CN106159318A - Novel slice type solid-state serondary lithium battery that garnet-type solid electrolyte supports and preparation method thereof - Google Patents

Abstract

The present invention relates to Novel slice type solid-state serondary lithium battery of a kind of garnet-type solid electrolyte support and preparation method thereof, in described solid-state serondary lithium battery, positive pole is coated in the side of solid electrolyte, positive pole composition includes positive electrode active materials, polymer, lithium ion conductor and conductive carbon, wherein, positive electrode active materials includes LiFePO₄、LiCoO₂、LiMn₂O₄、LiNi_0.5Mn_1.5O₄、LiNi_xCo_yMn_1-x-yO₂And/or Li [Li_xM_1-x]O₂, M is at least one in Ni, Co, Mn, and polymer includes that at least one in PEO, PVdF, PMMA, PAN, lithium ion conductor include lithium salts, positive electrode active materials: conductive carbon: polymer: the mass ratio of lithium ion conductor is 10: 2: 1: z, z≤10.

Description

A new type of solid-state secondary lithium battery supported by garnet-type solid electrolyte and its fabrication preparation method

technical field

The invention relates to a chip-type solid-state secondary lithium battery supported by a garnet-type solid electrolyte, which belongs to the technical field of batteries.

Background technique

In recent years, with the development of electric vehicles and the demand for grid energy storage and small energy storage, it is necessary to develop batteries that can be used in a wide temperature range, have high safety, high energy density, power density, and long life. Existing lithium-ion batteries use organic liquid electrolytes, which have problems such as flammability and low electrochemical windows, and cannot meet the dual requirements of high specific energy and high safety for future batteries. All-solid-state lithium batteries use pure solid-state inorganic solid electrolytes or polymer electrolytes instead of organic liquid electrolytes, which have better safety and thermal stability, and at the same time have a higher electrochemical window, which can be suitable for high-voltage cathode materials and have great potential for development Batteries with high voltage, long life, and high safety have excellent development prospects in portable electronic devices, electric vehicles, and large-scale energy storage devices.

The garnet-type solid electrolyte Li _7-x La ₃ Zr _2-x T _x O ₁₂ (x=0-1, T=Al, Ta, Nb, W, Ga, Y, Te, etc.) is a good comprehensive performance Oxide inorganic solid electrolyte, with high room temperature ionic conductivity (up to 10 ^-3 S/cm or more), wide electrochemical window (6V vs Li/Li ⁺ ), good thermal stability, stable to metal Li, Due to the long-term stability in air and the compatibility with most oxide cathodes, the development of all-solid-state batteries based on LLZTO oxide inorganic solid electrolytes has attracted much attention. However, the development of all-solid-state batteries with oxide inorganic solid electrolytes is not as smooth as sulfide inorganic solid electrolytes and polymer electrolytes. The reasons are as follows: the ionic conductivity of oxides at room temperature is usually an order of magnitude lower than that of sulfides, and oxides need to be sintered at high temperatures. A high-density ceramic solid electrolyte is formed, but high temperature has the problems of lithium volatilization, deviation from stoichiometric ratio, and decrease in ionic conductivity. Even more difficult is how common oxide cathodes such as LiCoO ₂ and LiFePO ₄ particles mixed with Li _7-x La ₃ Zr _2-x T _x O ₁₂ particles how composite cathodes with Li _7-x La ₃ Zr _2-x T _x O ₁₂ The ceramic electrolyte is combined to form a sulfide-like tight composite cathode/solid electrolyte interface, thereby reducing the charge transfer resistance.

At present, researchers use methods such as laser pulse deposition, aerosol deposition, and Sol-gel to prepare electrode films on oxide solid electrolytes; coat electrode pastes such as screen printing; and use spark plasma sintering technology and co-firing technology to Electrodes and electrolytes form an all-solid lithium battery. However, the capacity of thin-film batteries is limited, and the interface impedance of electrode paste coating methods such as screen printing is relatively large. Discharge plasma sintering technology and co-firing technology need to be at a higher temperature (>790 ° C), which cannot guarantee the chemical stability between the positive electrode and the electrolyte. . On this basis, considering that polymers have good bonding properties, and polymer solid electrolytes can also form good ion transport channels in composite positive electrodes, a new hybrid all-solid-state battery construction method can be considered to be developed: namely Polymer composite positive electrode/garnet-type solid electrolyte/negative electrode. This method uses a sintered garnet-type solid electrolyte without subsequent high-temperature treatment, thereby solving the problems encountered by all-solid-state lithium batteries based on oxide solid electrolytes. This method combines the respective advantages of garnet-type solid electrolytes and polymers, while making up for their respective shortcomings, and has great potential to develop high-voltage, long-life, and high-safety all-solid-state lithium batteries. However, there is no report on the above-mentioned novel hybrid all-solid-state battery in the prior art.

