Reverse-honeycomb lithium-rich nickel-based oxide and preparation method and application thereof

Abstract

The application discloses a structure of a reverse-honeycomb type lithium-rich nickel-based oxide, which is of a chemical formula of Li2NiO3 or [Li 2 / 3 Ni 1 / 3 ]O, a space group of C2 / m, and a cell parameter of alpha=90.00°, beta=146.02° and gamma=90.00°. The structure is different from that of Li[Li 1 / 3 Ni 2 / 3 ]O2 of a Li@Ni6 honeycomb type, and in the structure, each layer is of a Ni@Li6 reverse-honeycomb configuration. The synthesis process is as follows: under a transmission electron microscope, a nickel-lithium oxide or a lithium salt / nickel oxide mixture is heated by using an in-situ heating electron microscope rod, and structural changes are observed; the structure is generated at 600 DEG C; the crystallinity is best at 700 DEG C; and an atomic image of the structure is shot. Meanwhile, the structure is simulated by combining with a first principle calculation, and a three-dimensional structure is analyzed. The structure is a potential lithium-rich positive electrode material, and is expected to realize stable anion oxidation and reduction and improve the energy density of a lithium ion battery.

Description

Technical Field

[0001] This invention belongs to the field of materials synthesis and energy storage technology, specifically relating to an anti-honeycomb lithium-rich nickel-based oxide, its preparation method, and its application. Background Technology

[0002] Secondary batteries are widely used energy storage devices, ranging from small portable electronic devices (such as laptops, smartphones, and smart wearables) to large-scale equipment, especially in electric vehicles. Hybrid electric vehicles, plug-in hybrid electric vehicles, and pure electric vehicles have attracted significant attention due to their potential to replace traditional internal combustion engines, thereby reducing greenhouse gas emissions and dependence on fossil fuels. Lithium-ion batteries, with their advantages of high operating voltage, light weight, high power density, minimal memory effect, and environmental friendliness, have been widely adopted since their introduction in the early 1990s. However, as market demands for battery performance increase, traditional lithium-ion batteries can no longer fully meet these needs. Improving the energy density of cathode materials is currently the core objective of lithium-ion battery research, which means simultaneously improving the material's potential and capacity. While the potential can be easily adjusted by appropriately selecting the redox centers of the electrochemical reaction, increasing capacity while maintaining structural stability is more challenging. In lithium-rich transition metal oxides, the co-redox reactions of cations and anions have emerged as a new paradigm for increasing energy density. However, the additional capacity introduced by anions generally leads to structural instability, causing severe irreversibility during the initial charge-discharge cycle, capacity and voltage degradation in subsequent cycles, cation migration, and oxygen loss. This results in continuous electrode decomposition during cycling, a major drawback for practical applications. Chemical substitution and structural design offer hope for suppressing these irreversible effects, thereby enabling long-term cycling of high-energy-density electrodes. For example, three-dimensional β-Li₂IrO₃ cathode materials have shown excellent cycling performance; Li 1.3 Nb 0.3 Mn 0.4 O2 showed the highest first-charge capacity ever reported (>300mAh g). -1 Researchers have gradually realized the importance of structural design for anion redox reactions. Based on this, this invention discloses a structure of an anti-honeycomb lithium-rich nickel-based oxide and its synthesis method, which is expected to achieve reversible anion redox reactions, thereby improving the energy density of lithium-ion batteries. Summary of the Invention

[0003] Therefore, the purpose of this invention is to overcome the defects in the prior art and provide an anti-honeycomb lithium-rich nickel-based oxide, its preparation method, and its application.

[0004] Before describing the content of this invention, the following terms are defined as follows:

[0005] The term "Ni@Li6" refers to a structural configuration in which one nickel ion is surrounded by six lithium ions.

[0006] To achieve the above objectives, a first aspect of the present invention provides an anti-honeycomb lithium-rich nickel-based oxide, wherein the chemical formula of the anti-honeycomb lithium-rich nickel-based oxide is Li₂NiO₃ or [Li 2 / 3 Ni 1 / 3 ]O, and the space group of the anti-honeycomb lithium-rich nickel-based oxide is C2 / m.

[0007] According to the first aspect of the present invention, in the anti-honeycomb lithium-rich nickel-based oxide, oxygen ions are arranged in a cubic close-packed manner, and nickel ions and lithium ions are distributed in the octahedral cavities formed by oxygen ions.

