WO2018023326A1

WO2018023326A1 - Method for preparing graphene composite cathode material of lithium ion supercapacitor

Info

Publication number: WO2018023326A1
Application number: PCT/CN2016/092660
Authority: WO
Inventors: 肖丽芳; 钟玲珑
Original assignee: 肖丽芳
Priority date: 2016-07-31
Filing date: 2016-07-31
Publication date: 2018-02-08

Abstract

A method for preparing a graphene composite cathode material of a lithium ion supercapacitor, comprising the following steps: (1) uniformly mixing Li₂CO₃ and MoO₃, putting the mixture into a muffle furnace for a reaction, and obtaining a Li₂MoO₄ material after the reaction is completed; and (2) uniformly mixing graphite oxide with the obtained Li₂MoO₄ material, putting the mixture into the muffle furnace under the protection of hydrogen-nitrogen mixture atmosphere for a reaction, and obtaining a graphene composite Li₂MoO₃ material after the reaction is completed. The method has the following beneficial effects: (1) the graphene composite Li₂MoO3 material is used as a cathode of a lithium ion supercapacitor so that an anode no longer needs the addition of a lithium sheet or a complex lithium pre-intercalation process, and therefore the preparation process is simplified and the costs are reduced; and (2) the graphene composite Li₂MoO₃ material has high conductivity and a high specific surface area, can effectively replace conventional activated carbon cathode materials, and can achieve high energy density and high power density.

Description

Description: A method for preparing a lithium ion supercapacitor graphene composite cathode material

[0001] The present invention belongs to the technical field of lithium ion supercapacitors, and relates to a method for preparing a lithium ion supercapacitor cathode material.

Background technique

[0002] In recent years, lithium ion secondary batteries have been greatly developed. The battery negative electrode generally uses a carbon material such as graphite, and the positive electrode uses a lithium-containing metal oxide such as lithium cobaltate or lithium manganate. After the battery is assembled, the charged negative electrode supplies lithium ions to the positive electrode, and the lithium ion of the positive electrode of the discharge positive electrode returns to the negative electrode, so it is called a "rocking chair type battery". This battery is characterized by high safety and high cycle life compared to lithium batteries using metallic lithium.

[0003] However, since the positive electrode material is liable to undergo structural deformation during the process of deintercalating lithium, the cycle life of the lithium ion secondary battery is still restricted. Therefore, in recent years, research on a system in which a lithium ion secondary battery and a double layer capacitor are combined has become a new hot spot.

[0004] Lithium-ion capacitors generally use carbon materials such as graphite and hard carbon for the anode material, and activated carbon materials with double-layer characteristics for the cathode material, and the lithium anode is pre-diffused to the anode material, so that the potential of the anode is greatly reduced, thereby improving Energy Density. A lithium ion capacitor is disclosed in the special ljCN200580001498.2. The positive current collector and the negative current collector used in the lithium ion capacitor have holes penetrating the front and back surfaces, and the electrode layer is formed by the positive electrode active material and the negative electrode active material respectively. Electrochemical contact is made to the negative electrode, and lithium ions are carried in the negative electrode in advance. A pretreatment method for a negative electrode for an electrochemical capacitor is disclosed in the Japanese Patent Publication No. Hei. No. 1,200, 406, 9.6, a lithium layer is formed on a substrate by a vapor phase method or a liquid phase method, and then the lithium layer is transferred to an electrode layer of a negative electrode. These pre-excessive methods involve complex processes and require special handling of the raw materials, which makes the manufacturing process difficult.

technical problem

[0005] The technical problem to be solved by the present invention is to provide a method for preparing a lithium ion supercapacitor positive electrode material, and the positive electrode material prepared by the method can provide a lithium source in a lithium ion capacitor, thereby eliminating the need for complicated pre-processing of the negative electrode. Lithium-intercalation or lithium-ion capacitors in lithium-ion capacitors simplify lithium-ion capacitors The preparation process reduces the cost of the process.

Problem solution

Technical solution

[0006] The preparation method of the lithium ion supercapacitor cathode material provided by the invention is:

[0007] Step (1) Mixing Li ₂ CO ₃ and MoO ₃ in a ratio of 1-2:1, mixing uniformly, and placing in a muffle furnace at 500-700 ° C for 3-8 small inches, the reaction After completion, a Li ₂ MoO ₄ material was obtained.

