Sodium ion battery with long cycle life

Abstract

The invention discloses a long-cycle-life sodium ion battery which comprises a first additive A and a second additive B. The first additive A is one or more of chain compounds containing sulfonyl oxygen structures; the second additive B is one or more of halogenated and / or unsaturated double bond-containing five-membered cyclic carbonate structural compounds, and meets the following formula relations: 0.1% < = (a + b) * p / rho < = 8.75%, 0.01% < = a < = 2.5%, 0.05% < = b < = 3%, 2 [mu] m < = d < = 8 [mu] m, 0.25 < = p < = 3, 0.85 g / cm < 3 > < = rho < = 1.15 g / cm < 3 >, and a is the mass percentage content of the first additive A; b is the mass percentage content of the second additive B; d is the accumulated particle size distribution D50 value of the negative electrode material; rho is the compaction density of the negative pole piece; and p is the PDI value of the particle size uniformity of the negative electrode material, so that the problems of poor cycling stability and short service life of the sodium-ion battery are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of sodium ion batteries, and in particular to a sodium ion battery with a long cycle life. Background Art

[0002] Against the backdrop of rapidly growing global energy demand and the large-scale development and application of renewable energy, the development of energy storage technology is crucial. The low abundance of lithium in the Earth's crust contributes to the high price of lithium-ion batteries. To alleviate energy shortages and climate change, developing a new generation of secondary batteries with easily accessible materials and ultra-long cycle life is crucial. Sodium-ion batteries, with similar electrochemical properties to lithium-ion batteries and abundant sodium resources, are low-cost, and operate on similar principles to lithium-ion batteries, making them a research hotspot in the energy storage field. Despite this, sodium-ion battery technology is not yet fully mature, particularly in terms of chemical stability, which directly impacts the battery's service life.

[0003] Anode material particle size parameters, such as the cumulative particle size distribution (D50) and particle uniformity (PDI), have a significant impact on battery performance. A high PDI is one of the main reasons for the poor cycling performance of sodium-ion batteries. Reducing PDI can improve cycling stability. During battery cycling, sodium ion intercalation occurs primarily on particles of the three-dimensional active electrode material with low intercalation resistance during the early stages of charging—specifically, small anode particles with large surface area and short ion migration distances. As charging continues, the intercalation resistance of small anode particles increases, and sodium ion intercalation also begins in larger anode particles. This timing difference in sodium ion intercalation caused by particle size heterogeneity results in lower potentials for the particles that intercalate first, making sodium precipitation more likely and leading to rapid capacity decay. In battery manufacturing, a smaller PDI of the electrode active material can help mitigate sodium precipitation and cycling performance degradation caused by anode particle heterogeneity in the later stages of charging. However, continuously reducing the PDI of anode particles leads to high production costs, hindering the market adoption of sodium-ion batteries.

[0004] The growth of negative electrode impedance during cycling is another important reason for the reduced cycling performance of sodium-ion batteries. The continued growth of impedance can be prevented by adding film-forming additives to the electrolyte to form a better passivation film. 1,3-Propane sultone (1,3-PS) is a commonly used negative electrode film-forming additive. During formation, 1,3-PS is reduced and decomposed on the negative electrode surface to form a passivation film with good electron barrier properties, which can significantly reduce the degree of interfacial side reactions during cycling, thereby reducing the impedance growth during cycling and improving cycle stability. However, the initial impedance of the interfacial film formed by 1,3-PS is relatively large. Even though it can alleviate the impedance growth during cycling, its effect on improving cycle life is limited.

[0005] In view of this, it is necessary to develop a sodium ion battery that can alleviate the impedance growth during the cycle and has a long cycle life. Summary of the Invention

[0006] The present invention addresses the problems in the prior art of sodium ion batteries, such as high risk of sodium precipitation in the late stage of charging, surge in impedance during cycling, rapid capacity decay rate, and insufficient cycle stability, and discloses a sodium ion battery with a long cycle life. By constructing a dual-functional electrolyte additive system and systematically optimizing the combination and ratio of the electrolyte additives in the electrolyte, the cumulative particle size distribution D50 value of the negative electrode material in the battery, the compaction density of the negative electrode sheet in the battery, the particle size uniformity PDI value of the negative electrode material, and combining multi-parameter and multi-dimensional formula relationships, a synergistic optimization mechanism of the electrode / electrolyte interface dynamics and structural stability is established, providing a sodium ion battery with a long cycle life, and solving the problem of insufficient cycle performance of current sodium ion batteries.

[0007] The present invention is achieved through the following technical solutions:

[0008] The present invention first provides a sodium ion battery electrolyte with a long cycle life;

[0009] The long cycle life sodium ion battery electrolyte includes an electrolyte additive;

[0010] The electrolyte additives include a first additive A and a second additive B;

[0011] The first additive A is selected from one or more chain compounds containing a sulfonyloxy structure and has the following structure:

[0012] wherein R1 is selected from an alkali metal atom, a C1-C6 halogenated or non-halogenated hydrocarbon group, a C1-C6 halogenated or non-halogenated acyl group, a halogenated or non-halogenated sulfonyl group, or a halogenated or non-halogenated silyl group;

[0013] wherein R2 is selected from a halogen atom, a C1-C6 halogenated or non-halogenated hydrocarbon group, a C1-C6 halogenated or non-halogenated hydrocarbonoxy group, a C2-C6 halogenated or non-halogenated ester group (R3COO—), or a C1-C6 halogenated or non-halogenated sulfonic acid group (R4SO3—);

[0014] wherein R3 is selected from one of C1-C5 halogen atoms, halogenated or non-halogenated hydrocarbon groups, and R4 is selected from one of C1-C6 halogen atoms, halogenated or non-halogenated hydrocarbon groups;

[0015] The second additive B is selected from one or more cyclic carbonate compounds having halogenation and / or containing unsaturated double bonds, and has the following structure:

[0016]

[0017] wherein R5 and R6 are each independently selected from one of a methylene group (-CH2), a methine group (-CH=), and C; R7 and R8 are each independently selected from one of a hydrogen atom, a halogen atom, a C1-C3 halogenated or non-halogenated alkyl group, a C2-C3 halogenated or non-halogenated alkenyl group, a C2-C3 halogenated or non-halogenated alkynyl group, and a C1-C3 halogenated or non-halogenated alkoxy group; a single bond or a double bond is formed between R5 and R6; and at least one of R7 and R8 is a halogenated group, and / or the second additive B contains at least one unsaturated double bond;

[0018] Specifically, when the second additive B is When R5 and R6 are both methine (-CH=), there is a double bond between R5 and R6;

[0019] When the second additive B is When R5 and R6 are both C, there is a double bond between R5 and R6;

[0020] The amounts of the first additive A and the second additive B in the electrolyte satisfy the following formula: 0.1%≤(a+b)*p / ρ≤8.75%, 0.01%≤a≤2.5%, 0.05%≤b≤3%, 2μm≤d≤8μm, 0.25≤p≤3, 0.85g / cm 3 ≤ρ≤1.15g / cm 3 , where a is the mass percentage of the first additive A in the electrolyte; b is the mass percentage of the second additive B in the electrolyte; d is the cumulative particle size distribution D50 value of the negative electrode material in the battery; ρ is the compaction density of the negative electrode sheet in the battery; and p is the particle size uniformity PDI value of the negative electrode material.

[0021] Wherein, PDI=(D90-D10) / D50, wherein D90 is the cumulative D90 value of the negative electrode material particle size distribution in the battery, and D10 is the cumulative D10 value of the negative electrode material particle size distribution in the battery.

[0022] As a further solution, the amounts of the first additive A and the second additive B in the electrolyte meet the following conditions: 0.3%≤(a+b)*p / ρ≤5.5%, 0.01%≤a≤2.5%, 0.05%≤b≤3%, 2μm≤d≤8μm, 0.25≤p≤1, 0.85g / cm 3 ≤ρ≤1.15g / cm 3 When the above conditions are met, the capacity retention rate is ≥81% after 5000 cycles at 25℃ and ≥85% after 3000 cycles at 45℃.

[0023] As a further preferred embodiment, R2 in the first additive A is selected from one of a halogen atom, a C1-C3 halogenated hydrocarbon group or a C1-C3 halogenated hydrocarbonoxy group, and R1 is selected from one of a C1-C3 halogenated hydrocarbon group, a C1-C3 halogenated acyl group, a halogenated sulfonyl group, a non-halogenated silane group, and an alkali metal atom.

[0024] As a further preferred embodiment, in the first additive A, R2 is selected from a halogen atom, a C1 halogenated hydrocarbon group or a C1 halogenated hydrocarbonoxy group, and R1 is selected from a C1 halogenated hydrocarbon group or an alkali metal atom.

[0025] As a further preferred embodiment, in the first additive A, as an even further preferred embodiment, the first additive A is selected from one or more of compound A1 to compound A25;

[0026]

[0027] As a further preferred solution, the first additive A is one or more of A1, A2, A6, A7, A11, and A12.

[0028] As a further preferred solution, the second additive B is selected from One of them.

[0029] As a further preferred solution, the second additive B is selected from R7 is selected from a halogen atom, a C1-C3 halogenated alkyl group, or a C2-C3 halogenated or non-halogenated alkenyl group.

