Organic sacrificial salt, positive pole piece, alkali metal ion energy storage device and pre-metallization method

Abstract

The invention provides an organic sacrificial salt, a positive pole piece, an alkali metal ion energy storage device and a pre-metallization method, and relates to the technical field of alkali metal ion energy storage devices. The low-decomposition-voltage organic sacrificial salt disclosed by the invention has a structure as shown in a formula I: R-CH2-COOM formula I, in the formula (I), R is selected from any one of-N (CH3) 2,-NHCH3,-NH2,-OCH3,-OPh and-Ph; m is selected from any one of Li, Na or K. A specific electron-donating group in the structure of the organic sacrificial salt can endow the organic sacrificial salt with a relatively high HOMO energy level through a hyperconjugation effect, so that the oxidation potential of the organic sacrificial salt is effectively reduced; when the organic sacrificial salt is used as a positive pole piece additive in the alkali metal ion energy storage device, the capacity retention ratio of the alkali metal ion energy storage device comprising the organic sacrificial salt can be remarkably improved by pre-metallization, and the degradation of an electrolyte solvent and an electrode structure is inhibited; and the alkali metal ion energy storage device with excellent cycling stability and rate capability is obtained.

Description

[0001] This invention claims priority to Chinese patent application CN202511280859.7, the contents of which are incorporated in their entirety into and form part of the original description of this invention. The applicant further declares that it has the right to amend the description and claims of this invention based on this priority document. Technical Field

[0002] This invention relates to the field of alkali metal ion energy storage device technology, specifically to an organic sacrificial salt, a positive electrode, an alkali metal ion energy storage device, and a pre-metallization method. Background Technology

[0003] Alkali metal (including Li, Na, K, etc.) ion energy storage devices (AESDs) are a class of energy storage devices that use alkali metal ions as energy carriers, encompassing batteries and capacitors based on alkali metal ion energy storage. Taking Li as an example, typical devices include lithium-ion batteries, lithium-ion capacitors, lithium-ion-sulfur batteries, and lithium-ion-oxygen batteries. The energy storage principle of these devices is based on the reversible storage and release of alkali metal ions by the negative electrode active material, thereby realizing energy conversion and storage. However, during the initial charging process of AESDs, a solid electrolyte interface (SEI) layer spontaneously forms on the surface of the negative electrode material. The formation of this SEI layer irreversibly consumes some of the alkali metal ions from the positive electrode, leading to a decrease in the device's coulombic efficiency, specific capacity decay, and shortened cycle life, which to some extent restricts the performance improvement and application expansion of AESDs. Therefore, to compensate for the metal ions irreversibly consumed during the first charging process due to the formation of the SEI layer, a pre-metallization strategy becomes a necessary technical means.

[0004] Pre-metallization, or pre-intercalation of metal ions, is considered a technique to provide an additional sufficient metal source in electrochemical energy storage systems. Pre-metallization plays a crucial role in electrochemical energy storage systems, not only effectively compensating for initial capacity loss in metal-ion batteries but also increasing the operating voltage of hybrid-ion capacitors and reducing electrolyte consumption. Pre-metallization strategies can be implemented in various ways: A traditional pre-metallization method involves using a metal electrode. The process is as follows: first, a target negative electrode and a metal foil are combined to form a half-cell and discharged. The elemental metal is oxidized, losing electrons and transforming into metal ions. These metal ions migrate towards and embed into the target negative electrode under the influence of an electric field. Then, the pre-metallized negative electrode is combined with a positive electrode material to form a full cell, which is then subjected to normal charge-discharge testing. This method allows for precise control of the metal ion embedding potential of the target electrode. However, due to the high reactivity of metals, this method has poor safety. Pre-metallization can only be performed in an inert atmosphere free of H2O and O2, which is detrimental to the mass production of high-performance AESDs.

[0005] Another pre-metallization method is achieved through the irreversible oxidation reaction of sacrificial salts. The operational logic is as follows: the pre-metallizer is used as the positive electrode additive in the AESD. During the initial charging process, the sacrificial salt undergoes irreversible oxidation, releasing metal ions. These metal ions diffuse and embed into the negative electrode material under the influence of an electric field, thereby achieving in-situ compensation of metal ions to the negative electrode. The sacrificial salt pre-metallization method offers advantages such as ease of operation and high safety.

[0006] Current research primarily focuses on inorganic sacrificial salt candidates, including lithium oxide (Li₂O), lithium peroxide (Li₂O₂), Li₅FeO₄, and Li₆CoO₄, all of which can improve the electrochemical performance of lithium-ion batteries to some extent. However, these inorganic sacrificial salts still face significant challenges in practical applications: their sensitivity to environmental humidity leads to increased interfacial impedance and impaired reaction kinetics, severely limiting the achievable specific capacity. In recent years, this limitation has prompted a shift in research focus for sacrificial salt pre-metallization to organic sacrificial salts (OSS), such as lithium squaric acid (Li₂C₄O₄), lithium oxalate (Li₂C₂O₄), and lithium carboxylate (HCOOLi and CH₃COOLi). Organic compounds offer diverse structures, allowing for precise control of their decomposition thermodynamics through strategic functional group selection. However, existing OSSes generally possess excessively high oxidation potentials, easily leading to electrolyte decomposition and electrode structure degradation during operation. Furthermore, energy storage devices constructed using OSSes exhibit poor electrochemical performance (such as cycle stability and rate performance), failing to meet the application requirements of high-performance AESDs. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention discloses an organic sacrificial salt, a positive electrode, an alkali metal ion energy storage device, and a pre-metallization method. The organic sacrificial salt has the advantage of low decomposition voltage. When used as an additive for the positive electrode in an alkali metal ion energy storage device, it can achieve effective alkali metal compensation for the negative electrode through at least one charge-discharge cycle, resulting in an alkali metal ion energy storage device with excellent cycle stability and rate performance.

[0008] To achieve the above technical objectives, on the one hand, this invention proposes a low-decomposition-voltage organic sacrificial salt, wherein the organic sacrificial salt has the structure of Formula I: R-CH2-COOM Formula I; Wherein, R is selected from any one of -N(CH3)2, -NHCH3, -NH2, -OCH3, -OPh, -Ph; M is selected from any one of Li, Na, or K.

[0009] Lithium acetate (Li-Ac) is a traditional organic sacrificial salt that releases lithium ions via the Körber reaction to compensate for initial capacity loss. However, it suffers from drawbacks such as a high oxidation potential, requiring a higher charging cutoff voltage, which may compromise electrolyte stability and electrode integrity. To overcome these shortcomings, our research team has innovatively proposed a molecular engineering strategy to reduce the OSS decomposition potential through substituent effects. By utilizing the correlation between electron-donating groups (EDGs) and the highest occupied molecular orbital (HOMO) energy level—that is, the stronger the electron-donating ability, the higher the HOMO energy level and the lower the oxidation potential—a series of derivatives were prepared by replacing the α-hydrogen of lithium acetate with functional groups of different electron-donating abilities. Subsequently, the organic sacrificial salt shown in Formula I was obtained by calculating the HOMO energy level using density functional theory (DFT) and combining it with exploratory experiments.

