Pre-sodium modification agent, sodium-ion battery electrode, preparation of sodium-ion battery electrode and application of sodium-ion battery electrode in battery

Abstract

The invention provides a pre-sodium modification agent, a sodium ion battery electrode, preparation of the sodium ion battery electrode and application of the sodium ion battery electrode in a battery. A compound with the chemical formula of CxHyOz is used as a battery sodium pre-modification agent, x is 9-26, y is 6-18, and z is 0-2; the sodium-ion battery electrode is prepared from a compound formed by a pre-sodium-modifying agent CxHyOz and an electrode, and is used for preparing a sodium-ion battery. The problem of insufficient capacity or loss in the first charging and discharging process can be effectively solved, and the first-circle coulombic efficiency can be greatly improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of sodium ion battery electrodes, and in particular relates to a battery pre-sodiumization agent, a sodium ion battery electrode, a preparation method thereof, and an application thereof in a battery. Background Art

[0002] Today, with technological advancements, large-scale energy storage applications urgently need a new energy source. In 1980, J. Goodenough's groundbreaking work laid a solid foundation for the development of modern lithium-ion batteries. However, the severe shortage of lithium resources remains a significant challenge. Naturally, sodium metal, due to its abundance, has become a strong contender for replacing lithium. Sodium-ion batteries (SIBs) are widely researched due to their low cost, environmental friendliness, and exceptional safety.

[0003] The commercial application of sodium-ion batteries is inseparable from the research on electrode materials. At present, the research on sodium storage electrode materials mainly focuses on layered metal oxides, polyanionic compounds, Prussian blue and its analogues, carbon-based materials, metal elements or alloys, metal oxides, metal sulfides, elemental phosphorus and its compounds. These materials have high sodium storage capacity, long cycle life and rate performance; but most materials are prone to electrolyte decomposition or partial sodium ions are embedded in the electrode to become inactive sodium during the charge and discharge process, resulting in low first-cycle efficiency, incomplete capacity release and poor electrode efficiency matching, which greatly limits the energy density of sodium-ion batteries and seriously affects the commercial application of sodium-ion batteries. For example, the positive electrode material P2-Na in Energy Storage Materials, 2024, 70: 103511 0.78 Ni 0.2 Mn 0.7 Li 0.05 Ti 0.05 The first-cycle charge-discharge capacity of O2 is only 139.8 mAh / g, while the corresponding negative electrode material outputs a capacity of 290 mAh / g, with an initial efficiency of only 75.8%. Although researchers have improved the positive electrode material by adding sacrificial sodium salt, it still has a certain impact on the electrode structure.

[0004] Therefore, significantly improving the initial efficiency of electrode materials and resolving the low energy density of sodium-ion batteries caused by the mismatch in existing electrode efficiencies are urgent issues. This paper provides a method for chemical pre-sodiumization of electrodes to address these issues and facilitate the practical development of high-energy-density sodium battery systems. Summary of the Invention

[0005] The purpose of the present invention is to provide a battery pre-sodiumization agent, sodium ion battery electrode preparation and application thereof to significantly improve the first-cycle coulombic efficiency and charge-discharge reversible capacity of sodium ion batteries, thereby improving their energy density.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A compound is used as a battery pre-sodium agent, the chemical formula is C x H y O z The compound is used as a battery pre-sodium agent, wherein x is 9 to 26, y is 6 to 18, and z is 0 to 2.

[0008] Furthermore, the chemical formula is C x H y O z The compound includes at least the following structure:

[0009]

[0010] A sodium ion battery electrode, pre-sodium agent C x H y O z Soaking sodium ion battery electrodes, pre-sodium agent C x H y O z The contact reaction time with the sodium ion battery electrode is 5 to 30 minutes, and the drying temperature is 30 to 80°C.

[0011] Furthermore, the pre-sodium agent C x H y O z The contact reaction time with the sodium ion battery electrode is 8 to 10 minutes, and the drying temperature is 60°C.

[0012] Furthermore, the sodium ion battery electrode includes a sodium ion battery electrode active material, a conductive additive and a binder.

[0013] Furthermore, the sodium ion battery electrode active material is a positive electrode active material, and the positive electrode active material is one or more of layered transition metal oxides, polyanion compounds, Prussian blue and the like.

[0014] Furthermore, the layered transition metal oxide is one or more of a single metal oxide, a manganese-rich / iron-rich system, and a binary / ternary metal oxide.

[0015] Furthermore, the binary / ternary metal oxide is one or more of O3-type layered oxide and P2-type layered oxide.

[0016] Furthermore, the active material of the sodium ion battery electrode is a negative electrode active material, and the negative electrode active material is one or more of carbon-based materials, silicon-based materials, tin-based materials, antimony-based materials, phosphorus-based elements and their composites, metal oxides, metal sulfides, and metal phosphides.

[0017] Furthermore, the conductive additive is one or more of acetylene black (AB), Ketjen black (KB), conductive carbon black (Super P), graphene (G) or carbon nanotubes (CNT); the binder is one or more of polyvinylidene fluoride (PVDF), sodium carboxymethyl cellulose (CMC-Na), and polyphthalamide (PAA).