[0008] According to the first aspect of the present invention, in the anti-honeycomb type lithium-rich nickel-based oxide, there is no stratification of nickel ions and lithium ions, and each layer is configured as a Ni@Li6 anti-honeycomb.

[0009] According to the first aspect of the present invention, the anti-honeycomb lithium-rich nickel-based oxide, wherein the electron diffraction characteristic crystal planes of the anti-honeycomb lithium-rich nickel-based oxide along the

[100] zone axis include (001) and (020);

[0010] Preferably, the electron diffraction characteristic crystal planes of the anti-honeycomb lithium-rich nickel-based oxide along the

[100] zone axis further include (002), (003), (040), (060) and (022).

[0011] According to a first aspect of the present invention, an anti-honeycomb lithium-rich nickel-based oxide, wherein the cell parameters of the anti-honeycomb lithium-rich nickel-based oxide are: α=90.00°, β=146.02°, γ=90.00°.

[0012] A second aspect of the present invention provides a method for preparing the anti-honeycomb type lithium-rich nickel-based oxide described in the first aspect, the method comprising the following steps:

[0013] The anti-honeycomb lithium-rich nickel-based oxide is obtained by heating a nickel-lithium oxide or a mixture of lithium salt and nickel oxide;

[0014] Preferably, the heating is performed on the in-situ heated electron microscope rod of the transmission electron microscope.

[0015] According to the preparation method of the second aspect of the present invention, the lithium nickel oxide is selected from one or more of the following: LiNiO2, LiNi2O4, Li2NiO2;

[0016] The lithium salt is selected from one or more of the following: lithium carbonate, lithium nitrate, lithium acetate, lithium formate, lithium oxalate, lithium citrate; and / or

[0017] The nickel oxide is selected from one or more of the following: nickel oxide, nickel dioxide.

[0018] According to the preparation method of the second aspect of the present invention, the heating temperature is 600-1000°C, preferably 650-850°C, more preferably 650-750°C, and most preferably 675-725°C; and / or

[0019] The heating time is 3 to 10 minutes, preferably 4 to 8 minutes, more preferably 5 to 6.5 minutes, and most preferably 5.5 to 6 minutes.

[0020] According to the preparation method of the second aspect of the present invention, the molar ratio of lithium salt to nickel oxide in the mixture of lithium salt and nickel oxide is 2.5:1.0 to 1.5:1.0, preferably 2.3:1.0 to 1.0:1.0, more preferably 2.2:1.0 to 1.5:1.0, and most preferably 2.1:1.0 to 1.9:1.0.

[0021] A third aspect of the present invention provides an electrode material comprising the anti-honeycomb lithium-rich nickel-based oxide described in the first aspect or an anti-honeycomb lithium-rich nickel-based oxide prepared according to the method described in the second aspect.

[0022] This invention provides the structure and synthesis method of an anti-honeycomb lithium-rich nickel-based oxide. Specifically, it discloses the chemical formula, space group, cell parameters, three-dimensional structure, atomic occupancy, atomic images, electron diffraction, and the ratio of lithium nickel oxide or lithium salt / nickel oxide mixture and the reaction temperature for synthesizing this structure. This invention also provides the use of the anti-honeycomb lithium-rich nickel-based oxide as an electrode material in lithium, sodium, potassium, magnesium, aluminum, and calcium-ion batteries, supercapacitors, and electrocatalysis.

[0023] The anti-honeycomb type lithium-rich nickel-based oxide of the present invention may have, but is not limited to, the following beneficial effects:

[0024] The anti-honeycomb lithium-rich nickel-based oxide of the present invention is a potential lithium-rich cathode material that is expected to achieve stable anion redox and improve the energy density of lithium-ion batteries. Attached Figure Description

[0025] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings, wherein:

[0026] Figure 1 A schematic diagram of the structure of the anti-honeycomb type lithium-rich nickel-based oxide of the present invention is shown, wherein, Figure 1Figure a shows a schematic diagram of the three-dimensional structure of an anti-honeycomb lithium-rich nickel-based oxide. Figure 1 b shows a schematic diagram of the Ni@Li6 anti-honeycomb configuration in each layer of the anti-honeycomb lithium-rich nickel-based oxide.

[0027] Figure 2 The image shows a reverse honeycomb-type lithium-rich nickel-based oxide HAADF-STEM image and structural schematic diagram along the

[100] direction; wherein, Figure 2 a shows a HAADF-STEM image of an anti-honeycomb-type lithium-rich nickel-based oxide along the

[100] direction; Figure 2 b shows a schematic diagram of the anti-honeycomb lithium-rich nickel-based oxide structure along the

[100] direction.

