Patent Application
20250027184
The present invention belongs to the field of recycling high-value utilization of secondary resources from waste titanium dioxide carriers, and relates to a method for directly preparing lithium-ion battery material from waste. In particular, the present invention relates to a method for preparing titanium-based self-doped lithium-battery negative electrode material from waste titanium dioxide carrier.
The advantages of titanium dioxide as a catalyst carrier lie in its high chemical stability, large specific surface area, low cost, simple process and so on. At the same time, it also has good performance, can use sunlight or ultraviolet light to excite its surface charge and thus promote the reaction. At present, catalysts using titanium dioxide as a carrier have been widely used in many fields, such as environmental pollution control, energy storage, organic materials and other fields. With the increasing use of titanium dioxide carriers, the number of titanium dioxide carriers scrapped every year is also increasing. If these scrapped catalyst carriers cannot be effectively recycled, they will not only pollute the environment, but also cause a waste of resources. Therefore, proper disposal of waste titanium dioxide carriers has strong economic benefits and environmental significance.
Lithium-ion batteries have the characteristics of high energy density, long life, and rapid charge and discharge. Currently, commercial lithium-ion batteries are not very capable in special battery usage areas, such as deep sea, polar regions, aviation and other application scenarios. This is mainly because most of them use layered graphite-based carbon materials as negative electrodes, which have low working potential (about 0.1V vs Li+/Li). During the charge and discharge process, “lithium dendrites” are easily generated, causing short circuits and restricting their further development. TiNb2O7 not only has the advantages of long cycle life and high safety, but also has a high theoretical specific capacity (387 mAh/g). Moreover, TiNb2O7 shows excellent structural stability during lithiation/delithiation and relatively high operating potential (1.6V relative to Li+/Li), which can effectively prevent the formation of “lithium dendrites” and greatly improve the safety of the battery system. At present, with the rapid development of the new energy industry and the saturation of the petroleum industry, the recovery and preparation of high-value materials from waste catalysts has become a more promising catalyst recycling route.
CN114058853A discloses a method for separating and recovering titanium, vanadium, and tungsten from waste SCR catalyst, which comprises the following contents: dusting and pulverizing the waste SCR catalyst, acidolyzing the waste catalyst powder using concentrated sulfuric acid, leaching the acidolysis product, and making titanium, tungsten, and vanadium in the waste catalyst enter the leach solution together, and then extracting titanium and tungsten using a weakly alkaline extractant, and stripping titanium from the loaded organic phase using sulfuric acid and hydrogen peroxide. However, the added value of the prepared product is low. Therefore, the preparation of new energy materials with higher added value has become a research frontier in the field.
Based on the above content, in view of the problems existing in the present process such as long recycling process, large amount of waste acid and waste alkali used in the recycling process, and failure to utilize the recycled products in high value, the present invention provides a self-doped titanium-niobium-oxygen negative electrode material by using a waste titanium dioxide carrier, a negative electrode material and a lithium-ion battery. The method can directly recycle impurities represented by TiO2 and Al2O3 in the waste titanium dioxide carrier, directly prepare a self-doped TiNb2O7 (titanium niobium oxide) negative electrode material with excellent performance in a short process, realizes a high-value utilization of waste catalysts, improves environmental conditions and saves production costs.
The present invention provides a method for preparing a self-doped TiNb2O7 negative electrode material for lithium battery using waste titanium dioxide carrier, comprising the following steps:
In the present invention, the waste titanium dioxide carrier is a waste catalyst using titanium dioxide as a catalyst carrier, such as a waste SCR catalyst, a vanadium/titanium dioxide catalyst (V-TiO2) and other waste catalysts. In specific embodiments of the present invention, the preparation method of the present invention is described in detail, taking the waste SCR catalyst as a waste titanium dioxide carrier as an example.