[0008] Step (2) The graphite oxide and the obtained Li ₂ Mo0 ₄ material are mixed by mass 50-5:1, uniformly mixed uniformly, and then placed in a muffle furnace protected by a hydrogen-nitrogen mixed gas atmosphere containing 5% hydrogen 500- The reaction was carried out at 900 ° C for 5-10 hours, and after completion of the reaction, a graphene composite Li ₂ MoO ₃ material was obtained.

[0009] The present invention provides a lithium ion supercapacitor preparation process as follows:

[0010] (1) The graphene composite Li ₂ MoO ₃ material, the conductive agent, and the binder are added to the NMP in a mass ratio of 90:5:5 to be mixed into a slurry, and then coated on the positive electrode current collector aluminum foil. After drying, a positive electrode sheet is obtained.

[0011] (2) graphite or hard carbon anode material, conductive agent, binder is added to the NMP in a mass ratio of 90:5:5 to form a slurry, and then coated on the anode current collector copper foil After drying, a negative electrode sheet is obtained.

[0012] (3) The negative electrode sheet, the separator and the positive electrode sheet are assembled into a battery cell by laminating according to a usual preparation process of a lithium ion battery, and then an electrolyte is injected into the battery case, and the injected electrolyte is 1 mol/L LiPF ₆ DOL-DME solution (DOL and DME volume ratio is 1:1), sealed, to get lithium ion supercapacitor

[0013] The process for preparing a lithium ion supercapacitor using the positive electrode material of the present invention is a general lithium ion battery preparation process, which greatly simplifies the preparation process of the lithium ion supercapacitor.

[0014] The graphene composite Li ₂ MoO ₃ material prepared by the invention is used as a lithium ion supercapacitor cathode material, and the Li 2MoO ₃ material provides a lithium source, and the lithium ion ion stripping Li ₂ MoO ₃ material is inserted into the graphite anode in the first charging. Therefore, the anode potential is pulled low, so that a lithium metal sheet or a complicated pre-lithium process is not required in the anode; Li ₂ M ₀ 0 _{3 in the} graphene composite Li ₂ Mo0 material supports the graphene sheet structure, effectively preventing graphene material agglomerated and specific surface area decreases; Li ₂ formed after removal of the lithium ion Li ₂ MoO ₃ inches with material - is electrochemically inert material _x MoO ₃ material, does not affect the normal use of the battery.

Advantageous effects of the invention

Beneficial effect [0015] The present invention has the following beneficial effects: (1) The graphene composite Li ₂ Mo0 ₃ material is used as the positive electrode of the lithium ion supercapacitor, so that the negative electrode does not need to be added with a lithium sheet or a complicated pre-intercalation lithium process, which simplifies the preparation process and reduces The cost; (2) Graphene composite Li ₂ Mo0 ₃ material has high conductivity and high specific surface area, which can effectively replace the conventional activated carbon cathode material to achieve high energy density and high power density.

Brief description of the drawing

DRAWINGS

1 is a cycle life diagram of a supercapacitor of the present invention.

Embodiments of the invention

[0017] The preferred embodiments of the present invention are further described in detail below with reference to the accompanying drawings:

Embodiment 1

[0019] (1) Li ₂ C0 ₃ and Mo0 ₃

The mixture was mixed at a molar ratio of 1:1, uniformly mixed, and placed in a muffle furnace at 500 ° C for 3 hours, and after completion of the reaction, a Li ₂ MoO ₄ material was obtained.

[0020] (2) The graphite oxide and the obtained Li ₂ MoO ₄ material are mixed by mass 50:1, uniformly mixed uniformly, and then placed in a muffle furnace protected by a hydrogen-nitrogen mixed gas atmosphere containing 5% hydrogen at 500 ° C for reaction 5 After the reaction, a graphene composite Li ₂ MoO ₃ material was obtained.

[0021] (3) Graphene composite Li ₂ MoO ₃

Material, conductive agent, Ketjen black, binder PVDF was added to NMP in a mass ratio of 90:5:5 to form a slurry, which was then coated on a positive electrode current collector aluminum foil, and dried to obtain a positive electrode sheet.

[0022] (4) The graphite negative electrode material, the conductive agent Ketjen black, and the binder PVDF are added to the NMP in a mass ratio of 90:5:5 to be mixed into a slurry, and then coated on the negative electrode current collector copper foil foil. Above, after drying, a negative electrode sheet is obtained.

[0023] (5) The negative electrode sheet, the separator and the positive electrode sheet are laminated by means of a usual lithium ion battery preparation process, and then an electrolyte is injected into the battery case, and the injected electrolyte is 1 mol/L LiPF ₆ DOL-DME solution (DOL and DME volume ratio is 1:1), sealed, to get lithium ion supercapacitor

[0024] [0025] Example 2

(1) Li ₂ C0 ₃ and Mo0 ₃

The mixture was mixed at a molar ratio of 2:1, uniformly mixed, and placed in a muffle furnace at 700 ° C for 8 hours, and after completion of the reaction, a Li ₂ MoO 4 material was obtained.