[0010] Through numerous experiments, the research and development team of this invention has confirmed that the decomposition voltage of the organic sacrificial salt shown in Formula I is effectively reduced. It is speculated that the electron-donating group shown in Formula I can endow OSS with a higher HOMO energy level through hyperconjugation, so that it does not need to increase the charging cut-off voltage during use. When used in the preparation of positive electrode, it can avoid electrolyte decomposition caused by excessively high voltage during pre-metallization, so that the electrolyte can maintain good stability and thus maintain the long-term cycle stability of the electrochemical energy storage device.

[0011] Furthermore, the preparation method of the organic sacrificial salt shown in Formula I of the present invention can be selected as follows: it is prepared by acid-base reaction of an organic carboxylic acid and an alkali metal hydroxide as raw materials. More optionally, it is prepared by reacting the organic carboxylic acid and the alkali metal hydroxide in a solvent; specifically, it further includes adjusting the pH of the reacted material to 9-10, then separating and removing the solvent, washing, and drying to obtain the organic sacrificial salt; wherein the solvent can be water, ethanol, a water-ethanol mixture, etc., and the molar ratio of the organic carboxylic acid to the alkali metal hydroxide can be selected as (0.5-2):1, preferably 1:1; in addition, the organic carboxylic acid and alkali metal hydroxide used in the preparation of the organic sacrificial salt can be commercially available or self-made, and the overall preparation method is simple, low-cost, and has a high yield, making it easy for industrial application.

[0012] Based on extensive experimental data, in a further example of the present invention, R is any one of -N(CH3)2, -NHCH3, -NH2, and -OCH3. In an optional example of the present invention, R is -N(CH3)2. The organic sacrificial salts of the present invention containing this group exhibit a higher HOMO energy level and therefore can possess a lower decomposition voltage. In an optional example of the present invention, R is -N(CH3)2. N,N-dimethylamino is endowed with the highest HOMO energy level (-7.78 eV, compared to -9.19 eV for lithium acetate) through hyperconjugation, indicating its lowest oxidation potential. Further exploratory experiments confirmed that the positive electrode containing (CH3)2N-CH2-COOM can release a capacity close to the theoretical value during the first charge. In addition, (CH3)2N-CH2-COOM is an amino acid derivative, which is widely available and cost-effective as a bio-based material. Moreover, the byproduct formed by (CH3)2N-CH2-COOM after the metal ions are compensated can be dissolved in the electrolyte, will not hinder electron and ion transport, and will not react with other active or inactive materials in the positive electrode, which is beneficial to improving the stability of alkali metal ion energy storage devices.

[0013] In a further example of the invention, the highest occupied molecular orbital (HOMO) level of the organic sacrificial salt is -7.78 eV, the decomposition initiation voltage is 3.54 V, and the specific capacity is 238.2 mAh g. -1 .

[0014] On the other hand, the present invention proposes a positive electrode sheet for alkali metal ion energy storage devices, wherein the positive electrode sheet is prepared by coating a slurry containing a positive active material, a first conductive agent, a first binder and the aforementioned low decomposition voltage organic sacrificial salt onto a first metal current collector and then drying it.

[0015] In a further example of the present invention, the first metal current collector includes aluminum foil, carbon cloth, nickel foam or stainless steel mesh, and a suitable first metal current collector can be selected as needed in practical applications.

[0016] In a further example of the present invention, the alkali metal ion energy storage device is an alkali metal ion battery, an alkali metal ion capacitor, an alkali metal ion-sulfur battery, or an alkali metal ion-oxygen battery. The organic sacrificial salt of the present invention can be used in a variety of alkali metal ion energy storage devices and has strong versatility.

[0017] Further, an appropriate amount of the low decomposition voltage organic sacrificial salt can achieve a better negative electrode lithium supplementation effect; when the alkali metal ion energy storage device is an alkali metal ion battery, the dosage of the above-mentioned low decomposition voltage organic sacrificial salt is 1% - 13% of the mass of the positive electrode active material, preferably 1% - 8%, more preferably 2% - 6%, and still more preferably 4%; when the alkali metal ion energy storage device is an alkali metal ion capacitor, the dosage of the above-mentioned low decomposition voltage organic sacrificial salt is 10% - 60% of the mass of the positive electrode active material, preferably 20% - 60%, more preferably 30% - 50%, and still more preferably 40%; when the alkali metal ion energy storage device is an alkali metal ion-sulfur battery, the dosage of the above-mentioned low decomposition voltage organic sacrificial salt is 20% - 70% of the mass of the positive electrode active material, preferably 30% - 60%, more preferably 40% - 50%, and still more preferably 45%; when the alkali metal ion energy storage device is an alkali metal ion-oxygen battery, the dosage of the above-mentioned low decomposition voltage organic sacrificial salt is 10% - 60% of the mass of the positive electrode active material, preferably 20% - 50%, more preferably 20% - 40%, and still more preferably 30%. Examples of the present invention verify that an appropriate addition amount of the organic sacrificial salt can significantly improve the cycle stability of the battery.

[0018] Further, when the alkali metal ion energy storage device is a lithium ion battery, the positive electrode active material includes at least one of LiCoO2, LiNi x Co y Mn z O2 (0 < x < 1, 0 < y < 1, 0 < z < 1 and x + y + z = 1), LiNi x Co y Al z O2 (0 < x < 1, 0 < y < 1, 0 < z < 1 and x + y + z = 1), LiFePO4, LiMn2O4, LiNi 0.5 Mn 1.5 O4; the first conductive agent includes at least one of conductive carbon black, acetylene black, Ketjen black, carbon nanotubes, graphene; the first binder includes at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), sodium carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), polyacrylic acid (PPA), polyimide (PI). In an optional example of the present invention, the mass ratio of the above-mentioned low decomposition voltage organic sacrificial salt, positive electrode active material, first conductive agent, and first binder in the positive electrode sheet is (2 - 20):(68 - 76):(20 - 2):(10 - 2).

[0019] Further, when the alkali metal ion energy storage device is a sodium ion battery, the positive electrode active material includes NaCoO2, NaFeO2, NaFePO4, NaNi x [[ID=2�]]Coy Mn z O2 (0 < x < 1, 0 < y < 1, 0 < z < 1 and x + y + z = 1), Na3V2(PO4)3, Na4Fe3(PO4)2P2O7, Na2FePO4F, Na x Fe[Fe(CN)6] (0 < x ≤ 2), Na x Mn[Fe(CN)6] (0 < x ≤ 2), at least one of them; the first conductive agent includes at least one of conductive carbon black, acetylene black, Ketjen black, carbon nanotubes, and graphene; the first binder includes at least one of PVDF, PTFE, CMC, SBR, PPA, and PI. In an optional example of the present invention, the mass ratio of the positive electrode active material, the first conductive agent, and the first binder in the positive electrode sheet is (2~20):(68~76):(20~2):(10~2).

