Lithium supplement additive, preparation method thereof, electrode plate and battery

Abstract

The invention discloses a lithium supplement additive, a preparation method thereof, an electrode plate and a battery. The lithium supplement additive comprises an organic lithium salt, the organic lithium salt comprises a molecular body and lithium ions, a dynamic coordination bond is formed between the lithium ions and the molecular body, the molecular structure general formula I of the molecular body is shown in the specification, R0 in the molecular structure general formula I is a substituted or unsubstituted cyclic structure group, and R0 in the molecular structure general formula I is a substituted or unsubstituted cyclic structure group. A plurality of tertiary carbon atoms connected with R0 are connected to different loop chain atoms of the cyclic structure group; r1 to R9 are the same or different steric hindrance groups. The electrode plate and the battery contain the lithium supplement additive.

Description

Technical Field

[0001] This application belongs to the field of batteries, specifically relating to a lithium supplementation additive and its preparation method, electrode sheet and battery. Background Technology

[0002] Lithium-ion batteries are widely used in new energy vehicles, energy storage systems, and consumer electronics, placing higher demands on their energy density and lifespan. During the first charge of a lithium-ion battery, a solid electrolyte interphase (SEI) film forms at the interface between the negative electrode and the electrolyte. While the formation of the SEI film helps improve the interfacial stability of the negative electrode material, it also consumes a significant amount of Li₂ extracted from the positive electrode material. + This results in significant capacity loss and a decrease in initial coulombic efficiency in lithium-ion batteries, thereby reducing the battery's energy density and lifespan.

[0003] To reduce capacity loss and improve the initial coulombic efficiency of lithium-ion batteries, lithium replenishment materials are typically added. These materials can compensate for the irreversible lithium loss from the negative electrode during charging, especially the first charge, by providing a significant amount of irreversible capacity to offset the lithium loss during the first charge. + This reduces losses, thereby improving the capacity and initial coulombic efficiency of lithium-ion batteries.

[0004] Existing lithium-ion supplementary materials are generally binary or ternary lithium-ion supplementary materials. Although these materials are rich in lithium, they have a high residual alkali content, which is detrimental to electrode processing and adversely affects the battery's electrical performance. While existing coating technologies can mitigate the harmful effects of residual alkali to some extent, the residual alkali still exists and cannot be effectively eliminated. Furthermore, it sacrifices active lithium, reducing the lithium-ion supplementary capacity of the material. Summary of the Invention

[0005] The purpose of this application is to overcome the above-mentioned deficiencies of the prior art and provide a lithium supplementation additive to solve the technical problem that the residual alkali contained in existing inorganic lithium supplementation materials has an adverse effect on processing or battery electrical performance.

[0006] To achieve the aforementioned objectives, in a first aspect, this application provides a lithium supplementation additive. The lithium supplementation additive of this application comprises an organic lithium salt, wherein the organic lithium salt includes a molecular body and lithium ions, and the lithium ions and the molecular body form dynamic coordination bonds. The structural formula of the molecular body is shown in General Formula I below:

[0007]

[0008] In the general formula I, R0 is a substituted or unsubstituted cyclic structural group, and multiple tertiary carbon atoms connected to R0 are attached to different ring chain atoms of the cyclic structural group; R1 to R9 in the general formula I are sterically hindered groups, which may be the same or different.

[0009] The lithium-replenishing additive of this application contains an organic lithium salt whose molecular body is centered on a cyclic structure group as shown in R0. This cyclic structure, connected to multiple steric hindrance groups via multiple tertiary carbon atoms, forms a specific three-dimensional spatial structure that provides space for lithium ions. In a non-charge / discharge environment, the steric hindrance groups in the organic lithium salt molecular body act as steric barriers, preventing harmful environmental factors such as H2O and CO2 from penetrating into the three-dimensional space. Because dynamic coordination bonds are formed between lithium ions and the molecular body, the probability of lithium ions contacting these harmful environmental factors is reduced, effectively lowering the risk of residual alkali formation from the reaction of lithium ions with these factors, thus effectively reducing the residual alkali content of the organic lithium salt. In a charge / discharge environment, the steric hindrance groups in the organic lithium salt molecular body undergo some displacement, and the three-dimensional spatial structure of the molecular body also undergoes some deformation. The dynamic coordination bonds formed with lithium ions break, allowing lithium ions to effectively delithiate and exert their lithium-replenishing capacity.

[0010] A second aspect of this application provides a method for preparing the lithium supplement additive described in the above application. The method for preparing the lithium supplement additive includes the following steps for preparing an organic lithium salt:

[0011] Reactant A, including at least one of the following general structural formulas II1 to II3, is subjected to a Suzuki coupling reaction with a boric acid compound containing an R0 group to generate an intermediate having a general molecular structural formula I.

[0012]

[0013] The intermediate is subjected to a lithiation reaction with metallic lithium and a reducing agent to generate the organolithium salt containing the molecular body shown in the general formula I;

[0014] Wherein, the R0 group contained in the boric acid compound, and R0 in general formula III are substituted or unsubstituted cyclic structural groups; R1 to R3 in general formulas II1 and III are sterically hindered groups, R4 to R6 in general formulas II2 and III are sterically hindered groups, R7 to R9 in general formulas II3 and III are sterically hindered groups, and X1 in general formula II1, X2 in general formula II2, and X3 in general formula II3 are halogen atoms, which are the same or different.

[0015] The organic lithium salt prepared in this application can construct a specific three-dimensional spatial structure through multiple steric hindrance groups connected by multiple tertiary carbon atoms in the molecular body, providing space for lithium ions. In a non-charging environment, the three-dimensional spatial structure of the molecular body can prevent adverse factors such as H2O and CO2 from penetrating into the three-dimensional spatial structure of the molecule, thereby effectively reducing the probability of lithium ions coming into contact with adverse factors in the environment, effectively reducing the risk of lithium ions reacting with adverse factors such as H2O and CO2 to generate residual alkali, and effectively reducing the residual alkali content of the organic lithium salt. In a charging and discharging environment, the steric hindrance groups in the molecular body of the organic lithium salt will undergo certain displacement and the three-dimensional spatial structure of the molecular body will also undergo certain deformation. The dynamic coordination bonds formed with lithium ions will break, thereby enabling lithium ions to effectively delithiate and exert lithium replenishment capacity.

[0016] A third aspect of this application provides an electrode sheet. The electrode sheet includes a current collector and an active material layer disposed on at least one surface of the current collector, the active material layer comprising the lithium-replenishing additive described above or a lithium-replenishing additive prepared by the method described above.

[0017] The organic lithium salt in the lithium-replenishing additive of this application can effectively isolate H2O, CO2, and other substances in the air, reducing residual alkali content, and has good processing performance and can fully utilize the lithium-replenishing capacity. Therefore, the quality of the active material layer contained in the electrode sheet of this application embodiment is improved, thereby improving the initial coulombic efficiency and cycle performance of the battery.

[0018] A fourth aspect of this application provides a battery. The battery includes a positive electrode plate, said positive electrode plate including the lithium-adding additive described above.

[0019] In this application embodiment, the battery can at least during the first charge process, the lithium replenishment additive described above can delithiate and provide active lithium ions, thereby improving the battery's initial efficiency and energy density. Detailed Implementation

[0020] To make the technical problems, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0021] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0022] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0023] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0024] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0025] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass described in the embodiments of this application can be a mass unit known in the chemical industry, such as μg, mg, g, or kg.

[0026] The terms "first" and "second" are used for descriptive purposes only, to distinguish objects, such as substances, from one another, and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. For example, without departing from the scope of the embodiments of this application, "first XX" may also be referred to as "second XX," and similarly, "second XX" may also be referred to as "first XX." Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0027] During the first charge of a lithium-ion battery, a solid electrolyte interphase (SEI) film forms inside. The formation of this SEI film consumes a significant amount of Li₂ extracted from the cathode material. + This results in a loss of lithium-ion battery capacity and a decrease in initial coulombic efficiency.

