WO2023217191A1 - Current collector and sodium metal battery - Google Patents

Abstract

Disclosed in the present disclosure are a current collector and a sodium metal battery comprising the current collector. The current collector comprises a current collector substrate and a coating arranged on at least one side surface of the current collector substrate, wherein the coating comprises a carbon material embedded with sodiophilic particles, and/or the coating comprises a corrugated or serrated step coating. In the present disclosure, by coating a current collector substrate with a carbon material embedded with sodiophilic particles, the current collector is endowed with the characteristics of a low nucleation potential of sodium metal; and/or a reserved space is obtained by means of the design of a corrugated or serrated step coating, such that the huge volume change brought about for a battery cell during the deposition/dissolution performance process of the sodium metal can be improved, the structure of the battery cell is stabilized, and the cycling stability, the coulombic efficiency and the cycle life of the battery are improved.

Description

A current collector and sodium metal battery Technical field

The present disclosure belongs to the technical field of secondary ion batteries, and specifically relates to a current collector and a sodium metal battery including the current collector.

Background of the invention

At present, the energy density of sodium-ion batteries is low (40-200Wh kg ^-1 ), which limits its application scenarios. The sodium metal anode has a high theoretical capacity (1166mAh g ^-1 ) and a low reaction site (-2.73V vs. SHE), and has been proposed to build high-energy-density batteries.

Compared with sodium metal batteries, negative electrode-free sodium metal batteries are a more ideal concept. Negative-electrode-free sodium metal batteries use a current collector as the negative electrode during the assembly process. During the charging process, the sodium ions released from the positive electrode are deposited on the current collector to form a sodium metal negative electrode. Since there is no negative active material layer, the mass and volume of the battery can be greatly reduced and the energy density of the battery can be increased. However, due to the high chemical/electrochemical activity and deposition nucleation potential of metallic sodium, it is easy to react with the electrolyte and deposit unevenly, causing instability of the SEI film and growth of sodium dendrites, resulting in low Coulombic efficiency and short battery cycle life. ; In addition, since metallic sodium is directly deposited on the current collector, it will cause a great change in the cell volume, which brings great challenges to the cell structure design and hinders the practical application of negative electrode-free batteries.

Contents of the invention

In order to make up for the shortcomings of the prior art, the present disclosure provides a current collector and a sodium metal battery including the current collector. The current collector has the characteristics of low nucleation potential of metallic sodium by coating the current collector substrate with a carbon material embedded with sodium-philic particles, and/or is obtained by designing a corrugated or zigzag step coating. The reserved space can improve the huge volume changes caused by the deposition/dissolution process of metallic sodium to the battery core, stabilize the battery core structure, and improve the cycle stability, Coulombic efficiency and cycle life of the battery.

The purpose of this disclosure is achieved through the following technical solutions:

A first aspect of the present disclosure provides a current collector. The current collector includes a current collector substrate and a coating disposed on at least one side surface of the current collector substrate. The coating includes carbon embedded with sodium-philic particles. material, and/or the coating includes a corrugated or jagged step coating.

In one example, the coating includes a carbon material embedded with sodium-philic particles, and the carbon material embedded with sodium-philic particles includes carbon particles and sodium-philic particles embedded in the carbon particles.

In one example, the coating includes a corrugated or jagged step coating, and the coating path of the corrugated step coating is a water corrugated curve, a sine curve or a cosine curve, and the zigzag step coating The coating path of the coating is a polyline.

In one example, the coating includes a carbon material embedded with sodium-philic particles, the carbon material embedded with sodium-philic particles includes carbon particles and sodium-philic particles embedded in the carbon particles, and the coating The layer includes a corrugated or zigzag step coating, the coating path of the corrugated step coating is a water ripple curve, a sine curve or a cosine curve, and the coating path of the zigzag step coating is a zigzag line .

A second aspect of the disclosure provides a sodium metal battery, which includes the current collector described in the first aspect of the disclosure.

Beneficial effects of this disclosure:

The present disclosure provides a current collector used in sodium metal batteries. The current collector of the present disclosure can slow down the repeated deposition/dissolution process of metallic sodium to bring large volume changes to the battery core, stabilize the battery core structure, and improve the cycle stability of the battery. , Coulombic efficiency and cycle life.

Description of the drawings

Figure 1 is a schematic structural diagram of the current collector of the present disclosure.

Figure 2 is a top view of a current collector with a corrugated step coating of the present disclosure.

Figure 3 is a top view of a current collector with a zigzag step coating of the present disclosure.

4 is an oblique side view of a current collector with a corrugated or zigzag step coating of the present disclosure.

Figure 5 is a front view of a current collector with a corrugated or zigzag step coating of the present disclosure.

Reference signs: 1 is a carbon material embedded with sodium-philic particles; 2 is a coating including a carbon material embedded with sodium-philic particles; 3 is a current collector substrate; 4 is a step coating.

Detailed ways

<Current collector>

A first aspect of the present disclosure provides a current collector. The current collector includes a current collector substrate and a coating disposed on at least one side surface of the current collector substrate. The coating includes carbon embedded with sodium-philic particles. material, and/or the coating includes a corrugated or jagged step coating.

In one example, the coating includes a carbon material embedded with sodium-philic particles, and the carbon material embedded with sodium-philic particles includes carbon particles and sodium-philic particles embedded in the carbon particles.

In one example, the coating includes a corrugated or jagged step coating, and the coating path of the corrugated step coating is a water corrugated curve, a sine curve or a cosine curve, and the zigzag step coating The coating path of the coating is a polyline.

In one example, the coating includes a carbon material embedded with sodium-philic particles, the carbon material embedded with sodium-philic particles includes carbon particles and sodium-philic particles embedded in the carbon particles, and the coating The layer includes a corrugated or jagged step coating, and the coating path of the corrugated step coating is a water corrugated curve, a normal Chordal curve or cosine curve, the coating path of the zigzag step coating is a polyline.