[0020] Further, when the alkali metal ion energy storage device is a potassium ion battery, the positive electrode active material includes KCoO2, KNi x Co y Mn z O2 (0 < x ≤ 2), K3V2(PO4)3, KFePO4, K x Fe[Fe(CN)6] (0 < x ≤ 2), K x Mn[Fe(CN)6] (0 < x ≤ 2), at least one of them; the first conductive agent includes at least one of conductive carbon black, acetylene black, Ketjen black, carbon nanotubes, and graphene; the first binder includes at least one of PVDF, PTFE, CMC, SBR, PPA, and PI. In an optional example of the present invention, the mass ratio of the positive electrode active material, the first conductive agent, and the first binder in the positive electrode sheet is (2~20):(68~76):(20~2):(10~2).

[0021] Further, when the alkali metal ion energy storage device is an alkali metal ion capacitor, the positive electrode active material includes at least one of activated carbon, porous carbon, and graphene; the first conductive agent includes at least one of conductive carbon black, acetylene black, Ketjen black, carbon nanotubes, and graphene; the first binder includes at least one of PVDF, PTFE, CMC, SBR, PPA, and PI; furthermore, the mass ratio of the positive electrode active material, the first conductive agent, and the first binder in the positive electrode sheet is (20~50):(50~46):(20~2):(10~2).

[0022] Furthermore, when the alkali metal ion energy storage device is an alkali metal ion-sulfur battery, the positive electrode active material includes at least one of sulfur-porous carbon composite material, sulfur-carbon nanotube composite material, sulfur-graphene composite material, and sulfurized polyacrylonitrile; the first conductive agent includes at least one of conductive carbon black, acetylene black, Ketjen black, carbon nanotubes, and graphene; the first binder includes at least one of PVDF, PTFE, CMC, SBR, PPA, and PI. Even further, the mass ratio of the positive electrode active material, the first conductive agent, and the first binder in the positive electrode sheet is (20~50):(50~46):(20~2):(10~2).

[0023] Furthermore, when the alkali metal ion energy storage device is an alkali metal ion-oxygen battery, the positive electrode active material includes at least one of graphene, carbon nanotubes, carbon paper or carbon cloth supported on a catalyst layer of Ru, Ir, MnO2, Co3O4, etc.; the first conductive agent includes at least one of conductive carbon black, acetylene black, Ketjen black, carbon nanotubes, and graphene; the first binder includes at least one of PVDF, PTFE, CMC, SBR, PPA, and PI; even further, the mass ratio of the positive electrode active material, the first conductive agent, and the first binder in the positive electrode sheet is (20~50):(50~46):(20~2):(10~2).

[0024] It should be noted that the organic sacrificial salt of the present invention can be an organic sacrificial salt of alkali metals such as lithium, sodium or potassium containing different R groups. When different organic sacrificial salts are used to prepare the positive electrode, if there is more than one type of organic sacrificial salt added to the positive electrode, an organic sacrificial salt containing the same alkali metal element can be selected.

[0025] It should be noted that the present invention does not limit the solvent used to mix the positive electrode active material, the organic sacrificial salt, the first conductive agent, and the first binder to form a slurry. Any solvent capable of dissolving or dispersing the above components without adversely affecting the electrode performance can be selected. For example, nitrogen-containing polar aprotic solvents, such as N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-ethylpyrrolidone (NEP), etc.; ether solvents, such as tetrahydrofuran (THF), 1,4-dioxane, ethylene glycol dimethyl ether, etc.; or ketone solvents, ester solvents, etc. In some optional examples of the present invention, N-methylpyrrolidone (NMP) or a mixture thereof with butanone is preferred as a solvent to balance solubility, evaporation rate, and environmental friendliness.

[0026] On the other hand, the present invention proposes an alkali metal ion energy storage device comprising the above-described positive electrode.

[0027] Furthermore, the alkali metal energy storage device includes an alkali metal ion battery, an alkali metal ion capacitor, an alkali metal ion-sulfur battery, or an alkali metal ion-oxygen battery.

[0028] Furthermore, the alkali metal ion energy storage device also includes a negative electrode sheet, which is prepared by coating a mixture of negative electrode active material, a second conductive agent, and a second binder onto the surface of a second metal current collector and then drying it.

[0029] Furthermore, the negative electrode active material includes graphite, hard carbon, soft carbon, Si, and SiO. x Sn, Ge, Li4Ti5O 12 At least one of Na2Ti3O7, NaTi2(PO4)3, Sb, and Bi; Furthermore, the second conductive agent includes at least one of conductive carbon black, acetylene black, Ketjen black, carbon nanotubes, and graphene.

[0030] Furthermore, the second adhesive includes at least one of PVDF, PTFE, CMC, SBR, PPA, and PI.

[0031] Furthermore, in the negative electrode sheet, the mass ratio of the negative electrode active material, the second conductive agent and the second binder is (70~95):(20~3):(10~2).

[0032] Furthermore, the second metal current collector includes copper foil, carbon cloth, nickel foam, or stainless steel mesh.

[0033] It should be noted that the present invention does not limit the solvent used to mix the negative electrode active material, the second conductive agent, and the second binder to form a slurry. Any solvent capable of dissolving or dispersing the above components without adversely affecting the electrode performance can be used. For example, nitrogen-containing polar aprotic solvents, such as N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-ethylpyrrolidone (NEP), etc.; ether solvents, such as tetrahydrofuran (THF), 1,4-dioxane, ethylene glycol dimethyl ether, etc.; or ketone solvents, ester solvents, etc. In some optional examples of the present invention, N-methylpyrrolidone (NMP) or a mixture thereof with butanone is preferred as a solvent to balance solubility, evaporation rate, and environmental friendliness.

[0034] On the other hand, this invention proposes a pre-metallization method for the aforementioned alkali metal ion energy storage device. By performing at least one charge-discharge cycle on the alkali metal ion energy storage device, a pre-metallized alkali metal ion energy storage device is obtained. Embodiments of this invention demonstrate that, through the first charge of the alkali metal ion energy storage device, the organic sacrificial salt contained in the positive electrode can pre-lithiate the negative electrode and compensate for irreversible capacity loss.

[0035] Furthermore, the current density during the charge-discharge cycle is 0.02~0.2A g. -1 .

[0036] Furthermore, the charging cutoff voltage during the charge-discharge cycle is between 3.8 and 4.4V, and the discharging cutoff voltage is between 1.0 and 3.0V.

[0037] Furthermore, the number of charge-discharge cycles is 1 to 10 times, preferably 1 to 3 times.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows: The specific electron-donating groups in the low-decomposition-voltage organic sacrificial salt structure of this invention can impart a high HOMO energy level to the organic sacrificial salt through hyperconjugation, thereby effectively reducing its oxidation potential. When the organic sacrificial salt of this invention is used as a positive electrode additive in alkali metal ion energy storage devices, pre-metallization can be completed through at least one charge-discharge cycle, achieving effective lithium replenishment to the negative electrode. Simultaneously, it can significantly improve the capacity retention rate of alkali metal ion energy storage devices containing it and suppress the degradation of electrolyte solvent and electrode structure, resulting in alkali metal ion energy storage devices with excellent cycle stability and rate performance. The organic sacrificial salt of this invention has high specific capacity, widely available raw materials, a simple preparation method, and low cost, making it suitable for industrial application. Attached Figure Description

[0039] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 The HOMO levels of Li-Ac, Li-Gl, Li-NMA, Li-DMG, Li-HA and Li-MA in Example 1 are shown.

