titanate material of the present invention uses nitrogen to replace oxygen in lithium titanate and generates nitrided hypochlorite to improve the interface conductivity of the material, so that the lithium ion transmission channel is smoother, and the nitrided lithium titanate is used to improve the electronic conductivity on the surface of the composite lithium titanate material, and improve the transmission rate of electrons in the composite lithium titanate material. In addition, the preparation method can effectively ensure the chemical properties of the generated composite lithium titanate material are stable, and the composite lithium titanate electrode material has good high-rate performance, good safety performance, high efficiency, and is suitable for industrial large-scale production.
[0009] Since the negative electrode of the present invention and the lithium ion battery or supercapacitor of the present invention both contain the composite lithium titanate material of the present invention, the negative electrode has low resistance, high lithium ion conduction rate, high structural stability and high capacity retention rate, giving the lithium ion battery high initial charge and discharge efficiency and the lithium ion battery or supercapacitor good cycle performance, extending the cycle life and having high safety performance. BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Figure 1 1 is a schematic diagram of a process flow of a method for preparing a silicon oxide composite material according to an embodiment of the present invention; Figure 2 This is the XRD pattern of the composite lithium titanate electrode material obtained in Example 4 of the present invention; Figure 3 The first charge and discharge curve of the composite lithium titanate electrode material of Example 4 of the present invention (that is, the lithium ion battery of Example 11) at 0.1C; Figure 4 1 is a comparison diagram of the first charge and discharge curves of the composite lithium titanate electrode materials obtained in Examples 2, 3, and 4 of the present invention (that is, the lithium ion batteries of Examples 9, 10, and 11) at 0.1C; wherein, Curve 1 is the first charge and discharge curve of the composite lithium titanate electrode material obtained in Example 2, Curve 2 is the first charge and discharge curve of the composite lithium titanate electrode material obtained in Example 4, and Curve 3 is the first charge and discharge curve of the composite lithium titanate electrode material obtained in Example 3; Figure 5 This is a cycle performance diagram of the composite lithium titanate electrode material obtained in Example 4 of the present invention at 50C; Figure 6 This is the coulombic efficiency diagram of the composite lithium titanate electrode material obtained in Example 4 of the present invention at 50C. DETAILED DESCRIPTION Embodiment 1
[0011] This embodiment 1 provides a composite lithium titanate material and a preparation method thereof. The composite lithium titanate material is prepared according to a method comprising the following steps: S11: Anhydrous lithium acetate and tetrabutyl titanate are weighed at a Li:Ti molar ratio of 0.84:1, and ethanol is used as a dispersant to dissolve anhydrous lithium acetate and tetrabutyl titanate in ethanol respectively, and then formamide and barium hypochlorite are dissolved in the lithium acetate solution at a Li:N:Ba molar ratio of 1:0.34:0.1, and 10 mL of acetic acid is dropped into it, and then the tetrabutyl titanate solution and the mixed solution of lithium acetate-formamide-barium hypochlorite are mixed under stirring; S12: stirring at a constant temperature of 80° C. for 6 hours, drying at 100° C., and then heating to 300° C. in a sintering furnace at a rate of 5° C. / min and sintering for 4 hours to obtain a lithium titanate precursor; S13: placing the obtained lithium titanate precursor in a three-stage furnace, introducing nitrogen, heating to 500° C. at 5° C. / min, and keeping the temperature for 12 hours; cooling, grinding, and obtaining a composite powder; S14: putting the composite powder into a three-stage furnace, heating it to 600° C. in an argon atmosphere, then replacing the argon with ammonia, heating it to 700° C. in an ammonia atmosphere, and keeping the temperature for 30 minutes to obtain the composite lithium titanate electrode material. Embodiment 2
