Layered double metal solid solution nitride negative electrode material and preparation method and application thereof

Abstract

The application provides a layered double metal solid solution nitride negative electrode material and a preparation method and application thereof, and belongs to the technical field of lithium ion batteries. The preparation method takes layered double transition metal carbide (TiVC or NbVC MXene) as raw material, places a proper amount of MXene in a corundum crucible, and then puts the corundum crucible into a tube furnace, and then introduces argon into the tube furnace to remove impurity gases in the tube; then, the temperature is programmed to a predetermined temperature, and ammonia is introduced for calcination; then, argon is introduced to cool to room temperature, and the layered double metal solid solution nitride negative electrode material is obtained. The method has the characteristics of simplicity and high efficiency, solves the problem that the preparation of a two-dimensional layered solid solution nitride is difficult, and the solid solution nitride prepared by the method has high capacity and excellent rate performance and cycle performance.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery storage technology, specifically to a layered bimetallic solid solution nitride anode material, its preparation method, and its application. Background Technology

[0002] In recent years, lithium-ion batteries (LIBs) have gained widespread application due to their abundant resources, safety, and high energy density. Among these, the anode material, as a key component of LIBs, is crucial. Transition metal nitrides (TMNs) have attracted considerable attention due to their relative stability and good conductivity; however, TMNs have relatively low capacity. Modifying the structure of TMNs is an effective way to improve capacity. Two-dimensional structural materials are widely used due to their large specific surface area, good stability, and high capacity. Accordion-shaped two-dimensional transition metal carbides / nitrides (MXenes) show great promise for applications in both energy storage and electronic engineering. Obtaining ideal layered transition metal nitrides by nitriding MXenes with ammonia is a feasible approach. However, the conductivity of single-metal TMNs remains limited. To further improve conductivity, solid solution strategies are an effective approach because bimetallic solid solutions can enhance the interactions between metals at the atomic level. Although solid solution anode materials have enormous application potential in lithium-ion batteries, there are few reports on the application of dual transition metal solid solution materials in energy storage. In particular, the preparation of layered solid solution nitrides is quite difficult, limiting its further research. Summary of the Invention

[0003] This invention provides a layered bimetallic solid solution nitride anode material, its preparation method, and its application to solve the above-mentioned technical problems. The synthesis method is simple and efficient, and the obtained material exhibits excellent rate performance and cycle stability during lithium-ion battery testing, as well as high conductivity and capacity.

[0004] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing a layered bimetallic solid solution nitride anode material, characterized in that the preparation method includes the following steps: Using layered bimetallic MXene (carbide) as raw material, an appropriate amount of MXene is first placed in a corundum crucible and then placed in a tube furnace. Argon gas is introduced into the tube furnace to remove impurity gases inside the tube. Then, the temperature is increased to a predetermined temperature and ammonia gas is introduced for calcination for 1-6 hours. After that, argon gas is introduced to cool to room temperature, and the layered bimetallic solid solution nitride anode material is obtained. It has a two-dimensional layered structure and XRD shows a single solid solution phase.

[0005] Preferably, the dual transition metal MXene raw material is TiVC or NbVC.

[0006] Preferably, the predetermined temperature is 700~1100 ℃.

[0007] Preferably, the ammonia nitriding reaction time is 1-6 h.

[0008] The preparation method described above yields a bimetallic (TiV or NbV) layered solid solution nitride anode material.

[0009] This invention also provides a method for preparing a lithium-ion battery anode: a solid solution nitride, carbon black (conductive agent), and polyvinylidene fluoride (PVDF, binder) in a mass percentage ratio of (70~85):(10~20):(5~10) are mixed and ground, and NMP is added to prepare a uniform slurry. This slurry is then uniformly coated onto a copper foil to obtain a lithium-ion battery anode. A lithium sheet is used as the positive electrode, a mixture of LiPF6, ethylene carbonate (EC), and dimethyl carbonate (DMC) (volume ratio 1:1) is used as the electrolyte, and a Celgard 2325 polypropylene porous membrane is used as the separator to assemble the battery.

[0010] This invention provides a layered bimetallic solid solution nitride anode material and its preparation method. Compared with the prior art, this material has the following advantages when used in lithium-ion batteries: 1) This preparation method is simple and efficient, and solves the problem of the difficulty in preparing two-dimensional solid solution nitrides.