Contents of the invention

The invention aims to overcome the performance defects of the existing solid-state secondary lithium battery, and the invention provides a solid-state secondary lithium battery and a preparation method thereof.

The invention provides a solid secondary lithium battery. In the solid secondary lithium battery, the positive electrode is coated on one side of the solid electrolyte, and the positive electrode composition includes positive electrode active materials, polymers, lithium ion conductors and conductive carbon, wherein , the positive electrode active material includes LiFePO ₄ , LiCoO ₂ , LiMn ₂ O ₄ , LiNi _0.5 Mn _1.5 O ₄ , LiNi _x Co _y Mn _1-xy O ₂ and/or Li[Li _x M _{1- x} ]O ₂ , M is At least one of Ni, Co, Mn, the polymer includes at least one of PEO, PVdF, PMMA, PAN, the lithium ion conductor includes lithium salt, the positive electrode active material: conductive carbon: polymer: the mass ratio of lithium ion conductor It is 10:2:1:z, z≤10.

Preferably, the lithium ion conductor includes LiClO ₄ , LiPF ₆ , LiAsF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , LiN(CF ₃ SO ₂ ) ₂ , LiN(C ₂ F ₅ SO ₂ ) ₂ , LiPF ₃ (CF ₃ CF ₂ ) ₃ , LiBF ₃ CF ₃ CF ₂ , LiC(CF ₃ SO ₂ ) ₃ , LiB(C ₂ O ₄ ) ₂ , LiBF ₂ (CO ₂ ) ₂ , lithium polyborate PLTB, lithium lanthanum zirconium oxide, lithium At least one of lanthanum titanyl oxide, lithium titanium aluminum phosphate, and lithium silicon phosphate.

Preferably, the conductive carbon includes at least one of acetylene black, graphite, graphene, graphene oxide, porous carbon, carbon nanotubes, carbon fibers, and nitrogen-doped carbon.

Preferably, the solid electrolyte is a ceramic sheet made of Li _7-x La ₃ Zr _2-x T _x O ₁₂ , x=0-1, T is Al, Ta, Nb, W, Ga, Y, Te At least one, the thickness of the solid electrolyte is 0.1 μm-10mm.

Preferably, the solid-state secondary lithium battery further includes a negative electrode coated on the other side of the solid electrolyte, an electrode collector, a packaging material, conductive tabs and/or poles.

Preferably, the composition of the negative electrode includes lithium, a lithium alloy and/or a compound containing metallic lithium, wherein the content of lithium in the lithium alloy is at least 20 wt%, and the lithium alloy also contains Mg, Ca, B, Al, Ga, In , at least one of Si, Ge, Sn, Pb, Sb;

The lithium metal-containing composite contains at least 20 wt% lithium metal, and also contains carbon particles, carbon nanotubes, carbon fibers, graphene, graphite flakes, porous metals, porous carbon, inert oxides and/or copper powder.

Preferably, the material of the positive electrode collector includes stainless steel, Ni, Al and/or Ti.

Preferably, the operating temperature of the solid secondary lithium battery is from room temperature to 150°C, preferably, the operating temperature is 60-100°C.

In addition, the present invention also provides a method for preparing the above-mentioned solid-state secondary lithium battery, comprising:

1) According to the composition of the positive electrode, prepare a slurry containing the composition of the positive electrode;

2) coating the slurry prepared in step 1) on one side of the solid electrolyte, and then compacting and drying the polymer to solidify;

3) Prepare the negative electrode on the other side of the solid electrolyte.