[0028] To compensate for the loss of active lithium ions during the first charge of a lithium-ion battery due to the formation of a solid electrolyte interphase (SEI) membrane, a lithium replenishing material is typically added. This material can delithilate lithium during charging, especially during the first charge, providing a significant amount of irreversible capacity to compensate for the irreversible lithium loss during the initial charge. + Losses are reduced to improve the capacity and initial coulombic efficiency of lithium-ion batteries.

[0029] Currently used lithium-based materials are generally lithium-containing inorganic binary or ternary lithium-based materials. Although these materials are rich in lithium, residual alkali is present due to raw material residues or process control issues in their preparation methods. This residual alkali readily reacts with binders and other components in the electrode slurry, leading to increased viscosity and gelation of the slurry, making it difficult to coat. Furthermore, residual alkali forms an insulating layer on the surface of the lithium-based material, hindering lithium-ion insertion / extraction and electron conduction, increasing charge transfer impedance, and consequently causing battery capacity and voltage decay. Simultaneously, the reaction of residual alkali with the electrolyte produces gases such as CO, CO2, and O2, causing battery swelling and severely impacting battery safety performance.

[0030] To mitigate the aforementioned hazards of residual alkali in existing lithium replenishment materials, some reports have suggested coating the materials with materials such as alumina. While this can alleviate the hazards of residual alkali to some extent, the residual alkali still exists and cannot be effectively eliminated. Furthermore, it sacrifices active lithium, reducing the lithium replenishment capacity of the material.

[0031] Due to the aforementioned shortcomings of existing lithium replenishment materials, it is difficult to meet the growing market demand for high-performance batteries. Based on these shortcomings, this application proposes the following solution.

[0032] [Lithium Supplement Additive]

[0033] Firstly, embodiments of this application provide a lithium supplement additive. The lithium supplement additive of this application includes an organic lithium salt, which comprises a molecular body and lithium ions, and a dynamic coordination bond is formed between the lithium ions and the molecular body. The molecular body has the following general formula I:

[0034]

[0035] In this general formula I, R0 is a substituted or unsubstituted cyclic structural group, and multiple substituted methyl groups connected to R0 are attached to different ring chain atoms of the cyclic structural group shown by R0; R1 to R9 are sterically hindered groups, which may be the same or different.

[0036] In the lithium supplement additives of this application, the cyclic group represented by R0 refers to a group in which atoms in the molecule are connected by covalent bonds to form a cyclic structure. The sterically hindered groups represented by R1 to R9, also known as stereo-sterically hindered groups or volumetric sterically hindered groups, refer to groups whose spatial arrangement makes it difficult for other molecules or groups to approach or react. Multiple substituted methyl groups refer to two or more, such as two or three or more, that is, the molar ratio of substituted methyl groups to R0 is greater than 2:1.

[0037] The lithium-replenishing additive in this application contains an organic lithium salt whose molecular body is composed of a cyclic structure group as shown in R0. Each of the multiple tertiary carbon atoms is connected to three steric hindrance groups, forming a specific three-dimensional spatial structure together with the tertiary carbon atoms and the cyclic structure group at the molecular center. This three-dimensional spatial structure provides space for lithium ions. Furthermore, it can form dynamic coordination bonds with lithium ions, giving the organic lithium salt its lithium-replenishing capacity. Because lithium ions are connected to the molecular body through dynamic coordination bonds and the three-dimensional spatial structure provides space for lithium ions, in a non-charging / discharging environment, i.e., a static environment, the steric hindrance groups in the organic lithium salt molecular body can play a steric hindrance role. Together with the three-dimensional spatial structure of the molecular body, they can prevent the penetration of adverse factors in the environment, including H2O and CO2, significantly reducing the probability of lithium ions coming into contact with these adverse factors. This effectively reduces the risk of lithium ions reacting with adverse factors in the environment, including H2O and CO2, to generate residual alkali, thereby effectively reducing the residual alkali content of the organic lithium salt. When in a charging and discharging environment, i.e. a dynamic environment, an external voltage is applied to the electrode. The steric groups contained in the molecular body of the organic lithium salt will undergo certain displacement and the three-dimensional spatial structure of the molecular body will also undergo certain deformation. This will reduce the steric hindrance effect of the steric groups on lithium ions, and the dynamic coordination bond formed with lithium ions will break. Lithium ions will be extracted from the three-dimensional space of the molecular body, thereby enabling lithium ions to effectively undergo delithiation and exert lithium replenishment capacity.

[0038] Furthermore, the steric hindrance groups contained in the molecular body of the organolithium salt are connected to the outside of the cyclic structural groups that serve as the molecular center through tertiary carbons. Therefore, these steric hindrance groups can effectively improve the stability of the interface with the electrolyte and reduce side reactions with the electrolyte.

[0039] In some embodiments, the cyclic structural group at the molecular center of the organolithium salt molecular body includes any one of the following groups: substituted or unsubstituted phenyl, naphthalene ring, pyridine ring, and adamantyl group.

[0040] The aforementioned cyclic structural groups, which serve as the molecular center within the molecule, effectively function as the molecular center. These groups enrich the three-dimensional structure constructed through multiple tertiary carbons, enhancing the dynamic coordination bonds between the molecule and lithium ions. This strengthens the steric hindrance function of the steric groups, reducing the penetration of adverse factors such as H2O and CO2 into the organolithium salt molecule in static environments and decreasing the probability of lithium ions contacting these adverse factors, thereby reducing the probability of residual alkali formation in the organolithium salt. Furthermore, the three-dimensional structure formed by these cyclic structural groups and the steric hindrance groups facilitates delithiation of ions in dynamic environments, maximizing lithium replenishment capacity.

[0041] Taking a phenyl group as an example, in this embodiment, the number of tertiary carbons can be three, and they can be attached to the 1, 3, and 5 positions of the phenyl group, forming the molecular body of the organolithium salt as shown in the general formula I1 below. In this way, the steric hindrance groups in the molecular body shown in general formula I1 are relatively evenly distributed, improving the three-dimensional structural stability and reducing the probability of adverse factors such as H2O and CO2 penetrating into the organolithium salt molecule in a static environment. This reduces the probability of lithium ions coming into contact with these adverse factors in the environment, further reducing the risk of lithium ions reacting with adverse factors such as H2O and CO2 to generate residual alkali, thereby effectively reducing the residual alkali content of the organolithium salt.

[0042]

[0043] In some embodiments, the steric hindrance groups contained in the molecular body of the organolithium salt, namely the steric hindrance groups shown in R1 to R9, may include any one of the following groups: substituted or unsubstituted aryl groups, substituted or unsubstituted cyclic aliphatic groups, or substituted or unsubstituted heterocyclic groups.

[0044] In the embodiments, when the sterically hindered group includes an aryl group, the aryl group may include at least one of phenyl, naphthyl, biphenyl, etc. For example, when it is naphthyl, the tertiary carbon may be tris(1-naphthyl)methyl (-C(C 10 H7)3), for example, when it is naphthyl, the tertiary carbon can be tris(biphenyl)methyl(-C(C6H5-C6H5)3).

[0045] In the embodiments, when the sterically hindered group includes a cyclic aliphatic group, the cyclic aliphatic group may include, but is not limited to, adamantyl group. For example, when it is adamantyl group, the tertiary carbon may be tris(1-adamantyl)methyl (-C(1-adamantyl)3).

[0046] In the embodiments, when the sterically hindered group includes a heterocyclic group, the heterocyclic group may include at least one of pyridyl, thienyl, furanyl, etc. For example, when it is pyridyl, the tertiary carbon may be tris(2-pyridyl)methyl (-C(C5H4N)3); when it is thienyl, the tertiary carbon may be tris(2-thienyl)methyl (-C(C4H3S)3); and when it is furanyl, the tertiary carbon may be tris(2-furanyl)methyl (-C(C4H3O)3), etc.