[0030] As a further preferred solution, the second additive B is selected from R7 is a halogen atom or a C2-C3 non-halogenated alkenyl group.

[0031] The second additive B is selected from one or more of compounds B1 to B5:

[0032]

[0033] As a further preferred solution, the second additive B is B1.

[0034] As a further solution, the electrolyte additive further includes 1,3-propane sultone (1,3-PS).

[0035] As a further solution, a long cycle life sodium ion battery electrolyte also includes sodium salt and an organic solvent.

[0036] As a further embodiment, the sodium salt is one or more of sodium hexafluorophosphate, sodium perchlorate, sodium bis(fluorosulfonyl)imide, sodium bis(trifluoromethylsulfonyl)imide, sodium tetrafluoroborate, sodium difluorooxalatoborate, sodium bis(oxalatoborate), sodium difluorophosphate, sodium nitrate, sodium hexafluoroantimonate, sodium hexafluoroarsenate, sodium difluorobis(oxalatophosphate), and sodium tetrafluorooxalatophosphate.

[0037] As a further embodiment, the sodium salt is sodium hexafluorophosphate.

[0038] As a further preferred solution, the mass percentage of the sodium salt in the electrolyte is 5% to 20%.

[0039] Further preferably, the mass percentage of the sodium salt in the electrolyte is 7.5% to 15%.

[0040] As a further preferred solution, the mass percentage of the sodium salt in the electrolyte is 13.5%.

[0041] The organic solvent includes one or more of a cyclic carbonate solvent, a chain carbonate solvent, a carboxylate solvent, a phosphate solvent, an ether solvent, and an ionic liquid.

[0042] As a further embodiment, the ether solvent is selected from one or more of ether solvents containing hydroxyl groups, ether solvents containing a single ether bond, and ether solvents containing complex functional groups.

[0043] As a further embodiment, the complex functional group is selected from one or more of C1-C10 alkoxy, alkenyl, and alkynyl groups.

[0044] As a further solution, the hydroxyl-containing ether solvent is selected from one or more of dipropylene glycol butyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol monomethyl ether, triethylene glycol monomethyl ether, and tetraethylene glycol dimethyl ether.

[0045] As a further solution, the ether solvent containing a single ether bond is selected from one or more of cyclopentyl methyl ether, ethyl ether, and propyl ether.

[0046] As a further solution, the ether solvent containing complex functional groups is selected from one or more of butynediol dipropoxy ether, propargyl ether, and propargyl ether.

[0047] As a further embodiment, the chain carbonate is selected from one of dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, and ethyl propyl carbonate;

[0048] As a further embodiment, the carboxylate solvent is selected from one or more of methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, methyl isobutyrate, ethyl butyrate, methyl trimethylacetate and ethyl trimethylacetate.

[0049] As a further solution, the cyclic carbonate is selected from one or more of ethylene carbonate, butylene carbonate, propylene carbonate, and pentylene carbonate.

[0050] As a further solution, the phosphate solvent includes at least one of trimethyl phosphate, triethyl phosphate, tripropyl phosphate, triphenyl phosphate, tris(2,2,2-trifluoroethyl) phosphite, and ethoxy(pentafluoro)cyclotriphosphazene.

[0051] The present invention also provides a sodium-ion battery with a long cycle life, which includes the electrolyte for the sodium-ion battery with a long cycle life, and further includes a positive electrode sheet, a negative electrode sheet, and a separator.

[0052] As a further solution, the positive electrode sheet is an aluminum foil sheet coated with a positive electrode active material, and the negative electrode sheet is a copper foil sheet or an aluminum foil sheet coated with a negative electrode active material.

[0053] As a further solution, the positive electrode active material is one of sodium vanadium phosphate, sodium iron phosphate, sodium fluorovanadate, and a manganese-containing metal layered oxide.

[0054] Preferably, the positive electrode active material is a manganese-containing metal layered oxide, and the general formula of the manganese-containing metal layered oxide is Na x Mn y M z O2, where 0.95 < x ≤ 1.05, 0.01 ≤ y ≤ 0.6, y + z = 1, and M represents a transition metal element with an unfilled d electron orbital, specifically including one or more of scandium (Sc), yttrium (Y), lanthanide elements (from lanthanum (La) to lutetium (Lu)), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), copper (Cu), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), and mercury (Hg).

[0055] As a further solution, M in the manganese-containing positive electrode active material includes at least one of Ni, Fe, and Cu.

[0056] The negative electrode active material is selected from at least one of soft carbon, hard carbon, expanded graphite, phosphorus-carbon composite material, and expanded graphite / hard carbon composite material.

[0057] Preferably, the negative electrode active material is hard carbon or a phosphorus-carbon composite material.

[0058] As a further solution, when the positive electrode active material is coated with an aluminum foil or the negative electrode active material is coated with a copper foil or an aluminum foil, a binder and a conductive agent are also used.

[0059] As a further solution, the binder is an oil-based binder, and the binder includes at least one of thermoplastic resin, acrylic resin, sodium carboxymethyl cellulose and styrene butadiene rubber.

[0060] As a further embodiment, the thermoplastic resin includes at least one of polyvinylidene fluoride, a copolymer of vinylidene fluoride, polytetrafluoroethylene, a copolymer of vinylidene fluoride-hexafluoropropylene, a copolymer of tetrafluoroethylene-hexafluoropropylene, a copolymer of tetrafluoroethylene-perfluoroalkyl vinyl ether, a copolymer of ethylene-tetrafluoroethylene, a copolymer of vinylidene fluoride-tetrafluoroethylene, a copolymer of vinylidene fluoride-trifluoroethylene, a copolymer of vinylidene fluoride-trichloroethylene, a copolymer of vinylidene fluoride-fluoroethylene, a copolymer of vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene, thermoplastic polyimide, polyethylene and polypropylene.

[0061] As a further solution, the acrylic resin includes at least one of vinyl acrylate resin, methyl acrylate resin, butyl acrylate resin, acrylic styrene resin, acrylate resin, acrylate copolymer resin, acrylic resin, and acrylic emulsion resin.

[0062] As a further solution, the binder is one or more of polyvinylidene fluoride (PVDF), styrene butadiene rubber (SBR), and sodium carboxymethyl cellulose (CMC).

[0063] As a further solution, the conductive agent includes one or more of conductive carbon black, conductive carbon balls, conductive graphite, carbon nanotubes, conductive carbon fibers, graphene and reduced graphene oxide.

[0064] As a further preferred solution, the conductive agent is one or more of conductive carbon black (Super P) and carbon nanotubes (CNTs).

[0065] As a further solution, the preparation of the wide temperature range sodium ion battery includes the following steps:

[0066] S1: The electrolyte solvent is fully mixed according to the target stoichiometric ratio, and then the sodium salt is dissolved in the mixed solvent according to the target stoichiometric ratio, and the target stoichiometric ratio of fluoroethylene carbonate, the first additive A, and the second additive B are added and stirred to obtain an electrolyte;

[0067] S2: dissolving the positive electrode active material, conductive agent, and binder in a solvent N-methyl-2-pyrrolidone (NMP) according to a target stoichiometric ratio, stirring evenly to obtain a positive electrode slurry, and then evenly coating the obtained positive electrode slurry on an aluminum foil, drying, cold pressing, and slitting to obtain a positive electrode sheet;

[0068] S3: The negative electrode active material, conductive agent, and binder are mixed according to the target stoichiometric ratio, deionized water is added and stirred evenly to obtain a negative electrode slurry, which is then coated on aluminum foil or copper foil, and then dried, cold pressed, and cut to obtain a negative electrode sheet;

[0069] S4: The positive electrode sheet, the negative electrode sheet, and the separator are formed into a battery through a winding process or a lamination process.

[0070] The characteristics and beneficial effects of the present invention are:

[0071] The present invention provides a long-cycle sodium-ion battery. By optimizing the combination of electrolyte additives and multi-dimensional electrode surface microstructure, this solution addresses the core issue of sodium-ion battery cycle performance degradation, achieving a balance between low initial impedance and high cycle stability. Its beneficial effects are primarily reflected in the following three aspects:

[0072] First, by optimizing the composition and ratio of electrolyte additives, a gradient SEI membrane was constructed: through a dual additive system with complementary functions, a gradient heterogeneous SEI membrane with a rigid skeleton with certain structural strength and flexible segments was constructed on the surface of the negative electrode. The first additive A formed a rigid skeleton rich in sulfur-containing inorganic phase, and its three-dimensional network structure established continuous ion channels through directional sulfur-oxygen bridge bonds, which significantly improved the interface Na + Conductivity, laying the foundation for low impedance dynamics; the second additive B forms a flexible organic-inorganic hybrid layer through electrochemical polymerization, and its cyclic molecular skeleton constructs a three-dimensional cross-linked network with dual functions: the rigid component forms a dense electron blocking layer to inhibit electron tunneling, and the dynamic flexible chain segments adapt to volume fluctuations through reversible bonding to effectively buffer mechanical stress; the two are bridged by chemical bonds to form a surface organic barrier and a gradient structure of inorganic ions at the bottom layer, which synergistically blocks the continuous decomposition of the electrolyte, inhibits the growth of sodium dendrites, achieves dynamic stability of the interface, and extends the cycle life of the battery at room temperature and high temperature.