[0027] (2) The graphite oxide and the obtained Li ₂ MoO ₄ material are mixed by mass 5:1, uniformly mixed uniformly, and then placed in a muffle furnace protected by a hydrogen-nitrogen mixed gas atmosphere containing 5% hydrogen at 900 ° C for reaction 10 After the reaction, a graphene composite Li ₂ MoO ₃ material was obtained.

(3) Graphene composite Li ₂ MoO ₃

[0029] (4) The graphite negative electrode material, the conductive agent Ketjen black, and the binder PVDF are added to the NMP in a mass ratio of 90:5:5 to be mixed into a slurry, and then coated on the negative electrode current collector copper foil foil. Above, after drying, a negative electrode sheet is obtained.

[0030] (5) The negative electrode sheet, the separator and the positive electrode sheet are assembled into a cell according to a preparation process of a usual lithium ion battery, and then an electrolyte is injected into the battery case, and the injected electrolyte is 1 mol/L LiPF ₆ DOL-DME solution (DOL and DME volume ratio is 1:1), sealed, to get lithium ion supercapacitor

[0031]

[0032]

Example 3

(1) Li ₂ C0 ₃ and Mo0 ₃

The mixture was mixed at a molar ratio of 1.3:1, uniformly mixed, and placed in a muffle furnace at 600 ° C for 7 hours, and after completion of the reaction, a Li ₂ MoO ₄ material was obtained.

[0035] (2) The graphite oxide and the obtained Li ₂ MoO ₄ material are mixed by mass 25:1, uniformly mixed uniformly, and then placed in a muffle furnace protected by a hydrogen-nitrogen mixed gas atmosphere containing 5% hydrogen at 700 ° C for reaction 8 After the reaction, a graphene composite Li ₂ MoO ₃ material was obtained.

(3) Graphene composite Li ₂ MoO ₃

The material, the conductive agent Ketchen Black, and the binder PVDF are added to the NMP in a ratio of 90:5:5 by mass. The slurry was formed and then coated on a positive electrode current collector aluminum foil, and dried to obtain a positive electrode sheet.

[0037] (4) The hard carbon anode material, the conductive agent Ketjen black, and the binder PVDF are added to the NMP in a mass ratio of 90:5:5 to be mixed into a slurry, and then coated on the negative electrode current collector copper foil. On the foil, after drying, a negative electrode sheet was obtained.

[0038] (5) The negative electrode sheet, the separator and the positive electrode sheet are formed into a battery cell by lamination according to a preparation process of a usual lithium ion battery, and then an electrolyte is injected into the battery case, and the injected electrolyte is 1 mol/L LiPF ₆ DOL-DME solution (DOL and DME volume ratio is 1:1), sealed, to get lithium ion supercapacitor

[0039]

Embodiment 4

(1) Li ₂ C0 ₃ and Mo0 ₃

The mixture was mixed at a molar ratio of 1.5:1, uniformly mixed, and placed in a muffle furnace at 650 ° C for 5 hours, and after completion of the reaction, a Li ₂ MoO ₄ material was obtained.

[0042] (2) The graphite oxide and the obtained Li ₂ MoO ₄ material are mixed by mass 15:1, uniformly mixed uniformly, and then placed in a muffle furnace protected by a hydrogen-nitrogen mixed gas atmosphere containing 5% hydrogen at 600 ° C for reaction 8 After the reaction, a graphene composite Li ₂ MoO ₃ material was obtained.

(3) Graphene composite Li ₂ MoO ₃

[0044] (4) The hard carbon anode material, the conductive agent Ketchen black, and the binder PVDF are added to the NMP in a mass ratio of 90:5:5 to be mixed into a slurry, and then coated on the negative electrode current collector copper foil. On the foil, after drying, a negative electrode sheet was obtained.

[0045] (5) was prepared in accordance with processes generally lithium ion battery negative electrode sheet, separator and positive electrode sheet stack by way of the composition of batteries, the electrolyte solution is then injected in the battery case, electrolyte is injected lmol / L LiPF ₆ DOL-DME solution (DOL and DME volume ratio is 1:1), sealed, to get lithium ion supercapacitor

[0046]

Embodiment 5 (1) Li ₂ C0 ₃ and Mo0 ₃

The mixture was mixed at a molar ratio of 1.7:1, uniformly mixed, and placed in a muffle furnace at 600 ° C for 6 hours, and after completion of the reaction, a Li ₂ MoO ₄ material was obtained.