[0028] Figure 3 An electron diffraction image of an anti-honeycomb lithium-rich nickel-based oxide along the

[100] direction is shown. Detailed Implementation

[0029] The present invention will be further illustrated below with specific embodiments. However, it should be understood that these embodiments are merely for more detailed and specific illustration and should not be construed as limiting the present invention in any way.

[0030] This section provides a general description of the materials and testing methods used in the experiments of this invention. While many of the materials and methods of operation used to achieve the objectives of this invention are well known in the art, the invention is still described in as much detail as possible herein. It will be apparent to those skilled in the art that, unless otherwise stated in the context, the materials and methods of operation used in this invention are well known in the art.

[0031] The reagents and instruments used in the following examples are as follows: Reagents:

[0032] LiNiO2, LiNi2O4, Li2CO3, NiO, CH3COOLi, Li2C2O, and NiO2 were purchased from Aladdin Reagent Co., Ltd.

[0033] instrument:

[0034] Transmission electron microscope, purchased from Nippon Electronics Corporation, model ARM-200.

[0035] Example 1

[0036] This embodiment illustrates the structure and preparation method of the anti-honeycomb lithium-rich nickel-based oxide of the present invention.

[0037] The chemical formula of the anti-honeycomb type lithium-rich nickel-based oxide of this invention is Li₂NiO₃ or [Li 2 / 3 Ni 1 / 3 [O, space group C2 / m, cell parameters are] α = 90.00°, β = 146.02°, γ = 90.00°; three-dimensional structure as follows Figure 1 As shown; the atomic occupancy is shown in Table 1; the atomic images are shown in... Figure 2 As shown; electron diffraction pattern as shown Figure 3 As shown.

[0038] The anti-honeycomb type lithium-rich nickel-based oxide of the present invention has a Ni@Li6 anti-honeycomb configuration in each layer; the electron diffraction characteristic crystal planes along the

[100] zone axis are (001) and (020); under a transmission electron microscope, the nickel-lithium oxide or lithium salt / nickel oxide mixture is heated in situ using a heated electron microscope rod and the structural changes are observed, and this structure is formed at 600-1000℃.

[0039] In this invention, the oxygen ions in the anti-honeycomb lithium-rich nickel-based oxide are arranged in a cubic close-packed configuration, with nickel and lithium ions distributed within the octahedral cavities formed by the oxygen ions. There is no stratification of nickel and lithium ions; each layer contains a Ni@Li6 anti-honeycomb arrangement, unlike traditional layered materials for lithium-ion batteries.

[0040] like Figure 3 As shown in the electron diffraction pattern, the anti-honeycomb lithium-rich nickel-based oxide of the present invention also has (002), (003), (040), (060) and (022) as characteristic crystal planes along the

[100] zone axis.

[0041] Table 1. Atomic Occupation of Anti-Honeycomb Type Lithium-Rich Nickel-Based Oxides

[0042]

[0043] The preparation method of the anti-honeycomb type lithium-rich nickel-based oxide of the present invention includes the following steps:

[0044] Under a transmission electron microscope, nickel-lithium oxide or lithium salt / nickel oxide mixtures were heated in situ using an in-situ heated electron microscope rod at a temperature of 600–1000 °C.

[0045] The nickel-lithium oxide is one or two of LiNiO2, LiNi2O4, and Li2NiO2.

[0046] The lithium salt is one of lithium carbonate, lithium nitrate, lithium acetate, lithium formate, lithium oxalate, and lithium citrate; the nickel oxide is one of nickel oxide and nickel dioxide. The molar ratio of the lithium salt to the nickel oxide is 2.5:1.0 to 1.5:1.0, preferably 2.3:1.0 to 1.0:1.0, more preferably 2.2:1.0 to 1.5:1.0, and most preferably 2.1:1.0 to 1.9:1.0.

[0047] Example 2

[0048] This embodiment illustrates the preparation method of the anti-honeycomb lithium-rich nickel-based oxide of the present invention.

[0049] 1.2 mg of LiNiO2 powder was ground for 0.5 h, dispersed in ethanol, and sonicated for 10 min. The powder was then dropped onto a microgrid, allowed to air dry, and fixed onto a heated electron microscope rod. The sample was heated to 700 °C and held at that temperature for 4.5 min in a transmission electron microscope, resulting in the formation of an anti-honeycomb-rich lithium-based oxide. Its HAADF-STEM results are shown below. Figure 2 As shown in a.