In the above method for preparing a self-doped TiNb2O7 negative electrode material for lithium battery using waste titanium dioxide carrier, in step S1, qualified TiO2 powder is obtained by controlling the contents of the main impurity elements in the waste TiO2 carrier after impurity removal, that is, the TiO2 powder; if the Ti content and Al content are not up to standard, a secondary impurity removal is required; based on the weight of oxide, the content of Al in the TiO2 powder is preferably 0.1 to 3.0%, more preferably 0.1 to 2.0%;
In the present invention, based on the weight of oxide, means that, the Ti content is calculated as TiO2, the Al content is calculated as Al2O3, the V content is calculated as V2O5, and the W content is calculated as WO3. In a specific embodiment of the present invention, after the TiO2 powder is digested with an acid, the content of each of the elements is obtained by ICP, and the digestion can be digested using HF or aqua regia.
In the above method for preparing a self-doped TiNb2O7 negative electrode material for lithium battery using waste titanium dioxide carrier, preferably, a mass percentage of titanium dioxide in the waste titanium dioxide carrier is 70% to 95%;
In a specific embodiment of the present invention, based on the total weight of the waste titanium dioxide carrier, the waste titanium dioxide carrier comprises 76.50 wt % of titanium dioxide, 5.31 wt % of aluminum oxide, 2.94wt % of tungsten trioxide, 0.93 wt % of vanadium pentoxide, 8.39 wt % of silica oxide and 0.30 wt % of molybdenum trioxide.
In the above method for preparing a self-doped TiNb2O7 negative electrode material for lithium battery using waste titanium dioxide carrier, preferably, the converting in step S1comprising:
The inventive concept of step S1 in the present invention is as follows:
TiO2 is separated using “sodium roasting+water leaching+acid leaching precipitation+roasting”. The metal oxides in the waste catalyst are converted into corresponding sodium salts (such as Na2TiO3, Na2WO4, NaVO3, etc.) through sodium roasting. The water-soluble components in the sodium salt are removed by water leaching, and the water-insoluble sodium titanium salts (such as Na2TiO3, Na8Ti5O14, etc.) can be dissolved in the solution by acid leaching. And then an appropriate amount of alkali is added to precipitate Ti by adjusting the pH of the solution. Finally, relatively pure TiO2 is obtained through high-temperature roasting.
The inventors of the present invention discovered during the research process that by using the above conversion method and controlling specific heat treatment conditions and leaching reagents, the TiO2 powder with higher content can be obtained, effectively leaching impurity ions efficiently and directly preparing high-value materials.
In step S10, the washing is washing with water and then drying. In a specific embodiment of the present invention, ultrasonic washing with deionized water is used to remove the fly ash impurities on the surface followed by drying in a vacuum drying oven at 60° C.
Preferably, the ball milling is passing the the waste titanium dioxide carrier through a 325-mesh sieve. The inventors found that the preferred embodiment can effectively reduce the particle size of the catalyst, which is beneficial to the subsequent heat treatment process.
In step S11, taking sodium carbonate as the roasting material as an example, the reaction equation that may occur during the sodium roasting process is as follows:
TiO2+Na2CO3→Na2TiO3+CO2↑
Al2O3+Na2CO3→2NaAlO2+CO2↑
WO3+Na2CO3→Na2WO4+CO2↑
V2O5+Na2CO3→2NaVO3+CO2↑
SiO2+Na2CO3→Na2SiO3+CO2↑
MoO3+Na2CO3→Na2MoO4+CO2↑
Through the above reactions, each of the elements in the waste titanium dioxide carrier is converted into the corresponding sodium salt.
The step S11 further comprises passing the clinker through a 200-mesh sieve for later use.
In step S12, preferably, a temperature of the first leaching can be 60° C. to 90° C., such as 60 to 80° C., 60° C., 70° C. or 80° C.
A time of the first leaching time is 1 h to 10 h, such as 6 h.
A material-to-liquid ratio of the first leaching can be 1 g:30 mL.
