WO2018032324A1

WO2018032324A1 - Method for manufacturing manganese dioxide-graphene foam composite electrode

Info

Publication number: WO2018032324A1
Application number: PCT/CN2016/095458
Authority: WO
Inventors: 肖丽芳; 钟玲珑
Original assignee: 肖丽芳
Priority date: 2016-08-16
Filing date: 2016-08-16
Publication date: 2018-02-22

Abstract

A method for manufacturing a manganese dioxide-graphene foam composite electrode. The method comprises the following steps: step (1) adding a graphite oxide and a polyacrylonitrile into a ball mill for ball milling, then adding a ball-milled mixture into a mixed solution of an ethanol and water for ultrasonic dispersion to form a suspension; step (2) immersing a nickel foam in the suspension, steam-drying the solvent and adding a gas mixture of hydrogen and nitrogen to protect a reaction within a muffle furnace, then reacting to completion followed by natural cooling; step (3) immersing a product from the previous step in hydrochloric acid, performing a reaction, then reacting to completion to obtain a graphene foam; and step (4) adding a nano-scale manganese dioxide into a toluene, using ultrasound to form a suspension, then drip coating the toluene suspension containing manganese dioxide onto the graphene foam, drying and placing in a muffle furnace for annealing, cooling, then rolling to obtain an electrode. The electrode manufactured using the method does not need adding an binder or a conducting agent typically required of a conventional electrode. The electrode has reduced material cost.

Description

Method for preparing manganese dioxide composite graphene foam electrode sheet

[0001] The present invention belongs to the technical field of supercapacitors, and in particular, to a method for preparing a manganese dioxide composite graphene foam electrode sheet.

Background technique

[0002] Graphene is a novel carbon nanomaterial that is closely packed into a two-dimensional honeycomb structure by a single layer of sp2 carbon atoms. Graphene has excellent electrical, thermal, optical and mechanical properties. The high theoretical specific surface area and excellent electrical conductivity of the same graphene determine its great potential as an electrode material in electrochemical energy storage devices.

[0003] Graphene's unique two-dimensional structure and excellent physical properties make it extremely attractive for use in supercapacitors. Compared with traditional Del porous carbon materials, graphene has a very high conductivity, a large specific surface area and a large number of interlayer structures, making it a promising electrode material for electric double layer capacitors. However, graphene tends to be stacked during the preparation process, which affects the dispersibility and surface wettability of the graphene material in the electrolyte, and reduces the effective specific surface area and electrical conductivity of the graphene material. Therefore, avoiding graphene stacking is a technical problem in preparing high energy density and high power density graphene supercapacitors. technical problem

[0004] The technical problem to be solved by the present invention is to provide a method for preparing a supercapacitor electrode sheet. The high specific surface area, high conductivity graphene foam composite electrode sheet prepared by the method can serve as both a current collector and an active material. After loading the activated carbon, the capacity of the electrode can be increased, and the process of preparing the supercapacitor can be simplified, and the process cost is reduced.

Problem solution

Technical solution

[0005] The present invention provides a preparation method of a nano manganese dioxide composite graphene foam electrode sheet:

[0006] Step (1) Adding graphite oxide and polypropylene fine to a ball mill for 30-60 min, and then adding the ball-milled mixture to a mixed solution of ethanol and water to ultrasonically disperse to form a suspension having a concentration of l-20 g/L. Liquid

[0007] Step (2) Soaking nickel foam in the above suspension for 10-60 minutes, evaporating the solvent, and then mixing the hydrogen and nitrogen The gas-protected muffle furnace is reacted at 800-1100 ° C for l-10 h, and the reaction is completely cooled.

[0008] Step (3) The above product is immersed in l-3 mol/L hydrochloric acid, and reacted at 60-80 ° C for 5-10 h, and after completion of the reaction, foamed graphene is obtained.

[0009] Step (4) Adding nanometer manganese dioxide to toluene, sonicating for 10-30 minutes to form a suspension, and then suspending the suspension of toluene containing manganese dioxide onto the foamed graphene, drying, and then placing the horse Annealing at 200-300 ° C for 30-60 min in the furnace, and cooling to obtain an electrode sheet.