Beneficial effects of the present invention:

1. Compared with other garnet-type all-solid-state batteries, the biggest difference of the present invention is that the composite positive electrode uses a polymer added with lithium-ion conductive materials to transmit lithium ions to improve lithium ion conductance, and at the same time, the excellent bonding performance of the polymer ensures that the composite positive electrode is compatible with ceramic inorganic materials. Solid electrolyte forms good solid-solid contact and reduces interface resistance;

2. This hybrid preparation scheme does not require high-temperature treatment of the active material, which is simpler and energy-saving. At the same time, the structure of the active material is maintained, and it has good cycle performance and rate performance. More than 93%, Coulombic efficiency is more than 99%;

3. This solid-state battery can work normally from room temperature to 150°C, which solves the high-temperature safety problem of liquid batteries. Within a certain range, the higher the temperature, the better the electrochemical performance, which can meet the application of batteries in special occasions, such as electric vehicles and space fields ;

4. The garnet-type solid electrolyte is used as a support, and lithium metal can be directly used as the negative electrode material, which can significantly increase the energy density of the battery.

Description of drawings

Fig. 1 is a schematic structural view of an all-solid-state secondary lithium battery in one embodiment of the present invention (shown in the figure is the cross-section of each component of the device), wherein, 1-negative metal lithium, 2-garnet type ceramic electrolyte sheet, 3 -Positive electrode active particles, 4-polymer, lithium salt and conductive carbon (3 and 4 constitute the polymer composite positive electrode), 5-stainless steel sheet, 6-encapsulation material;

Fig. 2 is the XRD pattern (2a) and room temperature AC impedance spectrum (2b) of Li _7-x La ₃ Zr _{2-x Tax} O ₁₂ (LLZTO) ceramic sheet in the present invention;

3 is a cross-sectional SEM image (3a) and a surface SEM image (3b) of an all-solid-state battery in Example 2 of the present invention;

Figure 4 is the first 10 charge-discharge curves (4a) of 1# all-solid-state battery at 0.05C rate and 60°C in the present invention, and the first 50 cycles of 1# all-solid-state battery at 60°C and 0.05C rate in the present invention performance (4b);

Figure 5 shows the rate performance of 2# all-solid-state battery at 60°C in the present invention;

Figure 6 shows the first 100 cycle performance of 3# all-solid-state battery in the present invention at 100°C and 1C rate;

Fig. 7 shows the rate performance of the 4# all-solid-state battery in the present invention at room temperature (25°C).

detailed description

The present invention will be further described below in conjunction with the drawings and the following embodiments. It should be understood that the drawings and the following embodiments are only used to illustrate the present invention rather than limit the present invention.

The purpose of the present invention is to propose a hybrid scheme using a polymer composite positive electrode combined with a garnet-type solid electrolyte in view of the disadvantages of high temperature difficulties and complicated processes in the structure of an all-solid-state lithium battery based on a garnet-type solid electrolyte.

The invention provides a novel chip-type solid-state secondary lithium battery supported by a garnet-type solid electrolyte. The support body; the negative electrode, including lithium, lithium alloy or metal lithium compound, forms a good interfacial contact with one side of the ceramic sheet; the positive electrode is made of positive active material, polymer, lithium ion conductor and conductive carbon composite, and The other side of the ceramic sheet forms a good interface contact; the electrode current collector is composed of a metal foil that is in stable chemical and electrochemical contact with the electrode material.

Preferably, in the lithium alloy, the content of lithium in the lithium alloy is at least 20wt%, and the lithium alloy also contains one or more of Mg, Ca, B, Al, Ga, In, Si, Ge, Sn, Pb, Sb ; Lithium-containing composites, containing at least 20wt% lithium metal, also containing carbon particles, carbon nanotubes, carbon fibers, graphene, graphite flakes, porous metals, porous carbon, inert oxides and/or copper powder.

Preferably, the garnet-type solid electrolyte is Li _7-x La ₃ Zr _2-x T _x O ₁₂ (x=0-1, T=Al, Ta, Nb, W, Ga, Y, Te, etc.) ceramics Sheet, thickness 0.1μm-10mm.

Preferably, in the polymer composite electrode, the polymer can be one or two blends of PEO, PVdF, PMMA, PAN and their copolymers.