[0011] 2) The unique two-dimensional layered structure inherited from MXene gives this material a fast lithium-ion diffusion channel and a large specific surface area.

[0012] 3) The combination of two-dimensional structure, bimetallic composition, and nitride properties gives the material high conductivity and capacity, making it a promising candidate for lithium-ion batteries. In the electrochemical performance tests conducted in this paper, TiVN achieved a conductivity of 1 A g / L. -1 The cycle life can be stabilized at 1000 times, and the capacity reaches 132 mAh g. -1 NbVN at 1 A g -1 The cycle life can be stabilized at 1400 times, and the capacity reaches 216 mAh g. -1 .

[0013] Taking advantage of these advantages, the synthesized layered bimetallic solid solution nitride anode material has good application prospects in lithium-ion batteries. Attached Figure Description

[0014] Figure 1The image shows the X-ray diffraction (XRD) pattern of Example 1. Comparison with the standard card confirms the successful preparation of the TiVN solid solution phase.

[0015] Figure 2 The X-ray diffraction (XRD) pattern is shown in Example 2.

[0016] Figure 3 The image shows the XRD pattern of Example 3. Comparison with the standard card confirms that the NbVN solid solution phase was successfully prepared.

[0017] Figure 4 The image shown is the XRD pattern of Example 4.

[0018] Figure 5 This is a scanned image (SEM) of Example 1.

[0019] Figure 6 This is a SEM image of Example 3. In Example 2, the formation of the surface porous structure is related to Nb, which increases the specific surface area and contributes to the improvement of electrochemical performance.

[0020] Figure 7 This is a high-resolution transmission electron microscope (TEM) image of Example 3.

[0021] Figure 8 This is the rate performance of the lithium-ion battery assembled in Example 1.

[0022] Figure 9 This is the rate performance of the lithium-ion battery assembled in Example 3.

[0023] Figure 10 After being assembled into a lithium-ion battery in Example 1, it was measured at 1 A g. -1 The loop performance is as follows.

[0024] Figure 11 After being assembled into a lithium-ion battery in Example 3, it was measured at 1 A g. -1 The loop performance is as follows. Detailed Implementation

[0025] The implementation process of the present invention will be further described below with reference to the accompanying drawings.

[0026] Example 1 Using layered bimetallic MXene (TiVC) as raw material, 0.2 g of TiVC was first placed in an alumina crucible and then placed in a tube furnace. Argon gas was introduced into the tube furnace to remove impurity gases inside the tube. Then, the temperature was programmed to rise (5 °C / min) to 700 °C and ammonia gas was introduced for calcination for 2 h. After that, argon gas was introduced to cool to room temperature, and the layered bimetallic solid solution TiVN anode material was obtained.

[0027] A solid solution nitride, carbon black, and PVDF in a mass ratio of 70:20:10 were mixed and ground, and then NMP was added to prepare a uniform slurry. This slurry was then uniformly coated onto copper foil to obtain the negative electrode for a lithium-ion battery. A lithium sheet was used as the positive electrode, a mixture of LiPF6, ethylene carbonate (EC), and dimethyl carbonate (DMC) (volume ratio 1:1) was used as the electrolyte, and a Celgard 2325 polypropylene porous membrane was used as the separator to assemble the battery.

[0028] Example 2 Unlike Example 1, Example 2 mainly changed the nitriding temperature to 900 °C.

[0029] Using layered bimetallic MXene (TiVC) as raw material, 0.2 g of TiVC was first placed in an alumina crucible and then placed in a tube furnace. Argon gas was introduced into the tube furnace to remove impurity gases inside the tube. Then, the temperature was programmed to rise (5 °C / min) to 900 °C and ammonia gas was introduced for calcination for 2 h. After that, argon gas was introduced to cool to room temperature, and the layered bimetallic solid solution TiVN anode material was obtained.

[0030] A solid solution nitride, carbon black, and PVDF in a mass ratio of 70:20:10 were mixed and ground, and then NMP was added to prepare a uniform slurry. This slurry was then uniformly coated onto copper foil to obtain the negative electrode for a lithium-ion battery. A lithium sheet was used as the positive electrode, a mixture of LiPF6, ethylene carbonate (EC), and dimethyl carbonate (DMC) (volume ratio 1:1) was used as the electrolyte, and a Celgard 2325 polypropylene porous membrane was used as the separator to assemble the battery.

