Use of organic carboxylic acids as chelating agents in the preparation of disordered rock salts, disordered rock salts, methods of making and batteries

Abstract

The application relates to the technical field of disordered rock salt preparation, and discloses application of an organic carboxylic acid with a dipole moment of 3-15 D, a polarizability of 30-120 and an average electrostatic potential of -1.1 to 1.1 as a chelating agent in sol-gel preparation of disordered rock salt. By selecting the organic carboxylic acid with the specific range of physicochemical parameters as the chelating agent, defects in the disordered rock salt can be effectively eliminated, the crystallinity and morphology of the disordered rock salt are improved, and the electrochemical performance of a battery prepared by using the disordered rock salt as an electrode active material is improved. The application further discloses a sol-gel preparation method of disordered rock salt, the disordered rock salt and the battery.

Description

Technical Field

[0001] This application relates to the field of disordered rock salt preparation technology, such as the application of an organic carboxylic acid as a chelating agent in the preparation of disordered rock salt, a sol-gel preparation method for disordered rock salt, and disordered rock salt and batteries. Background Technology

[0002] With extensive global research efforts, highly optimized lithium-ion batteries have emerged, making significant contributions to electric vehicles and grid storage applications. Advancing these technologies and accelerating the clean energy transition requires novel electrode materials with higher energy density, enhanced safety, and lower cost. Recently, lithium-rich cation disordered rock salt (DRX) materials have attracted attention as promising next-generation cathodes. Unlike traditional lithium-ion cathodes with fully ordered long-range crystal structures (such as layered, spinel, and olivine), DRX materials exhibit considerable cation arrangement disorder in the cation sublattice, facilitating lithium transport through the interconnection of localized O-TM lithium-rich clusters. DRX materials contain inexpensive, Earth-abundant elements such as Mn and Ti, achieving promising high specific energy densities (1000 Wh·kg⁻¹). -1 ) and capacity (300mAh·kg -1 ).

[0003] Currently, DRX materials (e.g., as cathode materials) are primarily synthesized via high-temperature solid-state processes. However, these processes face significant production scalability challenges. This is because they typically require extensive mechanical mixing or grinding to ensure rapid and uniform reactions during calcination. Consequently, these processes have been superseded by sol-gel and co-precipitation techniques; however, the electrochemical properties of the materials obtained using these techniques are not ideal and require further optimization.

[0004] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended as a general commentary, nor is it intended to identify key / important components or describe the scope of protection of these embodiments, but rather as a prelude to the detailed description that follows.

[0006] This disclosure provides an application of organic carboxylic acids as chelating agents in the preparation of disordered rock salt, disordered rock salt and its preparation method, and a battery. By selecting organic carboxylic acids with specific physicochemical parameter ranges as chelating agents, defects in disordered rock salt can be effectively eliminated, the crystallinity and morphology of disordered rock salt can be improved, and the electrochemical performance of batteries made from the disordered rock salt as electrode active materials can be improved.

[0007] In some embodiments, a corresponding monovalent anion satisfies a dipole moment of 3 to 15 D, a polarizability of 30 to 120, and an average electrostatic potential of -1.1 to... The application of organic carboxylic acids as chelating agents in the preparation of disordered rock salt by the sol-gel method.

[0008] In some embodiments, the method for preparing the sol-gel of disordered rock salt includes: preparing a solvent containing a chelating agent; wherein the chelating agent is an organic carboxylic acid that satisfies the following conditions: a dipole moment corresponding to a monovalent anion of 3 to 15 D, a polarizability of 30 to 120, and an average electrostatic potential of -1.1 to... According to the stoichiometry of disordered rock salt, the raw material is dissolved in a solvent to obtain solution A; solution A is heated to evaporate the solvent to obtain a gel; the gel is dried and pyrolyzed to obtain an intermediate oxide precursor; the intermediate oxide precursor is annealed in an inert gas environment to obtain the disordered rock salt product.

[0009] In some embodiments, the disordered rock salt, using the aforementioned corresponding monovalent anions, satisfies a dipole moment of 3 to 15 D, a polarizability of 30 to 120, and an average electrostatic potential of -1.1 to... The organic carboxylic acids are prepared by the sol-gel method; or by the aforementioned sol-gel preparation method of disordered rock salt.

[0010] In some embodiments, the battery comprises disordered rock salt prepared by the aforementioned sol-gel preparation method of disordered rock salt, or comprises the aforementioned disordered rock salt.

[0011] The application of organic carboxylic acids as chelating agents in the preparation of disordered rock salt, the disordered rock salt and its preparation method, and the battery provided in this disclosure can achieve the following technical effects:

[0012] In the applications of this disclosure, the organic carboxylic acid is used as the corresponding monovalent anion to satisfy a dipole moment of 3 to 15D (Debye), a polarizability of 30 to 120, and an average electrostatic potential of -1.1 to... Carboxylic acids. Organic carboxylic acids whose dipole moment, polarizability, and average electrostatic potential simultaneously satisfy their respective numerical ranges have large molecular volumes and high polarizability. In the preparation process (e.g., sol-gel method), they act as chelating agents, interacting closely with cations present on the surface and exhibiting a strong negative charge. This hinders larger clusters and further metal ion deposition, causing these organic carboxylic acids to reside only on the particle surface. Consequently, after removing the chelating agent, only shallow defects near the surface are formed on the product. These shallow defects can be effectively repaired during subsequent heat treatment, thereby effectively eliminating defects in disordered rock salt and improving the crystallinity and morphology of the prepared disordered rock salt.

[0013] In the sol-gel preparation method of disordered rock salt in this embodiment, an organic carboxylic acid that meets specific parameter ranges is used as a chelating agent. Taking advantage of the properties of the chelating agent, the gel is subjected to a three-step heat treatment process: low-temperature drying, medium-temperature pyrolysis, and high-temperature annealing, to obtain the disordered rock salt product. The preparation process is simple, reliable, and easy to operate. Furthermore, the high-temperature annealing requires a short annealing time, reducing energy consumption.

[0014] The disordered rock salt of this disclosure can be applied to batteries to obtain corresponding batteries including disordered rock salt. Disordered rock salt can be used as an electrode material in the battery, such as a cathode or anode material, which can improve the electrochemical performance of the battery, increase its specific capacity, improve cycle performance, and achieve a high specific capacity retention rate. Meanwhile, the battery structure and product shape are not limited; for example, it can be a full cell (disordered rock salt as the anode material, graphite or silicon as the negative electrode), a liquid electrolyte battery, a polymer battery, a (quasi-)solid-state battery, or a lithium metal battery, etc.; it can also be a button cell, a prismatic battery, a battery pack (e.g., a pouch cell), a cylindrical battery, etc. The battery form can be diverse to suit different electrical products. Electrical products can be electrical appliances, mobile devices, or automobiles, etc.

[0015] The above general description and the description below are exemplary and illustrative only and are not intended to limit this application. Attached Figure Description

[0016] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations and drawings do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are shown as similar elements. The drawings are not to be scaled. And wherein:

[0017] Figure 1 This is a flowchart illustrating a method for preparing a sol-gel of disordered rock salt according to an embodiment of this disclosure;

[0018] Figure 2 This is a flowchart of another method for preparing disordered rock salt sol-gel according to an embodiment of this disclosure;

[0019] Figure 3 This is a statistical histogram of the electrostatic potential of monovalent citrate ions in Example 1 of this disclosure;

[0020] Figure 4(a) is an X-ray diffraction pattern of various LMTO materials under different annealing times according to the embodiments of this disclosure;

[0021] Figure 4(b) is an X-ray diffraction pattern of various LMTO materials under different annealing times according to the embodiments of this disclosure;

[0022] Figure 4(c) is a normalized powder X-ray diffraction pattern of an LMTO material I according to Embodiment 1 of this disclosure;

[0023] Figure 4(d) is a normalized powder X-ray diffraction pattern of another LMTO material I in Embodiment 1 of this disclosure;

[0024] Figure 4(e) is a normalized powder X-ray diffraction pattern of another LMTO material I in Embodiment 1 of this disclosure;

[0025] Figure 5 These are the XRD patterns of LMTO material I of Example 1 and LMTO material I of Comparative Example 1 of this disclosure;

[0026] Figures 6(a) and 6(b) are scanning electron microscope images of LMTO material I in Embodiment 1 of this disclosure;

[0027] Figure 7 This is an in-situ high-resolution TEM analysis result of LMTO material I in Example 1 of this disclosure;

[0028] Figure 8 This is a normalized powder X-ray diffraction pattern of LMTO material II in Example 2 of this disclosure;

[0029] Figure 9 Here is a scanning electron microscope image of LMTO material II in Embodiment 2 of this disclosure;

[0030] Figure 10 This is an in-situ high-resolution TEM analysis result of LMTO material II in Example 2 of this disclosure;

[0031] Figure 11 This is a normalized powder X-ray diffraction pattern of LMTO material III in Example 3 of this disclosure;

[0032] Figure 12 This is a scanning electron microscope image of LMTO material III of Example 3 of the disclosed embodiments;

[0033] Figure 13This is an in-situ high-resolution TEM analysis result of LMTO material III in Example 3 of this disclosure;

[0034] Figure 14 This is a normalized powder X-ray diffraction pattern of the LMTO material in Comparative Example 1 of this disclosure, compared to I-1.