[0010] Further, in the step (1), the ball mill is 30-60 min;

[0011] Further, the mass of the polypropylene clear in the step (1) is 0.01-5% of the mass of the graphite oxide;

[0012] Further, the volume ratio of ethanol to water in the mixed solution of ethanol and water in the step (1) is 0.25-4

[0013] further, the step (1) in the concentration of the graphite oxide suspension is l-20g / L of the suspension;

[0014] Further, in the step (2), the foamed nickel is immersed in the graphite oxide suspension in the crucible is 10-60mi n;

[0015] Further, in the step (2), the atmosphere in the muffle furnace is a hydrogen-nitrogen mixed gas containing 5% hydrogen;

[0016] Further, the reaction temperature in the step (2) in the muffle furnace is 800-1100 ° C, and the reaction time is 1-

10h;

[0017] Further, the concentration of hydrochloric acid in the step (3) is l-3mol / L;

[0018] Further, the reaction temperature of the step (3) in hydrochloric acid is 60-80 ° C, and the reaction time is 5-10 h _;

[0019] Further, the mass concentration of the manganese dioxide toluene suspension in the step (4 is 30-70%;

[0020] Further, in the step (4, the ultrasound time is 10-30min;

[0021] Further, in the step (4, the annealing temperature is 200-300 ° C, and the annealing time is 30-60 min;

[0022] Further, the thickness of the electrode sheet obtained in the step (4) is 100-500 um.

Advantageous effects of the invention

Beneficial effect

[0023] The present invention has the following beneficial effects: (1) Graphene foam with high specific surface area and high conductivity serves as both a current collector and an active material, which simplifies the preparation process and reduces the cost; (2) After the manganese dioxide is loaded Both graphene and manganese dioxide can exert capacity and can effectively increase the capacity of the electrode; (3) The porous structure of graphene foam can provide effective electron and ion conduction channels, achieving high energy density and high power. Density; (4) The electrode sheet prepared by the method does not need to add a binder and a conductive agent as in the conventional electrode sheet, thereby reducing the cost of the material.

Brief description of the drawing

DRAWINGS

1 is a flow chart of a preparation process of the present invention.

Embodiments of the invention

[0025] The preferred embodiments of the present invention are further described in detail below with reference to the accompanying drawings:

Embodiment 1

[0027] (1) 10 g of graphite oxide and O. OOlg polypropylene were added to a ball mill for ball milling for 30 min, and then the ball milled mixture was ultrasonically dispersed in a mixed solution of ethanol and water volume ratio of 0.25 to form a concentration of lg / A suspension of L.

[0028] (2) The nickel foam was soaked in the above suspension for 10 min, the solvent was evaporated, and then placed in a muffle furnace protected by a hydrogen-nitrogen mixed gas containing 5% hydrogen at 800 ° C for 10 h, and the reaction was allowed to cool naturally. .

(3) The above product was immersed in 1 mol/L hydrochloric acid, and reacted at 60 ° C for 10 hours, and the reaction was completed to obtain a foamed graphene.

[0030] (4) Adding nanometer manganese dioxide to toluene, forming a 30% mass suspension with ultrasonic for 10 min, and then applying a suspension of toluene containing manganese dioxide to the foamed graphene, drying, and then placing It was annealed at 200 ° C for 60 min in a muffle furnace, and after cooling, it was pressed to obtain an electrode sheet.

[0031] (5) according to the usual supercapacitor preparation process, the electrode sheet, the separator and the electrode sheet are laminated to form a battery core, and then the electrolyte is injected, and the injected electrolyte is 1 mol/L Et ₄ NBF ^ AN solution. Seal and get a supercapacitor.

[0032]

[0033]

Example 2

[0035] (1) 10 g of graphite oxide and 0.5 g of polypropylene were added to a ball mill for ball milling for 60 min, and then the ball milled mixture was added to a mixed solution of ethanol and water volume ratio of 4 to ultrasonically disperse to form a concentration of 20 g / L Suspension. [0036] (2) The foamed nickel was immersed in the above suspension for 60 min, and the solvent was evaporated to dryness, and then placed in a muffle furnace protected by a hydrogen-nitrogen mixed gas containing 5% hydrogen at 1100 ° C for 1 h, and the reaction was allowed to cool naturally. .

