CN109872882B

CN109872882B - Application of negative electrode material in lithium ion supercapacitor

Info

Publication number: CN109872882B
Application number: CN201711248229.7A
Authority: CN
Inventors: 曲超; 张华民; 张洪章; 李先锋; 刘翠连
Original assignee: Dalian Institute of Chemical Physics of CAS
Current assignee: Dalian Institute of Chemical Physics of CAS
Priority date: 2017-12-01
Filing date: 2017-12-01
Publication date: 2021-12-14
Anticipated expiration: 2037-12-01
Also published as: CN109872882A

Abstract

The invention relates to an application of a negative electrode material in a lithium ion super capacitor, wherein the lithium ion super capacitor comprises a positive electrode, a diaphragm, a negative electrode and an electrolyte, and the negative electrode adopts a negative electrode material with lower potential, so that a device has higher voltage and better cycling stability, and the cost of the capacitor is lower.

Description

Application of negative electrode material in lithium ion supercapacitor

Technical Field

The invention relates to the field of electrochemical energy storage, and relates to a lithium ion capacitor and a preparation method thereof.

Background

The lithium ion super capacitor has the advantages of high safety, long service life, high power and the like as an energy storage device, combines the advantages of common double electric layer capacitors and lithium ion batteries, and has better application prospect in the fields of mobile communication, starting power supplies, standby power supplies and the like.

The lithium ion super capacitor has the following characteristics: (1) compared with a lithium ion battery, the lithium ion battery has higher power density, and can better meet the power requirement in a large-current application occasion, particularly in a high-energy pulse environment. (2) The charge-discharge cycle time is very short and is far shorter than that of the storage battery. (3) The battery has long service life and no need of maintenance for life. (4) The operation temperature is wide, and the normal work can be carried out within the range of minus 45-85 ℃.

Lithium ion supercapacitors generally fall into two categories. One type uses carbon material as negative electrode and active carbon as positive electrode, and this kind of lithium ion capacitor usually needs a large amount of pre-embedded lithium, which is very high in cost. In another type of lithium ion capacitor, the titanium oxide compound and the composite are used as a negative electrode, and the activated carbon is used as a positive electrode, so that the problem of the titanium oxide compound in generating gas needs to be well inhibited. The existing lithium ion super capacitor cathode material has the problems of low capacity, poor cycling stability, high cost, serious flatulence and the like, and needs to be improved urgently.

Disclosure of Invention

In order to solve the technical problems, the invention provides an application of a negative electrode material in a lithium ion capacitor, and the lithium ion capacitor has the characteristics of high voltage, high energy density, high cycle stability and the like.

In order to achieve the purpose of the invention, the technical proposal is specifically adopted as follows,

the lithium ion super capacitor comprises a positive electrode, a negative electrode, a diaphragm and electrolyte. The negative electrode comprises one or more than two of the following substances.

Substance I

Wherein

A₁,A₂,A₃,A₄＝C_nH_2n+1(n＝0-4)，C_mF_2m+1(m-0-4) may be the same or different.

Substance II

Wherein A is₁,A₂,A₃,A₄＝

C_nH_2n+1(n＝0-4)，C_mF_2m+1(m-0-4) may be the same or different.

The anode material comprises one or more than two of an activated carbon material, a conductive polymer and an oxide; the membrane comprises polyvinylidene fluorideOne or more of ethylene, polyvinylidene fluoride-hexafluoropropylene copolymer, polytetrafluoroethylene, polypropylene, polyethylene, cellulose acetate and glass fiber. The electrolyte comprises a solvent and a lithium salt. The solvent can be one or more than two of dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, acetonitrile, ethylene glycol dimethyl ether and dioxolane; the lithium salt comprises LiPF₆、LiA1(SO₂)N(SO₂) A2 wherein A1, A2 are C_xF_2x+1(x ═ 0 to 10), a1, a2 may be different; LiSO₃C_xF_y(x＝0-10)、LiBF₄One or two or more kinds of them, preferably LiBF₄。

The lithium ion capacitor provided by the invention has the beneficial effects that as the cathode material with lower potential is adopted, the device has higher voltage and better cycling stability, and the cost of the capacitor is lower.

Drawings

FIG. 1 is a charge-discharge curve of the lithium ion capacitor of example 1, with a charge-discharge current of 0.5Ag^-1(active material) and a charge-discharge cut-off voltage of 1.6 to 3.2V.

FIG. 2 is a graph showing the cycle stability of the lithium ion capacitor in the comparative example, with a charge/discharge current of 0.5Ag^-1(active material) and a charge-discharge cut-off voltage of 1.6 to 3.2V.

FIG. 3 shows the energy density (based on active material) of the lithium ion capacitor in example 1 and comparative example 1, 1A.g^-1Capacity retention after 10000 cycles at current (based on active).