[0035] Figure 15 This is a comparative example 1 of the present disclosure, namely Comparative I-1, Comparative I-2, and LMTO material I-3 of Example 1. 7 Li solid-state nuclear magnetic resonance spectrum;

[0036] Figures 16(a) and 16(b) are scanning electron microscope images of LMTO material comparison I of Comparative Example 1 of the present disclosure;

[0037] Figure 17 This is an in-situ high-resolution TEM analysis result of the LMTO material in Comparative Example 1 of this disclosure.

[0038] Figure 18 This is a normalized powder X-ray diffraction pattern of the LMTO material in Comparative Example 2 of this disclosure.

[0039] Figure 19 This is a scanning electron microscope image of LMTO material comparison II of Comparative Example 2 of the present disclosure;

[0040] Figure 20 This is an in-situ high-resolution TEM analysis result of the LMTO material in Comparative Example 2 of this disclosure, compared to Comparative Example II.

[0041] Figures 21(a) to 21(g) These are specific capacity-voltage distribution curves for various button cells.

[0042] Figures 22(a) to 22(e) The graphs show the specific capacity of various button batteries as a function of the number of cycles.

[0043] Figures 23(a) to 23(b) The figures show the second cycle voltage curves of button cell I and button cell comparison I under different specific currents. Detailed Implementation

[0044] To provide a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this disclosure. In the following technical description, for ease of explanation, several details are used to provide a full understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be simplified in their depiction to simplify the drawings.

[0045] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate for the embodiments of this disclosure described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0046] Unless otherwise stated, the term "multiple" means two or more.

[0047] In this embodiment of the disclosure, the character " / " indicates that the objects before and after it are in an "or" relationship. For example, A / B means: A or B.

[0048] The term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0049] It should be noted that, unless otherwise specified, the embodiments and features described in the present disclosure can be combined with each other.

[0050] This disclosure provides a method for producing a monovalent anion that satisfies a dipole moment of 3 to 15 D, a polarizability of 30 to 120, and an average electrostatic potential of -1.1 to... The application of organic carboxylic acids as chelating agents in the preparation of disordered rock salt.

[0051] In the applications of this disclosure, the organic carboxylic acid satisfies a dipole moment of 3 to 15D (Debye), a polarizability of 30 to 120, and an average electrostatic potential of -1.1 to... Carboxylic acids. These organic carboxylic acids, defined by their simultaneous satisfaction of their respective numerical ranges for dipole moment, polarizability, and average electrostatic potential, possess low dipole moment, low average electrostatic potential, large molecular volume, and high polarizability. During preparation processes (e.g., sol-gel method), they act as chelating agents, interacting closely with cations and exhibiting a strong negative charge. This hinders larger clusters and further metal ion deposition, causing these organic carboxylic acids to reside only on the cluster surface. Consequently, after removing the chelating agent, only shallow defects near the surface are formed on the product. These shallow defects can be effectively repaired during subsequent heat treatment, thereby improving the crystallinity and morphology of the prepared disordered rock salt.

[0052] In this embodiment of the disclosure, the disordered rock salt includes cationic disordered rock salt (DRX). Optionally, the cationic disordered rock salt (DRX) includes lithium-rich cationic disordered rock salt.

[0053] Optionally, a cationic disordered rock salt prepared using an organic carboxylic acid as a chelating agent, as defined in the embodiments of this disclosure, can be used as the electrode material for the battery. For example, a sol-gel method can be employed.

[0054] Optionally, the electrode material includes both cathode and anode materials. That is, the prepared cationic disordered rock salt can be used as both the cathode and anode materials of the battery.

[0055] In some embodiments, the organic carboxylic acid as defined in this disclosure is used as a chelating agent in the preparation of disordered rock salt by the sol-gel method.

[0056] Optionally, it satisfies a dipole moment of 6 to 15 D, a polarizability of 30 to 90, and an average electrostatic potential of -1.0 to... The application of organic carboxylic acids as chelating agents in the preparation of disordered rock salt cathode materials for batteries using the sol-gel method.

[0057] In this embodiment, the dipole moment and polarizability of the monovalent anion of an organic carboxylic acid are obtained using Gaussian software. Specifically, Gaussian software is used with the m062x basis set def2tzvp level, considering a temperature correction of 297.15 K, and an implicit solvent model (with the command scrf = (smd, solvent = ethanol) added), targeting the monovalent anion of an organic carboxylic acid. For example, Gaussian 16 software is used.

[0058] In this embodiment, the average electrostatic potential of organic carboxylic acids is obtained by combining Gaussian software and the Multiwfn program. Specifically, the electrostatic potential and molecular surface area of ​​the monovalent anion of the organic carboxylic acid are obtained using Gaussian software, and then a statistical histogram of the electrostatic potential of the monovalent anion versus the molecular surface area of ​​the organic carboxylic acid is plotted using the Multiwfn program (e.g., referring to...). Figure 3 The monovalent citrate ion shown is CA - The average electrostatic potential E is obtained by summing the products of the median electrostatic potential of each interval and the area of ​​that interval, and then dividing by the total surface area. The intervals of the electrostatic potentials in the statistical histogram are not limited and can be determined based on the actual situation; for example, the intervals can be 10–20 kcal·mol⁻¹. -1 For example, the Multiwfn program uses the Multiwfnv3.8 program.

[0059] That is, the average electrostatic potential E is obtained by the following formula: E=(∑E i ×η i ) / S, where η i =Si / S,E i The median electrostatic potential for each interval is given in kcal·mol⁻¹. -1 η i S represents the area percentage of each interval; i The area of ​​each interval is expressed as the interval surface area, in units of 1. S represents the total surface area, with units of...

[0060] In some embodiments, the organic carboxylic acid includes carboxylic acids with 2 to 10 carbon atoms and n-ary carboxylic acids containing a benzene ring, wherein 1 ≤ n ≤ 4. The specific number of carbon atoms can be determined based on the solvent used in the sol-gel method, so that the number of carbon atoms in the organic carboxylic acid matches the number of carbon atoms in the solvent, thereby improving miscibility.

[0061] Optionally, organic carboxylic acids include carboxylic acids having 2 to 5 carbon atoms and n-ary carboxylic acids containing a benzene ring, wherein 1 ≤ n ≤ 3.

[0062] Optionally, organic carboxylic acids include carboxylic acids with 2 to 4 carbon atoms and n-ary carboxylic acids containing a benzene ring, wherein 1 ≤ n ≤ 2.

[0063] Optionally, the organic carboxylic acid includes one or more of the following carboxylic acids: propionic acid, isopropionic acid, n-butyric acid, n-valeric acid, isovaleric acid, lactic acid, isobutyric acid, glycolic acid (all of which are monocarboxylic acids), tartaric acid, oxalic acid, malic acid, citric acid, oxalic acid, ascorbic acid (all of which are polycarboxylic acids), benzoic acid, phenylacetic acid, salicylic acid, phthalic acid, terephthalic acid, and isophthalic acid (all of which are aromatic acids).

[0064] In this embodiment, the specific data of dipole moment, polarizability and average electrostatic potential of some organic carboxylic acids are shown in Table 1 below.

[0065] Table 1

[0066]

[0067] In some embodiments, the organic carboxylic acid comprises compounds satisfying a dipole moment of 3 to 15 D, a polarizability of 30 to 120, and an average electrostatic potential of -1.1 to... Organic carboxylic acids. In this embodiment, the three parameters are further narrowed to ensure the crystallinity and morphology of the disordered rock salt obtained.

[0068] Combination Figure 1 As shown in the embodiments of this disclosure, a method for preparing a sol-gel of disordered rock salt is provided, comprising:

[0069] S10. Prepare a solvent to dissolve the chelating agent; wherein the chelating agent is an organic carboxylic acid that meets the following conditions: the dipole moment corresponding to the monovalent anion is 3 to 15 D, the polarizability is 30 to 120, and the average electrostatic potential is -1.1 to...

[0070] S20. Dissolve the raw materials in a solvent according to the stoichiometry of the disordered rock salt to obtain solution A;

[0071] S30. Heat solution A to evaporate the solvent and obtain a gel;

[0072] S40. Dry and pyrolyze the gel to obtain the intermediate oxide precursor;

[0073] S50. Anneal the intermediate oxide precursor in an inert gas environment to obtain disordered rock salt products.

[0074] In the sol-gel preparation method of disordered rock salt in this embodiment, an organic carboxylic acid with a dipole moment, polarizability, and average electrostatic potential simultaneously satisfying the corresponding numerical ranges is used as a chelating agent. Taking advantage of the characteristics of the chelating agent, the gel is subjected to a three-step heat treatment process: low-temperature drying, medium-temperature pyrolysis, and high-temperature annealing, to obtain the disordered rock salt product. The preparation process is simple, reliable, and easy to operate.

