CN114551788A - An ion field/electric field controllable three-dimensional metal negative electrode and preparation method thereof - Google Patents

Abstract

The invention discloses an ion field/electric field controllable three-dimensional metal cathode and a preparation method thereof, wherein the preparation method comprises the following steps: (1) configuring 3D printing ink: adding a metal-philic substance, a viscous agent, a conductive agent and/or an active substance into a solvent, and regulating and controlling the proportion of each component to obtain 3D printing ink with different compositions; (2) preparing a 3D printing three-dimensional metal cathode: and printing the 3D printing ink with different compositions into a three-dimensional current collector in a layer-by-layer superposed 3D printing mode, and performing post-treatment to obtain the three-dimensional current collector. Through 3D printing structure design and ink component optimization, effective regulation and control of an ion field and an electric field of a three-dimensional framework are achieved, growth of dendrites of a metal negative electrode is effectively inhibited, and the dendrite-free three-dimensional metal negative electrode with excellent cycle performance is obtained.

Description

An ion field/electric field controllable three-dimensional metal negative electrode and preparation method thereof

technical field

The invention belongs to the technical field of batteries, and in particular relates to an ion field/electric field controllable three-dimensional metal negative electrode and a preparation method thereof.

Background technique

Metal anodes (lithium, sodium, magnesium, aluminum, potassium, zinc, etc.) with extremely high theoretical specific capacities and low reduction potentials are considered as one of the most promising anode candidates for next-generation metal-ion batteries. However, the huge volume change of the metal anode is easily caused by side reactions such as hydrogen evolution during the charging and discharging process. At the same time, the uncontrollable dendrite growth of the metal anode will cause it to fall off from the substrate, resulting in severe capacity fading. In particular, the severe dendrite growth under high current may also pierce the separator and cause a short circuit of the battery, which brings safety hazards and seriously hinders the practical application of metal anodes.

So far, a great deal of research has been devoted to solving the problem of dendrite growth in metal anodes. Among them, three-dimensional metal anodes have received extensive attention from researchers due to their large specific surface area and high porosity. The large specific surface area of the three-dimensional metal anode can effectively reduce the local current density, which is conducive to uniform nucleation; at the same time, the three-dimensional structure can bind the metal in its porous structure, effectively limiting its volume change during charging and discharging. However, the 3D structure is affected by the electric field, and the ion concentration inside the structure tends to exhibit a gradient distribution, causing metal ions to preferentially nucleate and grow at the top of the ion concentration concentration and rarely migrate below the structure. The uneven plating/stripping process brought about by the ion concentration gradient will accelerate the dendrite growth and reduce the battery cycle life. Therefore, studying and improving the ion gradient distribution of three-dimensional metal anodes is of great significance for improving the cycle life of three-dimensional metal anodes.

SUMMARY OF THE INVENTION

In view of the above prior art, the present invention provides an ion field/electric field controllable three-dimensional metal negative electrode and a preparation method thereof, so as to solve the problems of gradient distribution, dendrite growth and low battery cycle life of the existing three-dimensional metal negative electrode. .

In order to achieve the above-mentioned purpose, the technical solution adopted in the present invention is to provide a preparation method of ion field/electric field controllable three-dimensional metal negative electrode, comprising the following steps:

(1) Configure 3D printing ink: Add metal-philic substances, viscous agents, conductive agents and/or active substances into the solvent, and by adjusting the proportion of each component, 3D printing inks with different compositions are obtained;

(2) Preparation of 3D printed 3D metal negative electrode: 3D printing inks of different compositions are printed into a 3D current collector by layer-by-layer 3D printing, and then post-processed.

The 3D printing ink is characterized in that the storage modulus is greater than the loss modulus to ensure the shape stability after printing, and the ink has obvious shear thinning behavior that meets the printing requirements. The present invention prepares a three-dimensional metal negative electrode by means of 3D printing, and at the same time, by adjusting the content of metal-philic substances in the ink, three-dimensional structures with different contents of metal-philic substances are prepared, and the three-dimensional collection is adjusted by means of 3D printing and ink component regulation. The electric field/ion field of the fluid can be adjusted to greatly improve the safety and cycle stability of metal-ion batteries. The addition of metalophilic substances can affect the distribution of the ion field inside the three-dimensional metal anode structure and provide power for the migration of metal ions. In addition, the strong adsorption of metal ions by metal-philic substances can play a role in immobilizing the migrated metal ions. At the same time, the lower nucleation overpotential caused by metalophilicity makes the deposition behavior of metal ions around it easier. Through the coordinated adjustment of the electric field and the ion field, the deposition site of the metal is changed, which effectively solves the problem of metal growth in the upper layer closer to the separator, and avoids the piercing of the separator by the upper layer dendrites.