Preferably, in the polymer composite electrode, the lithium ion conductor can be lithium salt LiClO ₄ , LiPF ₆ , LiAsF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , LiN(CF ₃ SO ₂ ) ₂ (LiTFSI), LiN(C ₂ F ₅ SO ₂ ) ₂ (LiBETI), LiPF ₃ (CF ₃ CF ₂ ) ₃ (LiFAP), LiBF ₃ CF ₃ CF ₂ (LiFAB), LiC(CF ₃ SO ₂ ) ₃ (LiTFSM), LiB(C ₂ O ₄ ) ₂ (LiBOB), LiBF ₂ (CO ₂ ) ₂ (LiODFB), one or more of the polymer lithium borate salt PLTB, or lithium lanthanum zirconium oxide, lithium lanthanum titanium oxide, lithium titanium aluminum phosphate, silicon phosphate One or several kinds of powder materials such as lithium.

Preferably, in the polymer composite electrode, the positive active material can be LiFePO ₄ , LiCoO ₂ , LiMn ₂ O ₄ , LiNi _0.5 Mn _1.5 O ₄ , ternary material LiNi _x Co _y Mn _1-xy O ₂ or lithium-rich manganese Base material Li[Li _x M _1-x ]O ₂ (M=Ni, Co, Mn or any combination).

Preferably, in the polymer composite electrode, the conductive material carbon may be one or more of acetylene black, graphite, graphene, graphene oxide, porous carbon, carbon nanotube, carbon fiber, and nitrogen-doped carbon.

Preferably, the positive current collector can be stainless steel, Ni, Al, Ti foil or their modified materials.

Preferably, the all-solid-state lithium battery also includes a battery packaging material for packaging the negative electrode, solid electrolyte layer, and polymer composite positive electrode, and conductive tabs and poles that can be used at operating temperatures.

Preferably, the working temperature of the all-solid secondary lithium battery is from room temperature to 150°C, preferably 60-100°C.

Preferably, the preparation method of the all-solid-state lithium battery is characterized by comprising the following steps:

1) According to the chemical formula Li _7-x La ₃ Zr _2-x T _x O ₁₂ (x=0-1, T=Al, Ta, Nb, W, Ga, Y, Te, etc.) The molar ratio of LiOH, La(OH) ₃ , ZrO ₂ and corresponding oxides T _x O _y is selected as raw materials, wherein the excess of LiOH is 5-20%, it is ball-milled in an alcohol medium for 10-30 hours and dried, and then Calcining at 850-1000°C for 6-10 hours to obtain Li _7-x La ₃ Zr _2-x T _x O ₁₂ ceramic powder. Transfer the ceramic powder into a carbon mold, and sinter it under Ar atmosphere by hot pressing at 1000-1200°C and 15MPa for 1-2 hours. Then processed into ceramic sheets of required thickness and size;

2) In a dry atmosphere, add an appropriate amount of lithium ion conductor and organic solvent into the mortar to fully disperse or dissolve the lithium ion conductor material, and then add the positive electrode active material, conductive carbon material and polymer solution to grind together to obtain a well-mixed Composite positive electrode. Wherein positive electrode active material: carbon: polymer: the mass ratio of lithium ion conductor is 10:2:1:z, z=0-10;

3) Apply a certain amount of composite positive electrode to one side of the ceramic sheet, cool it naturally at room temperature, then dry it in a drying oven, compact it with a stainless steel plate, and finally dry it in a vacuum drying oven to completely volatilize the organic solvent. curing polymer;

4) A lithium metal electrode and a current collector are prepared on the other side of the dried composite cathode-coated ceramic sheet, and then packaged, without adding electrolytes such as EC and PC during the assembly process.

Beneficial effects of the present invention:

1. Compared with other garnet-type all-solid-state batteries, the biggest difference of the present invention is that the composite positive electrode uses a polymer added with lithium-ion conductive materials to transmit lithium ions to improve lithium ion conductance, and at the same time, the excellent bonding performance of the polymer ensures that the composite positive electrode is compatible with ceramic inorganic materials. Solid electrolyte forms good solid-solid contact and reduces interface resistance;

2. This hybrid preparation scheme does not require high-temperature treatment of the active material, which is simpler and energy-saving. At the same time, the structure of the active material is maintained, and it has good cycle performance and rate performance. More than 93%, Coulombic efficiency is more than 99%;

3. This solid-state battery can work normally from room temperature to 150°C, which solves the high-temperature safety problem of liquid batteries. Within a certain range, the higher the temperature, the better the electrochemical performance, which can meet the application of batteries in special occasions, such as electric vehicles and space fields ;

4. The garnet-type solid electrolyte is used as a support, and lithium metal can be directly used as the negative electrode material, which can significantly increase the energy density of the battery.