[0075] In step S10, the selected chelating agent possesses low dipole moment, low average electrostatic potential, large molecular volume, and high polarizability. Dispersed in the solvent, it interacts closely with the cations present on the surface and exhibits a strong negative charge, thus hindering larger clusters and further metal ion deposition. This allows the organic carboxylic acid to reside on the cluster surface, resulting in shallow defects near the surface on the product after subsequent heat treatment to remove the chelating agent. Furthermore, during further heat treatment, crystal growth is accompanied by defect repair, effectively repairing deep defects and improving crystallinity and structural coherence, thereby improving the crystallinity and morphology of the prepared disordered rock salt. Moreover, using the obtained disordered rock salt as the electrode active material of the battery enables the battery to have higher capacity and cycle performance.

[0076] In some embodiments, in step S10, the chelating agent includes an organic carboxylic acid with 2 to 10 carbon atoms and an n-carboxylic acid containing a benzene ring, wherein 1 ≤ n ≤ 5. The specific number of carbon atoms can be determined based on the solvent used in the sol-gel method, so that the number of carbon atoms of the organic carboxylic acid matches the number of carbon atoms of the solvent, thereby improving miscibility.

[0077] Optionally, the chelating agent includes organic carboxylic acids having 2 to 5 carbon atoms and n-carboxylic acids containing a benzene ring, wherein 1 ≤ n ≤ 3.

[0078] Optionally, the chelating agent includes organic carboxylic acids having 2 to 4 carbon atoms and n-carboxylic acids containing a benzene ring, wherein 1 ≤ n ≤ 2.

[0079] Optionally, the chelating agent includes one or more of the following carboxylic acids: propionic acid, isopropionic acid, n-butyric acid, n-valeric acid, isovaleric acid, lactic acid, isobutyric acid, glycolic acid (all of which are monocarboxylic acids), tartaric acid, oxalic acid, malic acid, citric acid, oxalic acid, ascorbic acid (all of which are polycarboxylic acids), benzoic acid, phenylacetic acid, salicylic acid, phthalic acid, terephthalic acid, and isophthalic acid (all of which are aromatic acids).

[0080] Optionally, the chelating agent comprises an element having a dipole moment of 6 to 15 D, a polarizability of 30 to 90, and an average electrostatic potential of -1.0 to... Organic carboxylic acids. In this embodiment, the three parameters are further restricted to ensure the crystallinity and morphology of the disordered rock salt obtained.

[0081] In step S10, the type of solvent used to dissolve the chelating agent is not limited; solvents commonly used in the sol-gel method are acceptable, such as ethanol. Furthermore, the ratio of chelating agent to solvent is not limited and can be determined based on specific requirements.

[0082] In some embodiments, in step S10, the concentration of the chelating agent in the solvent containing the chelating agent is 0.01–5 mol / L. Controlling the concentration of the chelating agent allows for better control of the mixing uniformity between the chelating agent and the subsequent raw material salt compounds, as well as the ratio of the chelating agent to the cation.

[0083] Optionally, the concentration of the chelating agent is 0.05–3 mol / L.

[0084] Optionally, the concentration of the chelating agent is 0.1–2 mol / L.

[0085] Optionally, the concentration of the chelating agent is 0.1–1 mol / L.

[0086] Optionally, the concentration of the chelating agent is 0.1–0.8 mol / L.

[0087] Optionally, the concentration of the chelating agent is 0.1–0.5 mol / L.

[0088] Optionally, the concentration of the chelating agent is 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, or 0.5 mol / L.

[0089] In this embodiment of the disclosure, in step S20, the raw materials are determined based on the specific composition of the disordered rock salt. Optionally, the raw materials include lithium salts, manganese salts, and titanium salts. In this embodiment, the disordered rock salt includes Mn-Ti series disordered rock salt.

[0090] In some embodiments, in step S20, the raw material includes lithium salt; in solution A, the molar percentage of the chelating agent is 0.5% to 50% relative to the molar amount of Li. Controlling the molar ratio of the chelating agent to Li allows for better control of the ratio of the chelating agent to the cation.

[0091] Optionally, in solution A, the molar percentage of the chelating agent is 1% to 40% relative to the molar amount of Li.

[0092] Optionally, in solution A, the molar percentage of the chelating agent is 2% to 30% relative to the molar amount of Li.

[0093] Optionally, in solution A, the molar percentage of the chelating agent is 4% to 25% relative to the molar amount of Li.

[0094] Optionally, in solution A, the molar percentage of the chelating agent is 4% to 20% relative to the molar amount of Li.

[0095] Optionally, in solution A, the molar percentage of the chelating agent relative to the molar amount of Li is any one of 4%, 10%, 15%, 20%, or 2% to 30%.

[0096] In step S20, the amount of each raw material is determined based on the stoichiometry of the target disordered rock salt. For example, in Mn-Ti disordered rock salt, the amounts of lithium salt, manganese salt, and titanium salt are determined based on the stoichiometry of the Mn-Ti disordered rock salt. Moreover, the specific substances of lithium salt, manganese salt, and titanium salt are not limited, as long as they can dissolve in the corresponding solvent.

[0097] In some embodiments, in step S20, the raw material includes a lithium salt, which may include LiNO3, lithium formate, lithium acetate, or lithium chloride. Anhydrous lithium salt is used.

[0098] In some embodiments, in step S20, the raw material includes manganese salt, which includes Mn(CH3COO)2·4H2O, MnCl2, Mn(NO3)2 or MnSO4.

[0099] In some embodiments, in step S20, the raw material includes titanium salt, which includes titanium isopropoxide, titanium butoxide, or titanium chloride.

[0100] In some embodiments, step S20 involves dissolving the raw materials in a solvent according to the stoichiometry of the disordered rock salt to obtain solution A; this includes dissolving lithium salt, manganese salt, and titanium salt in a solvent according to the stoichiometry of the disordered rock salt to obtain solution A.

[0101] Optionally, dissolving the lithium salt, manganese salt, and titanium salt in a solvent includes: first dissolving the lithium salt and manganese salt sequentially in the solvent, and then adding the titanium salt and dissolving it in the solvent. In this embodiment, after dissolving the manganese salt in the solvent, the solution becomes a milky white suspension. Subsequently, after adding the titanium salt, the suspension only turns into a pale yellow solution A. Solution A only gradually turns yellow after aging for 8 hours. The aging conditions are: stirring at 70°C for 8 hours.

[0102] In some embodiments, step S30, heating solution A to evaporate the solvent to obtain a gel, includes: heating solution A at 50 to 100°C for 10 to 50 hours to evaporate the solvent to obtain a gel.

[0103] Optionally, solution A can be heated at 60–90°C for 20–40 h to evaporate the solvent and obtain a gel.

[0104] Optionally, solution A can be heated at 60–80°C for 20–30 h to evaporate the solvent and obtain a gel.

[0105] Optionally, solution A can be heated at 70–75°C for 20–25 h to evaporate the solvent and obtain a gel.

[0106] In step S40 of this embodiment, the temperature and time for gel drying are not limited, as long as a dry gel can be obtained.

[0107] In some embodiments, the drying conditions in step S40 include: a drying temperature of 60–200°C. Optionally, the drying temperature is 80–150°C. Optionally, the drying temperature is 90–130°C. Optionally, the drying temperature is 100–120°C. Optionally, the drying temperature is 110°C. Of course, the drying temperature can be any value within each temperature range, and they are not listed here.

[0108] In some embodiments, step S40 further includes the following drying conditions: drying time 1–20 h. Optionally, drying time 1–10 h. Optionally, drying time 1–4 h. Optionally, drying time 1–3 h. Optionally, drying time 1.5–2.5 h. Optionally, drying time 2 h. Of course, the drying time can be any value within each time interval, and they are not listed here.

[0109] In some embodiments, the drying conditions in step S40 include: a drying temperature of 60–200°C and a drying time of 1–20 h.

[0110] Optionally, the drying conditions include: a drying temperature of 80–150°C and a drying time of 1–10 hours.

[0111] Optionally, the drying conditions include: a drying temperature of 80–150°C and a drying time of 1–4 hours.

[0112] Optionally, the drying conditions include: a drying temperature of 100–140°C and a drying time of 1–3 hours.

[0113] Optionally, the drying conditions include: a drying temperature of 100–120°C and a drying time of 1–3 hours.

[0114] Optionally, the drying conditions include: a drying temperature of 110°C and a drying time of 1.5 to 2.5 hours.

[0115] Optionally, the drying conditions include: a drying temperature of 110°C and a drying time of 2 hours.

[0116] In some embodiments, in step S40, the pyrolysis conditions include: a pyrolysis temperature of 300–600°C. Optionally, the pyrolysis temperature is 300–500°C. Optionally, the pyrolysis temperature is 350–450°C. Optionally, the pyrolysis temperature is 400°C.