[0018] The advantages and beneficial effects of the present invention are:

[0019] The battery pre-sodiumization agent and sodium-ion battery electrode provided by this invention, through their unique structural design, can rapidly and efficiently replenish sodium at extremely low concentrations. This technology can significantly improve the first-cycle coulombic efficiency and reversible charge and discharge capacity of sodium-ion batteries, thereby effectively enhancing the battery's energy density. Furthermore, the preparation process of this pre-sodiumization agent is simple, gentle, time-saving, and highly safe, promising promising industrial applications.

[0020] On the other hand, this method, due to its rapid sodium replenishment characteristics, is particularly suitable for sodium-deficient electrode systems, such as P2-type cathode materials, hard carbon and soft carbon anodes, etc. This technical advantage can significantly improve the initial coulombic efficiency of the battery, thereby efficiently achieving high energy density requirements.

[0021] More importantly, for the negative electrode material, the pre-sodiumized electrode obtained after implementation of this method will form a uniform and thin solid electrolyte interface on the electrode surface when it comes into contact with the electrolyte, which also helps to improve the cycle stability and safety of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention is further described with reference to the accompanying drawings, but the embodiments in the accompanying drawings do not constitute any limitation to the present invention.

[0023] Figure 1 1 is a charge-discharge curve diagram of the hard carbon electrode before and after pre-sodiumization in the first cycle of Example 8;

[0024] Figure 2 1 is a charge-discharge curve diagram of the hard carbon electrode before and after pre-sodiumization in the first week of Example 10;

[0025] Figure 3 are the Raman images of the hard carbon electrodes of Examples 8 and 10 before and after pre-sodiumization;

[0026] Figure 4 1 is the XRD pattern of the hard carbon electrodes of Examples 8 and 10 before and after pre-sodiumization;

[0027] Table 1 shows the electrochemical properties of button batteries prepared using the positive electrode sheets in Examples 1 to 17 and Comparative Examples 1 to 7. DETAILED DESCRIPTION

[0028] The following examples further illustrate the technical solutions of the present invention, but these examples are not intended to limit the scope of protection of the present invention. Unless otherwise specified, the experimental materials involved in the following examples can be purchased from the market or obtained by conventional preparation methods in the art.

[0029] Example 1

[0030] (1) Preparation of pre-sodiumization reagent: At room temperature, 0.01 mol of azulene was added to 100 mL of ether (Et2O) solvent and stirred continuously for 5 min to obtain a 0.1 mol / L azulene-Et2O solution; 0.069 mol of metallic sodium (Na) was added to the azulene-Et2O solution and stirred thoroughly for 12 h to finally obtain azulene-Na-Et2O pre-sodiumization agent.

[0031] (2) Preparation of layered metal oxide positive electrode: Take 80 mg P2-Na 0.67 Fe 0.5 Mn 0.5 Mix the O2 positive electrode material, 10mg of acetylene black, and 10mg of polyvinylidene fluoride binder, then add 800µL of N-methylpyrrolidone solvent and grind into a uniform slurry. Apply the slurry to an aluminum foil current collector and dry in a vacuum oven at 80°C for 8 hours. Finally, cut the dried electrode into 12mm diameter discs using a cutting machine.

[0032] (3) Pre-sodiumization of the layered metal oxide positive electrode: The prepared layered metal oxide positive electrode was soaked in azulene-Na-Et2O pre-sodiumization agent for pre-sodiumization, and the reaction time was 5 min; the electrode was taken out and the soaked working electrode was rinsed with Et2O, and placed in a vacuum oven at 60°C for 20 min until completely dry, thereby obtaining a pre-sodiumized layered metal oxide positive electrode.

[0033] Example 2

[0034] (1) Preparation of pre-sodiumization reagent: At room temperature, 0.01 mol of indene was added to 100 mL of N,N-dimethylformamide (DMF) solvent and stirred continuously for 5 min to obtain a 0.1 mol / L indene-DMF solution; 0.069 mol of metallic sodium (Na) was added to the indene-DMF solution and stirred thoroughly for 12 h to finally obtain the indene-Na-DMF pre-sodiumization agent.

[0035] (2) Preparation of layered metal oxide positive electrode: Take 80 mg P2-Na 0.67 Fe 0.5 Mn 0.5Mix the O2 positive electrode material, 10mg of acetylene black, and 10mg of polyvinylidene fluoride binder, then add 800µL of N-methylpyrrolidone solvent and grind into a uniform slurry. Apply the slurry to an aluminum foil current collector and dry in a vacuum oven at 80°C for 8 hours. Finally, cut the dried electrode into 12mm diameter discs using a cutting machine.

[0036] (3) Pre-sodiumization of the layered metal oxide positive electrode: The prepared layered metal oxide positive electrode is immersed in the indene-Na-DMF pre-sodiumization agent for pre-sodiumization, and the reaction time is 5 minutes; the electrode is taken out and the soaked working electrode is rinsed with DMF, and placed in a vacuum oven at 60°C and kept for 20 minutes until completely dry to obtain a pre-sodiumized layered metal oxide positive electrode.

[0037] Example 3

[0038] (1) Preparation of pre-sodiumization reagent: At room temperature, 0.01 mol of acenaphthene was added to 100 mL of ethylene glycol dimethyl ether (DME) solvent and stirred continuously for 5 min to obtain a 0.1 mol / L acenaphthene-DME solution; 0.069 mol of metallic sodium (Na) was added to the acenaphthene-DME solution and stirred thoroughly for 12 h to finally obtain the acenaphthene-Na-DME pre-sodiumization agent.