The invention provides a new chip-type all-solid-state secondary lithium battery supported by a garnet-type solid electrolyte. It is characterized by a ceramic sheet of garnet-type solid electrolyte as a support. On one side of the ceramic, a composite positive electrode composed of polymer, lithium ion conductor, conductive carbon and electrode material is coated, and a good interface is formed between the two; On the other hand, deposit or press lithium, lithium alloys or composites containing metallic lithium as negative electrodes. The advantage of the composition of the composite positive electrode is to improve the conductivity of the positive electrode while effectively reducing the solid/solid interfacial resistance between the electrode/electrolyte. This solid-state battery construction method is simple and gentle, and does not require high-temperature processing. Batteries constructed with commonly used materials such as LiFePO ₄ exhibit excellent cycle and rate performance at 25, 60, and 100 °C. The battery constructed and produced by the invention can effectively solve the safety problem of the secondary lithium battery under the premise of ensuring high performance, and is of great significance for the development of secondary batteries used in the fields of electric vehicles and energy storage.

The working mechanism of the solid-state battery of the present invention is:

The solid-state battery does not add any organic solvents. In the polymer composite electrode, Li ⁺ forms a complex with the polymer. Through the repeated movement of the polymer chain segment, Li ⁺ and the polymer continue to dissociate and complex, and move forward at the same time. Thus conducting Li ⁺ , high temperature helps polymer chain segment movement, so the ion conductivity is higher when the temperature increases within a certain range.

Examples are given below to describe the present invention in detail. It should also be understood that the following examples are only used to further illustrate the present invention, and should not be construed as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art according to the above contents of the present invention all belong to the present invention scope of protection. The specific process parameters and the like in the following examples are only examples of suitable ranges, that is, those skilled in the art can make a selection within a suitable range through the description herein, and are not limited to the specific values exemplified below.

Example 1

A new hybrid all-solid-state secondary lithium battery based on garnet-type solid electrolyte. The structure of the device is shown in Figure 1. The negative electrode 1, solid electrolyte layer 2, and polymer composite positive electrodes 3 and 4 are used, as follows:

Solid electrolyte layer: use high-density Li _7-x La ₃ Zr _{2-x Tax} O ₁₂ (LLZTO) ceramic sheets (density greater than 96%), which can not only transport lithium ions but also protect the electrolyte layer of metal lithium, The thickness is 0.1μm-10mm;

Polymer composite positive electrode: In an inert atmosphere glove box, add appropriate amount of lithium salt and NMP into the agate mortar to fully dissolve the lithium salt, then add LiFePO ₄ and conductive carbon into the mortar, and finally take the pre-prepared PVdF solution (solvent NMP) was transferred to a mortar and grinded with a pestle to obtain a uniformly distributed composite positive electrode, wherein the mass ratio of LiFePO ₄ :C:PVdF:lithium salt was 10:2:1:x, x=0-10. Apply a certain amount of composite positive electrode to one side of the ceramic sheet with a scraper, cool it naturally at room temperature, then dry it in a drying oven, compact it with a stainless steel plate, and finally dry it in a vacuum drying oven to completely volatilize the solvent NMP to solidify the polymer;

Negative electrode: Place the ceramic sheet coated with the polymer composite positive electrode in an inert atmosphere glove box, then press the negative metal lithium sheet on the other side of the ceramic electrolyte sheet, and then use it to assemble the battery described in Figure 1. The battery was then tested at room temperature (25°C), 60°C, and 100°C.

Example 2

A novel hybrid all-solid-state secondary lithium battery based on a garnet-type solid electrolyte, the structure of the device is the same as in Example 1. The preparation method of the solid electrolyte layer is the same as in Example 1, and the relative density of the LLZTO ceramic sheet is 99%. Its XRD is shown in Figure 2a, and it can be seen that the main phase of the ceramic is a cubic garnet structure. Using a circular Li electrode as the test electrode, the electrical performance of the ceramic sample was tested at room temperature, and its AC impedance spectrum was obtained as shown in 2b. The room temperature ionic conductivity was calculated to be 6.6×10 ^-4 S·cm ^{- 1} .