<Current collector including carbon material embedded with sodium-philic particles>

According to a specific embodiment, the coating includes a carbon material embedded with sodium-philic particles. A current collector is obtained by coating a carbon material with embedded sodium-philic particles on a current collector substrate. The embedded particles in the carbon material with embedded sodium-philic particles can be used to reduce the deposition overpotential of metallic sodium and improve the deposition of metallic sodium/ The dissolution performance process brings huge volume changes to the battery core, stabilizes the battery core structure, and improves the cycle stability of the battery. During the first charge and discharge process of a sodium metal battery made from the current collector, the positive electrode sodium ions will deposit metallic sodium in situ on the current collector, thereby achieving uniform and reversible deposition/dissolution of metallic sodium and improving the Coulombic efficiency of the battery.

In one example, the carbon material embedded with sodium-philic particles includes carbon particles and sodium-philic particles embedded in the carbon particles.

In one example, the carbon particles are carbon particles with a hollow structure and/or a porous structure. Using carbon particles with a hollow structure and/or porous structure as a carrier, the hollow structure and/or porous structure can also provide space for the deposition of metallic sodium, slowing down the repeated deposition/dissolution process of metallic sodium that brings a large volume to the battery core. changes, stabilizes the cell structure, and improves the cycle stability of the battery.

In this disclosure, the hollow structure refers to a geometric structure constructed on the basis of a conventional structure, so that one or more internal cavities are generated inside the particles, and the special morphology of the shell is formed around these cavities. For example, as shown in Figure 1, the hollow structure is a single-cavity hollow structure or a multi-cavity hollow structure.

In this disclosure, the porous structure refers to a structure with regular pores or irregular pores inside. Illustratively, as shown in Figure 1, the porous structure is a regular porous structure or an irregular porous structure.

In the present disclosure, the embedding may be, for example, embedded in a hollow structure and/or porous structure, or may be embedded inside carbon particles.

In one example, the carbon particles have a porosity of 20% to 80% (eg, 20%, 30%, 40%, 50%, 60%, 70%, 80%). When the porosity of the carbon particles is limited to the above-mentioned specific range, it can be beneficial to the storage of sodium clusters and reduce the generation of sodium dendrites.

In one example, the median particle diameter D _v 50 of the carbon particles is 0.5 μm to 10 μm (eg, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm). The median particle size can be measured using a laser particle size analyzer.

In one example, the carbon particles are amorphous carbon particles.

In one example, the amorphous carbon is selected from metal-organic framework material pyrolytic carbon, resin pyrolytic carbon, organic polymer pyrolytic carbon, pyrolytic carbon black, biomass pyrolytic carbon, petroleum coke, needle coke at least one of them.

The sodium-philic particles may include metal elements and/or metal compounds.

In one example, the sodium-philic particles are selected from the group consisting of gold (Au), silver (Ag), platinum (Pt), zinc (Zn), Zinc oxide (ZnO), copper (Cu), copper oxide (CuO), tin (Sn), tin oxide (SnO), antimony (Sb), antimony oxide (Sb ₂ O ₃ , Sb ₂ O ₅ ), bismuth (Bi ), bismuth oxide (Bi ₂ O ₃ ), aluminum oxide (Al ₂ O ₃ ), and the like. The sodium-philic particles selected from the above range can effectively reduce the deposition potential of sodium, which is beneficial to the uniform deposition and reversible circulation of metallic sodium.

In one example, the median particle diameter D _v 50 of the sodium-philic particles is 2 nm to 100 nm (for example, 2 nm, 3 nm, 5 nm, 8 nm, 10 nm, 12 nm, 15 nm, 18 nm, 20 nm, 30 nm, 35 nm, 40 nm, 45 nm , 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, 85nm, 90nm, 95nm, 100nm). The median particle size can be measured using a laser particle size analyzer. When the median particle diameter of the sodium-loving particles is limited to the above-mentioned specific range, it is beneficial to obtain better processing performance and at the same time, the sodium-loving particles have a larger active surface to participate in the induction of sodium deposition, which is beneficial to Improve battery cycle performance.

In one example, based on the total weight of the carbon material embedded with the sodium-philic particles, the weight content of the sodium-philic particles is 0.5wt%-30wt% (for example, 0.5wt%, 1wt%, 2wt%, 3wt%, 5wt%, 8wt%, 10wt%, 12wt%, 15wt%, 18wt%, 20wt%, 22wt%, 24wt%, 25wt%, 26wt%, 28wt%, 30wt%). Naphilic particles are inactive components in the battery and will affect the energy density of the battery. By limiting the weight content of the sodium-philic particles in the carbon material embedded with the sodium-philic particles, it is possible to achieve better induction of metallic sodium deposition. It also reduces the energy density loss of the battery.

In one example, based on the total weight of the carbon material embedded with the sodium-philic particles, the weight content of the carbon particles is 70wt%-99.5wt% (for example, 70wt%, 72wt%, 75wt%, 78wt% , 80wt%, 82wt%, 85wt%, 88wt%, 90wt%, 92wt%, 95wt%, 96wt%, 98wt%, 99wt%, 99.5wt%).

In one example, the median particle diameter D _v 50 of the carbon material embedded with the sodium-philic particles is 0.5 μm-10 μm (for example, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9μm, 10μm). The median particle size can be measured using a laser particle size analyzer.

In one example, the coating further includes a first binder, a first conductive agent and a thickener.

In one example, based on the total weight of the coating, the weight content of the carbon material embedded with the sodium-philic particles is 75wt% to 98wt% (for example, 75wt%, 78wt%, 80wt%, 82wt%, 85wt%, 88wt%, 90wt%, 92wt%, 95wt%, 96wt%, 98wt%).

In one example, based on the total weight of the coating, the weight content of the carbon material embedded with sodium-philic particles is 85 wt% to 96 wt%.

In one example, based on the total weight of the coating, the weight content of the first binder is 0wt% to 10wt% (for example, 0wt%, 0.5wt%, 1wt%, 2wt%, 3wt% , 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%), the weight content of the first conductive agent is 0wt% ~ 15wt% (for example, 0wt%, 0.5wt%, 1wt% ,2wt%,3wt%,4wt%,5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%), the weight content of the thickener is 0wt% to 15wt% (for example, 0wt% , 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%) .

When the weight content of the first binder is 0 wt%, it means that the coating does not contain the first binder. When the weight content of the first conductive agent is 0 wt%, it means that the coating does not contain the conductive agent. When the weight content of the thickener is 0 wt%, it means that the coating does not contain the thickener.

