CN207517536U - A kind of solid lithium ion capacitor - Google Patents

Abstract

The utility model discloses a solid lithium ion capacitor. The solid lithium ion capacitor includes at least one structural unit, the structural unit includes a positive electrode and a negative electrode, and a layer of solid electrolyte sandwiched between the positive electrode and the negative electrode. The positive electrode includes The positive electrode current collector and the positive electrode coating layer attached to one side of the positive electrode current collector, the negative electrode includes the negative electrode current collector and a layer of metallic lithium pressed on one side of the negative electrode current collector, the positive electrode coating layer and the metallic lithium are respectively located on both sides of the solid electrolyte . The lithium ion capacitor of the utility model adopts a solid electrolyte, uses metallic lithium as the negative electrode, and prevents the occurrence of lithium dendrites and thermal runaway while the solid electrolyte acts as a diaphragm, completely eliminates the potential safety hazard caused by electrolyte leakage, and uses metallic lithium instead of carbon The anode-like material helps to increase the energy density of the system, and at the same time combines the porous current collector to further improve the energy density and power characteristics of the system.

Description

A solid lithium ion capacitor

technical field

The utility model relates to an electrochemical energy storage device, in particular to a solid lithium ion capacitor device.

Background technique

Lithium-ion capacitor (Lithium-ion capacitor) is a new type of energy storage device between supercapacitors and batteries. Compared with supercapacitors, lithium-ion capacitors have higher energy density and lower self-discharge. Compared with lithium-ion batteries, lithium-ion capacitors have more excellent rate and low-temperature characteristics. Lithium-ion capacitors have broad application prospects in the fields of rail transit, automobile starting power supply, and intelligent equipment.

The positive electrode of the lithium-ion capacitor uses a porous carbon material with a larger surface area, and the negative electrode uses the negative electrode material of the lithium-ion battery. During the process of multiple cycles, lithium dendrites will appear on the negative electrode, resulting in an increase in the internal resistance of the lithium-ion capacitor and a decrease in capacity. When lithium dendrites accumulate to a certain extent, there is a risk of piercing the separator and causing a short circuit of the battery cell. At the same time, the battery contains flammable, explosive, and volatile organic solvents, which pose a great safety hazard. There is a low energy density, which cannot meet a use requirement that requires high energy density.

Utility model content

The technical problem to be solved by the utility model is to provide a new type of lithium ion capacitor, which can eliminate the potential safety hazard of electrolyte leakage and improve energy density at the same time.

In order to solve the above technical problems, the utility model discloses a solid-state lithium ion capacitor, which includes at least one structural unit, the structural unit includes a positive electrode and a negative electrode, and a layer of solid state capacitor sandwiched between the positive electrode and the negative electrode An electrolyte, the positive electrode includes a positive electrode collector and a positive electrode paint layer attached to one side of the positive electrode collector, and the negative electrode includes a negative electrode collector and a layer of metal lithium pressed on one side of the negative electrode collector. The positive electrode coating layer and metal lithium are located on both sides of the solid electrolyte. The solid electrolyte can be an organic solid electrolyte or an inorganic solid electrolyte.

Further, the positive current collector is a porous foil with a thickness of 15-50 μm, preferably 15-35 μm.

Further, the porous foil of the positive current collector has a porosity of 10-50% and a pore diameter of 10-500 μm, preferably 10-50 μm.

The use of porous current collectors helps to increase the energy density of lithium-ion capacitors, facilitates the movement of lithium ions, and helps to improve the rate performance.

Further, the porous foil of the positive electrode current collector is any one of stainless steel, nickel or aluminum.

Further, the thickness of the lithium metal is 10-300 μm.

Further, the negative electrode current collector is porous copper foil with a thickness of 10 μm-50 μm, preferably 10-25 μm.

Further, the porous copper foil of the negative electrode current collector has a porosity of 30-70%, and a pore diameter of 10-500 μm, preferably 10-100 μm.

Furthermore, the metal lithium is 1-4 mm larger than the positive electrode coating layer in both length and width, and the solid electrolyte is 2-4 mm larger than the metal lithium in both length and width.