[0117] In some embodiments, in step S40, the pyrolysis conditions further include: a pyrolysis time of 0.5–10 h. Optionally, the pyrolysis time is 0.5–8 h. Optionally, the pyrolysis time is 0.5–6 h. Optionally, the pyrolysis time is 0.5–4 h. Optionally, the pyrolysis time is 0.5–3 h. Optionally, the pyrolysis time is 1–3 h. Optionally, the pyrolysis time is 1–2 h. Optionally, the pyrolysis time is 2 h.

[0118] Optionally, the pyrolysis conditions include: a pyrolysis temperature of 300–600℃ and a pyrolysis time of 0.5–10h.

[0119] Optionally, the pyrolysis conditions include: a pyrolysis temperature of 300–600℃ and a pyrolysis time of 0.5–4h.

[0120] Optionally, the pyrolysis conditions include: a pyrolysis temperature of 300–500℃ and a pyrolysis time of 0.5–3.5 h.

[0121] Optionally, the pyrolysis conditions include: a pyrolysis temperature of 400–500℃ and a pyrolysis time of 1–3 hours.

[0122] Optionally, the pyrolysis conditions include: a pyrolysis temperature of 450℃ and a pyrolysis time of 1 to 2 hours.

[0123] Optionally, the pyrolysis conditions include: a pyrolysis temperature of 450℃ and a pyrolysis time of 2h.

[0124] In some embodiments, in step S50, the inert gas environment includes a flowing inert gas environment.

[0125] In some embodiments, the inert gas in step S50 includes argon, nitrogen, etc.

[0126] In some embodiments, in step S50, the flow rate of the inert gas in the flowing inert gas environment is 20 to 80 mL / min.

[0127] In some embodiments, in step S50, the annealing conditions include: an annealing temperature of 700–1300°C. Optionally, the annealing temperature is 800–1200°C. Optionally, the annealing temperature is 900–1100°C. Optionally, the annealing temperature is 1000°C.

[0128] In some embodiments, step S50 further includes the following annealing conditions: an annealing time of not less than 5 minutes; optionally, an annealing time of not less than 20 minutes; optionally, an annealing time of 20 minutes to 12 hours; optionally, an annealing time of 20 minutes to 10 hours; optionally, an annealing time of 30 minutes to 8 hours; optionally, an annealing time of 30 minutes to 5 hours; optionally, an annealing time of 30 minutes to 2 hours.

[0129] Optionally, the annealing conditions include: an annealing temperature of 700–1300℃; and an annealing time of not less than 5 minutes. Specifically, the annealing time can be from 5 minutes to 10 hours.

[0130] Optionally, the annealing conditions include: an annealing temperature of 800–1200℃; and an annealing time of not less than 20 minutes. Specifically, the annealing time can be 20 minutes to 10 hours.

[0131] Optionally, the annealing conditions include: annealing temperature of 900–1100℃; annealing time of 20 min–10 h.

[0132] Optionally, the annealing conditions include: annealing temperature of 900–1100℃; annealing time of 30 min–8 h.

[0133] Optionally, the annealing conditions include: annealing temperature of 900–1100℃ and annealing time of 30 min–5 h.

[0134] Optionally, the annealing conditions include: annealing temperature of 1000℃ and annealing time of 0.5 to 5 hours.

[0135] Optionally, the annealing conditions include: annealing temperature of 1000℃ and annealing time of 0.5 to 2 hours.

[0136] This disclosure provides a disordered rock salt, employing the aforementioned properties of a dipole moment of 3 to 15D, a polarizability of 30 to 120, and an average electrostatic potential of -1.1 to... The organic carboxylic acids are prepared by the sol-gel method; or, they are prepared by the sol-gel method of any of the preceding methods for the preparation of disordered rock salt.

[0137] The disordered rock salt of this disclosure uses a chelating agent that meets specific parameter ranges during the preparation process, resulting in fewer defects, especially since the disordered rock salt is almost defect-free inside, thus having better crystallinity and morphology. As a result, when used as an electrode material for a battery, it can improve the electrochemical performance of the battery, increase the battery specific capacity, improve cycle performance, and has a high specific capacity retention rate.

[0138] This disclosure provides a battery comprising disordered rock salt, wherein the disordered rock salt is the disordered rock salt prepared by the sol-gel preparation method of any of the preceding claims or the disordered rock salt of any of the preceding embodiments.

[0139] In this embodiment, disordered rock salt can be used as an electrode material in the battery, such as a cathode or anode material, which can improve the electrochemical performance of the battery, increase its specific capacity, improve cycle performance, and achieve a high specific capacity retention rate. Furthermore, the battery's structure and shape are not limited; for example, it can be a full cell (disordered rock salt as the anode material, graphite or silicon as the negative electrode), a liquid electrolyte battery, a polymer battery, a (quasi-)solid-state battery, or a lithium metal battery, etc.; it can also be a button cell, a prismatic battery, a battery pack (e.g., a pouch cell), a cylindrical battery, etc. The battery form can be diverse to suit different electrical products. These electrical products can be electrical appliances, mobile devices, or automobiles, etc.

[0140] The following specific embodiments illustrate more specifically the application of organic carboxylic acids as chelating agents in the preparation of disordered rock salt by the sol-gel method, the preparation method of disordered rock salt, and the disordered rock salt itself.

[0141] Example 1: Application of citric acid (CA) as a chelating agent

[0142] The application of citric acid as a chelating agent in the preparation of disordered rock salt by the sol-gel method. The dipole moment of the corresponding monovalent citrate anion of citric acid is 5.51 D, the polarizability is 94.08, and the average electrostatic potential is...

[0143] The preparation method of cationic disordered rock salt using citric acid as a chelating agent in Example 1 and the sol-gel method is combined with Figure 2 As shown, it includes:

[0144] S11. Prepare an ethanol solvent to dissolve citric acid; wherein the concentration of citric acid in the ethanol solvent is 0.5 mol / L.

[0145] S21, according to Li 1.2 Mn0.4 Ti 0.4 The stoichiometry of O2 cation disordered rock salt was determined by dissolving 0.12 mol anhydrous LiNO3, 0.04 mol Mn(CH3COO)2·4H2O and 0.04 mol titanium isopropoxide in 40 g of ethanol solvent prepared in step S11 to obtain solution A.

[0146] S31. Heat solution A at 60–80°C for 20–30 hours to evaporate the solvent and obtain gel I; the heating temperature should be maintained within the range of 60–80°C. For example, it can be heated at 70°C for 25 hours. Gel I obtained under the evaporation conditions in step S31 has consistency.

[0147] S41. Dry gel I at 100–140°C for 1–4 h to obtain dry gel I, then pyrolyze at 300–500°C for 0.5–3 h to obtain the intermediate oxide precursor; for example, it can be dried at 110°C for 1–2 h, and the dry gel I obtained under the drying conditions of this step S41 has consistency. For example, it can be pyrolyzed at 450°C for 1–2 h, and the intermediate oxide precursor obtained under the pyrolysis conditions of this step S41 has consistency.

[0148] S51. Under an argon atmosphere (e.g., a flowing argon atmosphere), the intermediate oxide precursor is annealed at 800–1200 °C for 5 min–12 h to obtain Li. 1.2 Mn 0.4 Ti 0.4 O2-rich lithium-cation disordered rock salt (abbreviated as LMTO material I).

[0149] In Example 1, the dipole moment and polarizability of monovalent citrate ions, as well as related information such as electrostatic potential and molecular surface area, were obtained using Gaussian16 software. Then, the data were plotted at intervals of 15 kcal·mol using the Multiwfn v3.8 program. -1 The statistical histogram of electrostatic potential versus molecular surface area of ​​monovalent citrate ions, as shown below. Figure 3 As shown in Table 2, the initial electrostatic potential, termination electrostatic potential, median electrostatic potential, surface area of ​​each interval, and area percentage of each interval are information for different intervals. The average electrostatic potential of monovalent citrate ions is obtained by summing the products of the median electrostatic potential of each interval multiplied by the area percentage of that interval, and then dividing by the total surface area. From Table 2, the total surface area is... Calculations show that the average electrostatic potential of monovalent citrate ions is:

[0150] Table 2

[0151]

[0152] In Example 1, annealing was performed at a temperature of 1000°C for annealing times of 20 min, 25 min, 30 min, 5 h, and 10 h, respectively, yielding LMTO materials I-1, I-2, I-3, I-4, and I-5. For comparison, Example 1 also yielded four comparative LMTO materials I with annealing times of 0 min (unannealed), 5 min, 10 min, and 15 min at a temperature of 1000°C. Furthermore, LMTO material I-6 was obtained at an annealing temperature of 1200°C for 5 min, and LMTO material I-7 was obtained at an annealing temperature of 800°C for 2 h.

[0153] Figures 4(a) and 4(b) show the X-ray diffraction patterns of LMTO material I with different annealing times at 1000℃ using different plotting methods. It can be seen that without annealing, the material forms a spinel-like phase during pyrolysis. As annealing progresses, the characteristic Bragg peak of the spinel phase near 18° gradually weakens, becoming almost invisible after 10 minutes and finally disappearing after 15 minutes. Simultaneously, the intensity of the Bragg peak near 43° increases rapidly in the first 10 minutes and remains relatively stable after 30 minutes, accompanied by a continuous decrease in the full width at half maximum (FWHM) of the diffraction peak. This indicates that the rock salt phase forms rapidly at 1000℃, and its crystal quality gradually improves with prolonged annealing time, eventually stabilizing. Furthermore, the rock salt phase is a stable phase, and its condition remains unchanged even with further extension of the annealing time, for example, to 5 hours or even 10 hours.