[0047] The aforementioned steric hindrance groups have relatively large volumes, which enhances their steric hindrance effect within the organolithium salt molecule. Together with the cyclic structural groups serving as the molecular center, they improve the stability of the three-dimensional structure of the organolithium salt molecule. This enhances the isolation of lithium ions from the environment in a static setting, reducing the penetration of adverse factors such as H2O and CO2 into the organolithium salt molecule, thereby lowering the probability of residual alkali formation. Furthermore, the three-dimensional structure formed by these steric hindrance groups and the cyclic structural groups serving as the molecular center has minimal impact on delithiation in a dynamic environment.

[0048] In addition, these steric hindrance groups also have good rigidity. By connecting the cyclic structural groups that link the tertiary carbon to the C-C single bond of the molecular center, a highly rigid three-dimensional framework structure is constructed, which effectively improves the stability of the molecular bulk structure and three-dimensional spatial structure in organolithium salts as well as their thermal stability. Organolithium salts also have good thermal stability.

[0049] Based on the molecular body and its three-dimensional spatial structure of the organolithium salt in the above embodiments, since the molecular body contains multiple tertiary carbon atoms, and each tertiary carbon atom is connected to three sterically hindered groups, each tertiary carbon group (the group formed by the tertiary carbon atom and the three sterically hindered groups) can independently constitute a three-dimensional spatial structure. The three-dimensional spatial structure independently constituted by each tertiary carbon group is defined as a first-order three-dimensional spatial structure. Correspondingly, the molecular body has at least multiple first-order three-dimensional spaces composed of tertiary carbon groups. Moreover, the tertiary carbon groups are connected to the cyclic structure group shown in R0. Therefore, the multiple first-order three-dimensional spaces contained in the molecular body constitute more second-order three-dimensional spaces.

[0050] In this embodiment, taking the molecular body shown in the above-mentioned general structural formula I1 as an example, the molecular body contains three tertiary carbon atoms, and each tertiary carbon atom is connected to three sterically hindered groups. Therefore, each tertiary carbon group (the group formed by the tertiary carbon atom and the three sterically hindered groups) can independently constitute a primary three-dimensional spatial structure. Correspondingly, the molecular body shown in general structural formula I1 has three primary three-dimensional spaces. Furthermore, the three tertiary carbon groups are connected to the benzene ring group shown in R0. Therefore, the three primary three-dimensional spaces contained in the molecular body shown in general structural formula I1 also constitute multiple secondary three-dimensional spaces.

[0051] Based on the molecular body and its three-dimensional spatial structure of the organolithium salts in the above embodiments, such as the cyclic structural group R0 and the sterically hindered groups R1 to R9 in the above general formula I, in some embodiments, the molecular body of the organolithium salts contained in the above embodiments, as shown in general formula I, is a molecular cage structure. The molecular cage structure is a hollow structure formed by the self-assembly of the molecular body shown in general formula I through covalent bonds or non-covalent interactions (such as hydrogen bonds, π-π stacking, electrostatic interactions), and it has a clearly defined hollow cavity inside. The molecular cage structure of the molecular body has a rich three-dimensional spatial structure, and lithium ions can be connected to the three-dimensional spatial structure of the molecular cage structure through dynamic coordination bonds. In this way, in a static environment, lithium ions can be effectively encapsulated in the molecular cage structure, improving the isolation effect between lithium ions and the environment, reducing the penetration of adverse factors such as H2O and CO2 into the molecular cage structure of the organolithium salt, thereby reducing the residual alkali content of the organolithium salt. Moreover, it does not affect the lithium ion release and replenishment capacity in a dynamic environment.

[0052] Therefore, in the embodiments, in a static environment under non-discharge conditions, at least a portion of the lithium ions that form dynamic coordination bonds with the molecular body are encapsulated in the three-dimensional space of the molecular body, that is, at least a portion of the lithium ions are encapsulated in the three-dimensional space of the molecular cage structure of the molecular body.

[0053] In the embodiments, the lithium ions encapsulated in the three-dimensional space of the molecular body can be encapsulated in the molecular body by each tertiary carbon group (a group formed by a tertiary carbon atom and three sterically hindered groups) forming a three-dimensional space structure, that is, in the first-level three-dimensional space structure of the molecular body as shown in the general structural formula I. Of course, they can also be encapsulated in a second-level three-dimensional space composed of multiple first-level three-dimensional spaces, such as in the three-dimensional space of the molecular body.

[0054] In this way, lithium ions are connected and encapsulated in the three-dimensional space of the molecule through dynamic coordination bonds, which further enhances the environmental isolation effect of the molecule on lithium ions, further reduces the probability of lithium ions coming into contact with adverse factors in the environment, including H2O and CO2, and further reduces the risk of lithium ions being reacted to form residual alkali, thereby further reducing the residual alkali content of organolithium salts.

[0055] In some embodiments, the molar ratio of lithium ions to the molecular bulk in the above embodiments can be 2–4:1, optionally 2.95–3.05:1. In the embodiments, when the molecular bulk is as shown in general formula I1, and the lithium ions are encapsulated in the first-order three-dimensional space shown in general formula I1, then the molar ratio of lithium ions to the molecular bulk can be 2–3:1, such as 2:1 or 3:1. This range of molar ratios of lithium ions to the molecular bulk can improve the lithium replenishment capacity of organolithium salts, and can also improve the environmental isolation effect of the molecular bulk on lithium ions, further reducing the residual alkali content of organolithium salts.

[0056] Based on the molecular body and its three-dimensional spatial structure of the organolithium salt in the above embodiments, and when lithium ions are encapsulated in the three-dimensional space of the molecular body, in the embodiments, taking sterically hindered groups and cyclic structural groups as both being phenyl, the sterically hindered groups connected to the three tertiary carbons are all benzene rings, thus forming an organolithium salt with the molecular body shown in the general molecular structure formula I2 below. In this way, the three adjacent positions of the central benzene ring in the molecular body are respectively connected to triphenylmethyl groups (-C(C6H5)3), forming an "umbrella-shaped" molecular cage with C3 symmetry. The perpendicular arrangement of the benzene ring plane and the triphenylmethyl groups constitutes a pore size of 0.6–0.8 nm, smaller than the kinetic diameter of H2O molecules (approximately 0.3 nm) and CO2 molecules (0.33 nm). The benzene rings in the triphenylmethyl groups in the molecular cage form a flexible "molecular gate" through π-π stacking, which remains closed in a static state (spacing < 0.4 nm), only briefly opening during lithium ion insertion / extraction (spacing > 0.6 nm). This property dynamically blocks the permeation of H2O / CO2 from the environment while allowing controlled lithium-ion migration. Furthermore, the three benzene rings in the triphenylmethyl group are connected to the central phenyl group via tertiary carbons, forming a highly rigid "tripod" structure. Therefore, in the molecular body represented by general formula I2, the distribution of conjugated π-electron clouds between the benzene rings is homogenized, reducing local charge density and suppressing chemical bond breakage at high temperatures, resulting in high thermal stability for organolithium salts containing the molecular body represented by general formula I2. During charging (i.e., in a dynamic environment), an external voltage is applied to the electrodes, causing lithium ions to escape from the molecular cage pores and enter the electrolyte to replenish lithium capacity. During this process, the escape of lithium ions leads to a change in the local charge density of the benzene ring π-electron cloud, and the molecular cage conformation slightly expands, providing a channel for lithium-ion migration. After lithium ions are extracted or when entering a static environment, the triphenylmethyl groups in the molecular cage quickly return to their original position through π-π stacking and van der Waals forces, and the pores shrink to their original size.