[0040] Figure 2 The sacrificial behavior characterization of Li-DMG is shown. a) Li-DMG electrode at 0.1 mV / s -1 Cyclic voltammetry curves at scan rates. b) Li-DMG electrode at 0.05 Ag. -1c) Constant current charge-discharge curves at current density; the inset shows the dQ / dV curve for the first charge. d) Comparison of oxidation potentials for different organic sacrificial salts (OSSs). d) Voltage-potential curves of the Li-DMG||Cu|Li three-electrode system. e) XRD patterns of the Li-DMG electrode after charging to 4.2V, the original Li-DMG electrode, and the carbon-coated aluminum foil. f) FTIR spectra of the Li-DMG electrode after charging to 4.2V and the original Li-DMG electrode.

[0041] Figure 3 The images show a) the original Li-DMG / LFP cathode and b) SEM images of the Li-DMG / LFP electrode after 5 charge-discharge cycles in a Li-DMG / LFP||G battery.

[0042] Figure 4 Performance characterization of Li-DMG as a sacrificial additive for the positive electrode is shown. a) Constant current charge-discharge (GCD) curves of the Li-DMG / LFP electrode; b) Cyclic performance of the Li-DMG / LFP electrode; c) Voltage / potential curves of the Li-DMG / LFP||graphite||Li three-electrode system; d) Voltage / potential curves of the LFP||graphite||Li three-electrode system; e) GCD curves of the Li-DMG / LFP||graphite lithium-ion battery; f) Cyclic performance of the Li-DMG / LFP||graphite lithium-ion battery.

[0043] Figure 5 Show a) the voltage curves of Li-DMG / LFP||G and LFP||G lithium-ion batteries; b) the energy density of the two batteries.

[0044] Figure 6 XPS characterization results of graphite anodes after 5 charge-discharge cycles in Li-DMG / LFP||G (a, c, e) and LFP||G lithium-ion batteries (b, d, f): (a, b) C1s, (c, d) F1s and (e, f) Li1s XPS spectra.

[0045] Figure 7 This demonstrates how Li-DMG enhances the electrochemical performance of pouch-type lithium-ion batteries. a) Photograph and structural schematic diagram of a pouch-type Li-DMG / LFP||G lithium-ion battery; b) Constant current charge-discharge curves; c) Cycle stability; d) Energy density; e) Demonstration with LED lights on.

[0046] Figure 8 The voltage curves of pouch-type Li-DMG / LFP||G and LFP||G lithium-ion batteries are shown.

[0047] Figure 9The voltage-potential curves of the Li-DMG / LFP||G lithium-ion battery after 4000 cycles are shown.

[0048] Figure 10 A photograph of a PMMA clamp used to hold a pouch lithium battery is shown.

[0049] Figure 11 The voltage curves of Li-DMG as an additive to LiCoO2 are shown.

[0050] Figure 12 The cycling performance of Li-DMG as an additive to LiCoO2 is shown. Detailed Implementation

[0051] To facilitate understanding of the present invention, a more comprehensive description will be provided below, along with preferred embodiments. However, it should be understood that these embodiments are merely for more detailed explanation and should not be construed as limiting the invention in any way, i.e., not intended to limit the scope of protection of the invention.

[0052] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which this invention pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.

[0053] Furthermore, it should be noted that although the various steps of the preparation method of the present invention are described in a specific order in the description of the present invention, these orders are not restrictive. Without departing from the basic principles of the present invention, those skilled in the art can perform the steps in different orders.

[0054] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "multiple" or "at least one" means two or more.

[0055] The reagents used in the following examples were sourced from: N,N-dimethylglycine (DMG, 99%), lithium hydroxide (LiOH, 99%), lithium iron phosphate (LFP, 98%), conductive carbon black (Super P or ECP-600JD, 99.99%), and polyvinylidene fluoride (PVDF, 99.9%), which were purchased from Sigma-Aldrich (Shanghai) Co., Ltd.; graphite (99.9%), which was purchased from Macklin (Shanghai) Co., Ltd.; N-methyl-2-pyrrolidone (NMP) and electrolyte (1M LiPF6 dissolved in a 1:1 volume ratio mixture of ethylene carbonate EC and dimethyl carbonate DMC, and containing 5 vol% fluoroethylene carbonate FEC), which were purchased from Tianjin Damao Chemical Reagent Factory; polypropylene diaphragm (Celgard 3501), which was purchased from Shenzhen Sentai Technology Co., Ltd.; and lithium metal foil, which was purchased from China Energy Lithium Industry Co., Ltd.

[0056] The characterization methods in the following embodiments: Scanning electron microscopy (SEM) was performed on a Phenom XL G2 benchtop SEM with an accelerating voltage of 10 kV.

[0057] X-ray diffraction (XRD) was performed on a Bruker D2 PHASER (Cu Kα, λ=0.154 nm).

[0058] Fourier transform infrared (FTIR) spectra were acquired on a Bruker Vertex 70 spectrometer using the KBr pellet method.

[0059] X-ray photoelectron spectroscopy (XPS) was performed on a Thermo Fisher NEXSA spectrometer (monochrome Al Kα, 1486.7 eV).

[0060] To obtain XRD / FTIR samples, the Li-DMG||Li cells were disassembled after 5 cycles, and the Li-DMG positive electrode and Li negative electrode were removed. To obtain SEM / XPS samples, the Li-DMG / LFP||G or LFP||G cells were disassembled after 5 cycles, and the Li-DMG / LFP positive electrode and graphite negative electrode were removed. All electrodes were cleaned with dimethyl carbonate (DMC) and dried in a glove box.

[0061] Electrochemical tests were performed on the LAND CT2100A battery testing system.

[0062] Example 1

[0063] This invention proposes a low-decomposition-voltage organic sacrificial salt, which has the structure of Formula I: CH2-COOM Formula I; Wherein, R is selected from any one of -N(CH3)2, -NHCH3, -NH2, -OCH3, -OPh, -Ph; M is selected from any one of Li, Na, or K.

[0064] This embodiment illustrates the research team's exploration process in proposing the organic sacrificial salt of this invention by utilizing the correlation between electron-donating groups (EDGs) and the highest occupied molecular orbital (HOMO) energy level, combined with density functional theory (DFT) calculations. Specifically: Preparation of organic sacrificial salts: Stoichiometric amounts of DMG and LiOH were dissolved in deionized water, and the pH was adjusted to 9-10 with DMG or LiOH. The resulting solution was concentrated by rotary evaporation at 60°C, washed three times each with NMP (N-methylpyrrolidone) and diethyl ether, and then dried under vacuum at 60°C for 12 h to obtain lithium N,N-dimethylglycinate (Li-DMG).