[0039] (2) Preparation of layered metal oxide positive electrode: Take 80 mg P2-Na 0.67 Fe 0.5 Mn 0.5 Mix the O2 positive electrode material, 10mg of acetylene black, and 10mg of polyvinylidene fluoride binder, then add 800µL of N-methylpyrrolidone solvent and grind into a uniform slurry. Apply the slurry to an aluminum foil current collector and dry in a vacuum oven at 80°C for 8 hours. Finally, cut the dried electrode into 12mm diameter discs using a cutting machine.

[0040] (3) Pre-sodiumization of layered metal oxide positive electrode: The prepared layered metal oxide positive electrode is immersed in acenaphthene-Na-DME pre-sodiumization agent for pre-sodiumization, and the reaction time is 5 minutes; the electrode is taken out and the soaked working electrode is rinsed with DME, and placed in a vacuum oven at 60°C and kept for 20 minutes until completely dry to obtain a pre-sodiumized layered metal oxide positive electrode.

[0041] Example 4

[0042] (1) Preparation of pre-sodiumization reagent: At room temperature, 0.01 mol of fluorene was added to 100 mL of diethylene glycol dimethyl ether (DEGDME) solvent and stirred continuously for 5 min to obtain a 0.1 mol / L fluorene-DEGDME solution; 0.069 mol of metallic sodium (Na) was added to the fluorene-DEGDME solution and stirred thoroughly for 12 h to finally obtain a fluorene-Na-DEGDME pre-sodiumization agent.

[0043] (2) Preparation of layered metal oxide positive electrode: Take 80 mg P2-Na 0.67 Fe 0.5 Mn 0.5 Mix the O2 positive electrode material, 10mg of acetylene black, and 10mg of polyvinylidene fluoride binder, then add 800µL of N-methylpyrrolidone solvent and grind into a uniform slurry. Apply the slurry to an aluminum foil current collector and dry in a vacuum oven at 80°C for 8 hours. Finally, cut the dried electrode into 12mm diameter discs using a cutting machine.

[0044] (3) Pre-sodiumization of layered metal oxide positive electrode: The prepared layered metal oxide positive electrode is immersed in the pre-sodiumization agent of fluorene-Na-DEGDME for pre-sodiumization, and the reaction time is 5 minutes; the electrode is taken out and the soaked working electrode is rinsed with DEGDME, and placed in a vacuum oven at 60°C for 20 minutes until it is completely dry to obtain a pre-sodiumized layered metal oxide positive electrode.

[0045] Example 5

[0046] (1) Preparation of pre-sodiumization reagent: At room temperature, 0.01 mol of anthraquinone was added to 100 mL of ethylene glycol dimethyl ether (DME) solvent and stirred continuously for 5 min to obtain a 0.1 mol / L anthraquinone-DME solution; 0.138 mol of metallic sodium (Na) was added to the anthraquinone-DME solution and stirred thoroughly for 12 h to finally obtain an anthraquinone-Na-DME pre-sodiumization agent.

[0047] (2) Preparation of layered metal oxide positive electrode: Take 80 mg P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3 Mix the O2 positive electrode material, 10mg of acetylene black, and 10mg of polyvinylidene fluoride binder, then add 800µL of N-methylpyrrolidone solvent and grind into a uniform slurry. Apply the slurry to an aluminum foil current collector and dry in a vacuum oven at 80°C for 8 hours. Finally, cut the dried electrode into 12mm diameter discs using a cutting machine.

[0048] (3) Pre-sodiumization of layered metal oxide positive electrode: The prepared layered metal oxide positive electrode is soaked in anthraquinone-Na-DME pre-sodiumization agent for pre-sodiumization, and the reaction time is 5 minutes; the electrode is taken out and the soaked working electrode is rinsed with DME, and placed in a vacuum oven at 60°C and kept for 20 minutes until completely dry to obtain a pre-sodiumized layered metal oxide positive electrode.

[0049] Example 6

[0050] (1) Preparation of pre-sodiumization reagent: At room temperature, 0.01 mol of phenanthrenequinone was added to 100 mL of ethylene glycol dimethyl ether (DME) solvent and stirred continuously for 5 min to obtain a 0.1 mol / L phenanthrenequinone-DME solution; 0.138 mol of metallic sodium (Na) was added to the phenanthrenequinone-DME solution and stirred thoroughly for 12 h to finally obtain a phenanthrenequinone-Na-DME pre-sodiumization agent.

[0051] (2) Preparation of layered metal oxide positive electrode: Take 80 mg P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3 Mix the O2 positive electrode material, 10mg of acetylene black, and 10mg of polyvinylidene fluoride binder, then add 800µL of N-methylpyrrolidone solvent and grind into a uniform slurry. Apply the slurry to an aluminum foil current collector and dry in a vacuum oven at 80°C for 8 hours. Finally, cut the dried electrode into 12mm diameter discs using a cutting machine.

[0052] (3) Pre-sodiumization of layered metal oxide positive electrode: The prepared layered metal oxide positive electrode is immersed in phenanthrenequinone-Na-DME pre-sodiumization agent for pre-sodiumization, and the reaction time is 5 minutes; the electrode is taken out and the soaked working electrode is rinsed with DME, and placed in a vacuum oven at 60°C and kept for 20 minutes until completely dry to obtain a pre-sodiumized layered metal oxide positive electrode.