The addition of metalophilic substances can affect the distribution of the ion field inside the three-dimensional metal anode structure and provide power for the migration of metal ions. In addition, the strong adsorption of metal ions by metal-philic substances can play a role in immobilizing the migrated metal ions. At the same time, the lower nucleation overpotential caused by metalophilicity makes the deposition behavior of metal ions around it easier. Through the coordinated adjustment of the electric field and the ion field, the deposition site of the metal is changed, which effectively solves the problem of metal growth in the upper layer closer to the separator, and avoids the piercing of the separator by the upper layer dendrites.

Further, the mass ratio of the metal-philic substance, the viscous agent, the conductive agent and the active substance in the 3D printing ink is 10:1-10:0-10:0-10.

Further, the metalophilic substance is gold, silver, copper, nickel, tin, titanium, copper-zinc alloy, copper-tin alloy, Mxene, graphene, carbon nanotube, titanium dioxide, manganese dioxide, aluminum oxide, copper oxide, cobalt oxide, At least one of tin oxide, zinc sulfide, zinc selenide, zinc oxide and polyacrylamide.

Further, the thickening agent is bacterial cellulose, cotton cellulose, wood pulp cellulose, polyvinylidene fluoride, polyvinyl alcohol, fumed silica, sodium alginate, potassium alginate, sodium carboxymethyl cellulose, polymethyl cellulose At least one of base acrylate, polyvinyl acetal and styrene-butadiene latex.

Further, the conductive agent is at least one of gold, silver, copper, nickel, tin, Mxene, graphene, carbon nanotubes, carbon fibers and conductive carbon black.

Further, the active material is at least one of lithium, sodium, magnesium, aluminum, potassium, zinc metal or its corresponding metal oxide, metal sulfide, metal carbide or metal phosphide.

Further, the solvent is deionized water, ethyl acetate, N-methylpyrrolidone, acetone, dimethyl sulfoxide, acetonitrile, cyclohexane, carbon tetrachloride, N,N-dimethylacetamide, N,N - at least one of dimethylformamide and tetrahydrofuran.

Further, the 3D printing method is a direct ink writing method, the diameter of the printing needle is 100-700 μm, and the distance between the printed filaments is 100-700 μm.

Further, post-processing includes drying and metal loading; drying methods include thermal conduction drying, convective heat transfer drying, vacuum drying, atmospheric drying, freeze drying, flash drying, microwave heating drying, and infrared radiation drying; metal loading methods include electrical deposition, fused deposition, redox deposition.

The present invention also provides the ion field/electric field controllable three-dimensional metal negative electrode prepared by the above preparation method.

On the basis of the above technical solutions, the present invention can also be improved as follows.

The beneficial effects of the present invention are:

1. The present invention achieves effective regulation of the ion field and electric field of the three-dimensional metal negative electrode through 3D printing structure design and ink composition control, effectively suppresses the growth of metal negative electrode dendrites, and obtains a dendrite-free three-dimensional metal negative electrode with excellent cycle performance.

2. The present invention improves the ubiquitous tip effect caused by uneven distribution of ions/electrons in metal negative electrodes by combining simple 3D printing structure design and ink composition adjustment, and has great advantages for the design of metal negative electrodes with long cycle life. Universality.

3. The method of the present invention is simple in process and convenient in operation, and can be widely used in the preparation of metal negative electrodes such as lithium, sodium, magnesium, aluminum, potassium, and zinc.

Description of drawings

Figure 1 shows the EDS test of the 3D printed 3D current collector;

Figure 2 shows the XRD test of the 3D printed three-dimensional metal anode;

Figure 3 shows the nucleation overpotential test of the half-cell assembled by 3D printed three-dimensional current collectors;

Figure 4 shows the cycle performance test of the 3D printed 3D metal anode assembled into a symmetrical battery.

Detailed ways

The specific embodiments of the present invention will be described in detail below with reference to the examples.

Example 1

A preparation method of ion field/electric field controllable three-dimensional metal negative electrode, comprising the following steps:

(1) Using 10 mL of deionized water as a solvent, adding 1 g of pulp cellulose, 1 g of carbon nanotubes and 1 g of silver powder successively, and dispersed by a high-speed homogenizer to obtain the first component ink; adjust the quality of the silver powder is 0.5g, and the second component ink is prepared after dispersion; the mass of silver powder is adjusted to 0.5g, and the third component ink is prepared after dispersion;

(2) The three inks are printed in the order of the first component - the second component - the third component. The diameter of the printed needle is 400 μm, the printing pressure controlled by the air compressor is 22 psi, and the movement speed of the robotic arm is 8 mm /min, after removing the solvent from the printed product, a 3D printed three-dimensional current collector is obtained, and then the surface is galvanized by constant current deposition, the deposition time is controlled to 1 hour, and the deposition current density is 10 mA/cm ² . After washing and drying, 3D printed zinc metal anode.