[0073] Secondly, through the three-dimensional coordinated regulation of particle size distribution, compaction density and uniformity, a multi-level protection architecture of "mechanical stability-ion uniform flow-interface adaptation" is constructed: by optimizing the particle size gradient to balance energy density and mechanical strength, large particles maintain structural integrity and reduce side reactions, and small particles fill the pores to form short-range ion channels, which synergistically improve the capacity retention rate; establish an optimal balance between the electronic conductive network and the ion diffusion channel, moderate densification promotes particle surface contact to reduce interface resistance, while retaining the pores required for electrolyte penetration, and inhibiting the rupture of the coating layer caused by volume expansion; through moderate size differences, a "large particle skeleton-small particle filling" composite structure is formed to balance the spatial distribution of current, reduce local polarization, guide the uniform evolution of the SEI film, and avoid capacity attenuation caused by local excessive thickness or rupture of the membrane layer.

[0074] Thirdly, the dynamic adaptation equation (a+b)*p / ρ is used to quantitatively correlate electrolyte additives with the physical properties of the electrode plates, enabling simultaneous optimization of the film-forming properties, ionic conductivity, and cycle stability of the SEI film. This invention overcomes the difficulties of traditional technologies and achieves improved cycle life for sodium-ion batteries through molecular design, structural matching, and interface regulation. The total amount of the dual additives precisely matches the surface active sites, avoiding side reactions caused by excess and insufficient coverage caused by too little additive. The additive distribution efficiency is dynamically regulated by the ratio of particle size uniformity to compaction density, achieving directional growth of the gradient SEI film within the confined electrode space, forming a stable interface and exhibiting a synergistic enhancement effect, thereby enabling the battery to have better cycle performance and effectively extending its service life. BRIEF DESCRIPTION OF THE DRAWINGS DETAILED DESCRIPTION

[0075] To facilitate understanding of the present invention, a long cycle life sodium ion battery will be described in more detail below in conjunction with specific details and embodiments of the present invention, but the scope of the present invention is not limited thereby.

[0076] The present invention addresses the problems in the prior art of sodium ion batteries, such as high risk of sodium precipitation in the late stage of charging, surge in impedance during cycling, rapid capacity decay rate, and insufficient cycle stability, and discloses a sodium ion battery with a long cycle life. By constructing a dual-functional electrolyte additive system and systematically optimizing the combination and ratio of the electrolyte additives in the electrolyte, the cumulative particle size distribution D50 value of the negative electrode material in the battery, the compaction density of the negative electrode sheet in the battery, the PDI value of the particle size uniformity of the negative electrode material, and combining multi-parameter and multi-dimensional formula relationships, a synergistic optimization mechanism of the electrode / electrolyte interface dynamics and structural stability is established, providing a sodium ion battery with a long cycle life, and solving the problem of insufficient cycle performance of current sodium ion batteries.

[0077] The present invention is achieved through the following technical solutions:

[0078] The present invention first provides a sodium ion battery electrolyte with a long cycle life;

[0079] The long cycle life sodium ion battery electrolyte includes an electrolyte additive;

[0080] The electrolyte additives include a first additive A and a second additive B;

[0081] The first additive A is selected from one or more compounds having a chain sulfonyloxy structure and has the following structure:

[0082] wherein R1 is selected from an alkali metal atom, a C1-C6 halogenated or non-halogenated hydrocarbon group, a C1-C6 halogenated or non-halogenated acyl group, a halogenated or non-halogenated sulfonyl group, or a halogenated or non-halogenated silyl group;

[0083] wherein R2 is selected from a halogen atom, a C1-C6 halogenated or non-halogenated hydrocarbon group, a C1-C6 halogenated or non-halogenated hydrocarbonoxy group, a C1-C6 halogenated or non-halogenated ester group (R3COO—), or a C1-C6 halogenated or non-halogenated sulfonic acid group (R4SO3—);

[0084] wherein R3 is selected from one of C1-C5 halogen atoms, halogenated or non-halogenated hydrocarbon groups, and R4 is selected from one of C1-C6 halogen atoms, halogenated or non-halogenated hydrocarbon groups;

[0085] The second additive B is selected from one or more cyclic carbonate compounds having halogenation and / or containing unsaturated double bonds, and has the following structure:

[0086]

[0087] wherein R5 and R6 are each independently selected from one of a methylene group (-CH2), a methine group (-CH=), and C; R7 and R8 are each independently selected from one of a hydrogen atom, a halogen atom, a C1-C3 halogenated or non-halogenated alkyl group, a C2-C3 halogenated or non-halogenated alkenyl group, a C2-C3 halogenated or non-halogenated alkynyl group, and a C1-C3 halogenated or non-halogenated alkoxy group; a single bond or a double bond is formed between R5 and R6; and at least one of R7 and R8 is a halogenated group, and / or the second additive B contains at least one unsaturated double bond;

[0088] Specifically, when the second additive B is When both R5 and R6 are methine (-CH=), there is a double bond between R5 and R6;

[0089] When the second additive B is When R5 and R6 are both C, there is a double bond between R5 and R6;

[0090] The amounts of the first additive A and the second additive B in the electrolyte satisfy the following formula: 0.1%≤(a+b)*p / ρ≤8.75%, 0.01%≤a≤2.5%, 0.05%≤b≤3%, 2μm≤d≤8μm, 0.25≤p≤3, 0.85g / cm 3 ≤ρ≤1.15g / cm 3 , where a is the mass percentage of the first additive A in the electrolyte; b is the mass percentage of the second additive B in the electrolyte; d is the cumulative particle size distribution D50 value of the negative electrode material in the battery; ρ is the compaction density of the negative electrode sheet in the battery; and p is the particle size uniformity PDI value of the negative electrode material.

[0091] Wherein, PDI=(D90-D10) / D50, wherein D90 is the cumulative D90 value of the negative electrode material particle size distribution in the battery, and D10 is the cumulative D10 value of the negative electrode material particle size distribution in the battery.

[0092] The above-mentioned design of the present invention solves the problem of cycle performance degradation caused by uneven negative electrode particle size and limited impedance growth improvement of film-forming additives in the late charging period of sodium ion batteries by optimizing the first additive A, the second additive B, the compaction density of the negative electrode plate in the battery, the cumulative particle size distribution D50 value of the negative electrode material particles in the battery, and the negative electrode material particle size uniformity PDI value, thereby developing a sodium ion battery with strong film formation stability and high cycle performance.

[0093] By controlling the particle size distribution D50 of the negative electrode material and the particle size uniformity of the negative electrode material within a specific range, and adding the first additive A and the second additive B to the electrolyte to jointly participate in the passivation reaction of the negative electrode surface, when the cumulative particle size distribution percentage D50 value d of the negative electrode material particles, the compaction density ρ of the negative electrode pole piece in the battery, the particle size uniformity PDI value of the negative electrode material, the mass percentage content a of the first additive in the electrolyte, and the mass percentage content b of the second additive in the electrolyte meet the conditions: 0.01%≤a≤2.5%, 0.05%≤b≤3%, 2um≤d≤8um, 0.25≤p≤3, 0.85g / cm 3 ≤ρ≤1.15g / cm 3 , and when 0.1%≤(a+b)*p / ρ≤8.75%, the obtained sodium ion battery not only has a lower initial impedance, but also has a lower impedance growth during the cycle, showing excellent long-cycle performance.

[0094] On the one hand, a first additive A with good film-forming properties is used, and its mass percentage in the electrolyte is optimized, so that after reduction, a composite SEI film rich in sulfur-containing inorganic phases such as sodium sulfide, sodium sulfate, and sodium sulfite is formed on the surface of the negative electrode. The inorganic component forms a linear structure through the directional arrangement of sulfur-oxygen bridge bonds, constructing a three-dimensional network skeleton with continuous ion transmission channels; this high crystallinity and low porosity SEI film increases the Na + Conductivity, thereby reducing the initial impedance of the battery and laying a kinetic foundation for subsequent cycle stability;

[0095] A second additive B with a cyclic carbonate structure is used, and its mass percentage is optimized. Under the electrochemical polymerization reaction, a flexible organic-inorganic hybrid composite SEI layer rich in sodium alkoxy carbonate (NaORCO3) is constructed on the surface of the negative electrode. Its cyclic molecular skeleton self-assembles through π orbital interaction to form a three-dimensional cross-linked network structure, and the rigid molecular skeleton forms a dense electron blocking layer, which significantly inhibits the electron tunneling effect. At the same time, its dynamic flexible chain segments form a stress buffer structure through reversible bonding, which increases the toughness of the composite SEI layer and can adapt to the volume fluctuations during the sodium ion deintercalation process, so that the SEI has better electrochemical stability, thereby making the battery have a lower initial impedance and avoiding the occurrence of interfacial side reactions during the battery cycle, effectively improving the long-term cycle stability of the battery and extending the battery life.

[0096] The inorganic SEI film generated by the second additive B and the first additive A is bridged by chemical bonds to form a gradient heterogeneous structure: the organic layer on the surface blocks the continuous decomposition of the electrolyte through the steric effect, and the inorganic layer on the bottom layer ensures rapid ion conduction. The composite interface synergistically constructed by the two not only reduces the interfacial charge transfer impedance, but more importantly, by inhibiting the continuous decomposition of the electrolyte and the disordered growth of sodium dendrites, the electrode / electrolyte interface remains dynamically stable during long-term cycles, significantly improving the durability of the battery.