[0053] Example 7

[0054] (1) Preparation of pre-sodiumization reagent: At room temperature, 0.01 mol of naphthoquinone was added to 100 mL of triethylene glycol dimethyl ether (TEDM) solvent and stirred continuously for 5 min to obtain a 0.1 mol / L naphthoquinone-TEDM solution; 0.069 mol of metallic sodium (Na) was added to the naphthoquinone-TEDM solution and stirred thoroughly for 12 h to finally obtain a naphthoquinone-Na-TEDM pre-sodiumization agent.

[0055] (2) Preparation of layered metal oxide positive electrode: Take 80 mg P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3Mix the O2 positive electrode material, 10mg of acetylene black, and 10mg of polyvinylidene fluoride binder, then add 800µL of N-methylpyrrolidone solvent and grind into a uniform slurry. Apply the slurry to an aluminum foil current collector and dry in a vacuum oven at 80°C for 8 hours. Finally, cut the dried electrode into 12mm diameter discs using a cutting machine.

[0056] (3) Pre-sodiumization of layered metal oxide positive electrode: The prepared layered metal oxide positive electrode is soaked in naphthoquinone-Na-TEDM pre-sodiumization agent for pre-sodiumization, and the reaction time is 5 minutes; the electrode is taken out and the soaked working electrode is rinsed with TEDM, and placed in a vacuum oven at 60°C and kept for 20 minutes until completely dry to obtain a pre-sodiumized layered metal oxide positive electrode.

[0057] Example 8

[0058] (1) Preparation of pre-sodiumization reagent: At room temperature, 0.01 mol of dibenzoylmethane was added to 100 mL of ethylene glycol dimethyl ether (DME) solvent and stirred continuously for 5 min to obtain a 0.1 mol / L dibenzoylmethane DME solution; 0.069 mol of metallic sodium (Na) was added to the dibenzoylmethane-DME solution and stirred thoroughly for 6 h to finally obtain a dibenzoylmethane-Na-DME pre-sodiumization agent.

[0059] (2) Preparation of a hard carbon anode: 90 mg of commercial hard carbon material and 10 mg of sodium alginate binder were mixed, then ground into a uniform slurry with 800 μL of deionized water. The slurry was then applied to an aluminum foil current collector and dried in a vacuum oven at 80°C for 8 h. The dried electrode was then cut into 12 mm diameter discs using a cutting machine.

[0060] (3) Pre-sodiumization of the hard carbon negative electrode: The prepared hard carbon negative electrode was soaked in dibenzoylmethane-Na-DME pre-sodiumization agent for pre-sodiumization, and the reaction time was 10 min; the electrode was taken out and the soaked working electrode was rinsed with DME, and placed in a vacuum oven at 60 ° C for 20 min until completely dry to obtain a pre-sodiumized hard carbon negative electrode.

[0061] Example 9

[0062] (1) Preparation of pre-sodiumization reagent: At room temperature, 0.01 mol of naphthone was added to 100 mL of ethylene glycol dimethyl ether (DME) solvent and stirred continuously for 5 min to obtain a 0.1 mol / L naphthone-DME solution; 0.069 mol of metallic sodium (Na) was added to the naphthone-DME solution and stirred thoroughly for 6 h to finally obtain a naphthone-Na-DME pre-sodiumization agent.

[0063] (2) Preparation of layered metal oxide positive electrode: Take 80 mg P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3 Mix the O2 positive electrode material, 10mg of acetylene black, and 10mg of polyvinylidene fluoride binder, then add 800µL of N-methylpyrrolidone solvent and grind into a uniform slurry. Apply the slurry to an aluminum foil current collector and dry in a vacuum oven at 80°C for 8 hours. Finally, cut the dried electrode into 12mm diameter discs using a cutting machine.

[0064] (3) Pre-sodiumization of the layered metal oxide positive electrode: The prepared layered metal oxide positive electrode is soaked in a naphthalene ketone-Na-DME pre-sodiumization agent for pre-sodiumization, and the reaction time is 5 minutes; the electrode is taken out and the soaked working electrode is rinsed with DME, and placed in a vacuum oven at 60°C and kept for 20 minutes until completely dry to obtain a pre-sodiumized layered metal oxide positive electrode.

[0065] Example 10

[0066] (1) Preparation of pre-sodiumization reagent: At room temperature, 0.01 mol of anthrone was added to 100 mL of ethylene glycol dimethyl ether (DME) solvent and stirred continuously for 5 min to obtain a 0.1 mol / L anthrone-DME solution; 0.0345 mol of metallic sodium (Na) was added to the anthrone-DME solution and stirred thoroughly for 6 h to finally obtain anthrone-Na-DME pre-sodiumization agent.

[0067] (2) Preparation of a hard carbon anode: 90 mg of commercial hard carbon material and 10 mg of sodium alginate binder were mixed, then ground into a uniform slurry with 800 μL of deionized water. The slurry was then applied to an aluminum foil current collector and dried in a vacuum oven at 80°C for 8 h. The dried electrode was then cut into 12 mm diameter discs using a cutting machine.

[0068] (3) Pre-sodiumization of the hard carbon negative electrode: The prepared hard carbon negative electrode was soaked in anthrone-Na-DME pre-sodiumization agent for pre-sodiumization, and the reaction time was 10 min; the electrode was taken out and the soaked working electrode was rinsed with DME, and placed in a vacuum oven at 60 ° C for 20 min until completely dry to obtain a pre-sodiumized hard carbon negative electrode.