[0065] Electrode preparation: 1. Li-DMG electrode: Li-DMG, ECP-600JD and PVDF were ground in a mortar at a mass ratio of 8:1:1 for 30 min, then dispersed in NMP to form a slurry, which was then coated on aluminum foil and vacuum dried at 110°C for 24 h.

[0066] 2. Li-DMG / LFP electrode: Mix LFP, Li-DMG, ECP-600JD and PVDF in NMP at a mass ratio of 7.2:0.8:1:1 to form a slurry. Coating and drying are the same as above.

[0067] 3. LFP electrode: Mix LFP, ECP-600JD and PVDF in NMP at a mass ratio of 8:1:1 to form a slurry, and coat and dry as above.

[0068] 4. Graphite anode (G): Graphite, Super P and PVDF are mixed in NMP at a mass ratio of 8:1:1 to form a slurry. Coating and drying are the same as above.

[0069] Electrochemical testing: All batteries were assembled inside an argon-filled glove box.

[0070] Half-cell: Lithium foil is used as the counter / reference electrode.

[0071] Full cell: with graphite as the negative electrode and an N / P ratio of 1.1.

[0072] All diaphragms are made of PP (Celgard 3501).

[0073] Three-electrode system: •Li-DMG||Cu|Li: Li-DMG is the working electrode, Cu foil is the counter electrode, and Li foil is the reference electrode; •Li-DMG / LFP||G|Li or LFP||G|Li: Li-DMG / LFP or LFP is the working electrode, graphite is the counter electrode, and Li foil is the reference electrode.

[0074] Cyclic voltammetry (CV) was performed on a Princeton PMC CH808A electrochemical workstation at a scan rate of 0.1 mV / s. -1 .

[0075] Constant current charge-discharge tests were performed on the LANDCT2100A.

[0076] •Li-DMG / LFP||Li, Li-DMG / LFP||G and their corresponding three-electrode systems: 0.1C, 2.5-4.2V for the first 5 weeks; followed by 0.5C, 2.5-3.8V.

[0077] • LFP||Li, LFP||G and their corresponding three-electrode systems: 2.5-3.8V, 0.1C for the first 5 weeks, followed by 0.5C.

[0078] Molecular dynamics: Molecular and electronic structures were calculated using density functional theory (DFT). Geometric optimization was performed at the B3LYP / 6-31G(d) level, and the highest occupied molecular orbital (HOMO) energy was calculated at the higher precision LC-BLYP / 6-31G(d) level. Visualization of the molecular structure and orbitals was achieved using Multiwfn and Visual Molecular Dynamics (VMD) software.

[0079] Given the drawbacks of traditional lithium acetate (Li-Ac), such as high oxidation potential, the need for higher charging cut-off voltage, leading to low electrolyte stability and poor electrode integrity, the research team of this invention innovatively utilized the correlation between electron-donating groups (EDGs) and the highest occupied molecular orbital (HOMO) energy level. Specifically, the stronger the electron-donating ability, the higher the HOMO energy level and the lower the oxidation potential. By introducing strong electron-donating groups into the lithium acetate framework and replacing its α-hydrogen with functional groups of different electron-donating abilities, a series of derivatives were successfully prepared, including lithium glycinate (Li-Gl), lithium N-methylaminoacetate (Li-NMA), lithium N,N-dimethylaminoacetate (Li-DMG), lithium glycolate (Li-HA), and lithium methoxyacetate (Li-MA). The HOMO energy levels calculated using density functional theory (DFT) are shown in the following results. Figure 1 As shown.

[0080] from Figure 1It can be seen that the N,N-dimethylamino group of Li-DMG endows it with the highest HOMO energy level (-7.78 eV, compared to -9.19 eV of lithium acetate) through hyperconjugation, indicating its lowest oxidation potential; lithium methoxyacetate (Li-MA) also exhibits a low oxidation potential.

[0081] Furthermore, this embodiment confirms the sacrificial behavior of Li-DMG through testing, and the results are as follows: Figure 2 , Figure 3 As shown: (1) Testing the Li-DMG electrode at 0.1 mVs -1 Cyclic voltammetry curves at scan rate, such as Figure 2 a. The CV curve shows two independent anodic peaks, indicating that lithium in Li-DMG is gradually extracted. Initial oxidation occurs from 3.4V (vs. Li). + / Li) starts at 3.58V (vs. Li) + The maximum oxidation current is reached at 3.8V (vs. Li); the second oxidation peak appears at 3.8V (vs. Li). + / Li), peak current is at 4.00V (vs. Li + / Li). It is worth noting that these oxidation features completely disappeared during the subsequent cathode and anode processes, proving that Li-DMG only releases lithium ions during the first charge, a conclusion further verified by GCD results.

[0082] (2) The Li-DMG electrode was tested at 0.05 A g. -1 The constant current charge-discharge curves at current density are as follows: Figure 2 b. During the initial charging process, the specific capacity of the Li-DMG electrode reached 238.2 mAh g. -1 With a theoretical capacity of 248.9 mAh g -1 The high degree of agreement indicates efficient lithium release. The capacity was almost zero (approximately 10 mAh g⁻¹) in subsequent discharge / charge cycles. -1 This further highlights its sacrificial nature. The GCD curve shows two distinct voltage plateaus at 3.54V and 3.92V, consistent with the anode peak potential in the CV curve.

[0083] (3) The oxidation potentials of different organic sacrificial salts (OSS) were tested, such as Figure 2c. Consistent with the molecular engineering strategy of the research team, the oxidation potential of Li-DMG is significantly lower than that of other previously reported OSSes, such as Li2C2O4 / NaNO2 (3.67V), CH3COOLi (4.0V), Li2C4O4 (4.0V), Li2C2O4 / Co3O4 (4.0V), Li2C2O4 / Mo2C (4.16 or 4.22V), and Li2C2O4 / NiO (4.3V). The significantly reduced oxidation potential of Li-DMG helps mitigate two common failure mechanisms under high-voltage conditions: (i) electrode material structural damage; and (ii) excessive electrolyte decomposition.

[0084] (4) To visually verify the lithium release behavior of Li-DMG, a three-electrode system was constructed. Figure 2 Figure d shows the voltage-potential curve of the Li-DMG||Cu|Li three-electrode system. It can be seen that during the charging process, the Li-DMG electrode potential rapidly rises to above 3.5V, while the Cu foil potential rapidly drops to below 0V. This potential difference indicates that lithium deposition has occurred on the Cu foil, confirming that Li-DMG has successfully released lithium ions.

[0085] (5) To further verify the sacrificial behavior of Li-DMG, the research team systematically characterized the pre-lithiated Li-DMG / LFP electrode. Figure 2 Figure e shows the XRD patterns of the Li-DMG electrode after charging to 4.2V, the original Li-DMG electrode, and the carbon-coated aluminum foil. The results show that the characteristic diffraction peaks of the original Li-DMG electrode can be observed; after charging, these peaks completely disappear, indicating that the Li-DMG is completely decomposed during the oxidation process.