[0050] Example 3

[0051] This embodiment illustrates the preparation method of the anti-honeycomb lithium-rich nickel-based oxide of the present invention.

[0052] Take 1.5 mg of LiNi2O4 powder, grind it for 1.5 h, disperse it in ethanol, sonicate it for 10 min, drop it onto a microgrid, let it air dry naturally, fix it on a heated electron microscope rod, heat the sample to 800 °C in a transmission electron microscope, keep it at that temperature for 5 min, and an anti-honeycomb lithium-rich nickel-based oxide is generated.

[0053] Example 4

[0054] This embodiment illustrates the preparation method of the anti-honeycomb lithium-rich nickel-based oxide of the present invention.

[0055] Take 1.3 mg of Li2NiO2 powder, grind it for 1 hour, disperse it in ethanol, sonicate it for 10 minutes, drop it onto a microgrid, let it air dry naturally, fix it on a heated electron microscope rod, heat the sample to 600℃ in a transmission electron microscope, keep it at that temperature for 6 minutes, and an anti-honeycomb lithium-rich nickel-based oxide is generated.

[0056] Example 5

[0057] This embodiment illustrates the preparation method of the anti-honeycomb lithium-rich nickel-based oxide of the present invention.

[0058] Weigh 1.03 mg Li2CO3 and 1.01 mg NiO, grind for 2.5 h, mix evenly, disperse in ethanol, sonicate for 10 min, drop onto a microgrid, air dry naturally, fix on a heated electron microscope rod, heat the sample to 850 °C in a transmission electron microscope, hold for 4 min, and generate an anti-honeycomb lithium-rich nickel-based oxide.

[0059] Example 6

[0060] This embodiment illustrates the preparation method of the anti-honeycomb lithium-rich nickel-based oxide of the present invention.

[0061] Weigh 2.05 mg LiNO3 and 1.00 mg NiO, grind for 3.0 h, mix evenly, disperse in ethanol, sonicate for 10 min, drop onto a microgrid, air dry naturally, fix on a heated electron microscope rod, heat the sample to 650 °C in a transmission electron microscope, hold for 8 min, and generate an anti-honeycomb lithium-rich nickel-based oxide.

[0062] Example 7

[0063] This embodiment illustrates the preparation method of the anti-honeycomb lithium-rich nickel-based oxide of the present invention.

[0064] Weigh 1.01 mg Li2CO3 and 1.00 mg NiO2, grind for 2.0 h, mix evenly, disperse in ethanol, sonicate for 10 min, drop onto a microgrid, air dry naturally, fix on a heated electron microscope rod, heat the sample to 750 °C in a transmission electron microscope, hold for 5.5 min, and anti-honeycomb lithium-rich nickel-based oxide is generated.

[0065] Example 8

[0066] This embodiment illustrates the preparation method of the anti-honeycomb lithium-rich nickel-based oxide of the present invention.

[0067] Weigh 1.41 mg CH3COOLi and 1.45 mg NiO, grind for 2.0 h, mix evenly, disperse in ethanol, sonicate for 10 min, drop onto a microgrid, air dry naturally, fix on a heated electron microscope rod, heat the sample to 800 °C in a transmission electron microscope, hold for 6.5 min, and anti-honeycomb lithium-rich nickel-based oxide is generated.

[0068] Example 9

[0069] This embodiment illustrates the preparation method of the anti-honeycomb lithium-rich nickel-based oxide of the present invention.

[0070] Weigh 1.22 mg Li2C2O4 and 1.45 mg NiO2, grind for 1.0 h, mix evenly, disperse in ethanol, sonicate for 10 min, drop onto a microgrid, air dry naturally, fix on a heated electron microscope rod, heat the sample to 750 °C in a transmission electron microscope, hold for 5.5 min, and anti-honeycomb lithium-rich nickel-based oxide is generated.

[0071] Experimental Example 1

[0072] A slurry of the compounds synthesized in Examples 2 to 9 (80 wt.%), acetylene black (10 wt.%), and polyvinylidene fluoride (PVDF) (10 wt.%) was coated onto aluminum foil and dried under vacuum at 120°C for 12 hours to obtain the working electrode. A button cell (CR2032) was assembled in an argon-filled glove box using a 1M LiPF6 EC / DEC (volume ratio 1:1) solution as the electrolyte, pure lithium foil as the counter electrode, and glass fiber as the separator. Charge-discharge cycle tests of the lithium-ion half-cell were conducted on the Blue Electric BT2000 battery testing system (Wuhan) at different current densities within a voltage range of 3.0–5.0 V, yielding a high energy density.