[0069] Example 11

[0070] (1) Preparation of pre-sodiumization reagent: At room temperature, 0.01 mol of acenaphthylene was added to 100 mL of ethylene glycol dimethyl ether (DME) solvent and stirred continuously for 5 min to obtain a 0.1 mol / L acenaphthylene-DME solution; 0.069 mol of metallic sodium (Na) was added to the acenaphthylene-DME solution and stirred thoroughly for 12 h to finally obtain the acenaphthylene-Na-DME pre-sodiumization agent.

[0071] (2) Preparation of layered metal oxide positive electrode: Take 80 mg P2-Na 0.67 Fe 0.5 Mn 0.5 Mix the O2 positive electrode material, 10mg of acetylene black, and 10mg of polyvinylidene fluoride binder, then add 800µL of N-methylpyrrolidone solvent and grind into a uniform slurry. Apply the slurry to an aluminum foil current collector and dry in a vacuum oven at 80°C for 8 hours. Finally, cut the dried electrode into 12mm diameter discs using a cutting machine.

[0072] (3) Pre-sodiumization of the layered metal oxide positive electrode: The prepared layered metal oxide positive electrode is immersed in a pre-sodiumization agent of acenaphthylene-Na-DME for pre-sodiumization, and the reaction time is 5 minutes; the electrode is taken out and the soaked working electrode is rinsed with DME, and placed in a vacuum oven at 60°C for 20 minutes until completely dry to obtain a pre-sodiumized layered metal oxide positive electrode.

[0073] Example 12

[0074] (1) Preparation of pre-sodiumization reagent: At room temperature, 0.01 mol of diphenylethylene was added to 100 mL of acetonitrile (ACN) solvent and stirred continuously for 5 min to obtain a 0.1 mol / L diphenylethylene-ACN solution; 0.069 mol of metallic sodium (Na) was added to the diphenylethylene-ACN solution and stirred thoroughly for 6 h to finally obtain a diphenylethylene-Na-ACN pre-sodiumization agent.

[0075] (2) Preparation of layered metal oxide positive electrode: Take 80 mg P2-Na 0.44 Mix the MnO2 positive electrode material, 10mg of acetylene black, and 10mg of polyvinylidene fluoride binder, then add 800µL of N-methylpyrrolidone solvent and grind into a uniform slurry. Apply the slurry to an aluminum foil current collector and dry in a vacuum oven at 80°C for 8 hours. Finally, cut the dried electrode into 12mm diameter discs using a cutting machine.

[0076] (3) Pre-sodiumization of the layered metal oxide positive electrode: The prepared layered metal oxide positive electrode is soaked in a diphenylethylene-Na-ACN pre-sodiumization agent for pre-sodiumization, and the reaction time is 5 minutes; the electrode is taken out and the soaked working electrode is rinsed with ACN, and placed in a vacuum oven at 60°C and kept for 20 minutes until completely dry to obtain a pre-sodiumized layered metal oxide positive electrode.

[0077] Example 13

[0078] (1) Preparation of pre-sodiumization reagent: At room temperature, 0.01 mol of 9,10-phenylene was added to 100 mL of dimethyl sulfoxide (DMSO) solvent and stirred continuously for 5 min to obtain a 0.1 mol / L 9,10-phenylene-DMSO solution; 0.069 mol of metallic sodium (Na) was added to the 9,10-phenylene-DMSO solution and stirred thoroughly for 6 h to finally obtain a 9,10-phenylene-Na-DMSO pre-sodiumization agent.

[0079] (2) Preparation of layered metal oxide positive electrode: Take 80 mg P2-Na 0.44 Mix the MnO2 positive electrode material, 10mg of acetylene black, and 10mg of polyvinylidene fluoride binder, then add 800µL of N-methylpyrrolidone solvent and grind into a uniform slurry. Apply the slurry to an aluminum foil current collector and dry in a vacuum oven at 80°C for 8 hours. Finally, cut the dried electrode into 12mm diameter discs using a cutting machine.

[0080] (3) Pre-sodiumization of the layered metal oxide positive electrode: The prepared layered metal oxide positive electrode was immersed in 9,10-phenylene-Na-DMSO pre-sodiumization agent for pre-sodiumization, and the reaction time was 5 minutes; the electrode was taken out and the soaked working electrode was rinsed with DMSO, and placed in a vacuum oven at 60°C for 20 minutes until completely dry to obtain a pre-sodiumized layered metal oxide positive electrode.

[0081] Example 14

[0082] (1) Preparation of pre-sodiumization reagent: At room temperature, 0.01 mol of benzanthrone was added to 100 mL of ethylene glycol dimethyl ether (DME) solvent and stirred continuously for 5 min to obtain a 0.1 mol / L benzanthrone-DME solution; 0.069 mol of metallic sodium (Na) was added to the benzanthrone-DME solution and stirred thoroughly for 6 h to finally obtain a benzanthrone-Na-DME pre-sodiumization agent.

[0083] (2) Preparation of layered metal oxide positive electrode: Take 80 mg P2-Na 0.44Mix the MnO2 positive electrode material, 10mg of acetylene black, and 10mg of polyvinylidene fluoride binder, then add 800µL of N-methylpyrrolidone solvent and grind into a uniform slurry. Apply the slurry to an aluminum foil current collector and dry in a vacuum oven at 80°C for 8 hours. Finally, cut the dried electrode into 12mm diameter discs using a cutting machine.

