Anti-perovskite material, preparation method thereof, positive electrode material and lithium ion battery

Abstract

The application provides an inverse perovskite material, a preparation method of the inverse perovskite material, a positive electrode material and a lithium ion battery, and belongs to the technical field of electrode materials. 2±x M 1±y Ch m O n ; wherein 0<=x<=0.5, 0<=y<=0.3, 0.8<=m<=1.2, 0.8<=n<=1.2, and m<=n; M is selected from metal elements other than Li and / or metalloid elements other than Te, and M comprises at least five elements; and Ch is selected from chalcogen elements. The inverse perovskite material provided by the application has high crystal structure stability; when the inverse perovskite material is used as a positive electrode material, the lithium ion battery prepared by using the positive electrode material has good cycle performance, first charge-discharge efficiency and first discharge capacity.

Description

Technical Field

[0001] This application relates to the field of electrode materials technology, and more specifically, to an anti-perovskite material and its preparation method, a cathode material, and a lithium-ion battery. Background Technology

[0002] The cathode material of a lithium-ion battery is a crucial component that largely determines the battery's discharge capacity, cycle life, and safety performance.

[0003] Currently, commercially available lithium-ion battery cathode materials mainly include LiCoO2 (α-NaFeO2 type layered structure), LiFePO4 (olivine type), and LiMn2O4 (spinel type). However, these cathode materials still have significant room for improvement in terms of cycle performance and first-cycle discharge capacity, and cannot meet the performance requirements of cathode materials driven by continuous technological advancements. Summary of the Invention

[0004] The purpose of this application is to provide an anti-perovskite material and its preparation method, a cathode material, and a lithium-ion battery, which aims to simultaneously improve the cycle performance and first-cycle discharge capacity of the cathode material.

[0005] Firstly, this application provides an anti-perovskite material having an anti-perovskite structural phase, and the general chemical formula of the anti-perovskite material is Li. 2±x M 1±y Ch m O n Wherein, 0≤x≤0.5, 0≤y≤0.3, 0.8≤m≤1.2, 0.8≤n≤1.2, and m≤n; M is selected from metallic elements other than Li and / or metalloid elements other than Te, and M includes at least five elements; Ch is selected from chalcogenides.

[0006] This application utilizes Li, M (selected from metals other than Li and / or metalloids other than Te, and including at least five elements), chalcogenides, and oxygen in combination, and regulates the ratio of each element to form a cubic anti-perovskite material with an octahedral crystal structure. In the crystal structure of this anti-perovskite material, the M element occupies the vertex positions of the octahedron. The M element includes at least five elements, allowing the at least five M elements to share the same atomic sites and to exhibit random arrangement in the crystal structure of the anti-perovskite material, displaying short-range disorder. This results in a large mixing entropy for the anti-perovskite material, thereby giving it high crystal structure stability. Furthermore, m ≤ n (i.e., the number of O atoms is greater than or equal to the number of Ch (chalcogenide) atoms) can further improve the stability of the crystal structure of the anti-perovskite material. Using this anti-perovskite material as a cathode material enables lithium-ion batteries made with this cathode material to have better cycle performance, first-cycle charge-discharge efficiency, and first-cycle discharge capacity.

[0007] In conjunction with the first aspect, in an optional embodiment of this application, the ratio of the number of atoms of each element in M ​​to the total number of atoms in M ​​is ≤40%.

[0008] The above technical solution is conducive to further improving the cycle performance and first-cycle discharge capacity of lithium-ion batteries prepared using this anti-perovskite material as the cathode material.

[0009] In conjunction with the first aspect, in an optional embodiment of this application, the ratio of m to n is 1:(1.00-1.15). The above technical solution can improve the stability of the crystal structure of the anti-perovskite material, which in turn helps to improve the first-cycle discharge capacity of lithium-ion batteries prepared using the anti-perovskite material as the cathode material.

[0010] Optionally, the ratio of m to n is 1:(1.05-1.12).

[0011] In conjunction with the first aspect, in optional embodiments of this application, M is selected from at least five of the following: Na, K, Mg, Ca, Sr, Ba, Zn, Sc, Y, Al, Ga, Ti, Zr, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Ni, Si, Sn, and Sb.

[0012] In conjunction with the first aspect, in an optional embodiment of this application, M is selected from at least five metallic elements other than Li.

[0013] The above technical solution is conducive to further improving the first-cycle discharge capacity of lithium-ion batteries prepared using this anti-perovskite material as the cathode material.

[0014] Optionally, M is selected from at least five of Na, Fe, Co, Mn, Ni, Nb, V, and Ti.

[0015] In conjunction with the first aspect, in an optional implementation of this application, Ch is selected from S.

[0016] The above technical solution is conducive to further improving the first-cycle discharge capacity of lithium-ion batteries prepared using this anti-perovskite material as the cathode material.