[0097] Secondly, through multi-dimensional structural control of the negative electrode material system, the three core parameters of the cumulative particle size distribution D50 of the negative electrode material in the battery, the compaction density of the negative electrode sheet in the battery and the particle size uniformity (PDI) of the negative electrode material are systematically optimized to achieve precise coordination of the electrode microstructure / electrolyte interface characteristics.

[0098] By regulating the cumulative particle size distribution D50 of the negative electrode material, the overall regulation of the particle size distribution is reflected. When D50 is large, large-sized particles dominate the negative electrode material. They serve as a mechanical support skeleton to maintain the overall structural integrity of the electrode during the charge and discharge process. They have high mechanical strength and small volume expansion during charge and discharge, which can slow down the breakage of particles and electrode pulverization. At the same time, large-sized particles mean a lower specific surface area. The lower specific surface area reduces its contact with the electrolyte and reduces the side reactions between the electrode and the electrolyte. However, the sodium ion transmission distance inside the large particles increases, which will lead to a decrease in battery capacity and limited energy density. In addition, the solid phase diffusion distance inside the particles is long and the resistance is large, which makes it easy for sodium to precipitate. When D50 is small, small-sized particles in the negative electrode material are dominant. In particular, when submicron particles are used, the skeleton gaps can be filled to form nanoscale pore channels. The short-range ion diffusion path improves the fast charging capability and the volume capacity density. At the same time, this pore structure improves the electrolyte wetting efficiency, increases the contact area between the active material and the electrolyte, and provides orientation guidance for the growth of the SEI film derived from the additive. However, the high specific surface area brought about by the small D50 leads to accelerated decomposition of the electrolyte, and may also cause the thickening of the SEI film, increase the internal resistance, and make the negative electrode slurry particles easy to agglomerate and difficult to disperse, resulting in poor adhesion between the negative electrode active material particles and the negative electrode current collector and the negative electrode particles. At this time, the irreversible capacity loss increases and the cycle life decreases. Therefore, the present invention controls the cumulative particle size distribution D50 of the negative electrode material within a certain range, which not only ensures sufficient energy density and sufficient mechanical strength, but also ensures the capacity maintenance of the active particles during the cycle, improves the battery cycle capacity retention rate, and further extends the cycle life of the battery.

[0099] By precisely controlling the compaction density within a certain range, an optimal balance is established between the connectivity of the conductive network and the kinetics of ion transport. Moderate compression forms a densely packed structure, ensuring both rapid electron migration between the negative electrode active material coating layers and maintaining electrolyte permeation channels by retaining sufficient pores. Moderate compression transforms the active particles from loose point contact to surface contact, reducing interfacial contact resistance. Moderate compaction stress causes the coating layer to extend and form a continuous conductive network, effectively suppressing coating layer rupture caused by volume expansion during cycling and preventing debonding between the active material and the current collector. The densified structure reduces surface roughness, reduces the probability of electron tunneling, reduces side reactions, and reduces gas production, thereby improving the battery's cycle performance and extending its life.

[0100] When the compaction density is low, the formation of a higher porosity promotes full penetration of the electrolyte, ensures the effective diffusion of sodium ions inside the electrode, reduces concentration polarization, improves high-rate performance, and partially buffers the volume expansion caused by the insertion / extraction of sodium ions, reduces mechanical stress accumulation, and delays particle rupture. However, the higher porosity brings a discontinuous electron conduction path, the contact area between particles is small (mainly point contact), electron migration relies on the tunneling effect, the battery impedance increases, resulting in a decrease in capacity utilization, poor structural stability, and the particles are prone to migration and recombination during the cycle, the pore tortuosity increases, and the capacity decay is accelerated. At the same time, the rough surface induces repeated rupture and regeneration of the SEI film, and the electrolyte consumption rate increases, which is not conducive to the cycle performance.

[0101] When the compaction density is high, an efficient electron transmission network is formed, the surface contact ratio between particles is increased, the electron conductivity is further improved, the interface resistance is reduced, the rate performance is improved, the gas production of side reactions is reduced, and the cycle safety is improved; but too low a porosity drop leads to a decrease in the ion diffusion coefficient, aggravated concentration polarization, and dendrite growth; the rigid structure cannot buffer the volume strain, the stress between particles is large, the particles are prone to rupture, and the risk of stratification between the active layer and the current collector is increased, which is not conducive to long-cycle performance.

[0102] The PDI value is a core structural parameter influencing the cycling performance of sodium-ion batteries by regulating the homogeneity of current distribution, the evolution of the SEI film, and the path of mechanical stress dissipation. A moderate PDI value allows for moderate variations in particle size, avoiding the stringent process requirements of absolute uniformity in low-PDI systems. It also balances current distribution through a composite structure of "large particle skeleton + small and medium particle filling," resulting in a suitable local current density gradient. A moderate particle size distribution guides sodium ion intercalation and deintercalation through gradient pores, resulting in a more uniform SEI film with suitable structural strength and toughness, reducing side reactions, avoiding structural collapse, and extending cycle life.

[0103] When the PDI value is low, due to the high uniformity of particle size, the local current density gradient is eliminated, the difference in electrochemical activity between particles is reduced, and the consistency of particle surface curvature increases, prompting the additive molecules to form a lattice-matched SEI film through the epitaxial growth mechanism, and the film thickness fluctuation range is lower, but the overly uniform pore structure may limit the electrolyte penetration at high rates. Although the pore tortuosity is optimized, the overall electrolyte reserve is reduced, and the problem of local dry areas may occur during long cycles; when the PDI value is high, due to the presence of particles of different sizes, large particles form a mechanical support skeleton, the cyclic stress dispersion efficiency is improved, and small particles fill Pores form a mesoporous network, shortening the electrolyte wetting time and improving rate performance. However, when the PDI is high, the SEI film evolves non-uniformly. The high-curvature surface of small particles induces an excessively thick SEI, and the film layer in the flat area of ​​large particles is discontinuous, which increases side reactions and increases the interface impedance. This is because during battery cycling, the sodium ion embedding reaction in the early stage of the charging process mainly occurs on particles with low embedding resistance of the three-dimensional active electrode material, that is, small-sized negative electrode particles with large specific surface area and short ion migration distance. As charging continues, the embedding resistance of small-sized negative electrode particles begins to increase, and large-sized negative electrode particles also begin to undergo sodium ion embedding reactions. This difference in the timing of sodium ion embedding due to uneven particle size will result in a lower potential of the particles that embed sodium first, making it easy for sodium precipitation to occur and the capacity to decay rapidly. The active material is easy to fall off, which is not conducive to extending battery life.

[0104] The synergistic effects of these factors create a multi-level protective architecture for the electrode system: macroscopic mechanical stability, mesoscopic ion uniformity, and microscopic interface adaptation. A rational particle size distribution creates a stress-buffering framework, PDI optimization ensures spatially uniform current distribution, and compaction density control achieves a balanced solid-liquid transport system. This systematic design maximizes the functional properties of the electrolyte additive: the directionally grown gradient SEI film forms a chemical-mechanical interlocking structure with the anode particles, breaking through the lifespan bottleneck of existing sodium-ion batteries.

[0105] Thirdly, when the relationship 0.1%≤(a+b)*p / ρ≤8.75% is satisfied, the formation of the SEI film satisfies a certain relationship with the compaction density of the negative electrode sheet and the PDI value of the negative electrode material particle size uniformity. The sum of a and b in the formula reflects the complementarity of the first additive A and the second additive B, which need to synergistically construct a gradient SEI film. The total amount of a and b needs to cover the active sites on the electrode surface but not be excessive. The reduction product of the chain sulfonate additive mainly contributes to the ion transport performance of the SEI film. The inorganic phase SEI layer formed by its reduction constructs a three-dimensional network skeleton with continuous ion transport channels. The organic-inorganic hybrid composite SEI layer formed by the second additive B with a flexible cyclic carbonate structure increases the toughness of the composite SEI layer, can adapt to volume fluctuations during the sodium ion insertion and extraction process, and makes the SEI have better electrochemical stability, avoids the occurrence of interfacial side reactions during battery cycling, effectively improves the long-term cycle stability of the battery, and extends the battery life. The two functions complement each other and are indispensable. The ratio of p to ρ indicates the surface defect density under unit compaction density, which further reflects the distribution efficiency of the additive in a confined space. When the PDI value of the negative electrode material particle size uniformity and the negative electrode sheet compaction density ρ are in a certain proportional relationship, sufficient ion channels can be guaranteed, and the active particles are more uniform and the structure is more stable. Any aspect that is too low or too high has a huge impact on battery performance. When the ratio of p to ρ is too high, the compaction density is low, there are many surface defects and the structure is loose, the particle size is dispersed, the size distribution range is wide, the surface active site density varies greatly, the contact between particles is poor, the impedance increases, and the loose structure allows the electrolyte to penetrate deep into the electrode. The number of active sites for side reactions increases. When the ratio of p to ρ is too low, the electrode surface is smooth and has few defects, but the compaction density is high and the particles are too dense, so the electrolyte can only wet the surface layer, the sodium ion diffusion coefficient decreases, and the selective adsorption of additives is inhibited. Both situations are detrimental to the battery's cycling performance. Furthermore, by multiplying the sum of a and b by the ratio of P to ρ, the relationship between the amount of electrolyte additive and the electrode surface structure parameters is further optimized. For example, when the ratio of p to ρ is too high, the compaction density is low, particles of different sizes exist, and the structure is loose. In this case, the amount of electrolyte should be reduced to avoid the increase in side reactions caused by excessive electrolyte. When the ratio of p to ρ is too low, the electrode surface is smooth and has few defects, but the compaction density is high and the particles are too dense. In this case, the amount of additive should be increased to enhance the wetting of the electrolyte additive on the electrode surface. By balancing the electrolyte dosage and the physical parameters of the interface under this formula relationship, a synergistic optimization mechanism of the electrode / electrolyte interface dynamics and structural stability is established, which avoids the occurrence of interfacial side reactions during the battery cycle, reduces impedance, and further effectively improves the long-term cycle stability of the battery and extends the battery life.