[0057] Based on the cyclic structural group R0 and the sterically hindered groups R1 to R9 in the molecular body of the above general formula I, in the exemplary examples, the molecular body of the organolithium salt contained in the above embodiments may include at least one of the following (1) to (16):

[0058] (1) R0, R1 to R9 in the above general formula I are all phenyl;

[0059] (2) In the above general formula I, R0 is phenyl, and R1 to R9 are all naphthyl; for example, it can be tri(1-naphthyl)phenyltrilithium salt (Li3C 22 H 17 );

[0060] (3) In the above general formula I, R0 is phenyl, and R1 to R9 are all adamantyl alkyl; for example, it can be tri(1-adamantyl)benzenetrilithium salt (Li3C 28 H 25 ),Li3[C6H3(C(C) 10 H 15 )3)3] etc.;

[0061] (4) In the above general formula I, R0 is phenyl, and R1 to R9 are all pyridyl groups; for example, it can be tri(2-pyridyl)benzenetrilithium salt (Li3C 17 H 14 N3);

[0062] (5) In the above general formula I, R0 is naphthyl, and R1 to R9 are all phenyl;

[0063] (6) In the above general formula I, R0 is a naphthyl group, and R1 to R9 are all naphthyl groups, such as Li3[C 10 H6(C(C 10 H7)3)3];

[0064] (7) In the above general formula I, R0 is naphthyl, and R1 to R9 are all adamantyl groups;

[0065] (8) In the above general formula I, R0 is naphthyl, and R1 to R9 are all pyridyl;

[0066] (9) In the above general formula I, R0 is pyridyl, and R1 to R9 are all phenyl;

[0067] (10) In the above general formula I, R0 is pyridyl, and R1 to R9 are all naphthyl;

[0068] (11) In the above general formula I, R0 is pyridyl, and R1 to R9 are all adamantyl groups;

[0069] (12) In the above general formula I, R0 is pyridinyl, and R1 to R9 are all pyridinyl; for example, it can be Li3[C5H3N(C(C5H4N)3)3];

[0070] (13) In the above general formula I, R0 is adamantyl alkyl and R1 to R9 are all phenyl;

[0071] (14) In the above general formula I, R0 is adamantyl group, and R1 to R9 are all naphthyl groups;

[0072] (15) In the above general formula I, R0 is adamantyl alkyl, and R1 to R9 are all adamantyl alkyl;

[0073] (16) In the above general formula I, R0 is adamantyl group, and R1 to R9 are all pyridyl groups.

[0074] Among them, the molecular body in (1) above can be as shown in I2 below; the molecular bodies in (2) to (16) above can all be the structural formula shown in I2 below, such as the molecular body in (2) using naphthyl to replace the phenyl on the tertiary carbon in I2, and the molecular body in (5) using naphthyl to replace the central cyclic group in I2.

[0075]

[0076] The organolithium salts shown in the above examples all possess a molecular cage structure. In a static environment, this structure effectively encapsulates lithium ions, enhancing the isolation between lithium ions and the environment. This reduces the contact and reaction between lithium ions and adverse environmental factors, including H2O and CO2, thereby lowering the residual alkali content of the organolithium salt. Furthermore, it improves the lithium replenishment capacity of the organolithium salt in a dynamic environment.

[0077] In the embodiments, the delithiation voltage of the organic lithium salt in the above embodiments was detected to be 2.8V to 4.8V. Therefore, it can be seen that when this organic lithium salt is used as a lithium replenishing agent, it can release lithium ions during the first charge of the battery, exerting lithium replenishing capacity. Moreover, it has a relatively wide delithiation voltage range, making it applicable to a relatively large number of cathode material systems and enabling it to exert lithium replenishing capacity.

[0078] Secondly, embodiments of this application also provide a method for preparing the lithium-supplementing additive described above. In some embodiments, the method for preparing the lithium-supplementing additive includes the following steps for preparing an organic lithium salt:

[0079] S10: Reactant A, including at least one of the following general structural formulas II1 to II3, is subjected to a Suzuki coupling reaction with a boric acid compound containing an R0 group to generate an intermediate having the above general molecular structural formula I.

[0080]

[0081] S20: The intermediate generated in step S10 is subjected to a lithiation reaction with metallic lithium and a reducing agent to generate an organic lithium salt containing the molecular body shown in the general molecular formula I above.

[0082] In the lithium supplementation additive preparation method of this application embodiment, the R0 group contained in the boric acid compound in step S10, and R0 in general formula I, are substituted or unsubstituted cyclic structural groups. R1 to R3 in general formula II1 and I, whether the R1 to R3 are the same or different, are sterically hindered groups; R4 to R6 in general formula II2 and I, whether the R4 to R6 are the same or different, are sterically hindered groups; R7 to R9 in general formula II3 and I, whether the R7 to R9 are the same or different, are sterically hindered groups; R1 to R9 in general formula I, whether the R1 is the same or different, are sterically hindered groups; X1 in general formula II1, X2 in general formula II2, and X3 in general formula II3, whether the X1 is the same or different, include halogen atoms. In the exemplary example, the halogen atoms include chlorine (Cl), bromine (Br)(I), etc.

[0083] Thus, the organolithium salt generated by the reaction treatment in steps S10 and 20 has a molecular body, which includes a cyclic structural group as the molecular center and steric hindrance groups shown as R1 to R9. The steric hindrance groups are connected to the cyclic structural group as the molecular center through tertiary carbon atoms to construct a specific three-dimensional spatial structure, and the molecular body is connected to lithium ions through dynamic coordination bonds. Therefore, the organolithium salt prepared in this embodiment has lithium replenishment capacity, and in a non-charging static environment, it can prevent adverse factors such as H2O and CO2 from penetrating into the three-dimensional spatial structure of the molecule, thereby effectively reducing the probability of lithium ions contacting adverse factors such as H2O and CO2, reducing the risk of lithium ions reacting to form residual alkali, and effectively reducing the residual alkali content of the organolithium salt. In a charging and discharging environment, i.e., a dynamic environment, the steric hindrance groups contained in the molecular body of the organolithium salt will undergo certain displacement, and the three-dimensional spatial structure of the molecular body will also undergo certain deformation. The dynamic coordination bonds formed with lithium ions will break, thereby enabling lithium ions to effectively undergo delithiation and exert lithium replenishment capacity.

[0084] Step S10:

[0085] In step S10, reactant A provides the sterically hindered groups R1 to R9 contained in the target organolithium salt product containing the molecular body of the general formula I. Therefore, the sterically hindered groups R1 to R9 can further be the sterically hindered groups R1 to R9 in the molecular body of the general formula I described above. As in the embodiments, the sterically hindered group can include any one of the following: a substituted or unsubstituted aryl group, a substituted or unsubstituted cyclic aliphatic group, or a substituted or unsubstituted heterocyclic group.

[0086] When the steric hindrance groups shown in R1 to R9 in step S10 are the same, the reactants shown in general structural formulas II1 to II3 are the same reactant; when the steric hindrance groups shown in two of the three groups R1 to R3, R4 to R6, and R7 to R9 are the same, then the reactants shown in II1 to II3 are two reactants; when the steric hindrance groups shown in the three groups R1 to R3, R4 to R6, and R7 to R9 are different, then the reactants shown in II1 to II3 are three reactants.

[0087] Based on reactant A represented by general structural formulas II1 to II3, in some embodiments, reactant A may include: triphenylchloromethane (C(C6H5)3Cl), tris(4-tert-butylphenyl)chloromethane (Cl-C(C6H4-t-Bu)3), tris(1-naphthyl)bromomethane (Br-C(C... 10 At least one of H7)3) and tri(4-biphenyl)chloromethane (Cl-C(C6H5-C6H5)3). If reactant A includes triphenylchloromethane, then at least one of the three groups of R1 to R3, R4 to R6, and R7 to R9 contained in the intermediate of general formula I in step S10, which is also the target product of the organolithium salt in step S20, is phenyl.