Example 3

A novel hybrid all-solid-state secondary lithium battery based on a garnet-type solid electrolyte. The structure of the device is the same as that of Example 1. The negative electrode 1, solid electrolyte layer 2, polymer composite positive electrode 3 and 4 are used, and the details are as follows:

The solid electrolyte layer that adopts is the same as embodiment 1,2;

Negative electrode preparation step is with embodiment 1;

The mass ratio of polymer composite positive electrode LiFePO ₄ :C:PVdF:lithium salt is 10:2:1:5 (1# solid state battery);

Battery test temperature: 60°C;

The cross-sectional SEM secondary electron image of the composite cathode/LLZTO is shown in Figure 3a, and Figure 3b is the SEM backscattered electron image of the composite cathode surface. Figure 4a is the first 10 charge-discharge curves of 1# solid-state battery at 60°C and 0.05C rate, and Figure 4b is the first 50 cycle curves of 1# solid-state battery at 60°C and 0.05C rate.

Example 4

A novel hybrid all-solid-state secondary lithium battery based on a garnet-type solid electrolyte. The structure of the device is the same as in Example 1. The negative electrode 1, solid electrolyte layer 2, and polymer composite positive electrodes 3 and 4 are used, as follows:

The solid electrolyte layer that adopts is with example 1,2,3;

Negative electrode preparation steps are with embodiment 1,3;

The mass ratio of polymer composite positive electrode LiFePO ₄ :C:PVdF:lithium salt is 10:2:1:7.5 (2# solid state battery);

Battery test temperature: 60°C;

Figure 5 shows the rate performance of 2# solid-state battery at 60°C at 0.05C, 0.1C, 0.2C, 0.5C and 1C current.

Example 5

A novel hybrid all-solid-state secondary lithium battery based on a garnet-type solid electrolyte. The structure of the device is the same as in Example 1. The negative electrode 1, solid electrolyte layer 2, and polymer composite positive electrodes 3 and 4 are used, as follows:

The solid electrolyte layer used is the same as that of Examples 1, 2, 3, and 4;

Negative electrode preparation steps are with example 1,3,4;

The mass ratio of the polymer composite positive electrode LiFePO ₄ :C:PVdF:lithium salt is 10:2:1:7.5, same as in Example 4;

Battery test temperature: 100°C (3# solid-state battery);

Figure 6 shows the cycle performance of 3# solid-state battery at 100°C and 1C for the first 100 cycles.

Example 6

A novel hybrid all-solid-state secondary lithium battery based on a garnet-type solid electrolyte. The structure of the device is the same as in Example 1. The negative electrode 1, solid electrolyte layer 2, and polymer composite positive electrodes 3 and 4 are used, as follows:

The solid electrolyte layer used is the same as in Examples 1, 2, 3, 4, and 5;

Negative electrode preparation steps are with embodiment 1,3,4,5;

The mass ratio of the polymer composite positive electrode LiFePO ₄ :C:PVdF:lithium salt is 10:2:1:7.5, same as examples 4 and 5;

Battery test temperature: 25°C (4# solid-state battery);

Figure 7 shows the rate performance of 4# solid-state battery at room temperature (25°C) at 0.05C, 0.1C, 0.2C, and 0.5C.

The present invention has the following significant advantages:

(1) The production method is gentle and simple

Traditional solid-state batteries based on garnet-type solid electrolytes require high-temperature sintering of electrodes and electrolytes, which easily leads to reactions between electrodes and/or electrolytes, and the process is complicated. This hybrid scheme uses the prepared ceramic solid electrolyte, and the ceramic-based all-solid-state battery prototype can be obtained as long as the conventional electrode slurry preparation technology and coating process are used. There is no need to perform high temperature treatment on the composite electrode, maintaining the performance of the active material;

(2) Long cycle life

The solid-state battery is charged and discharged at 0.05C and 1C at 60 and 100°C respectively. After 100 cycles, the capacity retention rate is above 93%, and the Coulombic efficiency is above 99%.