[0017] In conjunction with the first aspect, in an optional embodiment of this application, the anti-perovskite material is Li. 1.8 Fe 0.2 Co 0.2 Mn 0.2 Ni 0.1 Nb 0.1 V 0.05 Ti 0.05 SO, Li 1.6 Fe 0.2 Co 0.2 Mn 0.2 Ni 0.1 Nb 0.1 V 0.05 Ti 0.05 S 0.9 O or Li 1.7 Fe 0.2 Co 0.2 Mn 0.2 Ni 0.1 Nb 0.1 V 0.05 Ti 0.05 S 0.95 O.

[0018] When the anti-perovskite material is selected from the above materials, the lithium-ion battery prepared using the anti-perovskite material as the cathode material has better cycle performance, first charge-discharge efficiency and first discharge capacity.

[0019] Optionally, the anti-perovskite material is Li 1.6 Fe 0.2 Co 0.2 Mn 0.2 Ni 0.1 Nb 0.1 V 0.05 Ti 0.05 S 0.9 O.

[0020] Secondly, this application provides a method for preparing the anti-perovskite material provided in the first aspect above, comprising: ball milling the raw material at a speed of 550-1000 rpm for at least 5 hours; wherein the raw material includes a lithium source and an M source. The lithium source is selected from Li2O and / or Li2Ch, and the M source includes at least one of the following: an element corresponding to M, an oxide of M, and a substance composed of M and Ch.

[0021] This application ball-mills the raw materials at a speed of 550-1000 rpm for at least 5 hours, which allows for sufficient contact between the raw materials and facilitates full reaction between them to form the target anti-perovskite structure phase, eliminating the need for further high-temperature (e.g., 750°C and above) sintering. Furthermore, the anti-perovskite material prepared using the method provided in this application has a large mixing entropy, which in turn gives the anti-perovskite material high crystal structure stability. Using this anti-perovskite material as a cathode material enables lithium-ion batteries made with this cathode material to have better cycle performance, first-cycle charge-discharge efficiency, and first-cycle discharge capacity.

[0022] Compared to the method of preparing anti-perovskite materials with the same composition by "mixing raw materials and sintering at high temperature", the method for preparing anti-perovskite materials provided in this application can not only reduce the energy consumption required for high-temperature sintering and reduce costs, but also improve the charge-discharge cycle performance and rate performance of lithium-ion batteries prepared using the obtained anti-perovskite materials.

[0023] Optionally, the preparation method of anti-perovskite materials further includes: after ball milling, the ball-milled system is heat-treated at 250-800℃.

[0024] Optionally, the heat treatment temperature is 500-800℃.

[0025] Thirdly, this application provides a cathode material, which includes the anti-perovskite material provided in the first aspect above.

[0026] The cathode material provided in this application adopts the anti-perovskite material with high crystal structure stability provided in the first aspect above. Using the anti-perovskite material as the cathode material enables the lithium-ion battery made with the cathode material to have better cycle performance, first charge-discharge efficiency and first discharge capacity.

[0027] Fourthly, this application provides a lithium-ion battery, which includes the positive electrode material provided in the third aspect above.

[0028] The lithium-ion battery provided in this application uses the cathode material provided in the third aspect above, which results in better cycle performance, first-cycle charge-discharge efficiency, and first-cycle discharge capacity of the lithium-ion battery made using the cathode material. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 A process flow diagram for the preparation of the anti-perovskite material provided in this application.

[0031] Figure 2 The XRD comparison diagrams are of the anti-perovskite materials prepared in Examples 2 and 13-14.

[0032] Figure 3 The image shows the XRD pattern of the material prepared in Comparative Example 8. Detailed Implementation

[0033] This application provides an anti-perovskite material, which has an anti-perovskite structural phase, and the general chemical formula of the anti-perovskite material is Li. 2±x M 1±y Ch m O n Wherein, 0≤x≤0.5, 0≤y≤0.3, 0.8≤m≤1.2, 0.8≤n≤1.2, and m≤n; M is selected from metallic elements other than Li and / or metalloid elements other than Te, and M includes at least five elements; Ch is selected from chalcogenides.

[0034] This application uses Li, M (selected from metals other than Li and / or metalloids other than Te, and including at least five elements), chalcogenides and oxygen to form cubic anti-perovskite material with an octahedral crystal structure by selecting Li, M (selected from metals other than Li and / or metalloids other than Te, and including at least five elements), chalcogenides and oxygen, and controls the ratio between each element.

[0035] The inventors discovered that in the crystal structure of the anti-perovskite material provided in this application, M is selected from metal elements other than Li and / or metalloid elements other than Te, and the M element occupies the vertex position of the octahedron; M includes at least five elements, such that in the crystal structure of the formed anti-perovskite material, at least five M elements share the same atomic sites and can be randomly arranged in the crystal structure of the anti-perovskite material, exhibiting short-range disorder, which makes the anti-perovskite material have a large mixing entropy, and thus makes the anti-perovskite material have high crystal structure stability; in addition, m≤n (that is, the number of O atoms is greater than or equal to the number of Ch (chalcogen elements) atoms), which can further improve the stability of the crystal structure of the anti-perovskite material; using the anti-perovskite material as a cathode material, the lithium-ion battery made with the cathode material can have better cycle performance, first charge and discharge efficiency and first discharge capacity.