In one example, based on the total weight of the coating, the weight content of the first binder is 2wt% ~ 8wt%, and the weight content of the first conductive agent is 2wt% ~ 10wt%, so The weight content of the thickener is 2wt% to 10wt%.

In one example, the first binder includes, but is not limited to: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), nitrile rubber (NBR), water-based acrylic One or more of resin, polyvinyl alcohol, polyvinyl butyral, polyurethane, fluorinated rubber, carboxymethyl cellulose (CMC) and polyacrylic acid (PAA).

In an example, the first conductive agent includes, but is not limited to, one or more of carbon-based materials, metal-based materials, and conductive polymers.

In one embodiment, the carbon-based material is selected from one or more of natural graphite, artificial graphite, graphene, carbon black, acetylene black, Ketjen black and carbon fiber.

In one example, the thickening agent includes, but is not limited to: sodium carboxymethylcellulose and/or lithium carboxymethylcellulose.

In one example, the thickness of the coating does not exceed 20 μm.

In one example, the thickness of the coating is 1 to 20 μm (eg, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 12 μm, 13 μm, 15 μm, 20 μm).

In one example, the thickness of the coating is 5-10 μm. When the thickness of the coating is limited to the above-mentioned specific range, the overall performance of the battery can be further improved; when the thickness of the coating is higher than 10 μm, the thickness of the coating is too thick and will affect the volumetric energy density of the battery; When the thickness of the coating is less than 5 μm, the thickness of the coating is too thin, and the coating cannot effectively induce sodium metal deposition.

In one example, the coating covers the surface of the current collector substrate by coating.

In one example, the current collector substrate includes, but is not limited to: one of copper foil, perforated copper foil, nickel foil, aluminum foil, perforated aluminum foil, stainless steel foil, titanium foil, nickel foam and copper foam, or Various.

In an example, the thickness of the current collector substrate may be 5 μm-20 μm (eg, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 12 μm, 13 μm, 15 μm, 20 μm).

In one example, a carbon material embedded with sodium-philic particles and an optional first conductive agent, a first binder, The thickener is dispersed in a solvent (such as water) to form a uniform slurry. The slurry is coated on the current collector base material, and after drying and other processes, the current collector is obtained.

<Preparation method of carbon materials embedded with sodium-philic particles>

In one example, the carbon material embedded with sodium-philic particles includes carbon particles and sodium-philic particles embedded in the carbon particles. The carbon particles are carbon particles with a hollow structure and/or a porous structure.

The carbon material embedded with sodium-philic particles can be prepared by selecting methods known in the art.

According to a specific embodiment, the carbon material embedded with sodium-philic particles can be prepared by the following method: first prepare carbon particles with a hollow structure and/or a porous structure, and then deposit the sodium-philic particles inside them.

The carbon particles with hollow structure and/or porous structure can be prepared by hard template method, soft template method and template-free method.

In the present disclosure, the hard template method uses a hard template with a fixed structure to combine with a carbon precursor and perform high-temperature carbonization in an inert gas. The hard template is then removed by chemical etching or dissolution to obtain a hollow structure. And/or porous structure, such as silicon-based template, metal oxide template, organic template, salt template method, ice template, etc.

In the present disclosure, the soft template in the soft template method refers to a type of surfactant or block copolymer that can be assembled to form a specific form in a solvent. In solvent, soft templates typically self-assemble with each other to form micelles, which are charged with the hydrophilic ends facing outward. These charged ends attract nearby carbon precursor molecules through electrostatic interactions, and then link these molecules to the soft template surface through covalent bonds, forming rigid organic micelles wrapped by the carbon precursor. During the subsequent carbonization process, the soft template decomposes or evaporates to generate pores in situ, obtaining a hollow structure and/or porous structure.

In the present disclosure, the template-free method is to pyrolyze a selected carbon precursor to obtain a carbon structure dominated by macropores. Secondly, a large number of mesopores and micropores are introduced through chemical activation or physical activation, without adding additional template agents during the process.

In one example, metal elements and/or metal compounds can be embedded into the pores of porous carbon particles through physical adsorption or chemical/electrochemical methods.

For example, the method for preparing a carbon material with a porous structure embedded with sodium-philic particles includes the following steps: using an activation method or a template method to prepare a carbon material with a porous structure, and then combining the carbon material with a porous structure with the sodium-philic particles. After ultrasonic mixing in the solution, through the effect of physical adsorption, the sodium-philic particles are adsorbed in the pore structure of the carbon material with a porous structure, and a carbon material with a porous structure embedded with the sodium-philic particles is obtained.

According to another specific embodiment, the carbon material embedded with sodium-philic particles can also be prepared by the following method: doping metal ions that form the sodium-philic particles into carbon particles that form a hollow structure and/or a porous structure. In the precursor, during the carbonization process, metal ions are reduced to metal elements and embedded Inside the carbon particles with hollow structure and/or porous structure.

In one example, the preparation method of carbon particles with hollow structure and/or porous structure includes activation method and template method; the method of depositing sodium-philic particles inside carbon particles with hollow structure and/or porous structure includes Physical adsorption, chemical deposition, electrochemical reduction, etc.

For example, the method for preparing a carbon material with a hollow structure embedded with sodium-philic particles includes the following steps: doping the metal ions that form the sodium-philic particles into a precursor for forming carbon particles with a hollow structure, and during the carbonization process , metal ions are reduced to metal elements and embedded inside carbon particles with a hollow structure.

For example, the preparation method of the carbon material with a hollow structure embedded with sodium philic particles includes the following steps: compounding the metal salt and the organic material to form a physical or chemical mixed composite, and during the carbonization process, the carbon is heated under the influence of heat. The reduction property under the conditions reduces the metal ions to metal elements, forming a carbon material with a hollow structure embedded with sodium-philic particles.

For example, the preparation method of the carbon material with a hollow structure embedded with sodium philic particles includes the following steps: preparing a metal-organic framework material, heating in an inert atmosphere, the organic ligands will be converted into carbon, and the metal ions will be reduced into metal elements, i.e., sodium-philic particles, to obtain a carbon material with a hollow structure embedded with sodium-philic particles.