[0073] Although the invention has been described to a certain extent, it is apparent that appropriate variations can be made to the various conditions without departing from the spirit and scope of the invention. It is understood that the invention is not limited to the described embodiments, but falls within the scope of the claims, which include equivalent substitutions for each of the elements.

Claims

1. An anti-honeycomb type lithium-rich nickel-based oxide, characterized in that, The chemical formula of the anti-honeycomb type lithium-rich nickel-based oxide is Li₂NiO₃ or [Li 2 / 3 Ni 1 / 3 ]O, and the space group of the anti-honeycomb lithium-rich nickel-based oxide is C2 / m, and the electron diffraction characteristic crystal planes of the anti-honeycomb lithium-rich nickel-based oxide along the [100] zone axis include (001), (020), (002), (003), (040), (060) and (022).

2. The anti-honeycomb lithium-rich nickel-based oxide according to claim 1, characterized in that, In the anti-honeycomb lithium-rich nickel-based oxide, oxygen ions are arranged in a cubic close-packed pattern, and nickel and lithium ions are distributed in the octahedral cavities formed by oxygen ions.

3. The anti-honeycomb lithium-rich nickel-based oxide according to claim 1 or 2, characterized in that, In the aforementioned anti-honeycomb lithium-rich nickel-based oxide, there is no stratification of nickel ions and lithium ions, and each layer contains a Ni@Li6 anti-honeycomb configuration.

4. The anti-honeycomb lithium-rich nickel-based oxide according to claim 1, characterized in that, The cell parameters of the anti-honeycomb lithium-rich nickel-based oxide are as follows: α=90.00°, β=146.02°, γ=90.00°.

5. The method for preparing the anti-honeycomb type lithium-rich nickel-based oxide according to any one of claims 1 to 4, characterized in that, The method includes the following steps: The anti-honeycomb lithium-rich nickel-based oxide is obtained by heating a nickel-lithium oxide or a mixture of lithium salt and nickel oxide.

6. The preparation method according to claim 5, characterized in that, The heating is performed in situ on the heating rod of the transmission electron microscope.

7. The preparation method according to claim 5, characterized in that, The lithium nickel oxide is selected from one or more of the following: LiNiO2, LiNi2O4, Li2NiO2; The lithium salt is selected from one or more of the following: lithium carbonate, lithium nitrate, lithium acetate, lithium formate, lithium oxalate, lithium citrate; and / or The nickel oxide is selected from one or more of the following: nickel oxide, nickel dioxide.

8. The preparation method according to any one of claims 5 to 7, characterized in that, The heating temperature is 600–1000℃; and / or The heating time is 3 to 10 minutes.

9. The preparation method according to claim 8, characterized in that, The heating temperature is 650–850°C; and / or The heating time is 4 to 8 minutes.

10. The preparation method according to claim 9, characterized in that, The heating temperature is 650–750°C; and / or The heating time is 5 to 6.5 minutes.

11. The preparation method according to claim 10, characterized in that, The heating temperature is 675–725°C; and / or The heating time is 5.5 to 6 minutes.

12. The method according to any one of claims 5 to 7, characterized in that, In the mixture of lithium salt and nickel oxide, the molar ratio of lithium salt to nickel oxide is 2.5:1.0 to 1.5:1.

0.

13. The method according to claim 12, characterized in that, In the mixture of lithium salt and nickel oxide, the molar ratio of lithium salt to nickel oxide is 2.3:1.0 to 1.0:1.

0.

14. The method according to claim 13, characterized in that, In the mixture of lithium salt and nickel oxide, the molar ratio of lithium salt to nickel oxide is 2.2:1.0 to 1.5:1.

0.

15. The method according to claim 14, characterized in that, In the mixture of lithium salt and nickel oxide, the molar ratio of lithium salt to nickel oxide is 2.1:1.0 to 1.9:1.

0.

16. An electrode material, characterized in that, The electrode material comprises any one of the anti-honeycomb lithium-rich nickel-based oxides according to claims 1 to 4, or an anti-honeycomb lithium-rich nickel-based oxide prepared according to any one of claims 5 to 15.

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