[0036] As an example, in the general chemical expression formula of the anti-perovskite material, the value of x can be any point or range between 0, 0.1, 0.2, 0.3, 0.4 and 0.5; the value of y can be any point or range between 0, 0.05, 0.1, 0.15, 0.2, 0.25 and 0.3; and the values ​​of m or n can each independently be any point or range between 0.8, 0.9, 1.0, 1.05, 1.1, 1.15 and 1.2.

[0037] In some feasible embodiments of this application, the ratio of the number of atoms of each element in M ​​to the total number of atoms in M ​​is ≤40%; this is beneficial to further improve the cycle performance and first-cycle discharge capacity of lithium-ion batteries prepared using this anti-perovskite material as the cathode material.

[0038] As an example, the ratio of the number of atoms of each element in M ​​to the total number of atoms in M ​​can be independently set to any one of 5%, 5.5%, 9%, 10%, 11%, 18%, 22%, 25%, 30%, 35%, and 40%, or a range between any two.

[0039] In some feasible embodiments of this application, the ratio of m to n is 1:(1.00-1.15), which can further improve the stability of the crystal structure of the anti-perovskite material, thereby helping to further improve the first-cycle discharge capacity of lithium-ion batteries prepared using the anti-perovskite material as the cathode material.

[0040] As an example, in the general chemical expression formula of anti-perovskite materials, the ratio of m to n can be any one of 1:1.00, 1:1.02, 1:1.05, 1:1.07, 1:1.10, 1:1.12 and 1:1.15 or any range between the two.

[0041] Furthermore, the ratio of m to n is 1:(1.05-1.12), which can further improve the stability of the crystal structure of the anti-perovskite material, thereby helping to further improve the first-cycle discharge capacity of lithium-ion batteries made using this anti-perovskite material as the cathode material.

[0042] As an example, M is selected from at least five of the following: Na, K, Mg, Ca, Sr, Ba, Zn, Sc, Y, Al, Ga, Ti, Zr, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Ni, Si, Sn, and Sb. It should be noted that in other feasible embodiments, M may not be limited to the elements listed above. For example, M may be selected from other metallic elements besides Li, such as Zn or Cu, or from other metalloid elements besides Te, such as B, Ge, or As.

[0043] Furthermore, in some feasible embodiments of this application, M is selected from at least five metal elements other than Li; compared to M being selected from metalloid elements other than Te, selecting M from at least five metal elements other than Li is beneficial to further improve the first-cycle discharge capacity of lithium-ion batteries prepared using this anti-perovskite material as the cathode material.

[0044] Furthermore, in some feasible embodiments of this application, when M is selected from at least five metal elements other than Li, M is selected from at least five of Na, Fe, Co, Mn, Ni, Nb, V and Ti; this is beneficial to further improve the first-cycle discharge capacity of lithium-ion batteries prepared using this anti-perovskite material as the cathode material.

[0045] In some feasible embodiments of this application, Ch is selected from S. Compared to Ch being selected from other chalcogenides besides S, selecting Ch from S is beneficial for further improving the first-cycle discharge capacity of lithium-ion batteries prepared using this anti-perovskite material as the cathode material.

[0046] In some feasible embodiments of this application, the general chemical expression formula of the anti-perovskite material is Li. 2±x M 1± y Ch m O n Furthermore, 0≤x≤0.4 and 0≤y≤0.1; this is beneficial for further improving the cycle performance and first-cycle discharge capacity of lithium-ion batteries prepared using this anti-perovskite material as the cathode material.

[0047] Furthermore, the general chemical formula for anti-perovskite materials is Li 2-x M 1±y Ch m O nFurthermore, 0.2≤x≤0.4, 0≤y≤0.1; this is beneficial for further improving the cycle performance, first charge-discharge efficiency, and first discharge capacity of lithium-ion batteries prepared using this anti-perovskite material as the cathode material.

[0048] In some feasible embodiments of this application, the anti-perovskite material is Li 1.8 Fe 0.2 Co 0.2 Mn 0.2 Ni 0.1 Nb 0. 1V 0.05 Ti 0.05 SO, Li 1.6 Fe 0.2 Co 0.2 Mn 0.2 Ni 0.1 Nb 0.1 V 0.05 Ti 0.05 S 0.9 O or Li 1.7 Fe 0.2 Co 0.2 Mn 0.2 Ni 0.1 Nb 0. 1V 0.05 Ti 0.05 S 0.95 When the anti-perovskite material is selected from the above materials, the lithium-ion battery prepared using this anti-perovskite material as the cathode material exhibits better cycle performance, first-cycle charge-discharge efficiency, and first-cycle discharge capacity.