[0012] This embodiment 1 provides a composite lithium titanate material and a preparation method thereof. The composite lithium titanate material is prepared according to a method comprising the following steps: S11: Anhydrous lithium acetate and tetrabutyl titanate were weighed at a Li:Ti molar ratio of 0.84:1, and ethanol was used as a dispersant to dissolve anhydrous lithium acetate and tetrabutyl titanate in ethanol respectively, and then formamide and sodium hypochlorite were dissolved in the lithium acetate solution at a Li:N:Na molar ratio of 1:0.29:0.19, and 10 mL of acetic acid was dropped into it, and then the tetrabutyl titanate solution and the mixed solution of lithium acetate-formamide-sodium hypochlorite were mixed under stirring; S12: stirring at a constant temperature of 60° C. for 6 hours, drying at 100° C., and then heating to 400° C. in a sintering furnace at a rate of 5° C. / min and sintering for 3 hours to obtain a lithium titanate precursor; S13: placing the obtained lithium titanate precursor in a three-stage furnace, introducing nitrogen, heating to 600° C. at 5° C. / min, and keeping the temperature for 10 hours; cooling, grinding, and obtaining a composite powder; The argon gas was then replaced with ammonia gas, and the temperature was raised to 750° C. in the ammonia atmosphere and kept at this temperature for 1 hour to obtain the composite lithium titanate electrode material. Embodiment 3
[0013] This embodiment 1 provides a composite lithium titanate material and a preparation method thereof. The composite lithium titanate material is prepared according to a method comprising the following steps: S11: Anhydrous lithium acetate and tetrabutyl titanate are weighed at a Li:Ti molar ratio of 0.84:1, and lithium hydroxide and tetrabutyl titanate are dissolved in ethanol respectively using ethanol as a dispersant. Then, formamide and sodium hypochlorite are dissolved in the lithium acetate solution at a Li:N:Na molar ratio of 1:0.2:0.28, and 10 mL of 30% acetic acid is dropped into the solution. Then, the tetrabutyl titanate solution and the lithium acetate-formamide-sodium hypochlorite mixed solution are mixed under stirring; S12: stirring at a constant temperature of 80° C. for 10 hours, drying at 110° C., and then heating to 300° C. in a sintering furnace at a rate of 5° C. / min and sintering for 5 hours to obtain a lithium titanate precursor; S13: placing the obtained lithium titanate precursor in a three-stage furnace, introducing nitrogen, heating to 600° C. at 5° C. / min, and keeping the temperature for 10 hours; cooling, and grinding to obtain a composite powder; S14: After the composite powder is fully ground, it is placed in a three-stage furnace and heated to 600° C. in a nitrogen atmosphere. The nitrogen is then replaced with ammonia and the temperature is raised to 650° C. in an ammonia atmosphere. The temperature is kept at this temperature for 30 minutes to obtain the composite lithium titanate electrode material. Embodiment 4
[0014] This embodiment 1 provides a composite lithium titanate material and a preparation method thereof. The composite lithium titanate material is prepared according to a method comprising the following steps: S11: Anhydrous lithium acetate and tetrabutyl titanate were weighed at a Li:Ti molar ratio of 0.79:1, and lithium hydroxide and tetrabutyl titanate were dissolved in ethanol respectively using ethanol as a dispersant, and then formamide and barium hypochlorite were dissolved in the lithium acetate solution at a Li:N:Ba molar ratio of 1:0.19:0.24. 10 mL of acetic acid was dropped, and then the tetrabutyl titanate solution and the lithium acetate-formamide-barium hypochlorite mixed solution were mixed under stirring; S12: stirring at a constant temperature of 80° C. for 8 hours, drying at 120° C., and then heating to 300° C. in a sintering furnace at a rate of 5° C. / min and sintering for 8 hours to obtain a lithium titanate precursor; S13: placing the obtained lithium titanate precursor in a three-stage furnace, introducing nitrogen, heating to 800° C. at 5° C. / min, and keeping the temperature for 8 hours; cooling, grinding, and obtaining a composite powder; S14: After the composite powder is fully ground, it is placed in a three-stage furnace and heated to 600° C. in an argon atmosphere. The argon is then replaced with ammonia and the temperature is raised to 700° C. in an ammonia atmosphere. The temperature is kept at this temperature for 30 minutes to obtain a nitrogen-nickel co-doped lithium titanate material. Embodiment 5