[0106] As a further solution, the amounts of the first additive A and the second additive B in the electrolyte meet the following conditions: 0.3%≤(a+b)*p / ρ≤5.5%, 0.01%≤a≤2.5%, 0.05%≤b≤3%, 2μm≤d≤8μm, 0.25≤p≤1, 0.85g / cm 3 ≤ρ≤1.15g / cm 3 When the above conditions are met, the capacity retention rate is ≥81% after 5000 cycles at 25℃ and ≥85% after 3000 cycles at 45℃.

[0107] As a further preferred embodiment, R2 in the first additive A is selected from one of a halogen atom, a C1-C3 halogenated hydrocarbon group or a C1-C3 halogenated hydrocarbonoxy group, and R1 is selected from one of a C1-C3 halogenated hydrocarbon group, a C1-C3 halogenated acyl group, a halogenated sulfonyl group, a non-halogenated silane group, and an alkali metal atom.

[0108] As a further preferred embodiment, in the first additive A, R2 is selected from a halogen atom, a C1 halogenated hydrocarbon group or a C1 halogenated hydrocarbonoxy group, and R1 is selected from a C1 halogenated hydrocarbon group or an alkali metal atom.

[0109] As a further preferred embodiment, in the first additive A, as an even further preferred embodiment, the first additive A is selected from one or more of compound A1 to compound A25;

[0110]

[0111] As a further solution, the first additive A is one or more of A1, A2, A6, A7, A11, and A12.

[0112] As a further preferred embodiment, the first additive A is compound A1.

[0113] As a further preferred solution, the second additive B is selected from One of the

[0114] As a further preferred solution, the second additive B is selected from and R7 is selected from a halogen atom, a C1-C3 haloalkyl group, a C2-C3 halogenated or non-halogenated alkenyl group;

[0115] As a further preferred solution, the second additive B is selected from and R7 is one of a halogen atom and a C2-C3 non-halogenated alkenyl group;

[0116] The second additive B is selected from one or more of compounds B1 to B5:

[0117]

[0118] As a further preferred solution, the second additive B is B1.

[0119] As a further solution, the electrolyte additive further includes 1,3-propane sultone.

[0120] As a further solution, a long cycle life sodium ion battery electrolyte also includes sodium salt and an organic solvent.

[0121] As a further embodiment, the sodium salt is one or more of sodium hexafluorophosphate, sodium perchlorate, sodium bis(fluorosulfonyl)imide, sodium bis(trifluoromethylsulfonyl)imide, sodium tetrafluoroborate, sodium difluorooxalatoborate, sodium bis(oxalatoborate), sodium difluorophosphate, sodium nitrate, sodium hexafluoroantimonate, sodium hexafluoroarsenate, sodium difluorobis(oxalatophosphate), and sodium tetrafluorooxalatophosphate.

[0122] As a further embodiment, the sodium salt is sodium hexafluorophosphate.

[0123] As a further preferred solution, the mass percentage of the sodium salt in the electrolyte is 5% to 20%.

[0124] As a further preferred solution, the mass percentage of the sodium salt in the electrolyte is 7.5% to 15%.

[0125] As a further preferred solution, the mass percentage of the sodium salt in the electrolyte is 13.5%.

[0126] The organic solvent includes one or more of a cyclic carbonate solvent, a chain carbonate solvent, a carboxylate solvent, a phosphate solvent, an ether solvent, and an ionic liquid.

[0127] As a further embodiment, the ether solvent is selected from one or more of ether solvents containing hydroxyl groups, ether solvents containing a single ether bond, and ether solvents containing complex functional groups.

[0128] As a further embodiment, the complex functional group is selected from one or more of C1-C10 alkoxy, alkenyl, and alkynyl groups.

[0129] As a further solution, the hydroxyl-containing ether solvent is selected from one or more of dipropylene glycol butyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol monomethyl ether, triethylene glycol monomethyl ether, and tetraethylene glycol dimethyl ether.

[0130] As a further solution, the ether solvent containing a single ether bond is selected from one or more of cyclopentyl methyl ether, ethyl ether, and propyl ether.

[0131] As a further solution, the ether solvent containing complex functional groups is selected from one or more of butynediol dipropoxy ether, propargyl ether, and propargyl ether.

[0132] As a further embodiment, the chain carbonate solvent is selected from one of dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, and ethyl propyl carbonate;

[0133] As a further embodiment, the carboxylate solvent is selected from one or more of methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, methyl isobutyrate, ethyl butyrate, methyl trimethylacetate and ethyl trimethylacetate.

[0134] As a further embodiment, the cyclic carbonate solvent is selected from one or more of ethylene carbonate, butylene carbonate, propylene carbonate, and pentyl carbonate.

[0135] As a further embodiment, the phosphate solvent includes at least one of trimethyl phosphate, triethyl phosphate, tripropyl phosphate, triphenyl phosphate, tris(2,2,2-trifluoroethyl)phosphite and ethoxy(pentafluoro)cyclotriphosphazene.

[0136] The present invention also provides a long-cycle-life sodium-ion battery, comprising the long-cycle-life sodium-ion battery electrolyte, a positive electrode sheet, a negative electrode sheet and a separator.

[0137] As a further solution, the positive electrode sheet is an aluminum foil sheet coated with a positive electrode active material, and the negative electrode sheet is a copper foil sheet or an aluminum foil sheet coated with a negative electrode active material;

[0138] As a further solution, the positive electrode active material is one of sodium vanadium phosphate, sodium iron phosphate, sodium vanadium fluorophosphate, and a metal layered oxide containing manganese.

[0139] Preferably, the positive electrode active material is a metal layered oxide containing manganese, and the general formula of the metal layered oxide containing manganese is Na x Mn y M zO₂, where 0.95 < x ≤ 1.05, 0.01 ≤ y ≤ 0.6, y + z = 1, and M represents a transition metal element with unfilled d electron orbitals, specifically including one or more of scandium (Sc), yttrium (Y), lanthanide elements (from lanthanum (La) to lutetium (Lu)), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), copper (Cu), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), and mercury (Hg).

[0140] As a further solution, M in the positive electrode active material containing manganese element includes at least one of Ni, Fe, and Cu.

[0141] The negative electrode active material is selected from at least one of soft carbon, hard carbon, expanded graphite, phosphorus-carbon composite material, and expanded graphite / hard carbon composite material.

[0142] Preferably, the negative electrode active material is hard carbon or phosphorus-carbon composite material.

[0143] As a further solution, when the positive electrode active material is coated with an aluminum foil sheet or the negative electrode active material is coated with a copper foil sheet or an aluminum foil sheet, a binder and a conductive agent are also used;

[0144] As an even further solution, the binder is an oil-based binder, and the binder includes at least one of thermoplastic resin, acrylic resin, sodium carboxymethyl cellulose, and styrene-butadiene rubber.

[0145] As a further solution, the thermoplastic resin includes at least one of polyvinylidene fluoride, copolymer of vinylidene fluoride, polytetrafluoroethylene, copolymer of vinylidene fluoride - hexafluoropropylene, copolymer of tetrafluoroethylene - hexafluoropropylene, copolymer of tetrafluoroethylene - perfluoroalkyl vinyl ether, copolymer of ethylene - tetrafluoroethylene, copolymer of vinylidene fluoride - tetrafluoroethylene, copolymer of vinylidene fluoride - trifluoroethylene, copolymer of vinylidene fluoride - trichloroethylene, copolymer of vinylidene fluoride - fluoroethylene, copolymer of vinylidene fluoride - hexafluoropropylene - tetrafluoroethylene, thermoplastic polyimide, polyethylene, and polypropylene.

[0146] As a further solution, the acrylic resin includes at least one of acrylic vinyl ester resin, acrylic methyl ester resin, acrylic butyl ester resin, acrylic styrene resin, acrylic ester resin, acrylic ester copolymer resin, acrylic resin, and acrylic emulsion resin.

[0147] As a further solution, the binder is one or more of polyvinylidene fluoride (PVDF), styrene butadiene rubber (SBR), and sodium carboxymethyl cellulose (CMC).

[0148] As a further solution, the conductive agent includes one or more of conductive carbon black, conductive carbon balls, conductive graphite, carbon nanotubes, conductive carbon fibers, graphene and reduced graphene oxide;

[0149] As a further preferred solution, the conductive agent is one or more of conductive carbon black (Super P) and carbon nanotubes (CNTs).