[0086] (6) FTIR spectrum Figure 2 In f), the original electrode is at 1606.7 cm. -1 The location belongs to COO - The strong characteristic peak of the functional group; this peak also disappears after charging. SEM images further corroborate this conclusion (e.g. Figure 3 The original Li-DMG / LFP electrode surface contains a large number of rod-shaped particles. Figure 3 a) After pre-lithiation, these particles disappear, leaving behind a large number of cavities ( Figure 3 b). This confirms that Li-DMG was completely decomposed after the first charge, fully demonstrating its typical sacrificial characteristics.

[0087] Furthermore, in this embodiment, a positive electrode sheet was prepared by incorporating Li-DMG into the positive electrode active material LiFePO4 (LFP) to evaluate its Li + Release behavior, the result is as follows Figure 4 , Figure 5 As shown: (1) Figure 4 a shows that the specific capacity of the Li-DMG / LFP electrode reaches 187.5 mAh g during the first charge. -1 This is significantly higher than the 153.0 mAh g of a pure LFP electrode. -1 This indicates that Li-DMG can provide additional capacity for the cathode.

[0088] (2) Figure 4 b shows that the specific capacity of the Li-DMG / LFP electrode at the first discharge is 148.4 mAh g. -1 , with the LFP electrode having a capacity of 141.8 mAh g -1 The similarity in capacitance indicates that Li-DMG has minimal interference with the reversible redox reaction of LFP. Furthermore, the similar capacity retention rates of both technologies further validate the electrochemical compatibility of Li-DMG.

[0089] (3) To further evaluate the Li-DMG's Li + To further investigate the release behavior, the research team also constructed a three-electrode system. In the Li-DMG / LFP||graphite||Li three-electrode system, the graphite electrode potential is 0.094V (vs. Li). + / Li, Figure 4 c), lower than the 0.134V of the LFP||graphite||Li system (vs. Li + / Li, Figure 4 d). The 40 mV negative shift indicates that the additional lithium ions released by Li-DMG have been embedded in the negative electrode.

[0090] (4) In the first pre-lithiation cycle, the discharge capacity of the Li-DMG / LFP|| graphite full cell was increased by 17.3% compared with the LFP|| graphite cell (114.4 vs. 97.5 mAhg). -1 () Figure 4 e); Figure 5 a shows that it is still 19.8% higher in the first lap of the subsequent cycle (106.7 vs. 89.1 mAhg). -1 After 200 cycles, the Li-DMG / LFP||graphite battery retained 43.1% more capacity (67.1 vs. 46.9 mAhg). -1 () Figure 6 f). Furthermore, the energy density increased by 30.2%, from 148.0 Wh / kg. -1 Increased to 212.1 Wh kg -1 ( Figure 5 b). Therefore, Li-DMG is an excellent organic sacrificial salt, and its introduction can significantly improve the electrochemical performance of lithium-ion batteries.

[0091] Furthermore, this embodiment also compared the chemical composition of the SEI layer formed by full cells containing and without Li-DMG using X-ray photoelectron spectroscopy (XPS), and the results are as follows: Figure 6 As shown: (1) In the C 1s spectrum ( Figure 6 In a) and b), distinct peaks appear at 284.8, 285.7, 287.1, 289.5, and 291.4 eV, corresponding to C–C, C–O, C=O, and CO3, respectively. 2- and C–F species. C–O, C=O and CO3 2- The CO32-C-F phase originates primarily from the reduction of electrolyte solvents (such as ethylene carbonate and diethyl carbonate), while C–F comes from the reduction of fluoroethylene carbonate (FEC). These results indicate that the SEI layer is composed of both organic and inorganic components. Notably, in the SEI layer of a full cell with added Li-DMG, CO32-... 2- The relative contents of Li-DMG (6.6% vs. 7.9%) and C–F (4.5% vs. 5.1%) were both lower than those of the sample without added Li-DMG.

[0092] (2) The F 1s XPS results further corroborate the above conclusions. Figure 6 (c, d) For the full cell containing Li-DMG, the C–F ratio within the SEI layer decreased to 9.7% (compared to 12.0% in the control group). Simultaneously, Li was detected at 688.2 eV. x PF y The LiF peak at 685.7 eV is attributed to incomplete decomposition of LiPF6; the LiF peak at 685.7 eV originates from the reduction of FEC and / or the decomposition of LiPF6. F 1s data show that the Li in the SEI layer of the Li-DMG-containing battery... x PF y The proportion of α was lower (8.9% vs. 12.8%), while the proportion of β was higher (79.4% vs. 75.2%).

[0093] (3) The Li 1s XPS results also show a similar trend: Li in the SEI layer of the battery containing Li-DMG x PF y The proportions of Li2CO3 (19.4% vs. 28.5%) and LiF (23.9% vs. 24.2%) decreased, while the proportion of LiF increased (56.7% vs. 47.4%). Figure 6 (e, f). Therefore, the introduction of Li-DMG increases the inorganic components and decreases the organic components in the SEI layer. This transformation may stem from the CO2 gas released during the decomposition of Li-DMG, which inhibits further decomposition of the electrolyte solvent.

[0094] Furthermore, this embodiment also verifies the industrial feasibility of Li-DMG: The R&D team assembled a soft-pack lithium-ion battery equipped with a dedicated exhaust chamber. Figure 7 a) to handle gaseous byproducts (such as CO2) generated from sacrificial decomposition. Li-DMG pre-lithiation improved the first-cycle discharge capacity by 31.3% (114.4 vs. 87.1 mAh g⁻¹). -1 , Figure 7 (b) Energy density increased by 32.4% (366.7 vs. 277.1 Wh / kg) -1 This is directly attributed to the effective replenishment of active lithium inventory. The pouch cell containing Li-DMG achieved a 32.5% capacity increase on the first cycle (104.7 vs. 79.0 mAh g⁻¹). -1 , Figure 8 It retains 62.0 mAh g after 4000 cycles. -1 ( Figure 7 c) with 195.8 Wh kg -1 ( Figure 7 (d), while the control group had a remaining capacity of only 45.4 mAh g after only 500 cycles. -1 The remaining energy density is only 148.9 Wh / kg. -1 These figures are 36.6% and 31.5% higher, respectively. After cycling, the graphite potential remained above 0V (0.11V vs. Li). + / Li, higher than the lithium plating threshold), effectively suppressing lithium dendrite formation ( Figure 9 It is worth noting that pouch cells exhibit superior electrochemical performance compared to coin cells. This is because pouch cells are sandwiched between two polymethyl methacrylate (PMMA) plates, allowing the gas generated during pre-lithiation to rapidly migrate from the electrodes to the gas chamber. Figure 10 In addition, the Li-DMG-containing pouch cell successfully lit up 2048 LEDs. Figure 7 e). Therefore, Li-DMG exhibits high efficiency in pouch cells. + The compensation capability confirms that Li-DMG has excellent industrial feasibility.