<Current collector including corrugated or jagged step coating>

According to a specific implementation, the coating is a corrugated or zigzag step coating. By setting up a corrugated or jagged step coating, a reserved space is obtained on the surface of the current collector, which slows down the huge volume changes brought to the battery core by the repeated deposition/dissolution process of metallic sodium, stabilizes the battery core structure, and improves the battery performance. Cycling stability.

In the present disclosure, the corrugated or zigzag step coating is a coating with a certain thickness formed by back-and-forth coating at a certain angle with the width direction of the current collector substrate. For the specific structure, see the top view of the current collector shown in Figures 2 and 3.

In one example, the coating path of the corrugated step coating is a water corrugated curve, a sine curve or a cosine curve, and the coating path of the zigzag step coating is a polyline. By setting the coating path of the corrugated or zigzag step coating, the overall thickness of the battery core can be made uniform, avoiding the structural distortion caused by the reserved step coating, and improving the structural stability of the battery core in the reserved space. It is beneficial to further improve the electrochemical performance of negative electrode-free sodium metal batteries.

In one example, the coating path of the corrugated or zigzag step coating has periodic distribution characteristics.

In an example, the current collector satisfies: 0.05W≤L≤2W (for example, L=0.05W, 0.1W, 0.2W, 0.3W, 0.4W, 0.5W, 0.6W, 0.7W, 0.8W, 0.9 W, 1W, 1.2W, 1.5W, 1.8W or 2W); where L is the length of the cycle of the corrugated or zigzag step coating, and W is the current collection The width of the base material.

In a preferred example, the current collector satisfies: 0.2W≤L≤1W.

In one example, the current collector satisfies: W1<W; where W1 is the width of the corrugated or zigzag step coating, and W is the width of the current collector substrate. Wherein, the width W1 of the corrugated or zigzag step coating refers to the distance between the outermost edges of both transverse sides of the step coating.

In one example, the width W1 of the corrugated or zigzag step coating ≥ the width of the matched cathode paste; wherein the width of the matched cathode paste is the active material layer of the matched cathode sheet width.

In one example, the width W2 of the corrugated or zigzag step coating satisfies: 1mm≤W2≤20mm (for example, W2 is 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm , 12mm, 13mm, 15mm, 18mm, 20mm). Wherein, the width W2 of the corrugated or zigzag step coating refers to the width of the coating path of the corrugated or zigzag step coating.

The thickness H2 of the corrugated or zigzag step coating can be adjusted with the change of the surface capacity of the positive electrode sheet of the designed battery core. For example, the thickness H2 of the corrugated or zigzag step coating satisfies: 5 μm ≤ H2≤50μm (for example, H2 is 5μm, 6μm, 8μm, 10μm, 12μm, 15μm, 18μm, 20μm, 22μm, 25μm, 28μm, 30μm, 32μm, 35μm, 38μm, 40μm, 42μm, 45μm, 48μm, 50μm). The thickness of the step is to reserve a certain space for the deposition of metallic sodium. When the thickness of the step is limited to the above-mentioned specific range, high volumetric energy density can be ensured while satisfying the deposition of metallic sodium.

In one example, the material forming the corrugated or zigzag step coating includes a second binder and ceramic particles.

In one example, the mass ratio of the binder and ceramic particles is (3-7):(7-3) (for example, 3:7, 4:6, 5:5, 6:4, 7:3 ). That is, based on the total weight of the binder and ceramic particles, the weight content of the binder is 30wt%-70wt%, and the weight content of the ceramic particles is 70wt%-30wt%.

In one example, the second binder includes, but is not limited to: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), nitrile-butadiene rubber (NBR), water-based acrylic Resin, polyvinyl alcohol, polyvinyl butyral, polyurethane, fluorinated rubber, carboxymethylcellulose (CMC), polyacrylic acid (PAA).

In one example, the ceramic particles include, but are not limited to, aluminum oxide (Al ₂ O ₃ ), boehmite (γ-AlOOH), silicon dioxide (SiO ₂ ), silicon carbide (SiC), magnesium oxide (MgO) ), zirconium oxide (ZrO ₂ ).

The corrugated or zigzag step coating can be achieved by moving extrusion coating or moving spray coating.

In one example, the current collector substrate includes, but is not limited to: copper foil, perforated copper foil, nickel foil, aluminum One or more of foil, perforated aluminum foil, stainless steel foil, titanium foil, nickel foam and copper foam.

In an example, the thickness of the current collector substrate is 5 μm-20 μm (eg, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 12 μm, 13 μm, 15 μm, 20 μm).

<Sodium metal battery without negative electrode>

A second aspect of the disclosure provides a sodium metal battery. The negative electrode-less sodium metal battery includes the current collector described in the first aspect of the disclosure.

In one example, the sodium metal battery has no negative electrode, that is, the sodium metal battery does not include a negative electrode sheet.

In one example, the sodium metal battery further includes a positive electrode sheet, a separator and an electrolyte.

The use of the negative electrode-less sodium metal battery is not particularly limited and can be used for various known uses. For example: mobile computers, notebook computers, portable phones, e-book players, portable fax machines, portable copiers, portable printers, stereo headsets, video recorders, LCD TVs, portable cleaners, calculators, memory cards, portable recorders , radios, backup power supplies, cars, motorcycles, electric ships, bicycles, lighting equipment, toys, game consoles, clocks, power tools, cameras, large household batteries, energy storage power stations, etc.

The battery core of the negative-electrode-less sodium metal battery may be a laminated structure formed by stacking a current collector, a separator, and a positive electrode sheet in sequence, or it may be a stacked structure by stacking a current collector, a separator, and a positive electrode sheet in order and then rolling. A coiled structure formed by winding.

<Positive sheet>

The positive electrode sheet may be a conventional positive electrode sheet in the art. For example, the positive electrode sheet includes a positive electrode current collector and an active material layer; the active material layer is coated on the surface of the positive electrode current collector; the active material layer includes an active material layer. substance.

In one example, the active material in the positive electrode sheet includes one or more of Prussian blue materials, polyanionic materials, and transition metal layered oxides.