[0150] As a further solution, the preparation of the wide temperature range sodium ion battery includes the following steps:

[0151] S1: The electrolyte solvent is fully mixed according to the target stoichiometric ratio, and then the sodium salt is dissolved in the mixed solvent according to the target stoichiometric ratio, and the target stoichiometric ratio of fluoroethylene carbonate, the first additive A, and the second additive B are added and stirred to obtain an electrolyte.

[0152] S2: dissolving the positive electrode active material, conductive agent and binder in the solvent N-methyl-2-pyrrolidone (NMP) according to the target stoichiometric ratio, stirring evenly to obtain positive electrode slurry, and then evenly coating the obtained positive electrode slurry on aluminum foil, drying, cold pressing and cutting to obtain positive electrode sheets.

[0153] S3: Mix the negative electrode active material, conductive agent, and binder according to the target metering ratio, add deionized water and stir evenly to obtain the negative electrode slurry, and then coat it on aluminum foil or copper foil, and then dry, cold press, and cut to obtain the negative electrode sheet.

[0154] S4: The positive electrode sheet, the negative electrode sheet, and the separator are formed into a battery through a winding process or a lamination process.

[0155] As a specific embodiment of the present invention, the following detailed cases are provided:

[0156] Example 1:

[0157] This embodiment provides a sodium ion battery with a long cycle life, wherein the sodium ion battery includes a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte.

[0158] The positive electrode sheet includes a positive electrode active material NaCu 1 / 20 Ni 6 / 20 Fe 6 / 20 Mn 7 / 20 O2, conductive carbon black Super-P, conductive agent CNT, binder polyvinylidene fluoride (PVDF) and aluminum foil;

[0159] The negative electrode sheet comprises a negative electrode active material hard carbon, conductive carbon black Super-P, a binder styrene-butadiene rubber (SBR), carboxymethyl cellulose (CMC) and an aluminum foil;

[0160] Preparation of the electrolyte: In an argon atmosphere, with the environmental indicators of the glove box being H2O≤0.5ppm and O2≤0.5ppm, first, solvents propylene carbonate (PC), diethyl carbonate (DEC), and ethyl methyl carbonate (EMC) are mixed in a mass ratio of 1:1:1, then sodium salt NaPF6 is dissolved in the mixed solvent, and then 1,3-propane sultone, a first additive A compound A1, and a second additive B compound B1 are added and stirred uniformly to obtain an electrolyte; based on the total mass of the electrolyte, the mass percentage of sodium salt NaPF6 is 13.5%, the mass percentage of the first additive A1 is 0.01%, and the mass percentage of the second additive B1 is 1%. The mass percentage of 1,3-propane sultone is 1%;

[0161] Preparation of the positive electrode sheet: the positive electrode active material NaCu 1 / 20 Ni 6 / 20 Fe 6 / 20 Mn 7 / 20 O2, conductive agent SuperP, conductive agent CNT, and binder PVDF are dissolved in solvent N-methyl-2-pyrrolidone (NMP) in a mass ratio of 96.5:1.5:0.5:1.5, and stirred evenly to obtain a positive electrode slurry with a slurry viscosity of 5000±1000mPa·s and a solid content of 65±0.5wt%. The obtained positive electrode slurry is then evenly coated on aluminum foil, and then dried, cold pressed, and cut to obtain positive electrode sheets;

[0162] Preparation of the negative electrode sheet: The negative electrode active material hard carbon, the conductive agent Super P, the binder CMC, and the binder SBR are mixed in a mass ratio of 94:2:1.5:2.5, and deionized water is added and stirred evenly to obtain a negative electrode slurry. The slurry viscosity is adjusted to 4500±500mPa·s and the solid content is 50±0.5wt%; then the slurry is coated on the negative electrode current collector aluminum foil, and then dried, cold pressed, and cut to obtain the negative electrode sheet. The cumulative particle size distribution D50 value d of the negative electrode material is controlled to be 4μm, and the compaction density of the negative electrode sheet is 1g / cm 3 , the PDI value of the particle size uniformity of the negative electrode material is 1.

[0163] Preparation of the sodium ion battery: The positive electrode sheet, the negative electrode sheet, and the separator are formed into an electrode assembly through a winding process or a lamination process. This embodiment adopts the winding process.

[0164] The outer packaging of the sodium ion battery can be a bag-type soft package or an aluminum shell, steel shell, etc. The shape of the sodium ion battery is not limited and can be cylindrical, square or any other shape. This embodiment uses a cylindrical aluminum shell.

[0165] Under the above conditions, the following tests were performed:

[0166] (1) Normal temperature cycle test: At room temperature (25°C), charge and discharge at 1C, perform charge and discharge cycles, and record the capacity retention rate after 5000 cycles.

[0167] (2) High temperature cycle test: At a high temperature of 45°C, charge and discharge at 1C, perform charge and discharge cycles, and record the capacity retention rate after 3000 cycles.

[0168] Examples 2 to 25, Comparative Examples 1 to 13:

[0169] A sodium ion battery was prepared and tested in the same manner as in Example 1, with some parameters modified. The parameter modifications and results are listed in Table 1.

[0170] The test results obtained in Examples 2 to 25 and Comparative Examples 1 to 13 are shown in Table 1:

[0171] Table 1

[0172]

[0173]

[0174] From Examples 1 to 25 and Comparative Examples 1 to 13, it can be observed that:

[0175] When 0.01%≤a≤2.5%, 0.05%≤b≤3%, 2μm≤d≤8μm, 0.25≤p≤3, 0.85g / cm 3 ≤ρ≤1.15g / cm 3 , and when the formula relationship of 0.1%≤(a+b)*p / ρ≤8.75% is satisfied, the battery has a capacity retention rate of ≥78% after 5000 cycles at 25°C 1C, and a capacity retention rate of ≥80% after 3000 cycles at 45°C 1C, which is significantly better than that of the embodiment. The above data proves that when the respective dosages and physical parameters of the negative electrode materials are within a certain range and a certain formula relationship is satisfied, better cycle performance of the sodium ion battery at high temperature and room temperature is obtained, and the battery service life is significantly extended.

[0176] Comparative Examples 1 to 7, 10 to 13 show that when 0.01%≤a≤2.5%, 0.05%≤b≤3%, 2μm≤d≤8μm, 0.25≤p≤3, 0.85g / cm 3≤ρ≤1.15g / cm 3 The relevant performance when the parameters are adjusted cannot guarantee the cycle performance requirements of sodium ion batteries.

[0177] Specifically, Comparative Examples 1-2 and Comparative Example 4 show the cases of no additives, only the second additive B, and only the first additive A, respectively. In these cases, the capacity retention rates under both high-temperature and room-temperature cycling are low. The first additive A and the second additive B play a key role in the formation and stabilization of the organic / inorganic composite cross-linked polymer-rich passivation layer, balancing ionic conductivity, and establishing continuous ion transport channels. Both are essential. The absence of either additive leads to an unstable SEI film, hindering the construction of a dense, complete S-rich interfacial film and reducing the battery's cycle life. The addition of a first additive A with a sulfonic acid group as the central group has excellent film-forming properties, surpassing those of general solvents and additives. It can form a negative electrode interface film rich in sulfur-containing inorganic components on the negative electrode surface, either by itself or in combination with sodium salt cations. The increase in inorganic components in the interface film is conducive to improving electrochemical stability, and the sulfur-containing inorganic components have advantages in the transport of sodium ions. Cyclic carbonate additives can reduce and decompose on the negative electrode surface to form organic components containing ester groups in the SEI, reducing the electron permeability of the SEI film while increasing its toughness, giving the SEI good electrochemical and mechanical stability. The film-forming area of ​​the cyclic carbonate additive acts simultaneously with the first additive A, resulting in an interlaced stacking of inorganic and organic components in the negative electrode interface film, improving stability while also achieving low impedance properties. If any of the electrolyte additives is lacking in the electrolyte, it will be difficult to improve the electrochemical and mechanical stability of the negative electrode interface film.

[0178] Comparative Examples 3 and 5 illustrate the use of an excess of either the first additive A or the second additive B. Excessive amounts of the first additive A can cause the film-forming additive to undergo a redox potential reaction earlier than the solvent, leading to a more reactive reaction in subsequent battery cycles and consumption of active sodium, resulting in capacity decay. Excessive amounts of the second additive B can also lead to excessive impedance in the protective film, hindering kinetic transport across the interfacial film.

[0179] Comparative Examples 6 and 7 show the situation when the cumulative particle size distribution D50 value of the negative electrode material particles in the battery is too low or too high. When the particle size D50 of the negative electrode active material is too large, there are few channels for sodium ions to be embedded in the negative electrode, and the solid-phase diffusion distance inside the particles is long and the resistance is large, which makes it easy for sodium to precipitate. There is a risk of sodium dendrites continuing to grow and piercing the diaphragm. The precipitated metallic sodium reacts violently with the electrolyte, resulting in continuous loss of active sodium, reduced cycle performance, and shortened battery life; when the particle size is too small, the negative electrode slurry particles are easy to agglomerate and difficult to disperse, resulting in poor adhesion between the negative electrode active material particles and the negative electrode current collector and the negative electrode particles, reduced solid-phase diffusion coefficient and electronic conductivity, and increased internal resistance of the sodium ion battery, which is not conducive to the cycle stability of the battery.