Detailed Description

Example 1

Mixing the negative electrode active material (as follows)

Uniformly mixing the carbon black with PVDF (polyvinylidene fluoride), conductive carbon black and NMP (N-methyl pyrrolidone) according to the mass ratio of 8:1:1:5, then blade-coating the mixture on a current collector, and drying the current collector at 70 ℃ to prepare the cathode. Mixing activated carbon and PUniformly mixing VDF, conductive carbon black and NMP according to the mass ratio of 8:1:1:10, then blade-coating the mixture on a current collector, and drying the current collector at 70 ℃ to prepare the anode.

Sequentially placing the prepared anode, polyethylene diaphragm and cathode, winding into an inner core, and immersing in 1mol/L LiBF₄And sealing the inner core with an aluminum-plastic film after the electrolyte (propylene carbonate is used as a solvent) is carried out, thus completing the preparation of the battery cell. The battery charge/discharge data are shown in fig. 1 and 3. The energy density of the battery based on the active material was 100Wh/kg, which was higher than that (60Wh/kg) in the comparative example because the present invention provides a negative electrode material having a higher capacity than lithium titanate.

Comparative example

Uniformly mixing LTO (lithium titanate), PVDF (polyvinylidene fluoride), conductive carbon black and NMP (N-methyl pyrrolidone) according to the ratio of 8:1:1:5, then blade-coating on a current collector, and drying at 70 ℃ to prepare the cathode. Uniformly mixing the activated carbon, PVDF, conductive carbon black and NMP according to the ratio of 8:1:1:10, then blade-coating the mixture on a current collector, and drying the current collector at 70 ℃ to prepare the positive electrode.

Placing the prepared anode, polyethylene diaphragm and cathode in sequence, winding to form an inner core, and immersing in 1mol/L LiPF₆And sealing the inner core with an aluminum-plastic film after the electrolyte (propylene carbonate is used as a solvent) is carried out, thus completing the preparation of the battery cell. The battery charge and discharge data are shown in fig. 2.

Example 2

Mixing the negative electrode active material (as follows)

Uniformly mixing the anode material with PVDF (polyvinylidene fluoride), conductive carbon black and NMP (N-methyl pyrrolidone) according to the ratio of 8:1:1:5, then blade-coating the mixture on a current collector, and drying the current collector at 70 ℃ to prepare the cathode. Uniformly mixing the activated carbon, PVDF, conductive carbon black and NMP according to the ratio of 8:1:1:10, then blade-coating the mixture on a current collector, and drying the current collector at 70 ℃ to prepare the positive electrode.

Placing the prepared anode, polyethylene diaphragm and cathode in sequence, winding into an inner core, and immersing in the solution 1mol/L LiPF₆And sealing the inner core with an aluminum-plastic film after the electrolyte (propylene carbonate is used as a solvent) is carried out, thus completing the preparation of the battery cell.

Example 3

Mixing the negative electrode active material (as follows)

Placing the prepared anode, polyethylene diaphragm and cathode in sequence, winding to form an inner core, and immersing in 1mol/L LiPF₆And sealing the inner core with an aluminum-plastic film after the electrolyte (propylene carbonate is used as a solvent) is carried out, thus completing the preparation of the battery cell.

Example 4

Mixing the negative electrode active material (as follows)

Example 5

Mixing the negative electrode active material (as follows)

Claims

1. The application of the negative electrode material in a lithium ion super capacitor, wherein the lithium ion super capacitor comprises a positive electrode, a diaphragm, a negative electrode and an electrolyte, and is characterized in that: the concrete application is as follows: mixing the negative electrode active material

Uniformly mixing with polyvinylidene fluoride, conductive carbon black and N-methyl pyrrolidone according to the ratio of 8:1:1:5, blade-coating on a current collector, and coating 70^oC, drying, namely preparing the cathode; uniformly mixing activated carbon, polyvinylidene fluoride, conductive carbon black and N-methyl pyrrolidone according to the ratio of 8:1:1:10, then blade-coating the mixture on a current collector, and 70^oC, drying, namely preparing the anode;

placing the prepared anode, polyethylene diaphragm and cathode in sequence, winding to form an inner core, and immersing in 1mol/L LiPF₆Electrolyte and propylene carbonate are taken as solvents, then the inner core is sealed by an aluminum plastic film, and the preparation of the battery cell is finished.

2. The application of the negative electrode material in the lithium ion super capacitor is characterized in that: the lithium ion super capacitor comprises a positive electrode, a diaphragm, a negative electrode and electrolyte, and is characterized in that: the concrete application is as follows: mixing the negative electrode active material

With polyvinylidene fluoride, conductive carbon black, N-methylpyrrolidoneUniformly mixing according to the proportion of 8:1:1:5, then blade-coating on a current collector, 70^oC, drying, namely preparing the cathode; uniformly mixing activated carbon, polyvinylidene fluoride, conductive carbon black and N-methyl pyrrolidone according to the ratio of 8:1:1:10, then blade-coating the mixture on a current collector, and 70^oC, drying, namely preparing the anode;