In one example, the transition metal layered oxide is selected from NaCoO ₂ , Na _2/3 [Cu _1/3 Mn _2/3 ]O ₂ , Na _2/3 [Fe _1/3 Mn _2/3 ] O ₂ , Na _2/3 [Li _1/3 Ni _2/3 ]O ₂ , Na [Ni _0.5 Co _0.5 ]O ₂ , Na _7/9 [Cu _2/9 Fe _1/9 Mn _2/3 ]O ₂ , Na _2/3 [Li _1/3 Mn _1/2 Ti _1/6 ]O ₂ , Na[Ni _0.5 Fe _0.5 ]O ₂ , Na[Co _0.5 Fe _0.5 ]O ₂ , Na[Ni _1/3 Fe _{1 /3} Mn _1/3 ]O ₂ and Na[Cu _1/9 Ni _2/9 Fe _1/3 Mn _1/3 ]O ₂ .

In one example, the chemical formula of the Prussian blue material is A _x M[Fe(CN) _6]y , where A is an alkali metal cation, M is a transition metal cation, 1≤x≤2, 0.9≤y≤ 1.

In one example, the Prussian blue material also contains crystal water.

A specifically can be Li, Na, K, Rb, Cs or Fr.

Specifically, M may be one or more of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr and Mo.

In one example, the Prussian blue material is selected from LiFe ₂ (CN) ₆ , LiCoFe(CN) ₆ , LiMnFe(CN) ₆ , NaFe ₂ (CN) ₆ , KFe ₂ (CN) ₆ , NaCuFe(CN) _6. One or more of NaNiFe(CN) ₆ , Na ₂ Fe ₂ (CN) ₆ , Na ₂ MnFe(CN) ₆ , Na ₂ CoFe(CN) ₆ and Na ₂ NiFe(CN) ₆ .

In one example, the chemical formula of the polyanionic material is A'_x'M'_y' (X _n' O _m ) _z F _w , where A' is Li or Na, and M' is a transition of a variable valence state One or more metal ions, X is P, S, V or Si, and x'≥1, y'>0, z≥1, w≥0, the values of n' and m comply with the principle of charge conservation.

In one example, M' is Ti, Fe or Mn.

In one example, the polyanionic material is selected from one of NaFePO ₄ , Na ₃ V ₂ (PO ₄ ) ₃ , Na ₂ MnP ₂ O ₇ , Na ₂ FeP ₂ O ₇ and Na ₂ FePO ₄ F or Various.

In one example, the Prussian blue material has a median particle diameter D _v 50 of 1 μm to 15 μm (for example, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13μm, 14μm, 15μm). The median particle size can be measured using a laser particle size analyzer.

In one example, the median particle diameter D _v 50 of the polyanionic material is 1 μm to 10 μm (eg, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm). The median particle size can be measured using a laser particle size analyzer.

In one example, the positive electrode sheet is used in a sodium metal battery without anode.

In one example, the active material layer in the positive electrode sheet further includes a second conductive agent and a third binder.

In an example, the second conductive agent includes, but is not limited to: carbon-based materials, metal-based materials, and conductive polymers.

In one example, the carbon-based material is selected from one or more of natural graphite, artificial graphite, graphene, carbon black, acetylene black, Ketjen black and carbon fiber.

In one example, the metal-based material is selected from metal powder, metal fiber, copper, nickel, aluminum, and silver.

In one example, the conductive polymer is a polyphenylene derivative.

In one example, the third binder includes, but is not limited to: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), nitrile rubber (NBR), water-based acrylic Resin, polyvinyl alcohol, polyvinyl butyral, polyurethane, fluorinated rubber, carboxymethylcellulose (CMC), polyacrylic acid (PAA).

In one example, based on the total weight of the active material layer, the weight content of the active material is 75wt% to 98wt% (for example, 75wt%, 80wt%, 82wt%, 85wt%, 90wt%, 95wt% , 96wt%, 98wt%), the weight content of the second conductive agent is 1wt% ~ 15wt% (for example, 1wt%, 2wt%, 5wt%, 10wt%, 15wt%), the third binder has The weight content is 1 to 10 wt% (for example, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%).

In a preferred example, based on the total weight of the active material layer, the weight content of the active material is 82wt%~96wt%, the weight content of the second conductive agent is 2wt%~10wt%, and the The weight content of the third binder is 2wt% to 8wt%.

In one example, the positive electrode current collector includes, but is not limited to, one or more of aluminum foil, carbon-coated aluminum foil, perforated aluminum foil, stainless steel foil, and polymer substrate covered with conductive metal.

The positive electrode sheet can be prepared according to conventional methods in the art. Usually, the active material and optional second conductive agent and third binder are dispersed in a solvent (such as NMP) to form a uniform positive electrode slurry. The positive electrode slurry is coated on the current collector and dried through processes such as Finally, the positive electrode sheet is obtained.

<Diaphragm>

The separator may be a conventional separator in the art. For example, the separator may be a polypropylene separator (PP), a polyethylene separator (PE), a polypropylene/polyethylene double-layer composite film (PP/PE), a polypropylene/polyethylene separator. Ethylene/polypropylene three-layer composite film (PP/PE/PP), polyimide electrospun separator (PI), cellulose non-woven separator, polyethylene terephthalate non-woven separator (PET) ), one of the ceramic-coated diaphragms.

The separator plays an isolation role between the positive electrode sheet and the current collector.

The present disclosure will be described in further detail below with reference to specific embodiments. It should be understood that the following examples are only illustrative and explain the present disclosure, and should not be construed as limiting the scope of the present disclosure. All technologies implemented based on the above contents of this disclosure are covered by the scope of protection intended by this disclosure.

The experimental methods used in the following examples are conventional methods unless otherwise specified; the reagents, materials, etc. used in the following examples can be obtained from commercial sources unless otherwise specified.

For simplicity, this disclosure explicitly discloses only certain numerical ranges. However, any lower limit can be combined with any upper limit to form an unexpressed range; and any lower limit can be combined with other lower limits to form an unexpressed range, and likewise any upper limit can be combined with any other upper limit to form an unexpressed range. In addition, although not explicitly stated, every point or individual value between the endpoints of a range is included in the range. Thus, each point or single value may serve as a lower or upper limit on its own in combination with any other point or single value or with other lower or upper limits to form a range not expressly recited.

In the description of this article, it should be noted that, unless otherwise stated, "above" and "below" are inclusive, and "multiple" in "one or more" means two or more.