(3) High security

This solid-state battery does not add any organic solvents, and there is no danger at a high temperature of 100°C. In addition, the LLZTO solid electrolyte itself has high thermal stability, high corrosion resistance and electrochemical window, which greatly improves the safety performance of the system during operation. At the same time, it can improve the electrochemical window of solid-state batteries and is suitable for high-voltage cathode materials;

(4) Wide operating temperature range

The solid-state battery has good electrochemical performance at room temperature (25°C), 60°C, and 100°C. At the same time, the ionic conductivity of the polymer lithium salt and ceramic solid electrolyte increases with the increase of temperature, and the impedance of the entire battery is at 100 The ℃ is significantly lowered, reaching the level of liquid batteries, with high current charge and discharge capabilities, and it is expected that the battery performance will be further improved at higher temperatures, especially suitable for applications with temperature control.

Claims (9)

1. a solid-state serondary lithium battery, it is characterised in that in described solid-state serondary lithium battery, positive pole is coated in the side of solid electrolyte, positive pole composition includes positive electrode active materials, polymer, lithium ion conductor and conductive carbon, and wherein, positive electrode active materials includes LiFePO₄、LiCoO₂、LiMn₂O₄、LiNi_0.5Mn_1.5O₄、LiNi_xCo_yMn_1-x-yO₂And/or Li [Li_xM_1-x]O₂, M is at least one in Ni, Co, Mn, and polymer includes that at least one in PEO, PVdF, PMMA, PAN, lithium ion conductor include lithium salts, positive electrode active materials: conductive carbon: polymer: the mass ratio of lithium ion conductor is 10:2:1:z, z≤10.

Solid-state serondary lithium battery the most according to claim 1, it is characterised in that lithium ion conductor includes LiClO₄、LiPF₆、LiAsF₆、LiBF₄、LiCF₃SO₃、LiN(CF₃SO₂)₂、LiN(C₂F₅SO₂)₂、LiPF₃(CF₃CF₂)₃、LiBF₃CF₃CF₂、LiC(CF₃SO₂)₃、LiB(C₂O₄)₂、LiBF₂(CO₂)₂, polymerization lithium borate salt PLTB, lithium lanthanum zirconium oxygen, Li-La-Ti oxygen, titanium phosphate aluminum lithium, silicon lithium phosphate at least one.

Solid-state serondary lithium battery the most according to claim 1 and 2, it is characterised in that conductive carbon includes at least one in acetylene black, graphite, Graphene, graphene oxide, porous carbon, CNT, carbon fiber, nitrogen-doped carbon.

4. according to described solid-state serondary lithium battery arbitrary in claim 1-3, it is characterised in that solid electrolyte be material be Li_7-xLa₃Zr_2-xT_xO₁₂Potsherd, x=0-1, T are at least one in Al, Ta, Nb, W, Ga, Y, Te, and solid electrolyte thickness is 0.1 μm-10 mm.

5. according to described solid-state serondary lithium battery arbitrary in claim 1-4, it is characterised in that described solid-state serondary lithium battery also includes being coated in the negative pole of solid electrolyte opposite side, electrode current collecting body, encapsulating material, conduction lug and/or pole.

6. according to described solid-state serondary lithium battery arbitrary in claim 1-5, it is characterized in that, the composition of negative pole includes lithium, lithium alloy and/or the complex containing lithium metal, wherein, in lithium alloy, the content of lithium is at least 20 wt%, and lithium alloy is possibly together with at least one in Mg, Ca, B, Al, Ga, In, Si, Ge, Sn, Pb, Sb；

Complex containing lithium metal at least contains 20 The lithium metal of wt%, also comprises carbon granule, CNT, carbon fiber, Graphene, graphite flake, porous metals, porous carbon, indifferent oxide and/or copper powder.

7. according to described solid-state serondary lithium battery arbitrary in claim 1-6, it is characterised in that the material of plus plate current-collecting body includes rustless steel, Ni, Al and/or Ti.

8. according to described solid-state serondary lithium battery arbitrary in claim 1-7, it is characterised in that the operating temperature of solid-state serondary lithium battery is room temperature to 150 DEG C, it is preferable that operating temperature is 60-100 DEG C.

9. the preparation method of arbitrary described solid-state serondary lithium battery in claim 1-8, it is characterised in that including:

1) according to the composition of described positive pole, the preparation slurry containing positive pole composition；

2) slurry prepared by step 1) is coated on the side of solid electrolyte, then carries out being compacted, being dried so that polymer solidifies；

3) opposite side at solid electrolyte prepares negative pole.