[0084] (3) Pre-sodiumization of the layered metal oxide positive electrode: The prepared layered metal oxide positive electrode is immersed in a benzanthrone-Na-DME pre-sodiumization agent for pre-sodiumization, and the reaction time is 5 minutes; the electrode is taken out and the soaked working electrode is rinsed with DME, and placed in a vacuum oven at 60°C for 20 minutes until completely dry to obtain a pre-sodiumized layered metal oxide positive electrode.

[0085] Example 15

[0086] (1) Preparation of pre-sodiumization reagent: At room temperature, 0.01 mol of o-terphenyl was added to 100 mL of methyl tert-butyl ether (MTBE) solvent and stirred continuously for 5 min to obtain a 0.1 mol / L o-terphenyl-MTBE solution; 0.069 mol of metallic sodium (Na) was added to the o-terphenyl-MTBE solution and stirred thoroughly for 6 h to finally obtain the o-terphenyl-Na-MTBE pre-sodiumization agent.

[0087] (2) Preparation of the Sb / C composite anode: 70 mg of Sb / C composite material, 15 mg of conductive carbon black (Super-P), and 15 mg of sodium carboxymethyl cellulose (CMC-Na) binder were mixed and ground into a uniform slurry with 800 μL of deionized water. The slurry was then applied to an aluminum foil current collector and dried in a vacuum oven at 80°C for 8 h. The dried electrode was then cut into 12 mm diameter discs using a cutting machine.

[0088] (3) Pre-sodiumization of Sb / C composite negative electrode: The prepared Sb / C composite negative electrode was immersed in o-terphenyl-Na-MTBE pre-sodiumization agent for pre-sodiumization, and the reaction time was 10 min; the electrode was taken out and the soaked working electrode was rinsed with MTBE, and placed in a vacuum oven at 60 ° C for 20 min until completely dry to obtain a pre-sodiumized Sb / C composite negative electrode.

[0089] Example 16

[0090] (1) Preparation of pre-sodiumization reagent: At room temperature, 0.01 mol of 9,10-diphenylanthracene was added to 100 mL of methyl tert-butyl ether (MTBE) solvent and stirred continuously for 5 min to obtain a 0.1 mol / L 9,10-diphenylanthracene-MTBE solution; 0.069 mol of metallic sodium (Na) was added to the 9,10-diphenylanthracene-MTBE solution and stirred thoroughly for 6 h to finally obtain a 9,10-diphenylanthracene-Na-MTBE pre-sodiumization agent.

[0091] (2) Preparation of a hard carbon anode: 90 mg of commercial hard carbon material and 10 mg of sodium alginate binder were mixed, then ground into a uniform slurry with 800 μL of deionized water. The slurry was then applied to an aluminum foil current collector and dried in a vacuum oven at 80°C for 8 h. The dried electrode was then cut into 12 mm diameter discs using a cutting machine.

[0092] (3) Pre-sodiumization of hard carbon negative electrode: The prepared hard carbon negative electrode was soaked in 9,10-diphenylanthracene-Na-MTBE pre-sodiumization agent for pre-sodiumization, and the reaction time was 10 min; the electrode was taken out and the soaked working electrode was rinsed with MTBE, and placed in a vacuum oven at 60 ° C for 20 min until completely dry to obtain a pre-sodiumized hard carbon negative electrode.

[0093] Example 17

[0094] (1) Preparation of pre-sodiumization reagent: At room temperature, 0.01 mol of 9-phenylanthracene was added to 100 mL of ethylene glycol dimethyl ether (DME) solvent and stirred continuously for 5 min to obtain a 0.1 mol / L 9-phenylanthracene-DME solution; 0.069 mol of metallic sodium (Na) was added to the 9-phenylanthracene-DME solution and stirred thoroughly for 6 h to finally obtain a 9-phenylanthracene-Na-DME pre-sodiumization agent.

[0095] (2) Preparation of the Sb / C composite anode: 70 mg of Sb / C composite material, 15 mg of conductive carbon black (Super-P), and 15 mg of sodium carboxymethyl cellulose (CMC-Na) binder were mixed and ground into a uniform slurry with 800 μL of deionized water. The slurry was then applied to an aluminum foil current collector and dried in a vacuum oven at 80°C for 8 h. The dried electrode was then cut into 12 mm diameter discs using a cutting machine.

[0096] (3) Pre-sodiumization of Sb / C composite negative electrode: The prepared Sb / C composite negative electrode was soaked in 9-phenylanthracene-Na-DME pre-sodiumization agent for pre-sodiumization, and the reaction time was 10 min; the electrode was taken out and the soaked working electrode was rinsed with DME, and placed in a vacuum oven at 60 ° C for 20 min until completely dry to obtain a pre-sodiumized Sb / C composite negative electrode.

[0097] Comparative Example 1

[0098] (1) Preparation of electrode materials without pre-sodiumization: Take 80 mg P2-Na 0.67 Fe 0.5 Mn 0.5 Mix the O2 positive electrode material, 10mg of acetylene black, and 10mg of polyvinylidene fluoride binder, then add 800µL of N-methylpyrrolidone solvent and grind into a uniform slurry. Apply the slurry to an aluminum foil current collector and dry in a vacuum oven at 80°C for 8 hours. Finally, cut the dried electrode into 12mm diameter discs using a cutting machine.