This summary of the present disclosure is not intended to describe each disclosed embodiment or every implementation in the disclosure. The following description illustrates exemplary embodiments in more detail. At various points throughout this application, guidance is provided through a series of examples, which may be used in various combinations. In each instance, the enumerations are representative only and should not be construed as exhaustive.

Example Group I

This Group I example is used to illustrate the current collector and anode-free sodium metal battery of the present disclosure including a carbon material embedded with sodium-philic particles.

Illustratively, the single-cavity structures mentioned in the Examples and Comparative Examples are prepared using a silicon-based template method, and the porosity of the carbon particles can be adjusted by adjusting the concentration of the template.

Illustratively, the irregular porous structures mentioned in the examples and comparative examples are prepared using a soft template method, such as using the cationic surfactant cetyltrimethylammonium bromide as a template in a carbon-based precursor, An irregular porous structure is formed during the high-temperature carbonization process.

Illustratively, the regular porous structure rules mentioned in the Examples and Comparative Examples are prepared by using a hard template method, such as closely packed polystyrene beads and silica beads as template agents, and the template agents are removed after carbonization. Carbon particles with an ordered pore structure can be obtained.

Illustratively, the preparation method of the sodium-philic particles mentioned in the Examples and Comparative Examples is as follows:

Gold and silver metal elements are soaked in salt solution combined with solution reduction method;

Zn, Bi, Sb, and Sn metal elements are prepared by soaking in salt solution combined with thermal reduction method. Carbon particles with hollow structure and/or porous structure are dispersed in the metal salt solution, filtered, dried, and then heated at high temperature in a reducing atmosphere. Heat treatment prepares elemental metal particles embedded in a porous carbon pore structure;

ZnO is prepared by soaking in a salt solution combined with heat treatment. Carbon particles with hollow structures and/or porous structures are dispersed in a metal salt solution, filtered and dried, and then heat treated at high temperature in an oxygen atmosphere to prepare a porous carbon pore structure embedded in it. of ZnO nanoparticles. In addition, the particle size of the generated sodium-philic particles is controlled by the concentration of the metal salt or the reaction time.

Example I1

(1) Preparation of carbon materials embedded with sodium-philic particles

Add 4 mL of tetraethoxysilane to a mixed solution of 50 mL of ethanol and 10 mL of deionized water. After stirring for 10 minutes, 2 mL of 28 wt% ammonia water was added dropwise to the above solution. After stirring for another 30 min, 0.3 g of resorcinol and 0.4 mL of formaldehyde were added to the solution, and then stirred at room temperature for 36 h. The pellet was centrifuged and washed three times with deionized water. The powder was dried at 80°C and then carbonized at high temperature (800°C/4h, argon atmosphere). Finally, carbon microspheres with a single cavity structure were obtained after etching the silica core (stirring in 5 wt% HF solution for 5 hours).

Disperse 5g of carbon microspheres with a single cavity structure into 100mL of 0.3mM chloroauric acid aqueous solution. After evenly dispersed, heat to 65°C and add 8mL of 1.0wt% sodium citrate aqueous solution. Then the solution temperature was increased to 80°C and reacted for 20 min. Cool, wash, filter and dry with deionized water to obtain hollow carbon microspheres embedded with gold nanoparticles.

(2) Preparation of current collector

According to the mass ratio of 95:0.5:2.5:2, weigh the embedded sodium-philic particles obtained in step (1). Carbon materials with hollow structure and/or porous structure, conductive agent carbon black (Super P), binder styrene-butadiene rubber (SBR), thickener sodium carboxymethylcellulose (CMC), mix the powder evenly Add an appropriate amount of deionized water, stir thoroughly to form a uniform slurry, apply the slurry on aluminum foil, and then dry, roll, and cut to obtain a current collector.

(3) Preparation of positive electrode sheet

Weigh the positive electrode active material (Na[Ni _1/3 Fe _1/3 Mn _1/3 ]O ₂ ), the third binder (PVDF), and the second conductive agent carbon black (Super P) according to 95:2.5:2.5 Mix with a mass ratio of Positive plate.

(4) Preparation of separator

Select a 7 μm wet polyethylene separator as the base material. First apply a 2 μm thick alumina ceramic coating on one surface of the base material, and then apply a PVDF-HFP adhesive layer with a thickness of 1 μm on both sides of the separator. The total thickness is 11μm separator, cut into required widths for later use.

(5) Electrolyte preparation

In an argon-filled glove box with a water content of <1 ppm, mix ethylene carbonate (EC), propylene carbonate (PC), and diethyl carbonate (DEC) at a mass ratio of 0.5:1.5:1.5, adding a concentration of 1.0mol/L sodium hexafluorophosphate (NaPF ₆ ), stir evenly, then add 1.0wt% sodium nitrate (NaNO ₃ ), continue stirring fully, and obtain an electrolyte.

(6) Preparation of sodium metal battery without negative electrode

Stack the current collector of step (2), the separator of step (4) and the positive electrode sheet of step (3) in order so that the separator is between the positive electrode sheet and the current collector, and then weld the tabs and wind to obtain the winding core , then place the roll core in an aluminum-plastic film packaging bag, and finally inject the above-mentioned electrolyte and go through processes such as vacuum sealing, standing, forming, and shaping to prepare a sodium metal battery without anode.

Other Examples and Comparative Examples

Refer to Example I1 for the specific process. The difference is the type, particle size and weight content of the sodium-philic particles, the structure, particle size and porosity of the carbon particles with a hollow structure and/or porous structure, and the coating thickness. The specific details are See Table 1.

Among them, the metal nanoparticles in Comparative Example I3 are dispersed in a solid nanostructure and are prepared by dispersing a metal salt in a carbon material precursor and performing simultaneous heat treatment and carbonization reduction. For example, zinc acetate solution can be dispersed in polyacrylonitrile slurry and heat treated in a reducing atmosphere to prepare a composite material in which metallic zinc nanoparticles are distributed in solid carbon materials.