[0049] Furthermore, the anti-perovskite material is Li 1.6 Fe 0.2 Co 0.2 Mn 0.2 Ni 0.1 Nb 0.1 V 0.05 Ti 0.05 S 0.9 At 0°C, the first-cycle discharge capacity of the anti-perovskite material as the cathode material is as high as 257.6 mAh / g, the first-cycle charge-discharge efficiency is 99.8%, and the capacity retention rate after 30 cycles is as high as 99.5%.

[0050] In the prior art, the method for preparing anti-perovskite materials for use as cathode materials is generally as follows: after mixing the raw materials according to the chemical formula of the anti-perovskite material, sintering them under high temperature (e.g., 750°C and above).

[0051] The inventors discovered that high-temperature sintering leads to significant lithium volatilization during the preparation of anti-perovskite materials, resulting in a higher proportion of impurity phases in the anti-perovskite materials. Consequently, the charge-discharge cycle performance and rate performance of lithium-ion batteries prepared using these anti-perovskite materials decrease. Furthermore, higher sintering temperatures also result in greater energy consumption, increasing the preparation cost of anti-perovskite materials.

[0052] To address the aforementioned issues, this application provides a method for preparing the anti-perovskite material described above, thereby avoiding the situation where "the charge-discharge cycle performance and rate performance of lithium-ion batteries prepared using the anti-perovskite material decreases and the preparation cost is high" due to high-temperature sintering.

[0053] This application provides a method for preparing the above-mentioned anti-perovskite material, the method comprising: ball milling the raw material at a speed of 550-1000 rpm for at least 5 hours; wherein the raw material includes a lithium source and an M source. The lithium source is selected from Li2O and / or Li2Ch, and the M source includes at least one of the following: the element corresponding to M, the oxide of M, and a substance composed of M and Ch.

[0054] According to the chemical formula of the target product, the raw materials are prepared by ball milling at a speed of 550-1000 rpm for at least 5 hours. This allows for sufficient contact between the raw materials and facilitates the full reaction between them to form the target anti-perovskite structure phase, eliminating the need for further high-temperature (e.g., 750°C and above) sintering. Furthermore, the anti-perovskite material prepared by the method provided in this application has a large mixing entropy, which in turn gives it high crystal structure stability. Using this anti-perovskite material as a cathode material enables lithium-ion batteries prepared with this cathode material to have better cycle performance, first-cycle charge-discharge efficiency, and first-cycle discharge capacity.

[0055] Compared to the method of preparing anti-perovskite materials with the same composition by "mixing raw materials and sintering at high temperature", the method for preparing anti-perovskite materials provided in this application can not only reduce the energy consumption required for high-temperature sintering and reduce costs, but also improve the charge-discharge cycle performance and rate performance of lithium-ion batteries prepared using the obtained anti-perovskite materials.

[0056] Figure 1 For a flow chart of the preparation process of the anti-perovskite material provided in this application, please refer to [link / reference needed]. Figure 1 The method for preparing anti-perovskite materials provided in this application includes:

[0057] S10, the raw material is ball-milled at a speed of 550-1000 rpm for at least 5 hours; wherein the raw material includes a lithium source and an M source. The lithium source is selected from Li2O and / or Li2Ch, and the M source includes at least one of the following: the element corresponding to M, the oxide of M, and a substance composed of M and Ch.

[0058] It should be noted that, in this application, the oxide of M refers to a substance composed of M and O elements.

[0059] According to the general chemical expression formula of anti-perovskite materials (Li 2±x M 1±y Ch m O n Wherein, 0≤x≤0.5, 0≤y≤0.3, 0.8≤m≤1.2, 0.8≤n≤1.2, m≤n; M is selected from metallic elements other than Li and / or metalloid elements other than Te, and M includes at least five elements; Ch is selected from chalcogenides. The raw materials used to prepare the anti-perovskite material are ball-milled at a speed of 550-1000 rpm for at least 5 hours, which can ensure sufficient contact between the raw materials and facilitate sufficient reaction between the raw materials to form the target anti-perovskite structure phase. If the ball milling speed is lower than 550 rpm and / or the ball milling time is less than 5 hours, the energy provided by the ball mill may not reach the activation energy required for the "reaction of the raw materials to generate the target anti-perovskite structure phase" (i.e., the target anti-perovskite structure phase may not be formed).

[0060] Furthermore, in some feasible embodiments of this application, the ball milling time is 5-24 hours; this is beneficial to further ensure sufficient reaction between raw materials and to further increase the proportion of the anti-perovskite structural phase in the anti-perovskite material, thereby further improving the cycle performance, first charge-discharge efficiency and first discharge capacity of lithium-ion batteries prepared using the anti-perovskite material as the cathode material.

[0061] As an example, the rotational speed of the ball mill can be any value among 550 rpm, 600 rpm, 650 rpm, 700 rpm, 750 rpm, 800 rpm, 900 rpm, 950 rpm, and 1000 rpm, or a range between any two; the ball milling time can be any value among 5 h, 7 h, 10 h, 12 h, 15 h, 17 h, 20 h, 22 h, and 24 h, or a range between any two.