[0031] Example 3 Unlike Example 1, Example 3 prepared NbVN.

[0032] Using layered bimetallic MXene (NbVC) as raw material, 0.2 g of NbVC was first placed in an alumina crucible and then placed in a tube furnace. Argon gas was introduced into the tube furnace to remove impurity gases inside the tube. Then, the temperature was programmed to rise (5 °C / min) to 700 °C and ammonia gas was introduced for calcination for 2 h. After that, argon gas was introduced to cool to room temperature, and the layered bimetallic solid solution NbVN anode material was obtained.

[0033] A solid solution nitride, carbon black, and PVDF in a mass ratio of 70:20:10 were mixed and ground, and then NMP was added to prepare a uniform slurry. This slurry was then uniformly coated onto copper foil to obtain the negative electrode for a lithium-ion battery. A lithium sheet was used as the positive electrode, a mixture of LiPF6, ethylene carbonate (EC), and dimethyl carbonate (DMC) (volume ratio 1:1) was used as the electrolyte, and a Celgard 2325 polypropylene porous membrane was used as the separator to assemble the battery.

[0034] Example 4 Unlike Example 3, Example 4 mainly changed the nitriding time to 5 hours.

[0035] Using layered bimetallic MXene (NbVC) as raw material, 0.2 g of NbVC was first placed in an alumina crucible and then placed in a tube furnace. Argon gas was introduced into the tube furnace to remove impurity gases and prevent oxidation or side reactions of the sample. Then, the temperature was programmed to rise (5 °C / min) to 700 °C and calcined with ammonia gas for 5 h. After that, argon gas was introduced to cool to room temperature, and the layered bimetallic solid solution NbVN anode material was obtained.

[0036] A solid solution nitride, carbon black, and PVDF in a mass ratio of 70:20:10 were mixed and ground, and then NMP was added to prepare a uniform slurry. This slurry was then uniformly coated onto copper foil to obtain the negative electrode for a lithium-ion battery. A lithium sheet was used as the positive electrode, a mixture of LiPF6, ethylene carbonate (EC), and dimethyl carbonate (DMC) (volume ratio 1:1) was used as the electrolyte, and a Celgard 2325 polypropylene porous membrane was used as the separator to assemble the battery.

[0037] The present invention provides a layered bimetallic solid solution nitride anode material and its preparation method, which have been clearly and thoroughly described through examples. Those skilled in the art can further understand and implement the present invention through appropriate combinations without departing from the above discussion. Any modifications and substitutions that are obviously similar to the present invention are within the protection scope of the present invention.

Claims

1. A method for preparing a layered bimetallic solid solution nitride anode material, characterized in that, The preparation method includes the following steps: using layered bimetallic MXene as raw material, an appropriate amount of MXene is first placed in an alumina crucible and then placed in a tube furnace. Argon gas is introduced into the tube furnace to remove impurity gases inside the tube. Subsequently, the temperature is increased to a predetermined temperature and ammonia gas is introduced for calcination to carry out an ammonia nitridation reaction. Afterward, argon gas is introduced to cool to room temperature to obtain the layered bimetallic solid solution nitride anode material, which has a two-dimensional layered structure and XRD shows a single solid solution phase. The bimetallic MXene raw material is TiVC or NbVC.

2. The method for preparing a layered bimetallic solid solution nitride anode material as described in claim 1, characterized in that, The predetermined temperature is 700~1100 ℃.

3. The method for preparing a layered bimetallic solid solution nitride anode material as described in claim 1, characterized in that, The ammonia nitriding reaction time is 1-6 h.

4. The method for preparing a layered bimetallic solid solution nitride anode material as described in claim 1, characterized in that, The obtained layered bimetallic solid solution nitride anode material is a layered bimetallic solid solution TiVN anode material or a layered bimetallic solid solution NbVN anode material.

5. The layered bimetallic solid solution nitride anode material obtained by the preparation method of the layered bimetallic solid solution nitride anode material according to any one of claims 1 to 4.

6. The application of the layered bimetallic solid solution nitride anode material as described in claim 5 in lithium-ion batteries.

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