Under the above conditions, the main components in the first leaching solution are NaVO3, Na2WO4, and NaAlO2, etc. The main components of the first leaching residue are titanium-containing sodium salts such as Na2TiO3, Na8Ti5O14, and Na2Ti3O7, as well as a small portion of unreacted Al2O3 and other impurity elements.
The drying of the first leaching residue is vacuum drying, and a temperature of the drying can be 60° C. to 90° C. (such as 60° C.), for a time of 12 hours.
In step S13, preferably, the acid is one or more of H2SO4 and HCl.
The acid is existed in the form of an aqueous solution, and a concentration of the acid in the aqueous solution can be 3 to 5 mol/L, such as 5 mol/L.
The second leaching can be performed in a temperature of 80-90° C., such as 80° C.
The second leaching can be performed for a time of 5 to 24 hours, such as 6 hours.
A material-to-liquid ratio of the second leaching is 1 g:30 mL, such as 1 g:30 mL.
Under the above conditions, a main component in the second leaching solution is TiOSO4.
In step S13, taking H2SO4 as the leaching acid as an example, a reaction equation that
may occur during the leaching process is as follows:
Na2TiO3+2H+→H2TiO3+2Na+
H2TiO3+SO42−+2H+→TiO2++SO42−+H2O
Through the above reaction, the water-insoluble sodium titanium salt in the waste titanium dioxide carrier is dissolved in the acid.
In the present invention, the leaching solution or leaching residue can be collected by solid-liquid separation of the leached system. The solid-liquid separation method includes but is not limited to centrifugation and other separation methods.
In step S13, preferably, the alkaline reagent can be one or more of ammonia, Na2CO3, NaOH, or urea.
The alkaline reagent is added in the form of an aqueous solution with a concentration of 1 to 100 g/L, such as 100 g/L.
The aqueous solution of the alkaline reagent is added dropwise in at a rate of 0.5 to 1 ml/min, such as 0.5 ml/min.
An addition amount of the alkaline reagent is controlled so that the pH value of the system can be 2.5 to 5, such as 4 to 5, 4 or 5;
The precipitate is H2TiO3, and TiO2+ in the solution is completely precipitated by adjusting pH in the solution using the alkaline reagent. Taking H2SO4 as the leaching acid as an example, a reaction equation that may occur when adding an alkali solution is as follows:
TiO2++SO42 −+H2O→H2TiO3+SO42−+2H+
In step S14, the drying is vacuum drying, a temperature of the drying is 60-80° C., such as 60° C., for a time of 12-24 h, such as 12 h.
In step S14, the roasting is performed in an air atmosphere, a temperature of the roasting is 600° C., and a holding time of the roasting is 3 to 5 hours (such as 3 hours). In the specific embodiment of the present invention, a heating rate is set to 5° C./min. A reaction equation is as follows:
H2TiO3→TiO2+H2O↑
In the above method for preparing self-doped TiNb2O7 negative electrode material for lithium battery using waste titanium dioxide carrier, in step S2, it is prepared by a high-temperature solid phase method;
In step S2, the roasting is performed in an air atmosphere, a temperature of the roasting can be 1100° C. to 1300° C., such as 1100° C., 1150° C., 1300° C., and a holding time of the roasting can be 8 to 12 hours, such as 10 hours. In a specific embodiment of the present invention, a heating rate is 5° C./min.
In a specific embodiment of the invention, the roasting is performed in a muffle furnace.
The present invention further provides a self-doped TiNb2O7 negative electrode material prepared by the method for preparing self-doped TiNb2O7 negative electrode material for lithium battery using waste titanium dioxide carrier as described in any one of the above.
The invention also provides a lithium-ion battery, which comprises a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte. The negative electrode sheet comprises a current collector and the self-doped TiNb2O7 negative electrode material loaded on the current collector.