Table 1 Composition and structure of carbon materials embedded with sodium-philic particles in Examples and Comparative Examples in Group I of Examples

Example Group II

Example II1

(1) Current collector preparation

Weigh the PVDF and Al ₂ O ₃ powders at a weight ratio of 1:1, mix the powders evenly, add an appropriate amount of N-methylpyrrolidone (NMP), stir thoroughly to form a uniform slurry, and squeeze by moving The slurry is coated on aluminum foil (width 380mm) by pressure coating. The shape parameters of the steps are as follows: corrugated step coating, L=0.5W=190mm, W1=350mm, W2=3mm, H2=30μm. Then it is dried, rolled, and cut to obtain a current collector.

(2) Preparation of positive electrode sheet

Weigh the positive electrode active material (Na[Ni _1/3 Fe _1/3 Mn _1/3 ]O ₂ ), the third binder (PVDF), and the second conductive agent carbon black (SuperP) according to 95:2.5:2.5 Mass ratio mixing, then add an appropriate amount of N-methylpyrrolidone (NMP) and stir thoroughly to form a uniform slurry. The slurry is coated on the positive electrode current collector carbon-coated aluminum foil, and then dried, rolled, and cut to obtain the positive electrode. chip, the design surface capacity is 2.5mAh/cm ² .

(3) Preparation of separator

Select a 9 μm wet polyethylene separator as the base material. First apply a 2 μm thick alumina ceramic coating on one surface of the base material, and then apply a PVDF-HFP adhesive layer with a thickness of 1 μm on both sides of the separator. The total thickness is 13μm separator, cut into required widths for later use.

(4) Electrolyte preparation

In an argon-filled glove box with a moisture content <1 ppm, place ethylene carbonate (EC), propylene carbonate (PC) and diethyl carbonate (DEC) are mixed according to the mass ratio of 0.5:1.5:1.5, add sodium hexafluorophosphate (NaPF ₆ ) with a concentration of 1 mol/L, stir evenly, and then add 1wt% sodium nitrate (NaNO ₃ ), continue to stir thoroughly and obtain the electrolyte.

(5) Preparation of sodium metal battery without negative electrode

Stack the current collector of step (1), the separator of step (3) and the positive electrode sheet of step (2) in order so that the separator is between the positive electrode sheet and the current collector, and then weld the tabs and wind to obtain the winding core , then place the roll core in an aluminum-plastic film packaging bag, and finally inject the above-mentioned electrolyte and go through processes such as vacuum sealing, standing, forming, and shaping to prepare a sodium metal battery without anode.

Other Examples and Comparative Examples

Referring to Example II1, the difference is that the morphology of the step coating is different, as shown in Table 2.

Table 2 Morphology of step coatings in Examples and Comparative Examples in Example II Group

test case

(1) First lap Coulomb efficiency test

Place the sodium metal battery without negative electrode at 25℃, charge it to the upper limit voltage (4.0V) at a constant current of 0.5C, then charge it at a constant voltage of 4.0V until the current is 0.05C, and let it stand for 5 minutes; then charge it at a constant current of 0.5C Discharge until the voltage is 2.0V, and the recorded discharge capacity is the discharge capacity of the first cycle; the Coulombic efficiency of the first cycle is the ratio of the specific discharge capacity and the specific charge capacity of the first cycle.

(2) Volume change rate test

Test the thickness of the original battery cell, recorded as h1, then charge it at 25°C with a constant current of 0.5C to the upper limit voltage (4.0V), then charge it with a constant voltage of 4.0V until the current is 0.05C, and let it sit for 5 minutes. When testing the cell thickness, record it as h2. Volume change rate=h2/h1*100%.

(3)Normal temperature cycle capacity retention test

Place the sodium metal battery without negative electrode at 25℃, charge it to the upper limit voltage (4.0V) at a constant current of 0.5C, then charge it at a constant voltage of 4.0V until the current is 0.05C, and let it stand for 5 minutes; then charge it at a constant current of 0.5C Discharge until the voltage is 2.0V and let it sit for 5 minutes. This is a charge and discharge cycle. Charge/discharge in this way, and record the ratio of the discharge capacity after the 100th cycle to the discharge capacity of the first cycle, which is the 100-cycle capacity retention rate.

Table 3 Electrochemical properties of different examples and comparative examples in Example Group I

The analysis of the results in Table 3 is as follows:

According to Examples I1, I2, I3, I4, I5 and I6, it can be seen that the smaller particle size of the sodium-philic particles is more conducive to the reversible deposition of sodium; significantly improves the cycle performance of the battery; compared with the irregular porous structure, the regular pore structure It has more advantages in guiding the deposition of metallic sodium and mitigating volume expansion. This is because the regular pore structure is mostly connected and the pore utilization rate is higher.

From the results of Comparative Examples I1-I4, Examples I5, I6 and I8, it can be seen that when there is a lack of sodium-philic particles, or the size of the sodium-philic particles is too large, or the carbon material has a solid structure, the coating can optimize the negative electrode-free sodium metal battery. limited ability. This is mainly because the particle size of the sodium-philic particles is too large, resulting in a reduction in the relatively active sites exposed on the surface, and has a weak effect in promoting sodium metal deposition; moreover, when the thickness of the coating is too thick, the surface area of the carbon material is too large , there are too many surface side reactions, resulting in reduced Coulombic efficiency.

Table 4 Electrochemical properties of different examples and comparative examples in Example II Group

The analysis of the results in Table 2 and Table 4 is as follows:

Comparing the above-mentioned Examples II1, II3 and II4, it can be seen that compared with the linear zigzag structure, the optimization effect of ordinary corrugations and steps with a regular sinusoidal structure is better. This may be attributed to the fact that the linear zigzag structure has a tip at the inflection point, which can easily cause tip discharge and produce metal dendrites, which is not conducive to the uniform deposition of metallic sodium.

Comparing the above-mentioned Examples II3 and II6, and Comparative Examples II1 and II2, it can be seen that the corrugation period length of the step coating is moderate and better. Excessive spacing will not provide good support, and too dense step distribution will affect the strength of metallic sodium. deposition.

In addition, if you choose a non-corrugated or non-serrated linear step coating, since the position of the linear step coating is generally fixed on both sides of the current collector, the thickness on both sides of the core will be stacked due to accumulation. If the thickness is significantly thicker than the middle part, it is easy to form a hollow structure in the middle part, and the structural stability is lacking. As a result, the battery core is easily deformed by force during the transfer process, causing the internal current collector to wrinkle, which is not conducive to the uniform deposition of sodium metal. Affect battery performance.