[0062] In some feasible embodiments of this application, ball milling is carried out under inert gas protection, which is beneficial to further increase the proportion of the anti-perovskite structural phase in the anti-perovskite material (reducing impurity phases), thereby further improving the cycle performance, first charge-discharge efficiency and first discharge capacity of lithium-ion batteries prepared using the anti-perovskite material as the cathode material.

[0063] In the embodiments of this application, the ball milling uses a dry ball milling method, and the ball milling beads used are zirconia ball milling beads with a particle size of 2-10 mm. The ball-to-material mass ratio during ball milling is (20-50):1.

[0064] It should be noted that in other feasible embodiments, ball milling can also be carried out using wet ball milling, that is, compared with the dry ball milling method described above, an appropriate amount of non-polar solvent (e.g., hexane, heptane or benzene, etc.) is added to the ball milling jar, and then vacuum drying is performed at a certain temperature (e.g., 60-150°C) after ball milling.

[0065] S20, after ball milling, the ball-milled system is heat-treated at 250-800℃.

[0066] After ball milling, the milled system is heated at 250-800℃ to improve the crystallinity of the anti-perovskite material and reduce surface defects caused by ball milling. This can reduce side reactions between the cathode material and the electrolyte in lithium-ion batteries using the anti-perovskite material as the cathode material, thereby improving the first charge-discharge efficiency and first discharge capacity of the lithium-ion battery.

[0067] As an example, the temperature of the heat treatment can be any one of 250°C, 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C and 800°C or a range between any two.

[0068] Furthermore, the heat treatment temperature is 500-800℃; this can further improve the crystallinity of the anti-perovskite material, reduce the surface defects of the anti-perovskite material caused by ball milling, and thus further improve the first charge-discharge efficiency and first discharge capacity of lithium-ion batteries prepared using this anti-perovskite material as the cathode material.

[0069] In some feasible implementations, the heat treatment time is at least 1 hour; this is beneficial to fully improve the crystallinity of the anti-perovskite material, reduce the surface defects of the anti-perovskite material caused by ball milling, and thus improve the first charge-discharge efficiency and first discharge capacity of lithium-ion batteries prepared using the anti-perovskite material as the cathode material.

[0070] Furthermore, the heat treatment time is 1-9 hours. As an example, the heat treatment time can be any value among 1 hour, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 6 hours, 7 hours, and 9 hours, or a range between any two.

[0071] This application also provides a cathode material, which includes the anti-perovskite material provided above.

[0072] The cathode material provided in this application, by employing the aforementioned anti-perovskite material with high crystal structure stability, enables lithium-ion batteries prepared using this anti-perovskite material as the cathode material to possess superior cycle performance, first-cycle charge-discharge efficiency, and first-cycle discharge capacity.

[0073] This application also provides a lithium-ion battery, which includes the positive electrode material provided above.

[0074] The lithium-ion battery provided in this application uses the positive electrode material described above, which results in better cycle performance, first-cycle charge-discharge efficiency, and first-cycle discharge capacity of the lithium-ion battery prepared using this positive electrode material.

[0075] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0076] Example 1

[0077] This embodiment provides an anti-perovskite material, the chemical formula of which is Li. 1.8 Fe 0.2 Co 0.2 Mn 0.2 Ni 0.1 Nb 0.1 V 0.05 Ti 0.05 SO is prepared using the following steps:

[0078] 0.3765g of Li₂O, 0.276g of Li₂S, 0.3516g of FeS, 0.364g of CoS, 0.348g of MnS, 0.1815g of NiS, 0.2498g of NbO₂, 0.0829g of VO₂, and 0.0799g of TiO₂ were placed in a zirconia ball mill jar. Zirconia grinding beads with an average particle size of 8mm were added at a ball-to-material mass ratio of 30:1. The ball mill jar was sealed, and the mixture was ball-milled at 600 rpm for 15 hours. The ball-milled system was then kept at 500℃ for 5 hours.

[0079] Example 2

[0080] This embodiment provides an anti-perovskite material, the chemical formula of which is Li. 1.8 Na 0.2 Fe 0.2 Co 0.2 Mn 0.2 Ni 0.2 Nb0.1 SO, the preparation method of which differs from that of Example 1 is as follows: the raw materials are 0.502g of Li2O, 0.0919g of Li2S, 0.1561g of Na2S, 0.3516g of FeS, 0.364g of CoS, 0.348g of MnS, 0.363g of NiS and 0.2498g of NbO2.

[0081] Example 3

[0082] This embodiment provides an anti-perovskite material, the chemical formula of which is Li. 2.4 Fe 0.1 Co 0.1 Mn 0.1 Ni 0.1 Nb 0.1 V 0.05 Ti 0.05 SO, the preparation method of which differs from that of Example 1 is as follows: the raw materials are 0.3765g of Li2O, 0.5514g of Li2S, 0.1758g of FeS, 0.182g of CoS, 0.174g of MnS, 0.1815g of NiS, 0.2498g of NbO2, 0.0829g of VO2 and 0.0799g of TiO2.