[0088] In step S10, the boric acid compound containing the R0 group provides the intermediate of general molecular formula I, i.e., the R0 group representing the molecular center of the target organolithium salt product, whose molecular formula can be represented as R0-B(OH)2. Therefore, the R0 group can be the R0 group shown in the molecular body as described in general molecular formula I above. In the examples, the R0 group can include any one of substituted or unsubstituted phenyl, naphthalene ring, pyridine ring, or adamantyl group. In the exemplary example, reactant A based on at least one of general structural formulas II1 to II3 can include at least one of phenylboronic acid (C6H5B(OH)2), naphthaleneboronic acid, naphthaleneboronic acid, pyridineboronic acid, or adamantylboronic acid.

[0089] In the Suzuki coupling reaction system, the molar ratio of reactant A and the boric acid compound containing the R0 group can be mixed according to the molar ratio of the central R0 group to the tertiary carbon connected to the R0 group in the intermediate of general molecular formula III. In order to improve the reaction rate of the Suzuki coupling reaction or the yield of the target intermediate shown in general molecular formula I, in some embodiments, reactant A or the boric acid compound containing the R0 group is in excess relative to the other reactant.

[0090] Since reactant A and the boric acid compound containing the RO group undergo a Suzuki coupling reaction, the reaction system containing reactant A and the boric acid compound containing the RO group in step S10 satisfies the conditions for a Suzuki coupling reaction. In some embodiments, this Suzuki coupling reaction system also includes a catalyst and a base reagent. The type and amount of the catalyst and base reagent are sufficient to meet the requirements of the Suzuki coupling reaction or improve its efficiency. In the embodiments, the catalyst may include, but is not limited to, a Pd catalyst, such as, but not limited to, a Pd(PPh3)4 catalyst. The base reagent is used to adjust the Suzuki coupling reaction system to an alkaline environment; in the embodiments, the base reagent may include, but is not limited to, K2CO3.

[0091] The solvent for this Suzuki coupling reaction system can be capable of effectively dissolving reactant A and a boric acid compound containing the RO group. More specifically, it can be a solvent that improves the yield of intermediates of general formula I. For example, in the embodiments, the solvent for this Suzuki coupling reaction system may include a mixture of toluene and water. The temperature of the Suzuki coupling reaction can be within the temperature range that allows for Suzuki coupling reactions.

[0092] Based on the Suzuki coupling reaction type in step S10, the chemical formula for the Suzuki coupling reaction between reactant A and a boric acid compound containing an R0 group can be as follows:

[0093] At least one of the above general structural formulas II1 to II3 + R0-B(OH)2 → intermediate shown in general molecular formula I + boric acid byproduct + HX (where X is at least one of X1, X2, and X3).

[0094] Furthermore, after the Suzuki coupling reaction in step S10, the intermediate of general formula III can be purified, for example by washing with water, to remove byproducts such as boric acid and HX, solvents, and residual reactants. The intermediate of general formula I prepared in step S10 theoretically possesses the three-dimensional spatial structure of the organolithium salt contained in the lithium supplement additives of the embodiments described above, as shown in the general formula I.

[0095] Step S20:

[0096] After the intermediate of general molecular structure I generated in step S10 undergoes a lithiation reaction, lithium ions are coated in the three-dimensional spatial structure of general molecular structure I through dynamic coordination bonds, thereby generating the organic lithium salt of the embodiment of this application containing the molecular body of general molecular structure I shown above.

[0097] In the lithiation reaction in step S20, the reducing agent acts as an electron transfer medium. Metallic lithium reacts with the reducing agent to form a lithium-reducing agent intermediate. That is, under the mediation of the reducing agent, metallic lithium ultimately transfers electrons to the benzene ring of the intermediate with general molecular formula I. This results in a dynamic coordination bond between the lithium ion and the intermediate with general molecular formula I, which is then encapsulated within the three-dimensional space of the intermediate with general molecular formula I, generating a trilithium salt, which is the organolithium salt of the molecular body shown in the embodiments of this application. In the embodiments, the reactants metallic lithium and the reducing agent in the lithiation reaction process can be in excess relative to the intermediate with general molecular formula I to improve the yield of the final product, the organolithium salt.

[0098] In the embodiments, the reducing agent may include at least one of naphthalene, biphenyl, anthracene, and phenanthrene. These reducing agents all have high reducing properties and act as electron transfer mediators, thereby improving the final transfer of electrons from metallic lithium to the benzene ring of the intermediate represented by general formula I.

[0099] The solvent in the lithiation reaction process of step S20 can be a solvent capable of effectively dissolving intermediates of general formula I, or more specifically, a solvent that improves the yield of organolithium salts. For example, in the embodiments, the solvent for the lithiation reaction may include tetrahydrofuran (THF) solvent. The lithiation reaction can be carried out at room temperature. Because it contains lithium metal, in the embodiments, the lithiation reaction can be carried out under a protective atmosphere, such as, but not limited to, an argon atmosphere.

[0100] Based on the lithiation reaction mechanism in step S20, the chemical formula for the lithiation reaction between the intermediate of general molecular formula III and metallic lithium and a reducing agent can be as follows:

[0101] Intermediate of general molecular formula I + Li + reducing agent → Organolithium salt containing the molecular bulk of general molecular formula I + Li- reducing agent complex

[0102] In addition, after the Suzuki coupling reaction in step S10, the organic lithium salt after the reaction can be purified, such as by centrifugation to remove impurities such as the Li-reducing agent complex and metallic lithium that were reacted, and finally by drying to evaporate the solvent.

[0103] [Electrode Plate]

[0104] Thirdly, embodiments of this application also provide an electrode sheet. The electrode sheet of this application embodiment includes a current collector and an active material layer disposed on at least one surface of the current collector. The active material layer includes an electrode active material and a lithium replenishing agent, and the lithium replenishing agent includes the lithium replenishing additive described in the embodiments of this application.

[0105] Because the electrode sheet of this application embodiment contains the lithium replenishing additive described in the above-mentioned application embodiment, the organic lithium salt in the lithium replenishing additive can effectively isolate H2O, CO2, etc. from the air, reducing the residual alkali content, and has good processing performance and can fully exert the lithium replenishing capacity. Therefore, the quality of the active material layer contained in the electrode sheet of this application embodiment is improved, thereby improving the initial coulombic efficiency and cycle performance of the battery.

[0106] In some embodiments, the mass ratio of the organic lithium salt in the lithium-replenishing additive of the above-described embodiments to the electrode active material in the electrode sheet can be (1-2.5):100, optionally (1.5-2):1. In exemplary cases, typical but not limited mass ratios such as 1:100, 1.3:100, 1.5:100, 1.8:100, 2:100, 2.2:100, and 2.5:100, or any range between two mass ratios, can be used. Organic lithium salts within this range can effectively utilize lithium-replenishing capacity, improving the battery's energy density and cycle performance. When the electrode sheet is a positive electrode sheet, the mass ratio of the organic lithium salt in the electrode sheet to the electrode active material in the electrode sheet is the same as the mass ratio of the organic lithium salt to the positive electrode active material in the electrode sheet.

[0107] Furthermore, the electrode active material contained in the electrode sheet of this application embodiment can be a positive electrode active material. In this case, the electrode sheet of this application embodiment is a positive electrode sheet. In the embodiment, the positive electrode current collector of the positive electrode sheet can be, but is not limited to, any one of copper foil and aluminum foil. The positive electrode active material layer of the positive electrode sheet includes components such as positive electrode active material, binder, and conductive agent. The content and type of the positive electrode active material, binder, and conductive agent can be conventional in the battery industry.

[0108] As in the embodiments, the positive electrode active material in the positive electrode active material layer may include one or more of lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium vanadium phosphate, lithium vanadium oxide phosphate, lithium fluorinated vanadium phosphate, lithium titanate, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, and lithium nickel cobalt aluminum oxide.

[0109] In the embodiments, the content of the binder in the positive electrode active material layer can be 2wt%-4wt%. In specific embodiments, the binder content can be typical but not limited to 2wt%, 3wt%, 4wt%, etc. In specific embodiments, the binder includes one or more of polyvinylidene fluoride, soluble polytetrafluoroethylene, styrene-butadiene rubber, hydroxypropyl methylcellulose, methylcellulose, carboxymethyl cellulose, polyvinyl alcohol, acrylonitrile copolymer, sodium alginate, chitosan, and chitosan derivatives.