In general, a corrugated or zigzag step coating of a certain thickness can form a reserved space on the surface of the current collector substrate, slow down the large volume changes caused by the repeated deposition/dissolution process of metallic sodium to the battery core, and stabilize the battery. core structure to improve the cycle stability of the battery. The important thing is that the corrugated or zigzag step shape design can make the overall thickness of the battery core uniform, avoid the structural distortion caused by the reserved steps, improve the structural stability of the battery core in the reserved space, and help further improve Electrochemical performance of anode-free sodium metal batteries.

The embodiments of the present disclosure have been described above. However, the present disclosure is not limited to the above-described embodiment. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this disclosure shall be included in the protection scope of this disclosure.

Claims (15)

A current collector, characterized in that the current collector includes a current collector substrate and a coating disposed on at least one side surface of the current collector substrate; the coating includes a carbon material embedded with sodium-philic particles, and /Or, the coating includes a corrugated or zigzag step coating. The current collector according to claim 1, wherein the coating includes a carbon material embedded with sodium-philic particles, and the carbon material embedded with sodium-philic particles includes carbon particles and embedded in the carbon particles. of sodium-philic particles; Preferably, the carbon particles have a hollow structure and/or a porous structure; Preferably, based on the total weight of the carbon material embedded with the sodium-philic particles, the weight content of the carbon particles is 70 wt%-99.5 wt%. The current collector according to claim 2, wherein the carbon particles have a porosity of 20% to 80%; And/or, the particle size of the carbon particles is 0.5 μm ~ 10 μm; And/or, the carbon particles include amorphous carbon particles; Preferably, the amorphous carbon is selected from the group consisting of metal-organic framework material pyrolytic carbon, resin pyrolytic carbon, organic polymer pyrolytic carbon, pyrolytic carbon black, biomass pyrolytic carbon, petroleum coke, and needle coke. At least one. The current collector according to any one of claims 1 to 3, characterized in that the sodium-philic particles include metal elements and/or metal compounds; preferably, the sodium-philic particles are selected from the group consisting of gold, silver, platinum, At least one of zinc, zinc oxide, copper, copper oxide, tin, tin oxide, antimony, antimony oxide, bismuth, bismuth oxide and aluminum oxide; And/or, the particle size of the sodium-philic particles is 2 nm-100 nm. The current collector according to any one of claims 1 to 4, characterized in that, based on the total weight of the carbon material embedded with the sodium-philic particles, the weight content of the sodium-philic particles is 0.5wt%- 30wt%; And/or, the particle size of the carbon material embedded with the sodium-philic particles is 0.5 μm-10 μm. The current collector according to any one of claims 1 to 5, wherein the coating further includes a first binder, a first conductive agent and a thickener; Preferably, based on the total weight of the coating, the weight content of the carbon material embedded with the sodium-philic particles is 75wt%-98wt%, and the weight content of the first binder is 0wt%-10wt% , the weight content of the first conductive agent is 0wt% ~ 15wt%, and the weight content of the thickener is 0wt% ~ 15wt%; Preferably, the first binder is selected from polyvinylidene fluoride, polytetrafluoroethylene, styrene-butadiene rubber, nitrile rubber, water-based acrylic resin, polyvinyl alcohol, polyvinyl butyral, polyurethane, and fluorinated rubber. , one or more of carboxymethylcellulose and polyacrylic acid; Preferably, the first conductive agent is selected from one or more of carbon-based materials, metal-based materials and conductive polymers; Preferably, the carbon-based material is selected from one or more of natural graphite, artificial graphite, graphene, carbon black, acetylene black, Ketjen black and carbon fiber; Preferably, the thickener is sodium carboxymethylcellulose and/or lithium carboxymethylcellulose. The current collector according to any one of claims 1 to 6, characterized in that the thickness of the coating does not exceed 20 μm. The current collector according to any one of claims 1 to 7, wherein the coating includes a corrugated or zigzag step coating, and the coating path of the corrugated step coating is a water ripple. curve, sine curve or cosine curve, and the coating path of the zigzag step coating is a polyline; Preferably, the coating path of the corrugated or zigzag step coating is periodically distributed. The current collector according to claim 8, wherein the current collector satisfies: 0.05W≤L≤2W; where L is the length of the cycle of the corrugated or zigzag step coating, and W is the current collector. The width of the substrate; Preferably, the current collector satisfies: 0.2W≤L≤1W. The current collector according to claim 8 or 9, characterized in that the current collector satisfies: W1<W; where W1 is the width of the corrugated or zigzag step coating, and W is the width of the current collector substrate. width; Preferably, the width W1 of the corrugated or zigzag step coating is ≥ the width of the matched positive electrode paste. The current collector according to any one of claims 8-10, characterized in that the width W2 of the corrugated or zigzag step coating satisfies: 1mm≤W2≤20mm. The current collector according to any one of claims 8 to 11, wherein the thickness H2 of the corrugated or zigzag step coating satisfies: 5 μm ≤ H2 ≤ 50 μm. The current collector according to any one of claims 8-12, wherein the material forming the corrugated or zigzag step coating includes a second binder and ceramic particles; Preferably, based on the total weight of the binder and ceramic particles, the weight content of the binder is 30wt%-70wt%, and the weight content of the ceramic particles is 70wt%-30wt%; Preferably, the second binder is selected from polyvinylidene fluoride, polytetrafluoroethylene, styrene-butadiene rubber, nitrile rubber, water-based acrylic resin, polyvinyl alcohol, polyvinyl butyral, polyurethane, and fluorinated rubber. , one or more of carboxymethylcellulose and polyacrylic acid; Preferably, the ceramic particles are selected from one or more of alumina, boehmite, silica, silicon carbide, magnesia and zirconia. The current collector according to any one of claims 1 to 13, characterized in that the current collector base material includes copper foil, perforated copper foil, nickel foil, aluminum foil, perforated aluminum foil, stainless steel foil, titanium foil, One or more of nickel foam and copper foam; Preferably, the thickness of the current collector substrate is 5 μm-20 μm. A sodium metal battery comprising the current collector according to any one of claims 1-14, preferably, The sodium metal battery has no negative electrode.