[0083] Example 4

[0084] This embodiment provides an anti-perovskite material, the chemical formula of which is Li. 1.6 Fe 0.2 Co 0.2 Mn 0.2 Ni 0.1 Nb 0.1 V 0.1 Ti 0.05 SO, the preparation method of which differs from that of Example 1 is as follows: the raw materials are 0.3137g of Li2O, 0.2757g of Li2S, 0.3516g of FeS, 0.364g of CoS, 0.348g of MnS, 0.1815g of NiS, 0.2498g of NbO2, 0.1659g of VO2 and 0.0799g of TiO2.

[0085] Example 5

[0086] This embodiment provides an anti-perovskite material, the chemical formula of which is Li. 1.8 Fe 0.2 Co 0.2 Mn 0.2 Ni 0.1 Nb 0.1 V 0.05 Ti 0.05 S0.8 O 1.2 The preparation method differs from that in Example 1 in that the raw materials are 0.502g of Li2O, 0.0919g of Li2S, 0.3516g of FeS, 0.364g of CoS, 0.348g of MnS, 0.1815g of NiS, 0.2498g of NbO2, 0.08294g of VO2, and 0.0799g of TiO2.

[0087] Example 6

[0088] This embodiment provides an anti-perovskite material, the chemical formula of which is Li. 1.5 Fe 0.2 Co 0.2 Mn 0.2 Ni 0.1 Nb 0.1 V 0.05 Ti 0.05 S 0.85 The preparation method of O differs from that of Example 1 in that the raw materials are 0.3765g of Li2O, 0.1379g of Li2S, 0.3516g of FeS, 0.364g of CoS, 0.348g of MnS, 0.1815g of NiS, 0.2498g of NbO2, 0.08294g of VO2, and 0.0799g of TiO2.

[0089] Example 7

[0090] This embodiment provides an anti-perovskite material, the chemical formula of which is Li. 1.6 Fe 0.2 Co 0.2 Mn 0.2 Ni 0.1 Nb 0.1 V 0.05 Ti 0.05 S 0.9 The preparation method of O differs from that of Example 1 in that the raw materials are 0.3765g of Li2O, 0.1838g of Li2S, 0.3516g of FeS, 0.364g of CoS, 0.348g of MnS, 0.1815g of NiS, 0.2498g of NbO2, 0.08294g of VO2, and 0.0799g of TiO2.

[0091] Example 8

[0092] This embodiment provides an anti-perovskite material, the chemical formula of which is Li. 1.7 Fe 0.2 Co 0.2 Mn 0.2 Ni0.1 Nb 0.1 V 0.05 Ti 0.05 S 0.95 The preparation method of O differs from that of Example 1 in that the raw materials are 0.3765g of Li2O, 0.2298g of Li2S, 0.3516g of FeS, 0.364g of CoS, 0.348g of MnS, 0.1815g of NiS, 0.2498g of NbO2, 0.08294g of VO2, and 0.0799g of TiO2.

[0093] Example 9

[0094] This embodiment provides an anti-perovskite material, the chemical formula of which is Li. 1.6 Fe 0.2 Co 0.2 Mn 0.2 Ni 0.1 Nb 0.1 V 0.05 Ti 0.05 Se 0.9 The preparation method of O differs from that of Example 1 in that the raw materials are 0.3765g of Li2O, 0.3714g of Li2Se, 0.5392g of FeSe, 0.5516g of CoSe, 0.5356g of MnSe, 0.2753g of NiSe, 0.2498g of NbO2, 0.08294g of VO2, and 0.0799g of TiO2.

[0095] Example 10

[0096] This embodiment provides an anti-perovskite material, the chemical formula of which is Li. 1.85 Fe 0.2 Co 0.2 Mn 0.2 Ni 0.1 Nb 0.1 Si 0.05 Sb 0.05 SO, the preparation method of which differs from that of Example 1 is as follows: the raw materials are 0.3922g of Li2O, 0.2757g of Li2S, 0.3516g of FeS, 0.364g of CoS, 0.348g of MnS, 0.1815g of NiS, 0.2498g of NbO2, 0.0601g of SiO2 and 0.1538g of Sb2O3.

[0097] Example 11

[0098] This embodiment provides an anti-perovskite material, the chemical formula of which is Li. 1.8 Na0.2 Fe 0.2 Co 0.2 Mn 0.2 Ni 0.2 Nb 0.1 SO, the difference between its preparation method and that of Example 2 is that the ball milling speed is 550 rpm.

[0099] Example 12

[0100] This embodiment provides an anti-perovskite material, the chemical formula of which is Li. 1.8 Na 0.2 Fe 0.2 Co 0.2 Mn 0.2 Ni 0.2 Nb 0.1 SO, the difference between its preparation method and that of Example 2 is that the ball milling speed is 1000 rpm.