[0015] This embodiment 1 provides a composite lithium titanate material and a preparation method thereof. The composite lithium titanate material is prepared according to a method comprising the following steps: S11: Anhydrous lithium acetate and tetrabutyl titanate are weighed at a Li:Ti molar ratio of 0.78:1, and ethanol is used as a dispersant to dissolve anhydrous lithium acetate and tetrabutyl titanate in ethanol respectively, and then formamide and barium hypochlorite are dissolved in the lithium acetate solution at a Li:N:Ba molar ratio of 1:0.33:0.16, and 10 ml of acetic acid is dropped into the solution, and then the tetrabutyl titanate solution and the mixed solution of lithium acetate-formamide-barium hypochlorite are mixed under stirring; S12: stirring at a constant temperature of 60° C. for 8 hours, drying at 100° C., and then heating to 500° C. at a rate of 5° C. / min in a sintering furnace and sintering for 4 hours to obtain a lithium titanate precursor; S13: placing the obtained lithium titanate precursor in a three-stage furnace, introducing nitrogen, heating to 800° C. at 5° C. / min, and keeping the temperature for 6 hours; cooling, grinding, and obtaining a composite powder; S14: putting the composite powder into a three-stage furnace, heating it to 600° C. in an argon atmosphere, then replacing the argon with a mixed gas of ammonia and nitrogen, heating it to 700° C. in the mixed gas atmosphere, and keeping the temperature for 45 minutes to obtain the composite lithium titanate electrode material. Embodiment 6
[0016] This embodiment 1 provides a composite lithium titanate material and a preparation method thereof. The composite lithium titanate material is prepared according to a method comprising the following steps: S11: Anhydrous lithium acetate and tetrabutyl titanate were weighed at a Li:Ti molar ratio of 0.82:1, and ethanol was used as a dispersant to dissolve anhydrous lithium acetate and tetrabutyl titanate in ethanol respectively, and then sodium hypochlorite was dissolved in the lithium acetate solution at a Li:Na molar ratio of 1:0.13, and 10 mL of acetic acid was dropped into it, and then the tetrabutyl titanate solution and the lithium acetate-sodium hypochlorite mixed solution were mixed under stirring; S12: stirring at a constant temperature of 80° C. for 4 hours, drying at 120° C., and then heating to 400° C. in a sintering furnace at a rate of 5° C. / min and sintering for 4 hours to obtain a precursor; S13: placing the obtained lithium titanate precursor in a three-stage furnace, introducing nitrogen, heating to 800° C. at 5° C. / min, and keeping the temperature for 6 hours; cooling, and grinding to obtain a composite powder; S14: Formamide is taken at a Li:N molar ratio of 1:0.28, and the composite powder is fully ground and placed in a three-stage furnace, and the temperature is raised to 600°C in an argon atmosphere, and then the argon is replaced with a mixed gas of nitrogen and ammonia, and the temperature is raised to 700°C in an atmosphere of a mixed gas of nitrogen and ammonia. The temperature is kept for 30 minutes to obtain the composite lithium titanate electrode material. Embodiment 7
[0017] This embodiment 1 provides a composite lithium titanate material and a preparation method thereof. The composite lithium titanate material is prepared according to a method comprising the following steps: S11: Anhydrous lithium acetate and tetrabutyl titanate are weighed at a Li:Ti molar ratio of 0.68:1, and ethanol is used as a dispersant to dissolve anhydrous lithium acetate and tetrabutyl titanate in ethanol respectively, and then sodium hypochlorite is dissolved in the lithium acetate solution at a Li:Na molar ratio of 1:0.3, and 10 mL of acetic acid is dropped into the solution, and then the tetrabutyl titanate solution and the mixed solution of lithium acetate-formamide-sodium hypochlorite are mixed under stirring; S12: stirring at a constant temperature of 70° C. for 4 hours, drying at 100° C., and then heating to 300° C. at a rate of 5° C. / min in a sintering furnace and sintering for 4 hours to obtain a precursor; S13: placing the obtained lithium titanate precursor in a three-stage furnace, introducing nitrogen, heating to 800° C. at 5° C. / min, and keeping the temperature for 8 h; cooling, grinding, and obtaining a composite powder; S14: Take formamide at a Li:N molar ratio of 1:0.42, grind it thoroughly with the composite powder, put it into a three-stage furnace, heat it to 600°C in an argon atmosphere, then replace the argon with a mixed gas of ammonia and nitrogen, heat it to 700°C in the atmosphere of the mixed gas, and keep it warm for 1 hour to obtain the composite lithium titanate electrode material.