The lithium ion capacitor of the utility model adopts a solid electrolyte, uses metallic lithium as the negative electrode, and prevents the occurrence of lithium dendrites and thermal runaway while the solid electrolyte acts as a diaphragm, completely eliminates the potential safety hazard caused by electrolyte leakage, and uses metallic lithium instead of carbon The anode-like material helps to increase the energy density of the system, and at the same time combines the porous current collector to further improve the energy density and power characteristics of the system.

This structural design method avoids the potential safety hazard caused by lithium dendrites, and provides a very good idea for high-energy-density and high-safety lithium-ion capacitors.

Description of drawings

Fig. 1 is the structural representation of the utility model;

Fig. 2 is the charging and discharging curve of the utility model.

In the figure: 1-positive electrode coating layer, 2-positive electrode porous foil current collector, 3-solid electrolyte, 4-porous copper foil current collector, 5-metal lithium.

Detailed ways

The utility model will be described in further detail below in conjunction with specific embodiments and with reference to the accompanying drawings. The implementation of the utility model is not limited to the following examples, and any modifications or changes made to the utility model should be within the protection scope of the present invention.

Example 1:

As shown in FIG. 1 , the structural unit of the solid lithium ion capacitor of the present invention includes a positive electrode, a solid electrolyte 3 and a negative electrode. Wherein, the positive electrode includes a positive electrode porous foil current collector 1 and a positive electrode paint layer 2 coated on one side thereof, the negative electrode includes a porous copper foil current collector 4 and metal lithium 5 pressed on one side thereof, the positive electrode paint layer 1 and the metal lithium 5 are located on both sides of the solid electrolyte 3 respectively. That is to say, the structural unit finally forms a laminated structure, which is the positive electrode porous foil current collector 1, the positive electrode paint layer 2, the solid electrolyte 3, the metal lithium 5 and the porous copper foil current collector 4.

The above unit structure can be prepared by the following method:

Positive electrode preparation: The positive electrode slurry prepared by Japanese Kuraray YP50F activated carbon is coated on a porous aluminum foil with a thickness of 20 μm, a porosity of 25%, and a pore diameter of 40 μm (the pores of the aluminum foil are made by mechanical or corrosion methods, that is, the positive electrode porous foil assembly Fluid 1).

Negative electrode preparation: use porous copper foil with a thickness of 15 μm (i.e. porous copper foil current collector 4), with a porosity of 45% and a pore size of 100 μm. The holes are processed by laser, mechanical or etching. The foil current collector 4 and metal lithium are obtained by pressing.

Solid electrolyte: PEO-based organic polymer electrolyte is used.

Assembly test: Assemble into a lithium ion capacitor structural unit in the order of positive electrode | PEO-based organic polymer electrolyte | negative electrode, in which the metal lithium 5 is 2 mm larger than the positive electrode coating layer 1 in the length and width directions, and the PEO-based organic polymer electrolyte (that is, the solid electrolyte 3) is 2 mm larger than the metal lithium 5 in both length and width directions.

Charge and discharge test: the voltage window is 2.2~3.8V, and the discharge current is 3~40C.

The above structural units are combined according to capacity design requirements, and when combined, adjacent structural units share one positive electrode porous foil current collector 1 or one more porous copper foil current collector 4 . That is, when another structural unit is extended to the positive electrode side, the positive electrode slurry is coated on both sides of the corresponding positive electrode porous foil current collector 1, and a positive electrode coating layer 2 is formed on both sides of the positive electrode porous foil current collector 1, Then stack the solid electrolyte one by one, and at least one side (when it is not necessary to combine structural units on this side, the side close to the solid electrolyte is enough; when it is necessary to combine structural units on this side, then both sides) are pressed with metallic lithium. Porous copper foil current collector. In the same way, it can be obtained that another structural unit extends to the negative electrode side to form a combined structure.