[0101] Example 13

[0102] This embodiment provides an anti-perovskite material, the chemical formula of which is Li. 1.8 Na 0.2 Fe 0.2 Co 0.2 Mn 0.2 Ni 0.2 Nb 0.1 SO, the difference between its preparation method and that of Example 2 is that the heat preservation temperature is 200℃.

[0103] Example 14

[0104] This embodiment provides an anti-perovskite material, the chemical formula of which is Li. 1.8 Na 0.2 Fe 0.2 Co 0.2 Mn 0.2 Ni 0.2 Nb 0.1 SO, the preparation method differs from that in Example 2 in that the "holding temperature at 500°C for 5 hours" operation is not performed after ball milling.

[0105] Comparative Example 1

[0106] This comparative example provides a material with the chemical formula Li2FeSO. The preparation method of this material differs from that of Example 1 in that the raw materials are 0.6275g of Li2O and 1.7582g of FeS.

[0107] Comparative Example 2

[0108] This comparative example provides a material with the chemical formula Li₂Fe. 0.6Co 0.2 Mn 0.1 Ni 0.1 SO, the preparation method of which differs from that of Example 1 is as follows: the raw materials are 0.6275g of Li2O, 1.055g of FeS, 0.364g of CoS, 0.174g of MnS and 0.1815g of NiS.

[0109] Comparative Example 3

[0110] This comparative example provides a material with the chemical formula Li₂Fe. 0.6 Co 0.2 Mn 0.1 Ni 0.1 SO, the preparation method of which differs from that of Example 1 is as follows: the raw materials are 0.6275g of Li2O, 1.055g of FeS, 0.364g of CoS, 0.174g of MnS and 0.1815g of NiS.

[0111] Comparative Example 4

[0112] This comparative example provides a material with the chemical formula Li. 1.8 Fe 0.2 Co 0.2 Mn 0.2 Ni 0.1 Nb 0.1 V 0.05 Ti 0.0 5S 1.2 O 0.8 The preparation method differs from that in Example 1 in that the raw materials are 0.251g of Li2O, 0.4595g of Li2S, 0.3516g of FeS, 0.364g of CoS, 0.348g of MnS, 0.1815g of NiS, 0.2498g of NbO2, 0.08294g of VO2, and 0.0799g of TiO2.

[0113] Comparative Example 5

[0114] The material provided in this comparative example is LiCoO2.

[0115] Comparative Example 6

[0116] The material provided in this comparative example is LiFePO4.

[0117] Comparative Example 7

[0118] The material provided in this comparative example is LiMn2O4.

[0119] Comparative Example 8

[0120] This comparative example provides a material with the chemical formula Li.1.8 Na 0.2 Fe 0.2 Co 0.2 Mn 0.2 Ni 0.2 Nb 0.1 SO, this material does not have an anti-perovskite structure phase, and its preparation method differs from that of Example 2 in that the ball milling speed is 250 rpm.

[0121] Comparative Example 9

[0122] This comparative example provides a material with the chemical formula Li. 1.8 Na 0.2 Fe 0.2 Co 0.2 Mn 0.2 Ni 0.2 Nb 0.1 SO, this material does not have an anti-perovskite structure phase, and its preparation method differs from that of Example 2 in that the ball milling time is 2 hours.

[0123] Experimental Example 1

[0124] The anti-perovskite materials prepared in Examples 2, 13-14, and Comparative Example 8 were characterized by X-ray diffraction, and the XRD patterns are shown below. Figure 2 and Figure 3 As shown.

[0125] from Figure 2 and Figure 3 The comparison shows that the materials prepared in Examples 2 and 13-14 of this application both have an anti-perovskite structure phase, indicating that anti-perovskite materials were prepared in Examples 2 and 13-14. However, the material prepared in Comparative Example 8 does not have an anti-perovskite structure phase, indicating that when the ball milling speed is low, the energy provided by the ball mill is insufficient to reach the activation energy required for the raw materials to react and generate the target anti-perovskite structure phase, that is, the target anti-perovskite structure phase cannot be formed.

[0126] Furthermore, from Figure 2 It can be seen that the crystallinity of the materials obtained in Examples 14, 13 and 2 increases sequentially, indicating that heating the ball-milled system can improve the crystallinity of the anti-perovskite material, and the crystallinity of the obtained material also increases with the increase of the heating temperature.

[0127] Experimental Example 2

[0128] The materials obtained in Examples 1-12 and Comparative Examples 1-9 were used as positive electrode materials to assemble liquid half-cells. The first-cycle discharge specific capacity, first-cycle charge-discharge efficiency and cycle performance of the prepared lithium-ion batteries were tested. The test results are shown in Table 1.

[0129] The preparation steps of the lithium-ion battery are as follows: The materials obtained in Examples 1-12 and Comparative Examples 1-9 are mixed with a conductive agent (Super P) and a binder (polyvinylidene fluoride) in a mass ratio of 7:2:1, and then dispersed in the solvent N-methylpyrrolidone (NMP). The mixture is then uniformly spin-coated onto the current collector aluminum foil. After the solvent is evaporated, the mixture is combined with a lithium battery separator, a lithium metal anode, and a lithium battery electrolyte (ethylene carbonate and dimethyl carbonate in a volume ratio of 1:1). LiClO4 (with a concentration of 1M in the electrolyte) is also added to assemble a liquid half-cell.