[0154] Figure 4(c) shows the normalized powder X-ray diffraction pattern of LMTO material I-3 (annealed at 1000℃ for 30 min) in Example 1 of this invention. The Rietveld method was used to refine and fit the observed XRD pattern. It can be seen that the prepared LMTO material I-3 belongs to the Fm-3m crystal system, and the diffraction peaks at the key Bragg positions are clearly visible. The observed and calculated values ​​are highly consistent, and the error curve is nearly linear, indicating a high degree of overlap between the two curves. The Rwp parameter was used to evaluate the difference between the observed and calculated values; in this example, the value is 4.81%, which can be considered a high degree of consistency between the observed and calculated values. The lattice constant α of LMTO material I-3 was obtained through Rietveld refinement. Furthermore, LMTO material I-3 is a single-phase DRX compound with no detectable impurity peaks.

[0155] Figure 4(d) shows the normalized powder X-ray diffraction pattern of LMTO material I-6 (annealed at 1200℃ for 5 min) in Example 1 of this invention. The Rietveld method was used to refine and fit the observed XRD pattern. It can be seen that the prepared LMTO material I-6 belongs to the Fm-3m crystal system, and the diffraction peaks at the key Bragg positions are clearly visible. The observed and calculated data are highly consistent, and the error curve is almost a straight line, proving that the two curves have a high degree of overlap. The Rwp parameter was used to evaluate the difference between the observed and calculated values; in this example, the value is 6.44%, which can be considered as a high degree of consistency between the observed and calculated values. The lattice constant α of LMTO material I-6 was obtained through Rietveld refinement. Furthermore, LMTO material I-6 is a single-phase DRX compound with no detectable impurity peaks.

[0156] Figure 4(e) shows the normalized powder X-ray diffraction pattern of LMTO material I-7 (annealed at 800℃ for 120 min) in Example 1 of this invention. The observed XRD pattern was refined and fitted using the Rietveld method. It can be seen that the prepared LMTO material I-6 belongs to the Fm-3m crystal system, and the diffraction peaks at the key Bragg positions are clearly visible. The observed and calculated values ​​are highly consistent, with the error curve being nearly linear, indicating a high degree of overlap between the two curves. The Rwp parameter was used to evaluate the difference between the observed and calculated values; in this example, the value is 4.48%, indicating a high degree of consistency between the observed and calculated values. The lattice constant α of LMTO material I-6 was obtained through Rietveld refinement. Furthermore, LMTO material I-7 is a single-phase DRX compound with no detectable impurity peaks.

[0157] like Figure 5 The XRD patterns of LMTO material I-3 in Example 1 and LMTO material I in Comparative Example 1 are shown. It can be seen that the Bragg peak of LMTO material I-3 in Example 1 is significantly stronger and narrower than that of LMTO material I in Comparative Example 1, indicating that LMTO material I-3 in Example 1 has better crystallinity.

[0158] As shown in the scanning electron microscope (SEM) images of LMTO material I-3 in Figures 6(a) and 6(b), it can be seen that LMTO material I-3 has relatively large secondary particles exceeding 10 μm in size, composed of primary particles with a size of approximately 2 μm. Notably, the particles exhibit a smooth and cohesive morphology. Comparing the SEM images of LMTO material contrast I in Comparative Example 1 shown in Figures 16(a) and 16(b), the particle size of LMTO material contrast I is approximately 5 μm, and the surface appears rough, decorated with many small particles smaller than 200 nanometers.

[0159] In this embodiment 1, in step S51, in-situ high-resolution TEM analysis was performed on the pyrolytic oxide (LMTO material I-3) sintered at 1000°C collected from the nearby area. The analysis results are as follows: Figure 7 As shown, Figure 7 In this context, "Surface" refers to the surface region of the target material particles, and "Bulk" refers to the internal volume region of the target material particles. Figure 7 The four images on the left correspond to magnified images of the surface region outlined by the white dashed circle in the middle image, and the diffraction patterns obtained after selected-area Fourier transform. The patterns obtained after inverse Fourier transform (IFFT) filtering of the selected diffraction spots are then shown as IFFT patterns. The four images on the right correspond to magnified images of the Bulk region outlined by the white dashed circle in the middle image, and the diffraction patterns obtained after selected-area Fourier transform. The patterns obtained after inverse Fourier transform (IFFT) filtering of the selected diffraction spots are then shown as IFFT patterns. It can be seen that although dislocation defects are still visible in the surface region, the IFFT pattern of the internal bulk region appears more complete, indicating the absence of obvious dislocation defects and better crystallinity.

[0160] Example 2: Application of lactic acid (LA) as a chelating agent

[0161] The application of lactic acid as a chelating agent in the preparation of disordered rock salt by the sol-gel method; the dipole moment of the corresponding monovalent lactate anion of lactic acid is 9.92 D, the polarizability is 65.52, and the average electrostatic potential is...

[0162] In the preparation method of cationic disordered rock salt using lactic acid as a chelating agent in Example 2 via the sol-gel method, the difference from the preparation method in Example 1 is that in step S11, an ethanol solvent containing dissolved lactic acid is prepared; wherein, in the ethanol solvent, the concentration of lactic acid is 1 mol / L; in step S31, solution A is heated at 100°C for 10 h to evaporate the solvent and obtain a gel; in step S41, the gel is dried at 200°C for 1 h to obtain a dry gel, and then pyrolyzed at 500°C for 0.5 h to obtain an intermediate oxide precursor; in step S51, the intermediate oxide precursor is annealed at 1100°C for 20 min to obtain Li 1.2 Mn 0.4 Ti 0.4 O2-rich lithium-cation disordered rock salt (abbreviated as LMTO material II). The remaining steps and parameters are the same as in Example 1.

[0163] In Example 2, the average electrostatic potential of the monovalent lactate anion was obtained using the same method as that of the monovalent citrate anion in Example 1. By plotting a statistical histogram of the electrostatic potential versus molecular surface area of ​​the monovalent lactate anion, the average electrostatic potential of the monovalent lactate anion was calculated as follows:

[0164] like Figure 8 The normalized powder X-ray diffraction pattern of LMTO material II in Example 2 is shown, where the observed XRD pattern was refined and fitted using the Rietveld method. It can be seen that the prepared LMTO material II belongs to the Fm-3m crystal system, and the diffraction peaks at the key Bragg positions are clearly visible. The observed and calculated data are highly consistent, with the error curve being nearly linear, indicating a high degree of overlap between the two curves. The Rwp parameter was used to evaluate the difference between the observed and calculated values; in this example, the value is 8.2%, which can be considered a high degree of consistency between the observed and calculated values. The lattice constant α of LMTO material II was obtained through Rietveld refinement. Furthermore, LMTO material II is a single-phase DRX compound with no detectable impurity peaks.

[0165] like Figure 9 The scanning electron microscope image of LMTO material II shown shows that the particles of LMTO material II have a uniform particle size in the range of 500 nm to 1 μm, and the particles exhibit a smooth and cohesive morphology, with the particles appearing as uniform blocks.

[0166] In this Example 2, in-situ high-resolution TEM analysis was performed on pyrolytic oxide (LMTO material II) sintered at 1000°C collected from a nearby area. The analysis results are as follows: Figure 10 As shown, Figure 10 In this context, "Surface" refers to the surface region of the target material particles, and "Bulk" refers to the internal volume region of the target material particles. Figure 10 The two images on the left correspond to the selected Fourier transform diffraction patterns obtained from the white dashed circles out of the internal volume region in the right image. The patterns obtained after inverse Fourier transform (IFFT) filtering of the delineated diffraction spots are then shown (IFFT patterns). It can be seen that the surface is smooth and cohesive; the interior has only scattered dislocations and is basically intact. As shown in the IFFT patterns, its lattice fringes are well-aligned, with no obvious dislocation defects.

[0167] Example 3: Application of Isobutyric Acid (IBA) as a Chelating Agent

[0168] The application of isobutyric acid as a chelating agent in the preparation of disordered rock salt by the sol-gel method. The dipole moment of the corresponding monovalent isobutyrate anion of isobutyric acid is 8.76D, the polarizability is 77.90, and the average electrostatic potential is...

[0169] In the preparation method of cationic disordered rock salt using isobutyric acid as a chelating agent in Example 3 via the sol-gel method, the difference from the preparation method in Example 1 is that in step S11, an ethanol solvent containing isobutyric acid is prepared; wherein, in the ethanol solvent, the concentration of isobutyric acid is 0.1 mol / L; in step S31, solution A is heated at 60°C for 30 h to evaporate the solvent and obtain a gel; in step S41, the gel is dried at 150°C for 2 h to obtain a dry gel, and then pyrolyzed at 300°C for 8 h to obtain an intermediate oxide precursor; in step S51, the intermediate oxide precursor is annealed at 800°C for 2 h to obtain Li 1.2 Mn 0.4 Ti 0.4 O2-rich lithium-cation disordered rock salt (abbreviated as LMTO material III). The remaining steps and parameters are the same as in Example 1.