[0180] Comparative Examples 10 and 11 show the cases where the compaction density of the negative electrode is too low or too high:

[0181] When the compaction density is too low, the formation of a higher porosity promotes full penetration of the electrolyte, ensures the effective diffusion of sodium ions inside the electrode, reduces concentration polarization, improves high-rate performance, and partially buffers the volume expansion caused by the insertion / extraction of sodium ions, reduces mechanical stress accumulation, and delays particle rupture. However, the higher porosity brings a discontinuous electron conduction path, the contact area between particles is small (mainly point contact), electron migration relies on the tunneling effect, the battery impedance increases, resulting in a decrease in capacity utilization, poor structural stability, and the particles are prone to migration and recombination during the cycle, the pore tortuosity increases, and the capacity decay is accelerated. At the same time, the rough surface induces repeated rupture and regeneration of the SEI film, and the electrolyte consumption rate increases, which is not conducive to cycle performance.

[0182] When the compaction density is high, an efficient electron transmission network is formed, the surface contact ratio between particles is increased, the electron conductivity is further improved, the interface resistance is reduced, and the rate performance is improved; the dense structure reduces the contact area between the active material and the electrolyte, the gas production of the side reaction is reduced, and the cycle safety is improved; but the porosity is too low, resulting in a decrease in the ion diffusion coefficient, aggravated concentration polarization, and induction of dendrite growth; the rigid structure cannot buffer the volume strain, the stress between the particles is large, the particles are prone to rupture, and the risk of stratification between the active layer and the current collector is increased, which is not conducive to long-cycle performance.

[0183] Comparative Example 12 shows the situation when the PDI of the electrode active material is too high. Due to the presence of particles of different sizes, large particles form a mechanical support skeleton, the cyclic stress dispersion efficiency is improved, small particles fill the pores, form a mesoporous network, the electrolyte wetting time is shortened, and the rate performance is improved. However, when the PDI is high, the SEI film evolves non-uniformly, the high-curvature surface of small particles induces the SEI to be too thick, the film layer in the flat area of ​​large particles is discontinuous, the side reactions increase, the interfacial impedance increases, the capacity decays in a diving manner, the active material is easy to fall off, which is not conducive to extending the battery life.

[0184] In particular, in Comparative Examples 8 and 9, the single parameters all satisfy 0.01%≤a≤2.5%, 0.05%≤b≤3%, 2um≤d≤8um, 0.25≤p≤3, 0.85g / cm 3 ≤ρ≤1.15g / cm 3 However, when the relationship of 0.1%≤(a+b)*p / ρ≤8.75% is not satisfied, the results are also poor. This shows that when each condition is met individually, if 0.1%≤(a+b)*p / ρ≤8.75% is not satisfied, the performance requirements are still not met. The relationship between the amount of electrolyte additives used and the electrode surface structural parameters cannot meet the cycle performance requirements. This may be related to the failure to achieve a balance between the distribution of active sites on the electrode surface and the penetration of the electrolyte. The different surface defect densities under unit compaction density lead to uneven distribution of additives in the confined space, which in turn affects the cycle performance of the battery.

[0185] Comparing Examples 1 to 8, 21, 24, 25 with Examples 9, 20, 22, 23, when 0.3% ≤ (a + b) * p / ρ ≤ 5.5%, and 0.01% ≤ a ≤ 2.5%, 0.05% ≤ b ≤ 3%, 2 μm ≤ d ≤ 8 μm, 0.25 ≤ p ≤ 1, 0.85 g / cm 3 ≤ρ≤1.15g / cm 3 When cycling at 25°C / 1C for 5000 cycles, the capacity retention rate is ≥81%, and when cycling at 45°C / 1C for 3000 cycles, the capacity retention rate is ≥85%. This shows that further optimizing the range of the (a+b)*p / ρ formula and the range of a single parameter can balance the relationship between the electrode surface microstructure and the electrolyte, further optimize the interface reaction, ion transport capacity, and structural strength, reduce the increase in battery impedance, and achieve better cycle performance.

[0186] According to Examples 2, 10, 14, 15, and 16, when compared with Examples 11 to 13, when R1 in the first additive M1 is selected from one of a fluorocarbon group or an alkali metal atom, the performance is better. This is because, compared with silane, sulfonyl fluoride, and acetyl fluoride groups, the alkali metal atom in R1 can provide more sodium to the electrolyte system, forming a pre-embedded ion transport channel in the SEI film, reducing the desolvation energy of sodium ions, significantly improving the ion diffusion rate, directly compensating for the active sodium consumption in forming the SEI film, reducing sodium loss, and improving the cycle performance; and the short-chain fluorocarbon group has a highly electronegative fluorine atom and a significant dipole moment, making it easier for it to be strongly adsorbed and oriented on the charged negative electrode surface. This ordered arrangement provides favorable sites for subsequent reduction reactions and promotes the formation of a more uniform and dense SEI film local structure. The strong polarity of the C-F bond can effectively weaken the interaction between the solvated sodium ions and the solvent molecules. The dense SEI blocks the continuous decomposition of the electrolyte and prolongs the battery life.

[0187] According to the comparison between Example 2 and Examples 17, 18, and 19, when the second additive B is When R7 is a halogen or non-halogenated alkenyl of C2, the cycle performance is better. This may be because the halogen in R7 usually undergoes reduction and decomposition at a lower potential. After reduction on the negative electrode surface, they will contribute F - Or organic fluoride fragments, participate in the formation of the SEI film. The alkenyl π bond captures free radicals generated by the decomposition of the electrolyte, blocking the chain reaction, reducing HF generation, and reducing interfacial side reactions. At the same time, its double bond can polarize the electric field, optimize the film-forming properties of the electrode surface, and further extend the cycle life of the battery.

[0188] According to the sodium ion battery provided by the present invention, the particle size distribution D50 and particle distribution uniformity PDI of the negative electrode material particles are controlled within a specific range, and a first additive and a second additive are added to the electrolyte to jointly participate in the passivation reaction on the negative electrode surface. When the cumulative particle size distribution percentage D50 value d of the negative electrode material particles, the negative electrode particle size distribution uniformity p, the mass percentage a of the first additive in the non-aqueous electrolyte, and the mass percentage b of the second additive in the non-aqueous electrolyte meet the following conditions: 0.01%≤a≤2.5%, 0.05%≤b≤3%, 2μm≤d≤8μm, 0.25≤p≤3, 0.85g / cm 3 ≤ρ≤1.15g / cm 3 , and when 0.1%≤(a+b)*p / ρ≤8.75%, the obtained sodium ion battery not only has a low initial impedance, but also has a low impedance growth during the cycle, showing excellent long-cycle performance. On a negative electrode with a certain particle size, it has good film-forming performance. After the first additive is reduced, the SEI on the negative electrode surface is rich in sulfur-containing inorganic components such as sodium sulfide, sodium sulfate, and sodium sulfite, which increases its Na ion conductivity, thereby lowering the initial impedance of the battery. At the same time, the cyclic carbonate second additive can form an SEI film rich in alkyl sodium carbonate on the negative electrode surface, reducing the electron permeability of the SEI film while increasing its toughness, making the SEI have better electrochemical stability, showing a synergistic enhancement effect, so that the battery has a low initial impedance, and avoids the occurrence of interfacial side reactions during the battery cycle, effectively improving the long-term cycle stability of the battery.

[0189] This technical solution systematically optimizes the combination and ratio of electrolyte additives in the electrolyte, the cumulative particle size distribution D50 value of the negative electrode material in the battery, the compaction density of the negative electrode sheet in the battery, the particle size uniformity PDI value of the negative electrode material, and combines multi-parameter and multi-dimensional formula relationships to establish a synergistic optimization mechanism for the electrode / electrolyte interface dynamics and structural stability, which significantly improves the cycle stability of sodium-ion batteries at room temperature and high temperature, helps to build a stable interface film, and enhances the interaction between the overall active particles and the binder. They work together to effectively prevent the structural collapse, active particle breakage, and excessive side reactions of the active particles during the cycle, thereby improving the cycle performance of the battery at room temperature and high temperature and significantly extending the battery life.