Example 2

A preparation method of ion field/electric field controllable three-dimensional metal negative electrode, comprising the following steps:

(1) use 12mL deionized water as solvent, add 1g vinyl alcohol and 1g graphene to it successively, adopt high-speed homogenizer to disperse, make the first component ink; change the quality of graphene to be 0.5g, disperse The second component ink is prepared; the mass of graphene is changed to 0.1 g, and the third component ink is prepared after dispersion;

(2) The three inks are printed in the order of the first component - the second component - the third component. The diameter of the printed needle is 100 μm, the printing pressure controlled by the air compressor is 22 psi, and the movement speed of the robotic arm is 8 mm /min, after removing the solvent from the printed product, a 3D printed three-dimensional current collector is obtained, and then in the glove box, lithium is deposited on the surface by fused deposition to obtain a 3D printed lithium metal negative electrode.

Example 3

A preparation method of ion field/electric field controllable three-dimensional metal negative electrode, comprising the following steps:

(1) Use 10 mL of deionized water as a solvent, and add 1 g of flower cellulose, 2 g of carbon nanotubes and 0.2 g of silver nanoparticles to it in turn, and use a high-speed homogenizer to disperse to obtain the first component ink; change; The mass of carbon nanotubes is 1g, and the second component ink is obtained by dispersing;

(2) The two inks are printed in the order of the first component and the second component. The diameter of the printed needle is 700 μm, the printing pressure controlled by the air compressor is 22 psi, the movement speed of the mechanical arm is 8 mm/min, and the printed product is After freeze-drying, the 3D printed three-dimensional current collector was obtained, and then the surface was galvanized by galvanostatic deposition method, the deposition time was controlled to be 1 hour, and the deposition current density was 10 mA/cm ² . After washing and drying, the 3D printed zinc metal was obtained. negative electrode.

Example 4

A preparation method of ion field/electric field controllable three-dimensional metal negative electrode, comprising the following steps:

(1) with 10mL N-methylpyrrolidone as solvent, add 2g vinylidene fluoride, 3g graphene and 8g zinc powder successively, adopt high-speed homogenizer to disperse, obtain the first component ink; Change graphite; The quality of alkene is 2g, and the second component ink is obtained by dispersion;

(2) Print the three-dimensional current collector with the two inks in the order of the first component and the second component. The diameter of the printed needle is 400 μm, the printing pressure controlled by the air compressor is 22 psi, and the movement speed of the robotic arm is 8 mm/min. The printed product is thermally dried to remove the solvent. In the glove box, sodium was deposited on the surface by fused deposition to obtain a 3D printed sodium metal anode.

Experimental example

The nucleation overpotential of the three-dimensional current collector obtained in Example 1 is characterized below in the form of a half-cell. The working electrode is a three-dimensional current collector with an area of 1 × 1 cm ² , the counter electrode is a zinc foil of the same size, and the electrolyte is 1M Zinc trifluoromethanesulfonate, tested at a current density of 10 mA/cm ² , this half-cell exhibited a low nucleation overpotential (28.6 mV).

The cycle performance of the 3D printed zinc metal negative electrode obtained in Example 1 was characterized in the form of a symmetrical battery, the electrolyte was 1M zinc trifluoromethanesulfonate, the tested current density was 1mA/cm ² , and the capacity was 1mAh/cm ² , the symmetric battery shows a good cycle life, the cycle life is up to 600 hours, and the voltage hysteresis is less than 20mV.

The nucleation overpotential of the three-dimensional current collector obtained in Example 2 was characterized in the form of a half-cell. The working electrode was a three-dimensional current collector with a diameter of 16 mm, the counter electrode was a lithium sheet of the same size, and the electrolyte was 1M bis-trifluoromethane. Lithium sulfoimide, tested at a current density of 10 mA/cm ² , this half-cell exhibits a very low nucleation overpotential (12.8 mV).

The cycle performance of the 3D printed lithium metal negative electrode obtained in Example 2 was characterized in the form of a symmetrical battery. The electrolyte was 1M lithium bis-trifluoromethanesulfonic acid imide, the tested current density was 1 mA/cm ² , and the capacity was 1 mAh. /cm ² , the symmetric battery showed good cycle life, with a cycle life of 1000 hours and a voltage hysteresis of 82mV.