Example 2

Positive electrode preparation: The positive electrode slurry prepared by Kuraray YP50F activated carbon in Japan is coated on a porous aluminum foil with a thickness of 20 μm, a porosity of 25%, and a pore diameter of 40 μm (ie, the positive electrode porous foil current collector 2);

Negative electrode preparation: use a porous copper foil with a thickness of 15 μm (ie, the porous copper foil current collector 4), a porosity of 35%, and a pore size of 200 μm, which are processed by laser, mechanical or etching methods. The thickness of the metal lithium 5 is 100 μm, and the porous copper foil The current collector 4 and metal lithium 5 are obtained by pressing.

Solid electrolyte: PEO-based organic polymer electrolyte;

Assembly test: Assemble into a lithium ion capacitor structural unit in the order of positive electrode | PEO-based organic polymer electrolyte | negative electrode, in which the metal lithium 5 is 2 mm larger than the positive electrode coating layer 1 in the length and width directions, and the PEO-based organic polymer electrolyte (that is, the solid electrolyte 3) is 2 mm larger than the metal lithium 5 in both length and width directions.

Charge and discharge test: the voltage window is 2.2~3.8V, and the discharge current is 3~40C.

The above structural units are combined according to the capacity design requirements, and the combination method is the same as that in Embodiment 1.

Example 3

Positive electrode preparation: The positive electrode slurry prepared by Japan’s Kuraray YP50F activated carbon was coated on a porous aluminum foil with a thickness of 30 μm, a porosity of 25%, and a pore diameter of 40 μm (ie, the positive electrode porous foil current collector 2).

Negative electrode preparation: porous copper foil with a thickness of 12 μm (i.e., the porous copper foil current collector 4), a porosity of 35%, and a pore diameter of 100 μm, which are processed by laser, mechanical or etching methods, and the thickness of the metal lithium 5 is 200 μm. The porous copper foil and Lithium metal is obtained by pressing.

Solid electrolyte: PEO-based organic polymer electrolyte;

Assembly test: Assemble into a lithium ion capacitor structural unit in the order of positive electrode | PEO-based organic polymer electrolyte | negative electrode, in which the metal lithium 5 is 2 mm larger than the positive electrode coating layer 1 in the length and width directions, and the PEO-based organic polymer electrolyte (that is, the solid electrolyte 3) is 2 mm larger than the metal lithium 5 in both length and width directions.

Charge and discharge test: the voltage window is 2.2~3.8V, and the discharge current is 3~40C.

The above structural units are combined according to the capacity design requirements, and the combination method is the same as that in Embodiment 1.

The discharge curves of Examples 1-3 are shown in Figure 2.

Claims (8)

1. a kind of solid lithium ion capacitor, it is characterised in that：The solid lithium ion capacitor includes at least one structural unit, The structural unit includes anode and cathode and one layer of solid electrolyte being folded between positive electrode and negative electrode, the anode packet It includes plus plate current-collecting body and is attached to the positive electrode coating layer of the plus plate current-collecting body side, cathode includes negative current collector and is compressed on this One layer of lithium metal of negative current collector side, positive electrode coating layer and lithium metal are located at the both sides of solid electrolyte respectively.

2. solid lithium ion capacitor according to claim 1, it is characterised in that：The plus plate current-collecting body is porous foil, Thickness is 15 ~ 50 μm.

3. solid lithium ion capacitor according to claim 2, it is characterised in that：The porous foil hole of the plus plate current-collecting body Gap rate 10 ~ 50%, 10 ~ 500 μm of aperture.

4. the solid lithium ion capacitor according to Claims 2 or 3, it is characterised in that：The porous foil of the plus plate current-collecting body Material is any one of stainless steel, nickel or aluminium.

5. solid lithium ion capacitor according to claim 1, it is characterised in that：The lithium metal thickness is 10 ~ 300 μm.

6. solid lithium ion capacitor according to claim 1, it is characterised in that：The negative current collector is porous copper foil, Thickness is 10 μm -50 μm.

7. solid lithium ion capacitor according to claim 6, it is characterised in that：The porous copper foil gas of the negative current collector Porosity is 30 ~ 70%, and aperture is 10 ~ 500 μm.

8. solid lithium ion capacitor according to claim 1, it is characterised in that：The lithium metal is equal in length and width Bigger 1 ~ 4mm than positive electrode coating layer, solid electrolyte is bigger 2 ~ 4mm than lithium metal in length and width.