[0099] Comparative Example 2

[0100] (1) Preparation of electrode materials without pre-sodiumization: Take 80 mg P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3 Mix the O2 positive electrode material, 10mg of acetylene black, and 10mg of polyvinylidene fluoride binder, then add 800µL of N-methylpyrrolidone solvent and grind into a uniform slurry. Apply the slurry to an aluminum foil current collector and dry in a vacuum oven at 80°C for 8 hours. Finally, cut the dried electrode into 12mm diameter discs using a cutting machine.

[0101] Comparative Example 3

[0102] (1) Preparation of pre-sodiumization reagent: At room temperature, 0.05 mol of naphthalene was added to 100 mL of ethylene glycol dimethyl ether (DME) solvent and stirred continuously for 20 min to obtain a 0.5 mol / L naphthalene-DME solution; 0.1725 mol of metallic sodium (Na) was added to the naphthalene-DME solution and stirred thoroughly for 24 h to finally obtain a naphthalene-Na-DME pre-sodiumization agent.

[0103] (2) Preparation of layered metal oxide positive electrode: Take 80 mg P2-Na 0.67 Fe 0.5 Mn 0.5 Mix the O2 positive electrode material, 10mg of acetylene black, and 10mg of polyvinylidene fluoride binder, then add 800µL of N-methylpyrrolidone solvent and grind into a uniform slurry. Apply the slurry to an aluminum foil current collector and dry in a vacuum oven at 80°C for 8 hours. Finally, cut the dried electrode into 12mm diameter discs using a cutting machine.

[0104] (3) Pre-sodiumization of the layered metal oxide positive electrode: The prepared layered metal oxide positive electrode is soaked in a naphthalene-Na-DME pre-sodiumization agent for pre-sodiumization, and the reaction time is 30 minutes; the electrode is taken out and the soaked working electrode is rinsed with DME, and placed in a 60°C vacuum oven and kept for 20 minutes until completely dry to obtain a pre-sodiumized layered metal oxide positive electrode.

[0105] Comparative Example 4

[0106] (1) Preparation of electrode materials without pre-sodiumization: Take 80 mg P2-Na 0.44 Mix the MnO2 positive electrode material, 10mg of acetylene black, and 10mg of polyvinylidene fluoride binder, then add 800µL of N-methylpyrrolidone solvent and grind into a uniform slurry. Apply the slurry to an aluminum foil current collector and dry in a vacuum oven at 80°C for 8 hours. Finally, cut the dried electrode into 12mm diameter discs using a cutting machine.

[0107] Comparative Example 5

[0108] (1) Preparation of electrode material without pre-sodiumization: 90 mg of commercial hard carbon material and 10 mg of sodium alginate binder were mixed, then ground into a uniform slurry with 800 μL of deionized water. The slurry was then spread onto an aluminum foil current collector and dried in a vacuum oven at 80°C for 8 h. The dried electrode was then cut into 12 mm diameter discs using a cutting machine.

[0109] Comparative Example 6

[0110] (1) Preparation of electrode material without pre-sodiumization: 70 mg of Sb / C composite material, 15 mg of conductive carbon black (Super-P), and 15 mg of sodium carboxymethyl cellulose (CMC-Na) binder were mixed and ground into a uniform slurry with 800 μL of deionized water. The slurry was then spread onto an aluminum foil current collector and dried in a vacuum oven at 80°C for 8 h. The dried electrode was then cut into 12 mm diameter discs using a cutting machine.

[0111] Comparative Example 7

[0112] (1) Preparation of pre-sodiumization reagent: At room temperature, 0.05 mol of biphenyl was added to 100 mL of ethylene glycol dimethyl ether (DME) solvent and stirred continuously for 20 min to obtain a 0.5 mol / L biphenyl-DME solution; 0.345 mol of metallic sodium (Na) was added to the biphenyl-DME solution and stirred thoroughly for 24 h to finally obtain a biphenyl-Na-DME pre-sodiumization agent.

[0113] (2) Preparation of a hard carbon anode: 90 mg of commercial hard carbon material and 10 mg of sodium alginate binder were mixed, then ground into a uniform slurry with 800 μL of deionized water. The slurry was then applied to an aluminum foil current collector and dried in a vacuum oven at 80°C for 8 h. The dried electrode was then cut into 12 mm diameter discs using a cutting machine.

[0114] (3) Pre-sodiumization of hard carbon negative electrode: The prepared hard carbon negative electrode was soaked in biphenyl-Na-DME pre-sodiumization agent for pre-sodiumization, and the reaction time was 30 min; the electrode was taken out and the soaked working electrode was rinsed with DME, and placed in a vacuum oven at 60 ° C for 20 min until completely dry to obtain a pre-sodiumized hard carbon negative electrode.

[0115] The electrodes obtained in Examples 1 to 17 and Comparative Examples 1 to 7 were placed in a glove box with water and oxygen contents <0.01ppm respectively, and the pre-sodiumized electrode and sodium metal formed a two-electrode system. The battery assembly model was a CR2032 button cell. 1.5MNaPF6 (solvent is DMC:EC:EMC=2:1:2Vol%) was used as the electrolyte; a glass fiber with a diameter of 19mm was used as the diaphragm, and a metal sodium sheet with a diameter of 14mm was used as the counter electrode. The entire assembly process was completed in an argon atmosphere glove box, and the voltage test range was 0.01~4.5V (vs.Na + / Na).