[0190] It should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A sodium ion battery electrolyte with a long cycle life, characterized in that including electrolyte additives; The electrolyte additives include a first additive A and a second additive B; The first additive A is selected from one or more compounds having a chain sulfonyloxy structure and has the following structure: wherein R1 is selected from an alkali metal atom, a C1-C6 halogenated or non-halogenated hydrocarbon group, a C1-C6 halogenated or non-halogenated acyl group, a halogenated or non-halogenated sulfonyl group, or a halogenated or non-halogenated silyl group; R2 is selected from a halogen atom, a C1-C6 halogenated or non-halogenated hydrocarbon group, a C1-C6 halogenated or non-halogenated hydrocarbonoxy group, a C2-C6 halogenated or non-halogenated ester group (R3COO—), or a C1-C6 halogenated or non-halogenated sulfonic acid group (R4SO3—); R3 is selected from one of C1 to C5 halogen atoms, halogenated or non-halogenated hydrocarbon groups, and R4 is selected from one of C1 to C6 halogen atoms, halogenated or non-halogenated hydrocarbon groups; The second additive B is selected from one or more cyclic carbonate compounds having halogenation and / or containing unsaturated double bonds, and has the following structure: wherein R5 and R6 are each independently selected from one of a methylene group (-CH2), a methine group (-CH=), and C; R7 and R8 are each independently selected from one of a hydrogen atom, a halogen atom, a C1-C3 halogenated or non-halogenated alkyl group, a C2-C3 halogenated or non-halogenated alkenyl group, a C2-C3 halogenated or non-halogenated alkynyl group, and a C1-C3 halogenated or non-halogenated alkoxy group; a single bond or a double bond is formed between R5 and R6; and at least one of R7 and R8 is a halogenated group, and / or the second additive B contains at least one unsaturated double bond; The amounts of the first additive A and the second additive B in the electrolyte satisfy the following formula: 0.1%≤(a+b)*p / ρ≤8.75%, 0.01%≤a≤2.5%, 0.05%≤b≤3%, 2μm≤d≤8μm, 0.25≤p≤3, 0.85g / cm 3 ≤ρ≤1.15g / cm 3 , where a is the mass percentage of the first additive A in the electrolyte, b is the mass percentage of the second additive B in the electrolyte, d is the cumulative particle size distribution D50 value of the negative electrode material in the battery, ρ is the compaction density of the negative electrode sheet in the battery; and p is the particle size uniformity PDI value of the negative electrode material.

2. The long cycle life sodium ion battery electrolyte according to claim 1, characterized in that The a, b, c, and ρ also satisfy 0.3%≤(a+b)*p / ρ≤5.5%, 0.01%≤a≤2.5%, 0.05%≤b≤3%, 2μm≤d≤8μm, 0.25≤p≤1, 0.85g / cm 3 ≤ρ≤1.15g / cm 3 .

3. The long cycle life sodium ion battery electrolyte according to claim 1, characterized in that In the first additive A, R2 is selected from a halogen atom, a C1-C3 halogenated hydrocarbon group, or a C1-C3 halogenated hydrocarbonoxy group, and R1 is selected from a C1-C3 halogenated hydrocarbon group, a C1-C3 halogenated acyl group, a halogenated sulfonyl group, a non-halogenated silyl group, or an alkali metal atom; Preferably, in the first additive A, R2 is selected from a halogen atom, a C1 halogenated hydrocarbon group or a C1 halogenated hydrocarbonoxy group, and R1 is selected from one of a C1 halogenated hydrocarbon group or an alkali metal atom; Preferably, the first additive A is selected from one or more of compounds A1 to A25: Preferably, the first additive A is one or more of A1, A2, A6, A7, A11, and A12.

4. The long cycle life sodium ion battery electrolyte according to claim 1, characterized in that The second additive B is selected from One of the Preferably, the second additive B is selected from and R7 is selected from a halogen atom, a C1-C3 haloalkyl group, a C2-C3 halogenated or non-halogenated alkenyl group; Preferably, the second additive B is selected from and R7 is a halogen atom or a C2-C3 non-halogenated alkenyl group; Preferably, the second additive B is selected from one or more of compounds B1 to B5:

5. The long cycle life sodium ion battery electrolyte according to claim 1, characterized in that The electrolyte additive further includes 1,3-propane sultone.

6. The long cycle life sodium ion battery electrolyte according to claim 1, characterized in that The long cycle life sodium ion battery electrolyte also includes sodium salt and organic solvent.

7. The long cycle life sodium ion battery electrolyte according to claim 6, characterized in that The sodium salt is selected from one or more of sodium hexafluorophosphate, sodium perchlorate, sodium bis(fluorosulfonyl)imide, sodium bis(trifluoromethylsulfonyl)imide, sodium tetrafluoroborate, sodium difluorooxalatoborate, sodium bis(oxalatoborate), sodium difluorophosphate, sodium nitrate, sodium hexafluoroantimonate, sodium hexafluoroarsenate, sodium difluorobis(oxalatophosphate), and sodium tetrafluorooxalatophosphate; Preferably, the sodium salt is sodium hexafluorophosphate; Further preferably, the mass percentage of the sodium salt in the electrolyte is 5% to 20%; Further preferably, the mass percentage of the sodium salt in the electrolyte is 7.5% to 15%.

8. The long cycle life sodium ion battery electrolyte according to claim 6, characterized in that The organic solvent is selected from one or more of cyclic carbonate solvents, chain carbonate solvents, carboxylate solvents, phosphate solvents, ether solvents, and ionic liquids; Preferably, the ether solvent is selected from one or more of ether solvents containing hydroxyl groups, ether solvents containing a single ether bond, and ether solvents containing complex functional groups; Preferably, the complex functional group is selected from one or more of C1-C10 alkoxy, alkenyl, and alkynyl groups; Preferably, the hydroxyl-containing ether solvent is selected from one or more of dipropylene glycol butyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol monomethyl ether, triethylene glycol monomethyl ether, and tetraethylene glycol dimethyl ether; Preferably, the ether solvent containing a single ether bond is selected from one or more of cyclopentyl methyl ether, ethyl ether, and propyl ether; Preferably, the ether solvent containing complex functional groups is selected from one or more of butynediol dipropoxy ether, propargyl ether, and propargyl ether; Preferably, the chain carbonate solvent is selected from one or more of dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, and ethyl propyl carbonate; Preferably, the carboxylate solvent is selected from one or more of methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, methyl isobutyrate, ethyl butyrate, methyl trimethylacetate and ethyl trimethylacetate; Preferably, the cyclic carbonate solvent is selected from one or more of ethylene carbonate, butylene carbonate, propylene carbonate, and pentyl carbonate; Preferably, the phosphate solvent is selected from one or more of trimethyl phosphate, triethyl phosphate, tripropyl phosphate, triphenyl phosphate, tris(2,2,2-trifluoroethyl)phosphite and ethoxy(pentafluoro)cyclotriphosphazene.

9. A sodium ion battery with a long cycle life, characterized in that: The fast-charging sodium-ion battery electrolyte comprises the fast-charging sodium-ion battery electrolyte according to any one of claims 1 to 8, and further comprises a positive electrode sheet, a negative electrode sheet and a separator.

10. The long cycle life sodium ion battery according to claim 9, characterized in that: The positive electrode sheet is an aluminum foil sheet coated with a positive electrode active material, and the negative electrode sheet is a copper foil sheet or an aluminum foil sheet coated with a negative electrode active material; Preferably, the positive electrode active material is one of sodium vanadium phosphate, sodium iron phosphate, sodium vanadium fluorophosphate, and a metal layered oxide containing manganese; Preferably, the positive electrode active material is a metal layered oxide containing manganese element, and the general formula of the metal layered oxide containing manganese element is Na x Mn y M z O2, where 0.95 < x ≤ 1.05, 0.01 ≤ y ≤ 0.6, y + z = 1, M represents a transition metal element with an unfilled d electron orbital, specifically including scandium (Sc), yttrium (Y), lanthanide elements (from lanthanum (La) to lutetium (Lu)), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), copper (Cu), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), or one or more of them; Preferably, M in the manganese-containing positive electrode active material includes at least one of Ni, Fe, and Cu; Preferably, the negative electrode active material is selected from at least one of soft carbon, hard carbon, expanded graphite, phosphorus-carbon composite material, and expanded graphite / hard carbon composite material; Preferably, the negative electrode active material is hard carbon or a phosphorus-carbon composite material; Preferably, when the positive electrode active material is coated on an aluminum foil or the negative electrode active material is coated on an aluminum foil or a copper foil, a binder and a conductive agent are also used; Preferably, the binder is an oil-based binder, and the binder includes at least one of a thermoplastic resin, an acrylic resin, sodium carboxymethyl cellulose, and styrene butadiene rubber; Preferably, the thermoplastic resin includes at least one of polyvinylidene fluoride, a copolymer of vinylidene fluoride, polytetrafluoroethylene, a copolymer of vinylidene fluoride-hexafluoropropylene, a copolymer of tetrafluoroethylene-hexafluoropropylene, a copolymer of tetrafluoroethylene-perfluoroalkyl vinyl ether, a copolymer of ethylene-tetrafluoroethylene, a copolymer of vinylidene fluoride-tetrafluoroethylene, a copolymer of vinylidene fluoride-trifluoroethylene, a copolymer of vinylidene fluoride-trichloroethylene, a copolymer of vinylidene fluoride-fluoroethylene, a copolymer of vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene, thermoplastic polyimide, polyethylene and polypropylene; Preferably, the acrylic resin includes at least one of vinyl acrylate resin, methyl acrylate resin, butyl acrylate resin, acrylic styrene resin, acrylate resin, acrylate copolymer resin, acrylic resin, and acrylic emulsion resin; Preferably, the binder is one or more of polyvinylidene fluoride (PVDF), styrene butadiene rubber (SBR), and sodium carboxymethyl cellulose (CMC); Preferably, the conductive agent includes one or more of conductive carbon black (SuperP), conductive carbon balls, conductive graphite, carbon nanotubes (CNTs), conductive carbon fibers, graphene, and reduced graphene oxide; Preferably, the conductive agent is one or more of conductive carbon black (Super P) and carbon nanotubes (CNTs).

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