[0018] Embodiments 8 to 14 The composite lithium titanate materials provided in each of the above embodiments 1 to 7 are used to prepare negative electrodes according to the following methods, and then assembled into lithium-ion batteries: Negative electrode: The composite lithium titanate material provided in each of Examples 1 to 7 is used as the active material, acetylene carbon black is used as the conductive agent, PVDF (polyvinylidene fluoride) is used as the binder, and NMP (N-methyl-2-pyrrolidone) is used as the solvent to prepare a slurry which is applied on copper foil to make pole pieces.
[0019] Lithium-ion battery: Assemble the prepared electrodes into test cells with lithium counter electrodes, electrolyte concentration of 1 mol / L, and polypropylene microporous membrane as the battery separator. Assemble button cells in a glove box filled with argon, and conduct the following electrochemical tests on each lithium-ion battery: 1. The charge and discharge voltage of each lithium-ion battery is 1V to 3V.
[0020] 2. Charge and discharge performance test: The lithium ion battery containing the composite lithium titanate material in Example 1 has a first discharge specific capacity of 191 mAh / g at 0.1C and a charge specific capacity of 177 mAh / g.
[0021] The lithium-ion battery containing the composite lithium titanate material in Example 2 has a first discharge specific capacity of 171 mAh / g and a charge specific capacity of 169 mAh / g at 0.1C.
[0022] The lithium-ion battery containing the composite lithium titanate material in Example 3 has a first discharge specific capacity of 179 mAh / g and a charge specific capacity of 174 mAh / g at 0.1C.
[0023] The lithium ion battery containing the composite lithium titanate material in Example 4 has a first discharge specific capacity of 207 mAh / g and a charge specific capacity of 189 mAh / g at 0.1C.
[0024] The lithium ion battery containing the composite lithium titanate material in Example 5 has a first discharge specific capacity of 191 mAh / g at 0.1C, and a charge specific capacity of 180 mAh / g.
[0025] The lithium ion battery containing the composite lithium titanate material in Example 6 has a first discharge specific capacity of 185 mAh / g and a charge specific capacity of 174 mAh / g at 0.1C.
[0026] The lithium ion battery containing the composite lithium titanate material in Example 7 has a first discharge specific capacity of 189 mAh / g and a charge specific capacity of 177 mAh / g at 0.1C.
[0027] In addition, the composite lithium titanate materials prepared in the above-mentioned embodiments 1 to 7 were subjected to X-ray diffraction (XRD) analysis, wherein the XRD pattern of the composite lithium titanate material prepared in embodiment 4 is as follows: Figure 2 The XRD patterns of the composite lithium titanate materials provided in other embodiments are similar to Figure 2 Approximately, therefore, the composite lithium titanate material prepared by the preparation method of the embodiment of the present invention has a stable structure;
[0106] The lithium ion batteries provided in the above-mentioned embodiments 8 to 14 were respectively tested for the first charge and discharge at 0.1C, the cycle performance at 50C and the coulombic efficiency performance at 50C. Among them, the first charge and discharge curve at 0.1C of the lithium ion battery of the embodiment 11 containing the composite lithium titanate material of the embodiment 4 is shown in Figure 3, and the cycle performance at 50C is shown in Figure 4. Figure 5 As shown, the Coulomb efficiency performance diagram at 50C is as follows Figure 6 The first charge and discharge diagram of the lithium-ion battery at 0.1C, the cycle performance diagram at 50C, and the coulombic efficiency performance diagram at 50C provided by other embodiments are respectively as follows: Figure 3 , Figure 5 , Figure 6 The curves are similar. The comparison of the first charge and discharge curves of the lithium-ion batteries provided in Examples 9, 10 and 11 at 0.1C is shown in the figure below. Figure 4 shown.