[0170] In Example 3, the average electrostatic potential of the monovalent isobutyrate anion was obtained using the same method as that of the monovalent citrate anion in Example 1. By plotting a statistical histogram of the electrostatic potential versus molecular surface area of ​​the monovalent isobutyrate anion, the average electrostatic potential of the monovalent lactate anion was calculated as follows:

[0171] like Figure 11 The normalized powder X-ray diffraction pattern of LMTO material III in Example 3 is shown, where the observed XRD pattern was refined and fitted using the Rietveld method. It can be seen that the prepared LMTO material III belongs to the Fm-3m crystal system, and the diffraction peaks at the key Bragg positions are clearly visible. The observed and calculated data are highly consistent, with the error curve being nearly linear, indicating a high degree of overlap between the two curves. The Rwp parameter was used to evaluate the difference between the observed and calculated values; in this example, the value is 9.4%, which can be considered a high degree of consistency between the observed and calculated values. The lattice constant α of LMTO material III was obtained through Rietveld refinement. Furthermore, LMTO material III is a single-phase DRX compound with no detectable impurity peaks.

[0172] like Figure 12 The scanning electron microscope image of LMTO material III shown shows that the particles of LMTO material III have a uniform particle size in the range of 1 to 2 μm, and the particles exhibit a smooth and cohesive morphology with a porous structure on the particle surface.

[0173] In this Example 3, in-situ high-resolution TEM analysis was performed on pyrolytic oxide (LMTO material III) sintered at 1000°C collected from a nearby area. The analysis results are as follows: Figure 13 As shown, Figure 13In this context, "Surface" refers to the surface region of the target material particles, and "Bulk" refers to the internal volume region of the target material particles. Figure 13 The two images on the left correspond to the diffraction patterns obtained by selecting the area Fourier transform at the location outlined by the white dashed circle in the inner volume region of the image on the right. The patterns obtained after filtering the selected diffraction spots using inverse Fourier transform (IFFT) are then shown (IFFT patterns). It can be seen that the surface is smooth and cohesive; the interior is dislocation-free and intact, just as the IFFT patterns show, with well-aligned lattice fringes and no dislocation defects.

[0174] Example 4: Application of Glycolic Acid (GA) as a Chelating Agent

[0175] The application of glycolic acid as a chelating agent in the preparation of disordered rock salt using the sol-gel method. The dipole moment of the corresponding monovalent glycolate anion of glycolic acid is 8.54 D, the polarizability is 48.47, and the average electrostatic potential is...

[0176] In the preparation method of cationic disordered rock salt using glycolic acid as a chelating agent in Example 4 via the sol-gel method, the difference from the preparation method in Example 1 is that in step S11, an ethanol solvent containing dissolved glycolic acid is prepared; wherein, in the ethanol solvent, the concentration of glycolic acid is 5 mol / L; in step S31, solution A is heated at 80°C for 20 h to evaporate the solvent and obtain a gel; in step S41, the gel is dried at 120°C for 1 h to obtain a dry gel, and then pyrolyzed at 400°C for 5 h to obtain an intermediate oxide precursor; in step S51, the intermediate oxide precursor is annealed at 1000°C for 50 min to obtain Li 1.2 Mn 0.4 Ti 0.4 O2-rich lithium-cation disordered rock salt (abbreviated as LMTO material IV). The remaining steps and parameters are the same as in Example 1.

[0177] In Example 4, the average electrostatic potential of the monovalent glycolate anion was obtained using the same method as that of the monovalent citrate anion in Example 1. By plotting a statistical histogram of the electrostatic potential versus molecular surface area of ​​the monovalent glycolate anion, the average electrostatic potential of the monovalent glycolate anion was calculated as follows:

[0178] Example 5: Application of Propionic Acid (PA) as a Chelating Agent

[0179] The application of propionic acid as a chelating agent in the preparation of disordered rock salt by the sol-gel method; the dipole moment of the corresponding monovalent propionate anion of propionic acid is 7.74 D, the polarizability is 60.58, and the average electrostatic potential is...

[0180] In the preparation method of cationic disordered rock salt using propionic acid as a chelating agent in Example 5 via the sol-gel method, the difference from the preparation method in Example 1 is that in step S11, an ethanol solvent containing propionic acid is prepared; wherein, in the ethanol solvent, the concentration of propionic acid is 2 mol / L; in step S31, solution A is heated at 80°C for 24 h to evaporate the solvent and obtain a gel; in step S41, the gel is dried at 100°C for 3 h to obtain a dry gel, and then pyrolyzed at 400°C for 2 h to obtain an intermediate oxide precursor; in step S51, the intermediate oxide precursor is annealed at 900°C for 1 h to obtain Li 1.2 Mn 0.4 Ti 0.4 O2-rich lithium-cation disordered rock salt (abbreviated as LMTO material V). The remaining steps and parameters are the same as in Example 1.

[0181] In Example 5, the average electrostatic potential of the monovalent propionate anion was obtained using the same method as that of the monovalent citrate anion in Example 1. By plotting a statistical histogram of the electrostatic potential versus molecular surface area of ​​the monovalent propionate anion, the average electrostatic potential of the monovalent propionate anion was calculated as follows:

[0182] Comparative Example 1: Comparative application of acetic acid (AA) as a chelating agent

[0183] The application of acetic acid as a chelating agent in the preparation of disordered rock salt by the sol-gel method. The dipole moment of the monovalent acetate anion of acetic acid is 5.57 D, the polarizability is 44.18, and the average electrostatic potential is...

[0184] In the preparation method of cationic disordered rock salt using acetic acid as a chelating agent in Comparative Example 1 via the sol-gel method, the difference from the preparation method in Example 1 is that in step S11, an ethanol solvent containing dissolved acetic acid is prepared; wherein, in the ethanol solvent, the concentration of acetic acid is 2.5 mol / L; in step S21, solution comparison A is obtained; in step S41, dry gel comparison I is obtained; in step S31, solution A is heated at 70°C for 25 h to evaporate the solvent and obtain a gel; in step S41, the gel is dried at 120°C for 1 h to obtain a dry gel, and then pyrolyzed at 450°C for 2 h to obtain an intermediate oxide precursor; in step S51, the intermediate oxide precursor is annealed at 1000°C for 30 min to 5 h. The remaining steps and parameters are the same as in Example 1.

[0185] In Comparative Example 1, the lithium-rich cationic disordered rock salt prepared by the sol-gel method using acetic acid as a chelating agent is abbreviated as LMTO material comparison I. Among them, the material obtained by annealing for 3 min is designated as comparison I-1, and the material obtained by annealing for 5 h is designated as comparison I-2.

[0186] The average electrostatic potential of the monovalent acetate anion in Comparative Example 1 was obtained using the same method as that used for the monovalent citrate anion in Example 1. By plotting a statistical histogram of the electrostatic potential versus molecular surface area of ​​the monovalent acetate anion, the average electrostatic potential of the monovalent lactate anion was calculated as follows:

[0187] like Figure 14 The normalized powder X-ray diffraction pattern of the LMTO material in Comparative Example 1 compared to I is shown, with the observed XRD pattern refined and fitted using the Rietveld method. It can be seen that the prepared LMTO material compared to I belongs to the Fm-3m crystal system, and the diffraction peaks at the key Bragg positions are clearly visible. The observed and calculated data are highly consistent, and their error curves are nearly linear, proving a high degree of overlap between the two curves. The Rwp parameter is used to evaluate the difference between the observed and calculated values; in this example, the value is 4.81%, which can be considered a high degree of consistency between the observed and calculated values. The lattice constant α of the LMTO material compared to I was obtained through Rietveld refinement. Additionally, LMTO material comparison I is a single-phase DRX compound.

[0188] like Figure 15 The figures shown are LMTO material I-3 from Example 1, and Comparative Example I-1 and Comparative Example I-2 from Comparative Example 1. 7 Li solid-state nuclear magnetic resonance (ssNMR) spectra were used to probe the local environment surrounding Li. Isotropic sideband separation was obtained using the projected magic angle rotation phase-adjusted sideband separation (pj MATPASS) method. 7 Li spectrum. Comparison shows that although binding... Figure 5 The XRD patterns shown in Comparison I-1 indicate that the XRD intensity of the rock salt phase increases after annealing for 30 min when acetic acid chelating agent is used as a ligand, suggesting that the reaction is essentially complete. However, combined with... Figure 15 This indicates that although the phase transformation is complete, some phases still belong to the ordered structure. This part of the structure is not conducive to performance improvement. Only when the annealing time is extended to 5 hours can it be completely eliminated, and only then can we obtain an effect (performance) similar to that of annealing for 30 minutes when citric acid is used as a ligand in Example 1.