[0130] The test voltage range was 1.2-3.0V, and the constant current density was 110mA / g.

[0131] Table 1

[0132]

[0133]

[0134] As can be seen from Table 1, the electrochemical performance (i.e., the combined performance of first-cycle discharge capacity, first-cycle charge-discharge efficiency, and cycle performance) of lithium-ion batteries prepared using the materials of Examples 1-12 of this application is better than that of lithium-ion batteries prepared using the materials of Comparative Examples 1-9. This indicates that the anti-perovskite material provided in this application can enable lithium-ion batteries to have better cycle performance, first-cycle charge-discharge efficiency, and first-cycle discharge capacity.

[0135] As can be seen from the comparison of Examples 1 and Examples 2-4, after appropriately adjusting the atomic ratio in the anti-perovskite material based on the chemical formula defined in this application, the cycle performance, first charge-discharge efficiency, and first discharge capacity of the lithium-ion battery are all better.

[0136] As can be seen from the comparison of Examples 1, Examples 5-8 and Comparative Example 4, when the number of O atoms in the prepared material is greater than or equal to the number of Ch (chalcogenide) atoms, the first-cycle discharge capacity of the lithium-ion battery can be improved; furthermore, the ratio of the number of O atoms to the number of Ch (chalcogenide) atoms can further affect the first-cycle discharge capacity of the lithium-ion battery.

[0137] A comparison of Examples 1 and 9 shows that choosing S instead of Se as the Ch (sulfide element) can effectively improve the first-cycle discharge capacity of lithium-ion batteries.

[0138] A comparison between Example 1 and Example 10 shows that M can be selected from metal elements other than Li or metalloid elements other than Te, which can enable lithium-ion batteries to have better cycle performance, first charge-discharge efficiency and first discharge capacity.

[0139] As can be seen from the comparison of Examples 2, 11-12 and Comparative Examples 8-9, when the ball milling speed is low or the time is short, the first discharge capacity, first charge-discharge efficiency and cycle performance of lithium-ion batteries will be significantly reduced.

[0140] As can be seen from the comparison between Example 1 and Comparative Examples 1-3, when M is selected from more than five elements, compared to one or four elements, the cycle performance, first charge-discharge efficiency and first discharge capacity of lithium-ion batteries can be improved.

[0141] As can be seen from the comparison between Examples 1-13 and Comparative Examples 5-7, compared with the α-NaFeO2 type layered structure, olivine type and spinel type cathode materials in the prior art, the anti-perovskite material provided in this application can enable lithium-ion batteries to have better cycle performance, first charge and discharge efficiency and first discharge capacity.

[0142] In summary, the anti-perovskite material provided in this application has high crystal structure stability; using this anti-perovskite material as a cathode material enables lithium-ion batteries prepared with this cathode material to have better cycle performance, first-cycle charge-discharge efficiency, and first-cycle discharge capacity.

[0143] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. An anti-perovskite material, characterized in that, The anti-perovskite material has an anti-perovskite structural phase, and the anti-perovskite material is Li. 1.8 Fe 0.2 Co 0.2 Mn 0.2 Ni 0.1 Nb 0.1 V 0.05 Ti 0.05 SO, Li 1.6 Fe 0.2 Co 0.2 Mn 0.2 Ni 0.1 Nb 0.1 V 0.05 Ti 0.05 S 0.9 O or Li 1.7 Fe 0.2 Co 0.2 Mn 0.2 Ni 0.1 Nb 0.1 V 0.05 Ti 0.05 S 0.95 O; The method for preparing the aforementioned anti-perovskite material includes: Ball mill the raw materials at a speed of 550-1000 rpm for at least 5 hours; The raw materials include a lithium source and an M source; the M source is selected from at least seven of the following: Fe, Co, Mn, Ni, Nb, V, and Ti. The lithium source is selected from Li2O and / or Li2S, and the M source includes at least one of the following: the element corresponding to M, the oxide of M, and a substance composed of the elements M and S; at least one of the lithium source and the M source contains the element S.

2. The anti-perovskite material according to claim 1, characterized in that, The anti-perovskite material is Li 1.6 Fe 0.2 Co 0.2 Mn 0.2 Ni 0.1 Nb 0.1 V 0.05 Ti 0.05 S 0.9 O.

3. The anti-perovskite material according to claim 1, characterized in that, The preparation method of the anti-perovskite material further includes: after ball milling, the ball-milled system is heat-treated at 250-800℃.

4. The anti-perovskite material according to claim 3, characterized in that, The temperature of the heat treatment is 500-800℃.

5. A positive electrode material, characterized in that, The cathode material includes the anti-perovskite material as described in any one of claims 1-4.

6. A lithium-ion battery, characterized in that, The lithium-ion battery includes the positive electrode material as described in claim 5.

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