[0028] Depend on Figures 3 to 6 It can be seen that the composite lithium titanate material provided by the embodiment of the present invention has stable performance, so that the electrochemical performance of the corresponding lithium ion battery prepared is also stable and excellent, and at the same time has high rate cycle performance.
[0029] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for preparing a composite lithium titanate material, It is characterized in that The steps include: According to the molar ratio of titanium element to lithium element in lithium titanate, a lithium source and a titanium source are measured respectively, and the lithium source, the titanium source and the hypochlorite are dissolved in a solvent to prepare a mixed solution; The mixed solution is heated to 40-90° C. and kept warm, and then the mixed solution is dried and sintered to obtain a precursor; The precursor is calcined in an inert atmosphere, and then ground to obtain a sintered powder; the sintered powder is subjected to a nitrogen-doping heat treatment in a nitrogen-containing atmosphere to obtain a composite lithium titanate material; Wherein, in the step of preparing the mixed solution, a nitrogen-containing organic compound is further added, and the nitrogen-containing organic compound is dissolved in the mixed solution; or / and A nitrogen-containing organic compound is also added in the grinding step, and the nitrogen-containing organic compound is ground together with the calcined precursor; The molar ratio of Li and Ti in the lithium source and titanium source is (0.66-0.96):1; the lithium source, nitrogen-containing organic compound and hypochlorite are added according to the molar ratio of Li:N:A=1:(0.15-0.45):(0.1-0.3), wherein A is the metal element contained in the hypochlorite.
2. The preparation method according to claim 1, Features: In the step of obtaining the precursor, the sintering temperature is 300 to 500° C. and the sintering time is 4 to 8 hours.
3. The preparation method according to claim 1, Features: In the step of obtaining the sintered powder, the calcination temperature is 400 to 1000° C. and the sintering time is 4 to 18 hours; and / or The inert atmosphere is an atmosphere formed by nitrogen or argon.
4. The preparation method according to claim 1, Features: In the step of nitrogen doping heat treatment, the temperature of the nitrogen doping heat treatment is 500-1000° C., and the holding time is 30-120 minutes; and / or The nitrogen-containing atmosphere is an atmosphere formed by at least one of nitrogen gas and ammonia gas.
5. The preparation method according to any one of claims 1 to 4, It is characterized in that The method for preparing the mixed solution comprises the following steps: The nitrogen-containing organic compound and the hypochlorite are dissolved in the lithium source solution, acetic acid is added, and then mixed with the titanium source solution to prepare the mixed solution.
6. The preparation method according to any one of claims 1 to 4, Features: The lithium source includes at least one of lithium hydroxide, lithium acetate and lithium nitrate; and / or The titanium source includes at least one of tetrabutyl titanate, tetraisopropyl titanate and titanium tetrachloride; and / or the nitrogen-containing organic compound includes at least one of formamide and acetamide; and / or The hypochlorite includes at least one of barium hypochlorite, sodium hypochlorite, lithium hypochlorite and potassium hypochlorite.
7. A composite lithium titanate material, It is characterized in that The composite lithium titanate material is prepared by the preparation method described in any one of claims 1-6.
8. A negative electrode comprising a current collector and an active layer bonded to the current collector, Features: The active layer comprises the composite lithium titanate material according to claim 7.
9. A lithium ion battery or supercapacitor comprising a negative electrode, Features: The negative electrode is the negative electrode according to claim 8.