(3) The above product was immersed in 3 mol/L hydrochloric acid, and reacted at 80 ° C for 5 hours, and the reaction was completed to obtain a foamed graphene.

[0038] (4) Adding nanometer manganese dioxide to toluene, sonicating for 10-30 minutes to form a 70% mass suspension

Then, a suspension of toluene containing manganese dioxide was sprayed onto the foamed graphene, dried, and then placed in a muffle furnace and annealed at 300 ° C for 30 minutes, and then cooled to obtain an electrode sheet.

[0039] (5) According to the usual supercapacitor preparation process, the electrode sheet, the separator and the electrode sheet are laminated to form a cell, and then the electrolyte is injected, and the injected electrolyte is 1 mol/L Et ₄ NBF ₄ AN solution. , Seal, get super capacitors.

[0040]

Embodiment 3

[0042] (1) 10 g of graphite oxide and O.lg polypropylene were added to a ball mill for ball milling for 45 min, and then the ball milled mixture was ultrasonically dispersed in a mixed solution of ethanol and water in a volume ratio of 0.5 to form a concentration of 3 g/ A suspension of L.

[0043] (2) The nickel foam was soaked in the above suspension for 30 min, the solvent was evaporated, and then placed in a muffle furnace protected with 5% hydrogen in a hydrogen-nitrogen mixed gas atmosphere at 900 ° C for 5 h, and the reaction was completely cooled. .

(3) The above product was immersed in 2 mol/L hydrochloric acid, and reacted at 75 ° C for 7 hours, and the reaction was completed to obtain a foamed graphene.

[0045] (4) Adding nanometer manganese dioxide to toluene, sonicating for 20 minutes to form a 50% mass suspension, and then spraying the toluene suspension containing manganese dioxide onto the foamed graphene, drying, and then placing It is annealed at 250 ° C for 450 min in a muffle furnace, and after cooling, it is pressed to obtain an electrode sheet.

[0046] (5) The electrode sheet, the separator and the electrode sheet are formed into a battery cell by lamination according to a preparation process of a usual supercapacitor, and then an electrolyte is injected, and the injected electrolyte is an AN solution of 1 mol/L Et ₄ NBF ₄ . , Seal, get super capacitors.

[0047]

Example 4

[0049] (1) 10 g of graphite oxide and 3 g of polypropylene were added to a ball mill for ball milling for 40 min, and then ball milled The mixture was ultrasonically dispersed in a mixed solution of ethanol and water in a volume ratio of 2 to form a suspension having a concentration of 10 g/L.

[0050] (2) Soaking nickel foam in the above suspension for 50 min, evaporating the solvent, and then reacting in a hydrogen-nitrogen mixed gas-protected muffle furnace containing 5% hydrogen at 1000 ° C for 3 h, and cooling naturally after completion of the reaction. .

(3) The above product was immersed in 1.5 mol/L hydrochloric acid, and reacted at 65 ° C for 9 hours, and the reaction was completed to obtain a foamed graphene.

[0052] (4) adding nanometer manganese dioxide to toluene, sonicating for 15 min to form a 50% mass concentration suspension, and then spraying the toluene suspension containing manganese dioxide onto the foamed graphene, drying, and then placing It was annealed at 220 ° C for 40 min in a muffle furnace, and after cooling, it was pressed to obtain an electrode sheet.

[0053] (5) The electrode sheet, the separator and the electrode sheet are formed into a battery cell by lamination according to a preparation process of a usual supercapacitor, and then an electrolyte is injected, and the injected electrolyte is an AN solution of 1 mol/L Et ₄ NBF ₄ . , Seal, get super capacitors.

[0054]

Example 5

[0056] (1) 10 g of graphite oxide and lg polypropylene were added to a ball mill for ball milling for 40 min, and then the ball milled mixture was added to a mixed solution of ethanol and water volume ratio 1 to ultrasonically disperse to form a concentration of 5 g / L suspension.