[0110] In the embodiments, the content of the conductive agent in the positive electrode active material layer can be 3wt%-5wt%. In specific embodiments, the content of the binder can be a typical but not limited content such as 3wt%, 4wt%, or 5wt%. In specific embodiments, the conductive agent includes one or more of graphite, carbon black, acetylene black, graphene, carbon fiber, C60, and carbon nanotubes.

[0111] In the embodiments, the preparation process of the positive electrode sheet can be as follows: the positive electrode active material, conductive agent, binder and lithium supplementation additive are mixed to obtain a positive electrode slurry, the positive electrode slurry is coated on the current collector, and the positive electrode sheet is prepared by drying, rolling and die cutting.

[0112] [Battery]

[0113] Fourthly, embodiments of this application also provide a battery. The battery of this application embodiment includes necessary components such as a positive electrode, a negative electrode, a separator and / or a solid electrolyte disposed between the positive and negative electrodes, and an electrolyte solution, and of course, other necessary or auxiliary components. The positive electrode includes the lithium-adding additive described in the embodiments of this application above.

[0114] Because the positive electrode of the battery in this embodiment contains the lithium replenishing additive described in the above embodiment, the battery in this embodiment can, at least during the first charge, have the lithium replenishing additive delithiated to provide active lithium ions, thereby improving the battery's initial efficiency and energy density.

[0115] The negative electrode sheet in the battery of this application embodiment can be a conventional negative electrode sheet. When the negative electrode sheet is a lithium metal foil, the lithium battery of this application embodiment can be a lithium metal battery.

[0116] The battery in this application embodiment can be assembled according to the existing assembly methods of wound cell batteries, cylindrical cells, or stacked cell batteries.

[0117] The following examples illustrate the lithium supplement additives, their preparation methods, and batteries of this application through several specific embodiments.

[0118] 1. Examples of lithium supplementation additives and their preparation methods:

[0119] Example A1:

[0120] This embodiment A1 provides an organic lithium salt lithium supplement additive. The organic lithium salt lithium supplement additive contains a molecular matrix and lithium ions, and dynamic coordination bonds are formed between the lithium ions and the molecular matrix; wherein the structural formula of the molecular matrix is ​​shown in I2 below:

[0121]

[0122] The organic lithium salt lithium supplement additive in Example A1 was prepared according to the following method:

[0123] S1. Triphenylchloromethane (C(C6H5)3Cl), phenylboronic acid (C6H5B(OH)2), Pd(PPh3)4 catalyst, and K2CO3 base were added to a toluene / water mixed solvent and subjected to a Suzuki coupling reaction at 80 °C for 24 h. Then, the mixture was purified by column chromatography (silica gel, petroleum ether / ethyl acetate = 10:1) to obtain the C6H5-(C-(C6H5)3)3 triphenylbenzene precursor (structural formula shown in I2).

[0124] S2. Dissolve the C6H5-(C-(C6H5)3)3 triphenylbenzene precursor from step S1 in ultra-dry THF, and add lithium metal flakes (Li) at a molar ratio of 1:3. 0 The mixture was reacted with naphthalene (electron transfer medium) and stirred at room temperature for 12 hours to induce a lithiumation reaction. The resulting product was then centrifuged and vacuum dried to obtain an organolithium salt lithium supplement containing the molecular matrix shown in structural formula I2. The yield of the organolithium salt lithium supplement was >85%.

[0125] Examples A2 to A4:

[0126] Examples A2 to A4 provide organic lithium salt lithium supplement additives. Each organic lithium salt lithium supplement additive contains a molecular body and lithium ions, and a dynamic coordination bond is formed between the lithium ions and the molecular body. The structural formula of each molecular body differs from that of I2 in Example A1 in that: in Example A2, the three phenyl groups attached to each tertiary carbon are replaced with three 1-naphthyl groups; in Example A3, the three phenyl groups attached to each tertiary carbon are replaced with three 1-adamantyl groups; and in Example A4, the three phenyl groups attached to each tertiary carbon are replaced with three 2-pyridyl groups. See Table 1 for examples A2 to A4 for details.

[0127] The preparation methods of the organic lithium salt lithium supplementation additives in Examples A2 to A4 are the same as those in Example A1, except that the reactant in step S1 of Example A2 is tris(1-naphthyl)chloromethane (C(C 10 H7)3Cl) replaces triphenylchloromethane; in step S1 of Example A3, the reactant is tri(1-adamantyl)chloromethane (C(C) 10 H 15 In Example A4, the reactant in step S1 was tri(pyridin-2-yl)chloromethane (C(C5H4N)3Cl) instead of triphenylchloromethane.

[0128] Examples A5, A9, and A13:

[0129] Examples A5, A9, and A13 each provide an organic lithium salt lithium supplement additive. Each organic lithium salt lithium supplement additive contains a molecular body and lithium ions, with dynamic coordination bonds forming between the lithium ions and the molecular body. The structural formula of the molecular body differs from that of I2 in Example A1 in the following ways: In Example A5, the cyclic structural group R0 of the molecular body is naphthyl, with three tertiary carbons substituted at positions 1, 4, and 5 of the naphthyl group; in Example A9, the cyclic structural group R0 of the molecular body is adamantyl, with three tertiary carbons substituted at positions 1, 3, and 5 of the adamantyl group; and in Example A13, the cyclic structural group R0 of the molecular body is pyridyl, with three tertiary carbons substituted at positions 2, 4, and 6 of the pyridyl group.

[0130] The preparation methods of the organic lithium salt lithium supplementation additives in Examples A5, A9, and A13 are all the same as those in Example A1, except that the reactant in step S1 of Example A5 is 1-naphthoboric acid (C 10 H7B(OH)2) was used instead of phenylboronic acid; in step S1 of Example A9, 1-adamantylboronic acid (C 10 H 15 B(OH)2) replaces phenylboronic acid; in step S1 of Example A13, 2-pyridineboronic acid (C5H4NB(OH)2) is used instead of phenylboronic acid.

[0131] Examples A6, A10, and A14:

[0132] Examples A6, A10, and A14 each provide an organic lithium salt lithium supplement additive. Each organic lithium salt lithium supplement additive contains a molecular matrix and lithium ions, with dynamic coordination bonds forming between the lithium ions and the molecular matrix. The structural formula of the molecular matrix differs from that of I2 in Example A2 in that: in Example A6, the cyclic structural group RO of the molecular matrix is ​​naphthyl; in Example A10, the cyclic structural group RO of the molecular matrix is ​​adamantyl; and in Example A14, the cyclic structural group RO of the molecular matrix is ​​pyridyl.

[0133] The preparation methods of the organic lithium salt lithium supplementation additives in Examples A6, A10, and A14 are all the same as those in Example A2, except that the reactant in step S1 of Example A6 is 1-naphthoboric acid (C 10 H7B(OH)2) was used instead of phenylboronic acid; in step S1 of Example A10, 1-adamantylboronic acid (C7B(OH)2) was used as the reactant. 10 H 15 B(OH)2) replaces phenylboronic acid; in step S1 of Example A14, 2-pyridineboronic acid (C5H4NB(OH)2) is used instead of phenylboronic acid.

[0134] Examples A7, A11, and A15:

[0135] Examples A7, A11, and A15 each provide an organic lithium salt lithium supplement additive. Each organic lithium salt lithium supplement additive contains a molecular matrix and lithium ions, with dynamic coordination bonds forming between the lithium ions and the molecular matrix. The structural formula of the molecular matrix differs from that of I2 in Example A3 in that: in Example A7, the cyclic structural group RO of the molecular matrix is ​​naphthyl; in Example A11, the cyclic structural group RO of the molecular matrix is ​​adamantyl; and in Example A15, the cyclic structural group RO of the molecular matrix is ​​pyridyl.