For example, the current collector is copper foil; the positive electrode sheet is a lithium metal sheet; the separator is a PE separator; and the electrolyte is EC:DMC=1:1 (vol) containing 1 mol/L LiPF6.
The present invention has the following beneficial effects:
The present invention will be described in further detail below in combination with specific embodiments. The examples given are only for illustrating the present invention and are not intended to limit the scope of the present invention. The examples provided below can serve as a guide for those skilled in the art to make further improvements, and do not limit the present invention in any way.
The experimental methods used in the following examples are conventional methods unless otherwise specified; the materials, reagents, etc. used can be obtained from commercial sources unless otherwise specified.
In the following examples, based on the total weight of the waste titanium dioxide carrier, the waste titanium dioxide carrier comprises 76.50 wt % of titanium dioxide, 5.31 wt % of aluminum oxide, 2.94 wt % of tungsten trioxide, 0.93 wt % of vanadium pentoxide, 8.39 wt % of silicon dioxide and 0.30 wt % of molybdenum trioxide.
The purity of commercial TiO2 in the following comparative examples is 99%.
The roasting in the following examples is performed in an air atmosphere (in a muffle furnace) unless otherwise specified.
This example provides a method for preparing self-doped negative electrode material TiNb2O7 for lithium battery using waste titanium dioxide carrier. As shown in
The XRD of the Al self-doped TiNb2O7 negative electrode material obtained in this example is shown in
The impedance performance of Al—TNO was tested; the frequency range of the test was 0.01-105 Hz and the amplitude of the sinusoidal alternating current signal was 5 mV. The battery impedance test was performed using Shanghai Chenhua CHI760E electrochemical workstation. FIG. 6 shows the impedance performance graph of the battery after being activated 3 times and cycled 10 times, 20 times, 50 times, and 100 times at a rate of 1 C. It can be seen that the initial electrochemical polarization resistance Rct of the battery is about 3 Ω, and increased after cycling and activation; especially after 100 cycles, the impedance increases from the initial 3Ω to about 22Ω. It indicates that the initial performance of the battery will be slightly reduced after Al doped, but the battery capacity will decay slowly. This may be because the addition of Al stabilizes the lattice gap.
The properties of the battery material prepared in this example are shown in Table 1.
This example used a method similar to that in Example 1 to prepare a titanium-based self-doped lithium battery negative electrode material TiNb2O7 using a waste titanium dioxide carrier. The difference was that in step (7), the roasting temperature was 1150° C. and the time was 8 hours.
The properties of the battery material prepared in this example are shown in Table 1.
This example used a method with (1) to (4) similar to that in Example 1 to prepare a titanium-based self-doped lithium battery negative electrode material TiNb2O7 using a waste titanium dioxide carrier. The difference were as follows: in step (5), the second leaching solution of 10 ml was placed in a 100 ml beaker for stirring, and an aqueous solution of urea (100 g/L) was slowly added dropwise into the mixed solution using a peristaltic pump at a rate of 0.5 ml/min until the pH value reached 4.
The properties of the battery material prepared in this example are shown in Table 1.
Example 4
This example used a method similar to that in Example 3 to prepare a titanium-based self-doped lithium battery negative electrode material TiNb2O7 using a waste titanium dioxide carrier. The difference was as follows: in step (2), NaOH was used as the added material. In step (6), after testing, the contents of the elements were as follows: Ti content (calculated as TiO2) was 96.66%, Al content (calculated as Al2O3) was 3.77%, V content (content calculated as V2O5) was 0.28%, and W content (calculated as WO3) was 0.19%.
The properties of the battery material prepared in this example are shown in Table 1.
This example used a method similar to that in Example 3 to prepare a titanium-based self-doped lithium battery negative electrode material TiNb2O7 using a waste titanium dioxide carrier. The difference was as follows: in step (5), NaOH was used as the added material. In step (6), after testing, the contents of the element were as follows: Ti content (calculated as TiO2) was 97.11%, Al content (calculated as Al2O3) was 2.43%, V content (content calculated as V2O5) was 0.09%, and W content (calculated as WO3) was 0.17%.