The nucleation overpotential of the three-dimensional current collector obtained in Example 3 was characterized in the form of a half-cell. The working electrode was a three-dimensional current collector with a diameter of 16 mm, the counter electrode was a sodium sheet of the same size, and the electrolyte was 1 M trifluoromethanesulfonic acid. Zinc oxide, tested at a current density of 10 mA/cm ² , this half-cell exhibits a very low nucleation overpotential (12.0 mV).

The cycle performance of the 3D printed zinc metal negative electrode obtained in Example 3 was characterized in the form of a symmetrical battery. The electrolyte was 1M zinc trifluoromethanesulfonate, the tested current density was 1mA/cm ² , and the capacity was 1mAh/cm ² . The symmetric cell exhibited good cycle life of 630 hours with a voltage hysteresis of 43mV.

The cycle performance of the 3D printed sodium metal negative electrode obtained in Example 3 was characterized in the form of a symmetrical battery. The electrolyte was 1M sodium hexafluorophosphate, the tested current density was 1 mA/cm ² , and the capacity was 1 mAh/cm ² . The battery showed good cycle life of 1000 hours with a voltage hysteresis of 25mV.

Although the specific embodiments of the present invention have been described in detail with reference to the examples, they should not be construed as limiting the protection scope of the present patent. Within the scope described in the claims, various modifications and variations that can be made by those skilled in the art without creative efforts still belong to the protection scope of this patent.

Claims (10)

1. a preparation method of ion field/electric field controllable three-dimensional metal negative electrode, is characterized in that, comprises the following steps: (1) Configure 3D printing ink: Add metal-philic substances, viscous agents, conductive agents and/or active substances into the solvent, and by adjusting the proportion of each component, 3D printing inks with different compositions are obtained; (2) Preparation of 3D printed 3D metal negative electrode: 3D printing inks of different compositions are printed into a 3D current collector by layer-by-layer 3D printing, and then post-processed. 2 . The preparation method according to claim 1 , wherein the mass ratio of the metal-philic substance, the viscous agent, the conductive agent and the active substance in the 3D printing ink is 10:1～10:0～10:0. 3 . ~10. 3. preparation method according to claim 1 and 2 is characterized in that: described metal-philic substance is gold, silver, copper, nickel, tin, titanium, copper-zinc alloy, copper-tin alloy, Mxene, graphene, carbon At least one of nanotubes, titanium dioxide, manganese dioxide, aluminum oxide, copper oxide, cobalt oxide, tin oxide, zinc sulfide, zinc selenide, zinc oxide, and polyacrylamide. 4. preparation method according to claim 1 and 2 is characterized in that: described viscous agent is bacterial cellulose, cotton cellulose, wood pulp cellulose, polyvinylidene fluoride, polyvinyl alcohol, fumed silica , at least one of sodium alginate, potassium alginate, sodium carboxymethyl cellulose, polymethacrylate, polyvinyl acetal and styrene-butadiene latex. 5. The preparation method according to claim 1 or 2, wherein the conductive agent is at least one of gold, silver, copper, nickel, tin, Mxene, graphene, carbon nanotubes, carbon fibers and conductive carbon black A sort of. 6. preparation method according to claim 1 or 2 is characterized in that: described active material is lithium, sodium, magnesium, aluminum, potassium, zinc metal or its corresponding metal oxide, metal sulfide, metal carbide or at least one of metal phosphides. 7. preparation method according to claim 1 and 2 is characterized in that: described solvent is deionized water, ethyl acetate, N-methylpyrrolidone, acetone, dimethyl sulfoxide, acetonitrile, cyclohexane, At least one of carbon tetrachloride, N,N-dimethylacetamide, N,N-dimethylformamide and tetrahydrofuran. The preparation method according to claim 1 or 2, wherein the 3D printing method is a direct ink writing method, the diameter of the printing needle is 100-700 μm, and the distance between the printed threads is 100-700 μm. 9. The preparation method according to claim 1 or 2, characterized in that: the post-treatment includes drying and metal loading; the drying method includes heat conduction drying, convective heat transfer drying, vacuum drying, atmospheric drying, freezing Drying, flash drying, microwave heating drying, infrared radiation drying; the metal loading methods include electrodeposition, fused deposition, and redox deposition. 10. An ion field/electric field controllable three-dimensional metal negative electrode prepared by the preparation method according to any one of claims 1 to 9.

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