[0095] Example 2

[0096] This embodiment uses Li-DMG as an example to explore the addition amount of the low decomposition voltage organic sacrificial salt of the present invention. Specifically: Preparation of the positive electrode sheet: LiCoO2, Li-DMG, Ketjenblack, and binder (PVDF) are uniformly dispersed in N-methylpyrrolidone to obtain a slurry with a solid content of 10~20wt%. This slurry is coated (aluminum foil is used as the current collector), dried, rolled, and cut to obtain a LiCoO2 positive electrode sheet containing lithium N,N-dimethylaminoacetate. The mass ratio of LiCoO2, lithium N,N-dimethylaminoacetate, Ketjenblack, and binder (PVDF) can be selected as (70-x):x:15:15, where x = 0~8.

[0097] This embodiment tested the voltage curves and cycle performance of positive electrode sheets prepared with different amounts of Li-DMG (the percentage of Li-DMG in the mass of LiCoO2). For example... Figure 11 As shown, as the Li-DMG addition increases from 0% to 8%, the charging specific capacity increases from approximately 170 mAh g⁻¹. -1 Increased to nearly 230mAh g -1 This indicates that the addition of Li-DMG significantly improved the reversible capacity of the electrode; such as Figure 12 As shown, as the Li-DMG addition increases from 0% to 8%, the cycle capacity retention of the positive electrode plate is significantly improved.

[0098] Therefore, in the positive electrode sheet of the present invention comprising a low decomposition voltage organic sacrificial salt, the amount of the low decomposition voltage organic sacrificial salt is 1% to 13% of the mass of the positive electrode active material, preferably 1% to 8%, more preferably 2% to 6%, and even more preferably 4%.

[0099] Example 3

[0100] This embodiment uses sodium methoxyacetate as an example to explore the addition amount of the low decomposition voltage organic sacrificial salt of the present invention in a sodium-ion capacitor. Specifically: Preparation of the positive electrode sheet: Activated carbon, sodium methoxyacetate, Ketjen black, and PVDF are uniformly dispersed in N-methylpyrrolidone to obtain a slurry with a solid content of 10-20 wt%. This slurry is coated (aluminum foil is used as the current collector), dried, rolled, and cut to obtain an activated carbon positive electrode sheet containing sodium methoxyacetate. The mass ratio of activated carbon, sodium methoxyacetate, Ketjen black, and PVDF can be selected as (80-x):x:10:10, where x = 20-30. As the amount of sodium methoxyacetate added increases from 20% to 30%, the charging specific capacity gradually increases, indicating that the addition of sodium methoxyacetate can provide additional sodium ions to the negative electrode. A full cell constructed with a matching graphite negative electrode has a specific capacity of 30-50 mAh g⁻¹. -1 The specific capacity of the full battery system without sodium methoxyacetate is only 10~20 mAh g. -1 In this embodiment, the amount of the low-decomposition-voltage organic sacrificial salt in the positive electrode sheet is 10% to 60% of the mass of the positive electrode active material, preferably 20% to 60%, more preferably 30% to 50%, and even more preferably 40%.

[0101] Example 4

[0102] This embodiment uses potassium phenoxyacetate as an example to explore the addition amount of the low decomposition voltage organic sacrificial salt of the present invention in a potassium-ion-sulfur battery. Specifically: Preparation of the positive electrode: Sulfur-porous carbon composite material, potassium phenoxyacetate, Ketjen black, and PVDF are uniformly dispersed in N-methylpyrrolidone to obtain a slurry with a solid content of 10-20 wt%. This slurry is coated (aluminum foil is used as the current collector), dried, rolled, and cut to obtain a sulfur-porous carbon composite positive electrode containing potassium phenoxyacetate. The mass ratio of sulfur-porous carbon composite material, potassium phenoxyacetate, Ketjen black, and PVDF can be selected as (60-x):x:30:10, where x = 30-50. As the amount of potassium phenoxyacetate added increases from 30% to 50%, the charging specific capacity gradually increases, indicating that the addition of potassium phenoxyacetate can provide additional potassium ions to the negative electrode. A full cell is constructed by matching a hard carbon negative electrode, with a specific capacity of 400-600 mAh g. -1 The specific capacity of a full battery system without sodium methoxyacetate is only 100~300 mAh g. -1 .

[0103] In this embodiment, the amount of the low-decomposition-voltage organic sacrificial salt in the positive electrode sheet is 20% to 70% of the mass of the positive electrode active material, preferably 30% to 60%, more preferably 40% to 50%, and even more preferably 45%.

[0104] Example 5

[0105] This embodiment uses lithium phenylacetate as an example to explore the addition amount of the low decomposition voltage organic sacrificial salt of the present invention in a lithium-ion-oxygen battery. Specifically: Preparation of the positive electrode: Ru-loaded carbon paper, lithium phenylacetate, Ketjen black, and PVDF are uniformly dispersed in N-methylpyrrolidone to obtain a slurry with a solid content of 10-20 wt%. This slurry is coated (aluminum foil is used as the current collector), dried, rolled, and cut to obtain a Ru-loaded carbon paper positive electrode containing lithium phenylacetate. The mass ratio of Ru-loaded carbon paper, lithium phenylacetate, Ketjen black, and PVDF can be selected as (70-x):x:20:10, where x = 10-40. As the amount of lithium phenylacetate added increases from 10% to 40%, the specific capacity gradually increases, indicating that the addition of lithium phenylacetate can provide additional lithium ions to the negative electrode. A full cell is constructed by matching it with a silicon negative electrode, achieving a specific capacity of 600-800 mAh g⁻¹. -1The specific capacity of the full battery system without sodium methoxyacetate is only 300~500 mAh g. -1 .

[0106] In the positive electrode sheet of the present invention, the amount of the low decomposition voltage organic sacrificial salt is 10% to 60% of the mass of the positive electrode active material, preferably 20% to 50%, more preferably 20% to 40%, and even more preferably 30%.

[0107] It should be noted that the above description, in conjunction with specific embodiments, provides a further detailed explanation of the present invention and should not be construed as limiting the specific implementation of the invention to these descriptions. For those skilled in the art, several simple modifications can be made without departing from the concept of the present invention, and all such modifications should be considered within the scope of protection of the present invention.

Claims

1. A low-decomposition-voltage organic sacrificial salt, characterized in that, The organic sacrificial salt has the structure of Formula I: R-CH2-COOM Formula I; Wherein, R is selected from any one of -N(CH3)2, -NHCH3, -NH2, -OCH3, -OPh, -Ph; M is selected from any one of Li, Na, or K.

2. The low decomposition voltage organic sacrificial salt according to claim 1, characterized in that, The R is any one of -N(CH3)2, -NHCH3, -NH2, and -OCH3, preferably -N(CH3)2.

3. A positive electrode for alkali metal ion energy storage devices, characterized in that, The positive electrode sheet is prepared by coating a slurry containing a positive active material, a first conductive agent, a first binder, and a low decomposition voltage organic sacrificial salt as described in any one of claims 1-2 onto a first metal current collector, and then drying it.