The properties of the battery material prepared in this example are shown in Table 1.
This example used a method similar to that in Example 3 to prepare a titanium-based self-doped lithium battery negative electrode material TiNb2O7 using a waste titanium dioxide carrier. The difference was that in step (8), the roasting temperature was 1300° C.
The properties of the battery material prepared in this example are shown in Table 1.
This example used a method similar to that in Example 1 to prepare a titanium-based self-doped lithium battery negative electrode material TiNb2O7 using a waste titanium dioxide carrier. The difference was as follows: in step (2), the amount of sodium carbonate was 12.5 g, that is, the ratio of the additive to the waste titanium dioxide carrier was 2.5. In step (6), after testing, the contents of the elements were as follows: Ti content (calculated as TiO2) is 95.58%, Al content (calculated as Al2O3) is 3.89%, V content (content calculated as V2O5) is 0.12%, W content (calculated as WO3) is 0.21%.
The properties of the battery material prepared in this example are shown in Table 1.
This example used a method similar to that in Example 1 to prepare a titanium-based self-doped lithium battery negative electrode material TiNb2O7 using a waste titanium dioxide carrier. The difference was as follows: in step (2), the amount of sodium carbonate was 15 g, that is, the ratio of the additive to the waste titanium dioxide carrier was 3. In step (6), after testing, the contents of the element were as follows: Ti content (calculated as TiO2) was 96.76%, Al content (calculated as Al2O3) was 3.11%, V content (content calculated as V2O5) was 0.08%, and W content (calculated as WO3) was 0.10%. The properties of the battery material prepared in this example are shown in Table 1.
This example used a method similar to that in Example 1 to prepare a titanium-based self-doped lithium battery negative electrode material TiNb2O7 using a waste titanium dioxide carrier. The difference was as follows: in step (2), the roasting temperature was 650° C. In step (6), after testing, the contents of the element were as follows: Ti content (calculated as TiO2) was 95.99%, Al content (calculated as Al2O3) was 3.76%, V content (content calculated as V2O5) was 0.19%, and W content (calculated as WO3) was 0.22%.
The properties of the battery material prepared in this example are shown in Table 1.
This example used a method similar to that in Example 1 to prepare a titanium-based self-doped lithium battery negative electrode material TiNb2O7 using a waste titanium dioxide carrier. The difference was as follows: in step (2), the roasting temperature was 750° C. In step (6), after testing, the contents of the element were as follows: Ti content (calculated as TiO2) was 96.81%, Al content (calculated as Al2O3) was 2.93%, V content (calculated as V2O5) was 0.06%, and W content (calculated as WO3) was 0.17%.
The properties of the battery material prepared in this example are shown in Table 1.
This example used a method similar to that in Example 2 to prepare a titanium-based self-doped lithium battery negative electrode material TiNb2O7 using a waste titanium dioxide carrier. The difference was as follows: in step (3), the leaching temperature was 70° C. In step (6), after testing, the contents of the elements were as follows: Ti content (calculated as TiO2) was 98.03%, Al content (calculated as Al2O3) was 3.15%, V content (calculated as V2O5) was 0.03%, and W content (calculated as WO3) was 0.16%.
This example used a method similar to that in Example 2 to prepare a titanium-based self-doped lithium battery negative electrode material TiNb2O7 using a waste titanium dioxide carrier. The difference was as follows: in step (3), the leaching temperature was 80° C. In step (6), after testing, the contents of the elements were as follows: Ti content (calculated as TiO2) is 98.64%, Al content (calculated as Al2O3) was 2.78%, V content (calculated as V2O5) was 0.05%, and W content (calculated as WO3) was 0.21%.
This example used a method similar to Example 1 to prepare a titanium-based lithium battery negative electrode material TiNb2O7. The difference was as follows: steps (1) to (5) were cancelled, and in step (6), a commercial TiO2 was mixed with Nb2O5.