[0116] Table 1 Comparison of electrochemical performance of half-cells assembled with electrodes obtained in Examples 1 to 17 and Comparative Examples 1 to 7

[0117]

[0118] In Table 1, it can be seen from the electrochemical performance test results of the half-cells prepared from the electrode pole pieces in Examples 1 to 17 and Comparative Examples 1, 2, 4 to 6 that the pole pieces after pre-sodiumization have improved their charge specific capacity, effectively compensating for the irreversible loss of sodium in the sodium ion battery. In addition, it can be seen from the cycle capacity retention rate that the pole pieces treated with the pre-sodiumization agent of this patent have a capacity retention rate higher than that of the comparative example, indicating that the pre-sodiumization agent of the present invention not only does not adversely affect the material as a whole, but also strengthens the structure of the sodium ion battery electrode material, effectively improving the embedding / extraction ability of sodium ions in the positive and negative electrode materials, thereby significantly improving the charge and discharge performance of the sodium ion battery. Among them, by comparing Examples 12, 14 with Comparative Example 3, and Examples 8, 10 with Comparative Example 7, it is concluded that the carbonyl group in the carbonyl (C=O) pre-sodiumization agent of the present invention has an electron-withdrawing effect, which balances the strong conjugation effect of polycyclic aromatic hydrocarbons and reduces the electron cloud density of the overall free radicals, thereby enabling it to gently improve battery performance and avoid the destruction of the electrode structure caused by excessive sodiumization. In addition, the pre-sodiumization agent of the present invention is mild in nature and stable to air, which makes the pre-sodiumization agent of the present invention have great practical application prospects in sodium ion batteries.

[0119] Secondly, Figure 1 and Figure 2 The first cycle charge and discharge curves of the hard carbon electrode before and after pre-sodium treatment in Examples 8 and 10 are shown respectively. By comparison, it is found that the hard carbon electrode pre-sodium treated in Example 8 can increase the first efficiency to 95.05%, effectively reducing the irreversible capacity of the first cycle; while Example 10 improves the reversible capacity, it also increases the first efficiency to 88.86%. Figure 3 and Figure 4 It shows that pre-sodium treatment has no obvious effect on the hard carbon material itself.

[0120] In summary, the pre-sodiumization agent and sodium ion battery electrode provided by the present invention can achieve sodium replenishment quickly and efficiently at extremely low concentrations due to their unique structural design. This technology can significantly improve the first-cycle coulombic efficiency and charge and discharge reversible capacity of sodium ion batteries, thereby effectively improving the battery energy density. At the same time, the preparation process of the pre-sodiumization agent is simple and mild, time-saving, and highly safe, and has good prospects for industrial application. On the other hand, this method is particularly suitable for electrode systems of sodium-poor systems, such as P2-type positive electrode materials, hard carbon and soft carbon negative electrodes, etc., due to its rapid sodium replenishment characteristics. This technical advantage can significantly improve the initial coulombic efficiency of the battery, thereby efficiently achieving high energy density requirements. More importantly, for negative electrode materials, the pre-sodiumization electrode obtained after implementation of this method will form a uniform and thin solid electrolyte interface on the electrode surface when it comes into contact with the electrolyte, which also helps to improve the cycle stability and safety of the battery.

[0121] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. A compound for use as a battery pre-sodium agent, characterized in that: The chemical formula is C x H y O z The compound is used as a battery pre-sodium agent, wherein x is 9 to 26, y is 6 to 18, and z is 0 to 2.

2. The use according to claim 1, characterized in that The chemical formula is C x H y O z The compound includes at least the following structure:

3. A sodium ion battery electrode, characterized in that The pre-sodium agent C according to claim 1 or 2 x H y O z Soaking the sodium ion battery electrode, the pre-sodium agent C x H y O z The contact reaction time with the sodium ion battery electrode is 5 to 30 minutes, and the drying temperature is 30 to 80°C.

4. The sodium ion battery electrode according to claim 3, characterized in that The pre-sodium agent C x H y O z The contact reaction time with the sodium ion battery electrode is 8 to 10 minutes, and the drying temperature is 60°C.

5. The sodium ion battery electrode according to claim 3, characterized in that The sodium ion battery electrode includes a sodium ion battery electrode active material, a conductive additive and a binder.

6. The sodium ion battery electrode according to claim 5, characterized in that The sodium ion battery electrode active material is a positive electrode active material, and the positive electrode active material is one or more of layered transition metal oxides, polyanion compounds, Prussian blue and the like.

7. The sodium ion battery electrode according to claim 6, characterized in that The layered transition metal oxide is one or more of a single metal oxide, a manganese-rich / iron-rich system, and a binary / ternary metal oxide.

8. The sodium ion battery electrode according to claim 7, characterized in that The binary / ternary metal oxide is one or more of an O3-type layered oxide and a P2-type layered oxide.

9. The sodium ion battery electrode according to claim 5, characterized in that The sodium ion battery electrode active material is a negative electrode active material, and the negative electrode active material is one or more of carbon-based materials, silicon-based materials, tin-based materials, antimony-based materials, phosphorus-based elements and their composites, metal oxides, metal sulfides, and metal phosphides.

10. The sodium ion battery electrode according to claim 5, characterized in that The conductive additive is one or more of acetylene black (AB), Ketjen black (KB), conductive carbon black (Super P), graphene (G) or carbon nanotubes (CNT); the binder is one or more of polyvinylidene fluoride (PVDF), sodium carboxymethyl cellulose (CMC-Na), and polyphthalamide (PAA).

Images