[0049] (2) The graphite oxide and the obtained Li ₂ MoO ₄ material are mixed at a mass of 35:1, uniformly mixed uniformly, and then placed in a muffle furnace protected by a hydrogen-nitrogen mixed gas atmosphere containing 5% hydrogen at 800 ° C for reaction 6 After the reaction, a graphene composite Li ₂ MoO ₃ material was obtained.

[0050] (3) Graphene composite Li ₂ MoO ₃

[0051] (4) The graphite negative electrode material, the conductive agent Ketjen black, and the binder PVDF are added to the NMP in a mass ratio of 90:5:5 to be mixed into a slurry, and then coated on the negative electrode current collector copper foil foil. Above, after drying, a negative electrode sheet is obtained.

[0052] (5) The negative electrode sheet, the separator and the positive electrode sheet are formed into a battery cell by lamination according to a preparation process of a usual lithium ion battery, and then an electrolyte is injected into the battery case, and the injected electrolyte is 1 mol/L LiPF _{6 .} DOL-DME solution (DOL and DME volume ratio is 1:1), sealed, to get lithium ion supercapacitor

[0053] The effect is shown in Table 1. As can be seen from Table 1, the energy density of the lithium ion supercapacitor prepared by the invention reaches 38.8-46.1 wh/kg, which reaches the energy density level of the common lithium ion supercapacitor.

It can be seen from FIG. 1 that the lithium ion supercapacitor prepared by the invention is charged and discharged 1000 times, and the energy is not significantly attenuated.

[0055]

Table 1

[] [Table 1]

[0057] [0058]

[0059]

[0060]

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 practiced without departing from the spirit and scope of the invention.

[0062].

Claims

Claim

[Claim 1] A method for preparing a lithium ion supercapacitor positive electrode material, comprising the following steps:

Step (1) mixing Li ₂ C0 ₃ and M ₀ 0 ₃ , mixing uniformly, and then putting them into a muffle furnace for reaction, and after completion of the reaction, obtaining a Li ₂ MoO ₄ material;

Step (2) The graphite oxide is mixed with the material obtained by Li ₂ Mo0 ₄ , uniformly mixed, and then placed in a muffle furnace protected by a hydrogen-nitrogen mixed gas atmosphere. After the reaction, a graphene composite Li ₂ MoO 3 material is obtained.

[Claim 2] The method according to claim 1, wherein the amount of Li ₂ C0 ₃ and MoO ₃ in the step (1) is mixed in a ratio of 1-2:1.

[Claim 3] The method according to claim 1, wherein the step (1) has a reaction temperature in the muffle furnace of 500 to 700 ° C and a reaction time of 3 to 8 Torr.

[Claim 4] The method according to claim 1, wherein the mass of the graphite oxide in the step (2) and the material obtained to obtain the Li ₂ MoO ₄ are mixed in a ratio of 50 to 5:1.

[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 a volume concentration of 5% hydrogen.

[Claim 6] The method according to claim 1, wherein the step (2) has a reaction temperature in the muffle furnace of 500 to 900 ° C and a reaction time of 5 to 10 Torr.

[Claim 7] A process for preparing a lithium ion supercapacitor, comprising the following steps: Step A: adding a graphene composite Li ₂ MoO ₃ material, a conductive agent, and a binder obtained according to claim 1. Mixing into a slurry into NMP, then coating on a positive current collector aluminum foil, and drying to obtain a positive electrode sheet;

Step B: adding graphite or hard carbon anode material, conductive agent, and binder to NMP to form a slurry, then coating on a negative current collector copper foil, and drying to obtain a negative electrode; Step C: according to usual In the preparation process of the lithium ion battery, the negative electrode sheet, the separator and the positive electrode sheet are laminated to form a battery core, and then an electrolyte solution is injected into the battery case to seal the lithium ion supercapacitor.

[Claim 8] The preparation process according to claim 7, wherein in the step A, the mass ratio of the graphene composite Li ₂ MoO ₃ material, the conductive agent, and the binder is 90:5:5.

[Claim 9] The preparation process according to claim 7, wherein in the step B, the mass ratio of the graphite or the hard carbon anode material, the conductive agent, and the binder is 90:5:5.

[Claim 10] The preparation process according to claim 7, wherein in the step C, the electrolyte is a 1 mol/L LiPF ₆ DOL-DME solution, wherein the volume ratio of DOL to DME is 1:1.