[0057] (2) The nickel foam was soaked in the above suspension for 20 min, and the solvent was evaporated to dryness, and then placed in a muffle furnace protected with 5% hydrogen in a hydrogen-nitrogen mixed gas atmosphere at 950 ° C for 80 hours, and the reaction was completely cooled. .

(3) The above product was immersed in 2.5 mol/L hydrochloric acid, and reacted at 75 ° C for 4 hours, and the reaction was completed to obtain a foamed graphene.

[0059] (4) Adding nanometer manganese dioxide to toluene, forming a suspension with a mass concentration of 60% after ultrasonication for 25 minutes, and then applying a suspension of toluene containing manganese dioxide to the foamed graphene, drying, and then placing It was annealed at 280 ° C for 35 min in a muffle furnace, and after cooling, it was pressed to obtain an electrode sheet.

[0060] (5) The electrode sheet, the separator and the electrode sheet are formed into a battery cell by lamination according to a preparation process of a usual supercapacitor, and then an electrolyte is injected, and the injected electrolyte is an AN solution of 1 mol/L Et ₄ NBF ₄ . , Seal, get super capacitors.

[0061] [0062] The method is shown in FIG. 1 , and the effect thereof is shown in Table 1. As can be seen from Table 1, the energy density of the supercapacitor prepared by the invention reaches 45.3-56.2 Wh/Kg.

[0063]

Table 1

[] [Table 1]

The above is a further detailed description of the present invention in connection with the specific preferred embodiments, and the specific embodiments of the present invention are not limited to the description. It will be apparent to those skilled in the art that the present invention may be made without departing from the spirit and scope of the invention.

Claims

Claim

[Claim 1] A method for preparing a nanometer manganese dioxide composite graphene foam electrode sheet, comprising the following steps:

Step (1) adding graphite oxide and polypropylene fine to a ball mill for ball milling, and then adding the ball milled mixture to a mixed solution of ethanol and water to ultrasonically disperse to form a suspension; and step (2) adding nickel foam to the above suspension Soaking in the medium, evaporating the solvent, and then reacting in a muffle furnace protected by a hydrogen-nitrogen mixed gas. After the reaction is completed, it is naturally cooled; Step (3) The above product is immersed in hydrochloric acid, and the reaction is completed to obtain foamed graphene. ;

Step (4) Adding nanometer manganese dioxide to toluene, ultrasonically forming a suspension, and then suspending the suspension of toluene containing manganese dioxide onto the foamed graphene, drying, and then annealing in a muffle furnace, cooling After pressing, the electrode sheets were obtained.

[Claim 2] The method according to claim 1, wherein in the step (1), the ball mill is

30-60min; the mass of the polypropylene fine in the step (1) is 0.01-5 of the mass of the graphite oxide.

[Claim 3] The method according to claim 1, wherein the volume ratio of ethanol to water in the mixed solution of ethanol and water in the step (1) is 0.25-4; the step (1) The concentration of the graphite oxide suspension is a suspension of 1-20 g/L.

[Claim 4] The method according to claim 1, wherein the foamed nickel is immersed in the graphite oxide suspension in the step (2) for 10-60 minutes.

[Claim 5] The method according to claim 1, wherein the atmosphere in the muffle furnace in the step (2) is a hydrogen-nitrogen mixed gas containing 5% hydrogen.

[Claim 6] The method according to claim 1, wherein the reaction temperature in the step (2) in the muffle furnace is 800-1100 ° C, and the reaction time is l-10 h.

[Claim 7] The method according to claim 1, wherein the concentration of hydrochloric acid in the step (3) is l-3 mol/L _; the reaction temperature in hydrochloric acid is 60-80 ° C, and the reaction time is It is 5-10h.

[Claim 8] The method according to claim 1, wherein the manganese dioxide toluene suspension in the step (4) has a mass concentration of 30-70%; and the ultrasonic inter-turn is 10-30 minutes.

[Claim 9] The method according to claim 1, wherein the annealing temperature in the step (4) is 200-300 ° C, and the annealing time is 30-60 min.

[Claim 10] The method according to claim 1, wherein the electrode sheet obtained in the step (4) has a thickness of 100 to 500 um.