[0136] The preparation methods of the organic lithium salt lithium supplementation additives in Examples A7, A11, and A15 are all the same as those in Example A3, except that the reactant in step S1 of Example A7 is 1-naphthoboric acid (C 10 H7B(OH)2) was used instead of phenylboronic acid; in step S1 of Example A11, 1-adamantylboronic acid (C 10 H 15 B(OH)2) replaces phenylboronic acid; in step S1 of Example A15, 2-pyridineboronic acid (C5H4NB(OH)2) is used instead of phenylboronic acid.

[0137] Examples A8, A12, and A16:

[0138] Examples A8, A12, and A16 each provide an organic lithium salt lithium supplement additive. Each organic lithium salt lithium supplement additive contains a molecular matrix and lithium ions, with dynamic coordination bonds forming between the lithium ions and the molecular matrix. The structural formula of the molecular matrix differs from that of I2 in Example A4 in that: in Example A8, the cyclic structural group RO of the molecular matrix is ​​naphthyl; in Example A12, the cyclic structural group RO of the molecular matrix is ​​adamantyl; and in Example A16, the cyclic structural group RO of the molecular matrix is ​​pyridyl.

[0139] The preparation methods of the organic lithium salt lithium supplementation additives in Examples A8, A12, and A16 are all the same as those in Example A4, except that the reactant in step S1 of Example A8 is 1-naphthoboric acid (C 10 H7B(OH)2) was used instead of phenylboronic acid; in step S1 of Example A12, 1-adamantylboronic acid (C7B(OH)2) was used as the reactant. 10 H 15 B(OH)2) replaces phenylboronic acid; in step S1 of Example A16, 2-pyridineboronic acid (C5H4NB(OH)2) is used instead of phenylboronic acid.

[0140] Comparative Example A1:

[0141] This embodiment A1 provides an organic lithium salt lithium supplement additive, which is lithium hexamethylbenzeneacetate (Li6C). 12 O 12 ).

[0142] Example A2:

[0143] This embodiment A1 provides an organic lithium salt lithium supplement additive, which is a lithium dioxaburate borate (LiBOB) derivative.

[0144] The relevant information of each composite organic lithium supplementation additive in Examples A1 to A16 and Comparative Examples A1 to A2 is shown in Table 1 below.

[0145] The methods for detecting the residual alkali content of each organic salt in Table 1 are as follows:

[0146] Accurately weigh 50 mg of the sample to be tested, add 20 mL of ultra-dry tetrahydrofuran (THF), and sonicate for 10 minutes. Add 5 mL of 0.1 M HCl (prepared with anhydrous ethanol), and stir for 30 minutes to ensure complete dissolution of LiOH / Li₂CO₃. Use an automatic potentiometric titrator, selecting 0.05 M HCl (ethanol solution) as the titrant to neutralize LiOH and Li₂CO₃. Determine the titration endpoint based on the potential jump.

[0147] Table 1

[0148]

[0149] 2. Example of a lithium-ion battery:

[0150] Examples B1 to B16 and Comparative Examples B1 to B2 each provide a lithium-ion battery. Each lithium-ion battery is assembled according to the following method:

[0151] 1) Positive electrode plate:

[0152] Positive electrode plates of lithium-ion batteries in Examples B1 to B16 and Comparative Examples B1 to B2:

[0153] The organic lithium salt lithium replenishing additives provided in Examples A1 to A16 and Comparative Examples A1 to Comparative Examples A2 were used as positive electrode lithium replenishing additives for lithium-ion batteries in Examples B1 to B16 and Comparative Examples B1 to Comparative Examples B2, respectively. Specifically, Example A1 was used as the positive electrode lithium replenishing additive for the lithium-ion battery in Example B1, Example A2 was used as the positive electrode lithium replenishing additive for the lithium-ion battery in Example B2, and so on, with Comparative Example A2 used as the positive electrode lithium replenishing additive for the lithium-ion battery in Comparative Example B2. Under the same conditions, the positive electrode slurry was prepared by mixing lithium iron phosphate positive electrode material, Su-P conductive agent, PVDF binder, and positive electrode lithium replenishing additive in an appropriate amount of NMP at a mass ratio of 91.63:3.9:2.6:1.87. The mixture was then used to prepare positive electrode sheets by homogenization, coating, drying, and cutting. The positive electrode sheets were baked in a vacuum oven at 100°C to remove trace amounts of water.

[0154] 2) Negative Electrode Sheet: A negative electrode slurry is prepared by uniformly mixing graphite (the negative electrode active material), Super P (the conductive agent), carboxymethyl cellulose (CMC) (the thickener), and styrene-butadiene rubber (SBR) (the binder) in deionized water. The mass ratio of graphite:Super P:CMC:SBR is 95:2:0.5:2.5. The negative electrode slurry is coated onto copper foil (the current collector), and after drying, rolling, and a second drying process, the negative electrode sheet is formed.

[0155] 3) Diaphragm: Polyethylene (PE) diaphragm is used.

[0156] 4) Electrolytes of lithium-ion batteries in Examples B1 to B16 and Comparative Examples B1 to B2: The electrolyte is a 1 mol / L LiPF6 solution, and the solvent is composed of EC (ethylene carbonate) and DEC (diethyl carbonate) in a volume ratio of 1:1.

[0157] 5) Assembly of secondary batteries:

[0158] The above-mentioned positive electrode, negative electrode, electrolyte and separator are assembled into a lithium-ion battery according to the lithium-ion battery assembly requirements.

[0159] Performance testing of lithium-ion batteries:

[0160] The lithium-ion batteries assembled in each embodiment and comparative example in Section 5) were subjected to the relevant performance tests shown in Table 2 below, and the results are shown in Table 2 below.

[0161] The relevant performance testing methods for lithium-ion batteries are as follows in Table 2:

[0162] The method for initial coulombic efficiency testing of lithium-ion batteries is as follows: Under a constant temperature environment of 25℃, charge the battery at a current of 0.1C within a voltage range of 2.0V to 4.1V until the voltage reaches 4.1V. Then, charge the battery at a constant voltage of 4.1V until the current reaches 0.01C, and record the capacity as C1. Let the battery rest for 5 minutes, then discharge it at a current of 0.1C until the voltage reaches 2.0V. Record the capacity of the lithium-ion battery at a discharge rate of 0.1C as D1. The initial coulombic efficiency is calculated as: Initial coulombic efficiency = D1 / C1.

[0163] The capacity retention rate test method for lithium-ion batteries is as follows: The first charge-discharge cycle is performed at a constant temperature of 25℃. The battery is charged at a constant current of 1C (the current required to fully discharge the battery's nominal capacity within 2 hours) until the voltage reaches the upper limit of 4.1V. Then, it is charged at a constant voltage until the current reaches 0.05C. The battery is then left to rest for 5 minutes, followed by a constant current discharge at 1C until the voltage finally reaches 2.0V. The first cycle discharge capacity is recorded. Subsequently, the charge and discharge cycles are repeated continuously. The capacity retention rate of a fully charged battery cycled at 25℃ is calculated at the end of the 100th cycle. That is, the capacity retention rate after 100 cycles = (100th cycle discharge capacity / first cycle discharge capacity) × 100%.

[0164] High-temperature storage gas generation test method: After assembling the gas-generating battery device, the battery is formed to release the generated gas. The formed gas-generating battery device is placed in a constant temperature environment of 45℃ for 48 hours. Differential electrochemical mass spectrometry is used to detect the amount of gas generated inside the gas-generating battery device to obtain the total amount of gas generated.