[0189] As shown in Figures 16(a) and 16(b), these are scanning electron microscope images of LMTO material comparison I in Comparative Example 1. The particle size of LMTO material comparison I is about 5 μm, and the surface looks very rough, decorated with many small particles smaller than 200 nanometers.

[0190] In Comparative Example 1, in-situ high-resolution TEM analysis was performed on pyrolytic oxides (LMTO material comparison I) sintered at 1000℃ collected from the nearby area. The analysis results are as follows: Figure 17 As shown, Figure 17 In this context, "Surface" refers to the surface region of the target material particles, and "Bulk" refers to the internal volume region of the target material particles. Figure 17 The two images on the left correspond to magnified images of the areas outlined by the white dashed circle in the inner bulk region of the right image, and the diffraction patterns obtained after selected-area Fourier transform. The patterns obtained after inverse Fourier transform (IFFT) filtering of the outlined diffraction spots are then presented as IFFT patterns. The four images on the right correspond to magnified images of the areas outlined by the white dashed circle in the bulk region of the middle image, and the diffraction patterns obtained after selected-area Fourier transform. The patterns obtained after inverse Fourier transform (IFFT) filtering of the outlined diffraction spots are then presented as IFFT patterns. It can be seen that the particle surface is rough; dislocation defects exist internally, and as shown in the IFFT patterns, the lattice fringes are generally well-aligned.

[0191] Comparative Example: Comparative Application of Formic Acid (FA) as a Chelating Agent

[0192] Formic acid is used as a chelating agent in the sol-gel method for preparing disordered rock salt. The corresponding monovalent formate anion of formic acid has a dipole moment of 2.50 D, a polarizability of 28.24, and an average electrostatic potential of [missing information].

[0193] In the preparation method of cationic disordered rock salt using formic acid as a chelating agent in Comparative Example 2 via the sol-gel method, the difference from the preparation method in Example 1 is that in step S11, an ethanol solvent containing formic acid is prepared; wherein, in the ethanol solvent, the formic acid concentration is 2.5 mol / L; in step S31, solution A is heated at 70°C for 25 h to evaporate the solvent and obtain a gel; in step S41, the gel is dried at 120°C for 1 h to obtain a dry gel, and then pyrolyzed at 450°C for 2 h to obtain an intermediate oxide precursor; in step S51, the intermediate oxide precursor is annealed at 1000°C for 30 min. The remaining steps and parameters are the same as in Example 1.

[0194] In Comparative Example 2, the lithium-rich cationic disordered rock salt prepared by the sol-gel method using formic acid as a chelating agent is referred to as LMTO material comparison II.

[0195] The average electrostatic potential of the monovalent formate anion in Comparative Example 2 was obtained using the same method as that of the monovalent citrate anion in Example 1. By plotting a statistical histogram of the electrostatic potential versus molecular surface area of ​​the monovalent lactate anion, the average electrostatic potential of the monovalent lactate anion was calculated as follows:

[0196] like Figure 18 The normalized powder X-ray diffraction pattern of LMTO material Comparison II shown in Comparative Example 2 is an example of this study. The observed XRD pattern was refined and fitted using the Rietveld method. It can be seen that the prepared LMTO material Comparison II belongs to the Fm-3m crystal system, and the diffraction peaks at the key Bragg positions are clearly visible. The observed and calculated data are highly consistent, with the error curve being nearly linear, indicating a high degree of overlap between the two curves. The Rwp parameter was used to evaluate the difference between the observed and calculated values; in this example, the value is 7.4%, which can be considered a high degree of consistency between the observed and calculated values. The lattice constant α of LMTO material Comparison II was obtained through Rietveld refinement. Furthermore, LMTO material comparison II is a single-phase DRX compound.

[0197] like Figure 19 The scanning electron microscope image of the LMTO material comparison II shown shows that the particle size of the LMTO material comparison II is uneven, with the large particle size reaching 5 μm and the surface of the large particles looking very rough, while decorated with many small particles with a size of less than 300 nanometers.

[0198] In Comparative Example 2, in-situ high-resolution TEM analysis was performed on pyrolytic oxides (LMTO material comparison II) sintered at 1000℃ collected from the nearby area. The analysis results are as follows: Figure 20 As shown, Figure 20 In this context, "Surface" refers to the surface region of the target material particles, and "Bulk" refers to the internal volume region of the target material particles. Figure 20 The two images on the left correspond to the selected Fourier transform diffraction patterns obtained from the white dashed circles out of the internal bulk region in the right image. The patterns obtained after inverse Fourier transform (IFFT) filtering of the delineated diffraction spots are then shown (IFFT patterns). It is evident that widespread dislocation defects are clearly visible in the surface region; scattered defects are still observed in the internal bulk region. As shown in the IFFT patterns, the lattice fringes are generally well-aligned, but scattered dislocation defects exist, indicating insufficient structural coherence and integrity.

[0199] Application Examples

[0200] In this embodiment of the disclosure, LMTO materials I-3, I-4, and I-5 from Example 1, LMTO materials from Examples 2 to 5, and LMTO materials from Comparative Examples 1 and 2 are respectively made into cathode films and assembled into button cells, thereby obtaining button cell I, button cell II, button cell III, button cell IV, and button cell V, as well as button cell comparison I and button cell comparison II.

[0201] The specific fabrication and assembly process is as follows: 280 mg of each synthesized LMTO material was mixed with 80 mg of Super C65 carbon black in a zirconium oxide flask and sealed in an argon-filled glove box. The mixture was milled on a shaker for 1 hour using a SPEX 8000M milling machine to obtain composite powder I. Composite powder I was manually mixed with polytetrafluoroethylene (PTFE) at a ratio of 9:1 using a mortar and pestle to obtain composite powder II. Composite powder II was then rolled into individual films and cut using an 8 mm diameter punch. The electrolyte used was 1 M LiPF6 in a solution of ethylene carbonate and dimethyl carbonate (volume ratio 1:1, Sigma-Aldrich). Glass microfibers (Whatman) were cut with an 18 mm punch and used as separators. Lithium foil discs were used as the anode. After sealing the button cell (CR2032), it was allowed to stand for 4 hours and then tested on a Land battery cycler at 25 °C. All cathode film fabrication and button cell assembly were carried out in an argon-filled glove box.

[0202] The tests yielded performance parameters for each coin cell, including initial specific capacity, initial specific energy, specific capacity after multiple cycles, and retention rate, as shown in Table 3 below. The test parameters were 1.5–4.8 V and 20 mA·g. -1 .

[0203] Table 3

[0204]

[0205] This disclosure provides Figures 21(a), 21(b), 21(c), 21(d), 21(e), 21(f), and 21(g), which correspond to button cell I-3, button cell I-4, button cell I-5, button cell II, and button cell III, respectively, as well as button cell comparison I and button cell comparison II, at 1.5–4.8V and 20mA·g. -1 The specific capacity-voltage distribution curve for the next cycle. Figures 22(a) to 22(e)The graphs show the specific capacity changes with the number of cycles for button cells I-3 (LMTO material I-3 from Example 1 was used as the active material), II, and III, as well as comparative I and II, to analyze cycle stability. Table 3 shows the specific capacity values ​​and corresponding retention rates of each button cell after 50 cycles. Retention rate = specific capacity after 50 cycles / initial specific capacity × 100%. It can be seen that button cells I, II, and III all have high initial specific capacities, and after 50 cycles, they achieve retention rates comparable to or even better than comparative I and II, exhibiting superior electrochemical performance.

[0206] Meanwhile, in this embodiment, cycle performance tests were conducted on button cell I (LMTO material I from Example 1 as the active material) and button cell comparison I at different specific currents. Figures 23(a) and 23(b) are the second cycle voltage curves of button cell I and button cell comparison I at different specific currents, respectively. The initial discharge specific capacity values ​​at different specific currents, as shown in Table 4, are also obtained, in mAh·g. -1 .

[0207] As shown in Table 4, the button battery I of this embodiment has a better initial discharge specific capacity, and the rate of decrease in the initial discharge specific capacity value is small as the specific current increases, thus exhibiting stronger adaptability.

[0208] Table 4

[0209]

[0210]

[0211] In this embodiment of the present disclosure, to verify the conclusion that the organic carboxylic acid, as defined by dipole moment, polarizability, and average electrostatic potential, resides on the surface during the sol-gel preparation process, the following verification method was employed: Equal amounts of dry gel were dissolved and leached, with or without grinding, and the pH of the ground and unground leachates was analyzed. The dissolving solution was either water or ethanol, and the amounts were identical. The results are shown in Table 5.

[0212] Table 5

[0213]

[0214] As shown in Table 5, in Example 1, the pH values ​​and proton concentrations of the leachate from the dry gel I (using citric acid as a chelating agent) were similar before and after grinding, indicating that the citric acid chelating agent was mainly located on the particle surface. In contrast, in Comparative Example 1, the pH value of the leachate from the dry gel I (using acetic acid as a chelating agent) after grinding was significantly lower than that of the leachate after non-grinding. This indicates that grinding exposes the acetic acid anions within the gel matrix, resulting in a significant decrease in the pH value of the grinding leachate and an increase in the proton concentration by three orders of magnitude, suggesting deep penetration of the acetic acid chelating agent within the gel.