The properties of the battery material prepared in this comparative example are shown in Table 1.
This example used a method similar to that of Example 2 to prepare a titanium-based lithium battery negative electrode material TiNb2O7. The difference was that in step (6), a commercial TiO2 was mixed with Nb2O5.
The properties of the battery material prepared in this comparative example are shown in Table 1.
This example used a method similar to that of Example 3 to prepare a titanium-based lithium battery negative electrode material TiNb2O7. The difference was that in step (7), a commercial TiO2 was mixed with Nb2O5.
The properties of the battery material prepared in this comparative example are shown in Table 1.
This example used a method similar to that of Example 4 to prepare a titanium-based lithium battery negative electrode material TiNb2O7. The difference was that in step (7), a commercial TiO2 was mixed with Nb2O5.
The properties of the battery material prepared in this comparative example are shown in Table 1.
This example used a method similar to that of Example 5 to prepare a titanium-based lithium battery negative electrode material TiNb2O7. The difference was that in step (7), a commercial TiO2 was mixed with Nb2O5.
The properties of the battery material prepared in this comparative example are shown in Table 1.
This example used a method similar to that of Example 6 to prepare a titanium-based lithium battery negative electrode material TiNb2O7. The difference was that in step (7), a commercial TiO2 was mixed with Nb2O5.
The properties of the battery material prepared in this comparative example are shown in Table 1.
This example used a method similar to that of Example 7 to prepare a titanium-based lithium battery negative electrode material TiNb2O7. The difference was that in step (6), a commercial TiO2 was mixed with Nb2O5.
The properties of the battery material prepared in this comparative example are shown in Table 1.
This example used a method similar to that of Example 8 to prepare a titanium-based lithium battery negative electrode material TiNb2O7. The difference was that in step (6), a commercial TiO2 was mixed with Nb2O5.
The properties of the battery material prepared in this comparative example are shown in Table 1.
This example used a method similar to that of Example 9 to prepare a titanium-based lithium battery negative electrode material TiNb2O7. The difference was that in step (7), a commercial TiO2 was mixed with Nb2O5.
The properties of the battery material prepared in this comparative example are shown in Table 1.
This example used a method similar to that of Example 10 to prepare a titanium-based lithium battery negative electrode material TiNb2O7. The difference was that in step (6), a commercial TiO2 was mixed with Nb2O5.
The properties of the battery material prepared in this comparative example are shown in Table 1.
This example used a method similar to that of Example 11 to prepare a titanium-based lithium battery negative electrode material TiNb2O7. The difference was that in step (6), a commercial TiO2 was mixed with Nb2O5.
The properties of the battery material prepared in this comparative example are shown in Table 1.
This example used a method similar to that of Example 12 to prepare a titanium-based lithium battery negative electrode material TiNb2O7. The difference was that in step (6), a commercial TiO2 was mixed with Nb2O5.
The properties of the battery material prepared in this comparative example are shown in Table 1.
It can be seen from Table 1 that, compared with the undoped TiNb2O7 negative electrode material, the aluminum self-doped TiNb2O7 lithium battery negative electrode material prepared by the present invention has an initial specific capacity slightly lower than that of the undoped commercial material, but has excellent cycle stability performance during the subsequent charge-discharge process.
The present invention has been described in detail above. For those skilled in the art, the present invention can be implemented in a wider range under equivalent parameters, concentrations and conditions without departing from the spirit and scope of the present invention. Although specific embodiments of the present invention have been shown, it should be understood that further modifications can be made to the invention. In short, based on the principles of the present invention, the present application is intended to include any changes, uses, or improvements to the present invention, including changes that depart from the scope disclosed in this application and are made using conventional techniques known in the art
| Number | Date | Country | Kind |
|---|---|---|---|
| 202310905266.X | Jul 2023 | CN | national |