[0165] Table 2

[0166]

[0167]

[0168] As shown in Table 1, under the premise that the cyclic structural groups (RO groups) of the organolithium salts are the same, the naphthyl / adamantyl groups contained in the tertiary carbon significantly reduce the total residual alkali of the organolithium salts compared to phenyl and pyridyl groups. This is due to the stronger steric hindrance and hydrophobicity of naphthyl / adamantyl groups compared to phenyl and pyridyl groups, resulting in better suppression of H2O / CO2 permeation. Compared to phenyl groups, pyridyl groups have relatively increased heterocyclic polarity, making them more prone to water adsorption, which leads to a higher residual alkali of the corresponding organolithium salts. Therefore, the steric hindrance strength is: adamantyl > naphthyl > triphenylmethyl, and the hydrophobicity is: adamantyl > naphthyl > triphenylmethyl > pyridyl. In contrast, the residual alkali content of the traditional organic lithium supplements (Li2C6O6, LiBOB) in Comparative Examples A1 and A2 is significantly higher than that of the molecular cage structure organolithium salt supplements in Examples A1 to A6, mainly due to the structural exposure and chemical instability of the traditional organic lithium supplements. The organic lithium salt in this application has a molecular cage structure, which can play a role in steric hindrance to isolate H2O / CO2 contact and can significantly reduce the residual alkali content in the organic lithium salt, such as reducing the residual alkali to <0.5%, which provides a key advantage for high-stability battery systems.

[0169] As can be seen from Tables 1 and 2, the organolithium salts in the embodiments of this application have advantages due to their molecular cage structure, such as Li3C in Example A2. 22 H 17 (Trinaphthyl) exhibits high initial efficacy due to its low residual alkali (0.26 wt%) and efficient lithium release; In Example A3 compared to Example A2, Example A7 compared to Example A6, Example A11 compared to Example A10, and Example A15 compared to Example A14, the Li3C contained in Examples A3, A7, A11, and A15... 28 H 25 The (adamantyl) molecular cage is relatively denser than that of (trinaphthyl) compounds, resulting in a slight increase in lithium-ion migration resistance and a decrease in the initial efficiency of the corresponding lithium-ion battery. The lithium-ion battery in Comparative Example B1, containing conventional organic Li2C6O6 in Comparative Example A1, only achieved an initial efficiency of 93.5% due to the residual alkali (5.3 wt%) consuming the electrolyte and generating additional SEI. The lithium-ion battery containing Li3C6O6 in Example A3... 28 H 25 In Example B3, the lithium-ion battery with (adamantyl) exhibited a 100-cycle retention rate of 96.5%, thanks to its ultra-high thermal stability (decomposition temperature > 400°C). Compared to Example B3, the pyridyl-containing lithium-ion battery, such as Li3C in Example A4, showed a significantly higher retention rate. 17 H 14N3 (pyridyl) exhibits reduced interfacial stability and retention due to its hygroscopicity. Since the organic lithium salts in this application also possess good thermal stability, they effectively reduce the gas production of lithium-ion batteries. For example, the adamantyl-containing organic lithium salt in Example A3 exhibits good thermal stability due to the rigid barrier of the molecular cage preventing thermal decomposition, resulting in a gas production rate of 0.03 mL / g for the lithium-ion battery in Example B3. In contrast, the Li2C6O6 in Comparative Example A1, due to the high-temperature decomposition of lithium carboxylate to generate CO2, results in a gas production rate as high as 0.35 mL / g for the lithium-ion battery in Comparative Example B1. As shown in Tables 1 and 2 above, the organic lithium salts in this application, through their molecular cage structure design, significantly improve their processing and storage stability, resulting in low residual alkali content and significantly enhanced thermal stability. This, in addition to improving the battery's initial efficiency, significantly improves the battery's cycle performance and suppresses gas production, thereby improving battery safety.

[0170] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A lithium supplement additive, characterized by, The organic lithium salt comprises a molecular body and lithium ions, and a dynamic coordination bond is formed between the lithium ions and the molecular body, and the structural formula of the molecular body is shown in the following general formula I: In the general formula I, R0 is a substituted or unsubstituted cyclic structure group, and a plurality of tertiary carbon atoms connected with R0 are connected to different ring chain atoms of the cyclic structure group; R1 to R9 in the general formula I are the same or different spatial steric hindrance groups.

2. The lithium supplement additive according to claim 1, characterized in that: The cyclic structure group comprises any one of a substituted or unsubstituted phenyl group, a naphthyl group, a pyridyl group and an adamantyl group; and / or The spatial steric hindrance group comprises any one of a substituted or unsubstituted aryl group, a substituted or unsubstituted cyclic aliphatic group and a substituted or unsubstituted heterocyclic group.

3. The lithium supplement additive according to claim 2, wherein: The aryl group comprises at least one of a phenyl group, a naphthyl group and a biphenyl group; and / or The cyclic aliphatic group comprises an adamantyl group; and / or The heterocyclic group comprises at least one of a pyridyl group, a thiophene group and a furan group.

4. Lithium supplementing additive according to any one of claims 1 to 3, characterized in that: The molecular body shown in the general formula I is a molecular cage structure, and the lithium ions are covered in a three-dimensional space of the molecular cage structure under non-discharge conditions; and / or The molar ratio of the lithium ions to the molecular body is 2-4:1; and / or.

5. The lithium supplement additive according to any one of claims 1 to 3, characterized in that: The molecular body comprises at least one of the following (1) to (16): (1) R0, R1 to R9 are all phenyl groups; (2) R0 is a phenyl group, and R1 to R9 are all naphthyl groups; (3) R0 is a phenyl group, and R1 to R9 are all adamantyl groups; (4) R0 is a phenyl group, and R1 to R9 are all pyridyl groups; (5) R0 is a naphthyl group, and R1 to R9 are all phenyl groups; (6) R0 is a naphthyl group, and R1 to R9 are all naphthyl groups; (7) R0 is a naphthyl group, and R1 to R9 are all adamantyl groups; (8) R0 is a naphthyl group, and R1 to R9 are all pyridyl groups; (9) R0 is a pyridyl group, and R1 to R9 are all phenyl groups; (10) R0 is a pyridyl group, and R1 to R9 are all naphthyl groups; (11) R0 is a pyridyl group, and R1 to R9 are all adamantyl groups; (12) R0 is a pyridyl group, and R1 to R9 are all pyridyl groups; (13) R0 is an adamantyl group, and R1 to R9 are all phenyl groups; (14) R0 is an adamantyl group, and R1 to R9 are all naphthyl groups; (15) R0 is an adamantyl group, and R1 to R9 are all adamantyl groups; (16) R0 is an adamantyl group, and R1 to R9 are all pyridyl groups.

6. The lithium supplementing additive according to any one of claims 1 to 3, characterized in that: At least part of the lithium ions is covered in a three-dimensional space formed by the spatial steric hindrance groups.

7. The lithium supplement additive according to any one of claims 1 to 3, characterized in that: The delithiation voltage of the organic lithium salt is 2.8V-4.8V.

8. A process for the preparation of a lithium supplementing additive as claimed in any one of claims 1 to 7, characterized in that, The method comprises the following steps for preparing the organic lithium salt: Suzuki coupling reaction is performed on a reactant A comprising at least one of the following structural general formulas II1 to II3 and a boronic acid compound containing an R0 group, to generate an intermediate with a molecular structure general formula I; The intermediate is subjected to a lithiation reaction with lithium metal and a reducing agent to generate an organic lithium salt containing the molecular body shown in the general formula I of the molecular structure; The R0 group contained in the boronic acid compound is a substituted or unsubstituted cyclic structure group; R1 to R3 in the general formula II1 and III are the same or different spatial steric hindering groups; R4 to R6 in the general formula II2 and III are the same or different spatial steric hindering groups; R7 to R9 in the general formula II3 and III are the same or different spatial steric hindering groups; X1 in the general formula II1, X2 in the general formula II2 and X3 in the general formula II3 are the same or different and include halogen atoms.

9. An electrode tab, characterized by: The lithium supplementing additive is prepared by the preparation method of claim 8.

10. A battery comprising a positive electrode sheet, characterized by, The positive electrode sheet comprises the electrode sheet of claim 9, and the active material layer comprises a positive electrode active material.

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