[0215] In this embodiment, the color changes of solution A in Example 1 and solution A in Comparative Example 1 were compared. It was found that in Example 1, after dissolving the manganese salt in the solvent, the solution became a milky white suspension. Subsequently, after adding the titanium salt, the suspension only turned into a pale yellow solution A. Solution A only gradually turned yellow after aging for 8 hours. In Comparative Example 1, after adding the manganese salt, the solution containing lithium salt and acetic acid remained transparent. Once the titanium salt was added, the solution turned yellow, indicating the immediate formation of a homogeneous precursor mixture. No further changes were observed during the subsequent 8-hour aging process. The aging conditions were stirring at 70°C for 8 hours.

[0216] In this embodiment of the disclosure, the powder X-ray diffraction (XRD) pattern was obtained using a Rigaku Miniflex diffractometer with Cu K Sources were obtained and refined using DIFFRAC TOPAS V6 software. A 2θ range of 15–85° was applied with a step size of 0.02° and an integration time of 2 seconds. HRTEM was obtained using a transmission electron microscope (JEOL, JEM-2100F) at an accelerating voltage of 200 kV. EDS quantification was performed on a 200 kV JEOL JEM-F200 transmission electron microscope. TEM images were acquired and processed using digital microscopy imaging software. Ion concentrations during the experiments were detected by ICP-OES (Thermo iCAP-Q). All extraction experiments were performed under ambient conditions.

[0217] This application is not limited to the structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

[0218] In this application, each embodiment may focus on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to each other.

Claims

1. The corresponding monovalent anion satisfies a dipole moment of 3 to 15 D, a polarizability of 30 to 120, and an average electrostatic potential of -1.1 to... The application of organic carboxylic acids as chelating agents in the preparation of disordered rock salt.

2. The application according to claim 1, characterized in that, Organic carboxylic acids include carboxylic acids with 2 to 10 carbon atoms and n-ary carboxylic acids containing a benzene ring, wherein 1 ≤ n ≤ 4.

3. The application according to claim 2, characterized in that, Organic carboxylic acids include carboxylic acids with 2 to 5 carbon atoms and n-ary carboxylic acids containing a benzene ring, where 1 ≤ n ≤ 3.

4. The application according to claim 2, characterized in that, Organic carboxylic acids include carboxylic acids with 2 to 4 carbon atoms and n-ary carboxylic acids containing a benzene ring, where 1 ≤ n ≤ 2.

5. The application according to claim 1, characterized in that, Organic carboxylic acids include one or more of the following carboxylic acids: Propionic acid, isopropionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, lactic acid, glycolic acid, tartaric acid, oxalic acid, malic acid, citric acid, oxalic acid, ascorbic acid, benzoic acid, phenylacetic acid, salicylic acid, phthalic acid, terephthalic acid, isophthalic acid.

6. The application according to claim 1, characterized in that, Organic carboxylic acids include those satisfying a dipole moment of 6 to 15 D, a polarizability of 30 to 90, and an average electrostatic potential of -1.0 to... Organic carboxylic acids.

7. The application according to any one of claims 1 to 6, characterized in that, Application as a chelating agent in the preparation of disordered rock salt by the sol-gel method.

8. The application according to any one of claims 1 to 6, characterized in that, The dipole moment and polarizability of monovalent anions were obtained using Gaussian software; the average electrostatic potential was obtained by combining Gaussian software and the Multiwfn program.

9. The application according to any one of claims 7, characterized in that, The dipole moment and polarizability of monovalent anions were obtained using Gaussian software; the average electrostatic potential was obtained by combining Gaussian software and the Multiwfn program.

10. A method for preparing a sol-gel of disordered rock salt, characterized in that, include: Prepare a solvent to dissolve the chelating agent; wherein the chelating agent is an organic carboxylic acid that meets the following conditions: a dipole moment corresponding to a monovalent anion of 3 to 15 D, a polarizability of 30 to 120, and an average electrostatic potential of -1.1 to... According to the stoichiometry of disordered rock salt, the raw material is dissolved in a solvent to obtain solution A; Solution A was heated to evaporate the solvent and obtain a gel. The gel was dried and pyrolyzed to obtain the intermediate oxide precursor; In an inert gas environment, the intermediate oxide precursor is annealed to obtain disordered rock salt products.

11. The sol-gel preparation method according to claim 10, characterized in that, The dipole moment and polarizability of monovalent anions were obtained using Gaussian software; the average electrostatic potential was obtained by combining Gaussian software and the Multiwfn program.

12. The sol-gel preparation method according to claim 10, characterized in that, Chelating agents include organic carboxylic acids with 2 to 10 carbon atoms and n-carboxylic acids containing a benzene ring, wherein 1 ≤ n ≤ 4.

13. The sol-gel preparation method according to claim 12, characterized in that, Organic carboxylic acids include organic carboxylic acids with 2 to 5 carbon atoms and n-aryalkaline acids containing a benzene ring, wherein 1 ≤ n ≤ 3.

14. The application according to claim 12, characterized in that, Organic carboxylic acids include organic carboxylic acids with 2 to 4 carbon atoms and n-aryalkaline acids containing a benzene ring, where 1 ≤ n ≤ 2.

15. The sol-gel preparation method according to claim 10, characterized in that, The chelating agent is an organic carboxylic acid that meets the following conditions: a dipole moment of 6 to 15 D corresponding to a monovalent anion, a polarizability of 30 to 90, and an average electrostatic potential of -1.0 to...

16. The sol-gel preparation method according to claim 10, characterized in that, Chelating agents include one or more of the following carboxylic acids: Propionic acid, isopropionic acid, butyric acid, valeric acid, isovaleric acid, lactic acid, isobutyric acid, glycolic acid, tartaric acid, oxalic acid, malic acid, citric acid, oxalic acid, ascorbic acid, benzoic acid, phenylacetic acid, salicylic acid, phthalic acid, terephthalic acid, isophthalic acid.

17. The sol-gel preparation method according to claim 10, characterized in that, In the solvent containing the chelating agent, the concentration of the chelating agent is 0.01–5 mol / L.

18. The sol-gel preparation method according to claim 17, characterized in that, In the solvent containing the chelating agent, the concentration of the chelating agent is 0.1–2 mol / L.

19. The sol-gel preparation method according to claim 10, characterized in that, The raw materials include lithium salts; in solution A, the molar percentage of the chelating agent is 0.5% to 50% relative to the molar amount of Li.

20. The sol-gel preparation method according to claim 19, characterized in that, In solution A, the molar percentage of the chelating agent is 2% to 30% relative to the molar amount of Li.

21. The sol-gel preparation method according to claim 10, characterized in that, Heating solution A to evaporate the solvent to obtain a gel includes: Solution A is heated at 50–100°C for 10–50 h to evaporate the solvent and obtain a gel.

22. The sol-gel preparation method according to claim 21, characterized in that, Solution A is heated at 60–80°C for 20–30 h to evaporate the solvent and obtain a gel.

23. The sol-gel preparation method according to any one of claims 10 to 22, characterized in that, The drying conditions include: a drying temperature of 60–200°C; and / or The pyrolysis conditions include: a pyrolysis temperature of 300–600°C; and / or The annealing conditions include an annealing temperature of 700–1300°C.

24. The sol-gel preparation method according to claim 23, characterized in that, The drying conditions include: a drying temperature of 80–150°C; and / or The pyrolysis conditions include: a pyrolysis temperature of 300–600°C; and / or The annealing conditions include an annealing temperature of 800–1200°C.

25. The sol-gel preparation method according to claim 23, characterized in that, The drying conditions also include: a drying time of 1–20 hours; and / or The pyrolysis conditions also include: a pyrolysis time of 0.5–10 h; and / or The annealing conditions also include: the annealing time is not less than 5 minutes.

26. The sol-gel preparation method according to claim 25, characterized in that, The drying conditions also include: a drying time of 1 to 4 hours; and / or The pyrolysis conditions also include: a pyrolysis time of 0.5–4 hours; and / or The annealing conditions also include: the annealing time is not less than 20 minutes.

27. The sol-gel preparation method according to claim 26, characterized in that, The drying conditions also include: a drying time of 1.5 to 3 hours; and / or The pyrolysis conditions also include: a pyrolysis time of 1–2 hours; and / or The annealing conditions also include an annealing time of 20 min to 12 h.

28. A disordered rock salt, characterized in that, It employs a monovalent anion as described in any one of claims 1 to 9, satisfying a dipole moment of 3 to 15 D, a polarizability of 30 to 120, and an average electrostatic potential of -1.1 to... Organic carboxylic acids were prepared as chelating agents via the sol-gel method. Alternatively, it can be prepared by the sol-gel preparation method of disordered rock salt as described in any one of claims 10 to 27.

29. A battery, characterized in that, The disordered rock salt obtained by the sol-gel preparation method of any one of claims 10 to 27; or the disordered rock salt as described in claim 28.

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