4. The positive electrode sheet for alkali metal ion energy storage devices according to claim 3, characterized in that, The alkali metal ion energy storage device is an alkali metal ion battery, an alkali metal ion capacitor, an alkali metal ion-sulfur battery, or an alkali metal ion-oxygen battery. And / or, the first metal current collector includes aluminum foil, carbon cloth, nickel foam, or stainless steel mesh.

5. The positive electrode sheet for alkali metal ion energy storage devices according to claim 4, characterized in that, When the alkali metal ion energy storage device is an alkali metal ion battery, the amount of the low decomposition voltage organic sacrificial salt according to any one of claims 1-2 is 1% to 13% of the mass of the positive electrode active material, preferably 1% to 8%, more preferably 2% to 6%, and even more preferably 4%; when the alkali metal ion energy storage device is an alkali metal ion capacitor, the amount of the low decomposition voltage organic sacrificial salt according to any one of claims 1-2 is 10% to 60% of the mass of the positive electrode active material, preferably 20% to 60%, more preferably 30% to 50%, and even more preferably 40%; when the alkali metal... When the alkali metal ion energy storage device is an alkali metal ion-sulfur battery, the amount of the low decomposition voltage organic sacrificial salt according to any one of claims 1-2 is 20% to 70% of the mass of the positive electrode active material, preferably 30% to 60%, more preferably 40% to 50%, and even more preferably 45%; when the alkali metal ion energy storage device is an alkali metal ion-oxygen battery, the amount of the low decomposition voltage organic sacrificial salt according to any one of claims 1-2 is 10% to 60% of the mass of the positive electrode active material, preferably 20% to 50%, more preferably 20% to 40%, and even more preferably 30%.

6. The positive electrode sheet for alkali metal ion energy storage devices according to claim 4, characterized in that, When the alkali metal ion energy storage device is a lithium-ion battery, the positive electrode active material includes LiCoO2, LiNi x Co y Mn z O2 (0 < x < 1, 0 < y < 1, 0 < z < 1 and x + y + z = 1), LiNi x Co y Al z O2 (0 < x < 1, 0 < y < 1, 0 < z < 1 and x + y + z = 1), LiFePO4, LiMn2O4, LiNi 0.5 Mn 1.5 O4 and at least one of them; the first conductive agent includes at least one of conductive carbon black, acetylene black, Ketjen black, carbon nanotubes, graphene; the first binder includes at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), sodium carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), polyacrylic acid (PPA), polyimide (PI); And / or, when the alkali metal ion energy storage device is a sodium ion battery, the positive electrode active material includes NaCoO2, NaFeO2, NaFePO4, NaNi x Co y Mn z O2 (0 < x < 1, 0 < y < 1, 0 < z < 1 and x + y + z = 1), Na3V2(PO4)3, Na4Fe3(PO4)2P2O7, Na2FePO4F, Na x Fe[Fe(CN)6] (0 < x ≤ 2), Na x Mn[Fe(CN)6] (0 < x ≤ 2), and at least one of them; the first conductive agent includes at least one of conductive carbon black, acetylene black, Ketjen black, carbon nanotubes, graphene; the first binder includes at least one of PVDF, PTFE, CMC, SBR, PPA, PI; And / or, when the alkali metal ion energy storage device is a potassium ion battery, the positive electrode active material includes KCoO2, KNi x Co y Mn z O2 (0 < x ≤ 2), K3V2(PO4)3, KFePO4, K x Fe[Fe(CN)6] (0 < x ≤ 2), K x Mn[Fe(CN)6] (0 < x ≤ 2), and at least one of them; the first conductive agent includes at least one of conductive carbon black, acetylene black, Ketjen black, carbon nanotubes, and graphene; the first binder includes at least one of PVDF, PTFE, CMC, SBR, PPA, and PI; And / or, when the alkali metal ion energy storage device is an alkali metal ion capacitor, the positive electrode active material includes at least one of activated carbon, porous carbon, and graphene; the first conductive agent includes at least one of conductive carbon black, acetylene black, Ketjen black, carbon nanotubes, and graphene; the first binder includes at least one of PVDF, PTFE, CMC, SBR, PPA, and PI. And / or, when the alkali metal ion energy storage device is an alkali metal ion-sulfur battery, the positive electrode active material includes at least one of sulfur-porous carbon composite material, sulfur-carbon nanotube composite material, sulfur-graphene composite material, and sulfurized polyacrylonitrile; the first conductive agent includes at least one of conductive carbon black, acetylene black, Ketjen black, carbon nanotubes, and graphene; the first binder includes at least one of PVDF, PTFE, CMC, SBR, PPA, and PI. And / or, when the alkali metal ion energy storage device is an alkali metal ion-oxygen battery, the positive electrode active material includes at least one of graphene, carbon nanotubes, carbon paper or carbon cloth supported on a catalyst layer of Ru, Ir, MnO2, Co3O4, etc.; the first conductive agent includes at least one of conductive carbon black, acetylene black, Ketjen black, carbon nanotubes, and graphene; the first binder includes at least one of PVDF, PTFE, CMC, SBR, PPA, and PI.

7. An alkali metal ion energy storage device comprising the positive electrode sheet according to any one of claims 4 to 6; Preferably, the alkali metal energy storage device includes an alkali metal ion battery, an alkali metal ion capacitor, an alkali metal ion-sulfur battery, or an alkali metal ion-oxygen battery.

8. The alkali metal ion energy storage device according to claim 7, characterized in that, The alkali metal ion energy storage device also includes a negative electrode sheet, which is prepared by coating a mixture of negative active material, a second conductive agent, and a second binder onto the surface of a second metal current collector and then drying it. Preferably, the negative electrode active material includes graphite, hard carbon, soft carbon, Si, and SiO. x Sn, Ge, Li4Ti5O 12 At least one of Na2Ti3O7, NaTi2(PO4)3, Sb, and Bi; Preferably, the second conductive agent includes at least one of conductive carbon black, acetylene black, Ketjen black, carbon nanotubes, and graphene; Preferably, the second adhesive comprises at least one of PVDF, PTFE, CMC, SBR, PPA, and PI; Preferably, the second metal current collector includes copper foil, carbon cloth, nickel foam, or stainless steel mesh.

9. The pre-metallization method for the alkali metal ion energy storage device according to claim 7 or 8, characterized in that, By performing at least one charge-discharge cycle on the alkali metal ion energy storage device, a pre-metallized alkali metal ion energy storage device is obtained.

10. The pre-metallization method for alkali metal ion energy storage devices according to claim 9, characterized in that, The current density during the charge-discharge cycle is 0.02~0.2A g. - ¹; And / or, the charging cut-off voltage during the charge-discharge cycle is between 3.8 and 4.4V, and the discharging cut-off voltage is between 1.0 and 3.0V; And / or, the number of charge-discharge cycles is 1 to 10 times, preferably 1 to 3 times.

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