Pretreatment method and application of conductive agent for all-solid-state battery

Abstract

The invention provides a pretreatment method and application of a conductive agent for an all-solid-state battery, and relates to the technical field of solid-state batteries. Specifically, the method comprises the following steps that a conductive agent is placed in a reducing atmosphere, the temperature is increased at the speed of 0.5 DEG C / min-5 DEG C / min, and after the temperature is increased to 750 DEG C-900 DEG C, heat preservation is conducted for 1 h-5 h; and keeping the temperature at 100-150 DEG C for 5-12 hours under a vacuum condition to obtain the modified conductive agent for the all-solid-state battery. By adopting a specific thermal reduction modification process, the interface side reaction between the conductive agent and the sulfide solid electrolyte in the all-solid-state battery is greatly reduced, the capacity fading of the solid-state battery in the charging and discharging process is inhibited, and the method has a good application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of solid-state batteries, and in particular to a pretreatment method and application of a conductive agent for an all-solid-state battery. Background Art

[0002] Traditional lithium-ion batteries typically use organic electrolytes as the electrolyte for ion transport. However, during battery cycling, uneven ion diffusion at the interface between the organic electrolyte and the negative electrode leads to excessively high local current density and the easy formation of lithium dendrites. As the cycle increases, lithium dendrites gradually form and pierce the battery separator, causing a short circuit and significantly reducing the battery life. Furthermore, organic electrolytes are flammable and volatile, leading to serious safety issues in organic electrolyte-based lithium-ion batteries. Solid-state electrolytes can avoid the above-mentioned shortcomings of organic electrolytes. At the same time, all-solid-state batteries based on solid-state electrolytes have attracted widespread attention due to their advantages such as high energy density and high safety.

[0003] Solid electrolytes lack fluidity and wettability, so electrolytes need to be added during the electrode preparation process as an ion transport medium between the active material and the electrolyte. However, in the positive electrode of all-solid-state lithium-ion batteries, taking the commonly used commercial transition metal layered oxide active materials as an example, the electronic conductivity is generally less than 10 -4 S / cm; therefore, it is imperative to improve the electronic conductivity of the positive electrode of all-solid-state batteries. Carbon-based conductive agents have become the first choice for constructing conductive networks in secondary battery electrodes due to their low density and high electronic conductivity. Sulfide solid electrolytes, as a widely used solid electrolyte, have high ionic conductivity, excellent mechanical properties and low synthesis temperature. Sulfide-based all-solid-state batteries are considered to be the most promising all-solid-state battery systems for commercialization. However, the oxygen-containing functional groups on the surface of the conductive agent will undergo uncontrollable adverse side reactions with the sulfide solid electrolyte; the products formed by this side reaction, such as sulfate, bridging sulfur, and phosphorus pentasulfide, have extremely low ion transport capabilities, which causes the charge transfer impedance at the positive electrode interface to continue to increase, resulting in a serious decline in the electrochemical performance of the battery. Therefore, the rational construction of the conductive network in the positive electrode is a major challenge in the current field of sulfide all-solid-state batteries.

[0004] In response to the above-mentioned defects, there is currently an existing technology that uses Ketjen black as a precursor and undergoes ultra-high temperature treatment at 2400°C to prepare hollow carbon nanoparticles whose surface does not have oxygen-containing functional groups. Sulfide all-solid-state batteries based on hollow carbon nanoparticles exhibit better electrochemical performance. However, the preparation of hollow carbon nanoparticles consumes a lot of energy and is difficult to use for industrial production. Patent CN202110820948 addresses the problem of interface instability between conductive agents and sulfide solid electrolytes and proposes a method for surface point coating of conductive agents. However, this will also weaken the surface electron transmission ability of the conductive agent, and a large amount of conductive agent must be added to achieve the establishment of a complete positive electrode conductive network.

[0005] Therefore, how to establish a complete conductive network in the positive electrode at a lower cost while inhibiting the interfacial side reactions between the conductive agent and the sulfide to ensure that the battery performance does not suffer serious performance degradation is an important research direction for the industrial development of sulfide all-solid-state batteries.

[0006] In view of this, the present invention is proposed. Summary of the Invention

[0007] The first purpose of the present invention is to provide a pretreatment method for a conductive agent for an all-solid-state battery, which is mainly used to solve the defects of the interfacial side reaction between the sulfide solid electrolyte and the conductive agent in the all-solid-state battery.

[0008] A second object of the present invention is to provide an all-solid-state battery.

[0009] The third object of the present invention is to provide an electrical device.

[0010] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are adopted: A method for pretreating a conductive agent for an all-solid-state battery comprises the following steps: S1. Place the conductive agent in a reducing atmosphere, heat it at a rate of 0.5°C / min to 5°C / min, and keep it at 750°C to 900°C for 1h to 5h; S2. Under vacuum conditions, keep the temperature at 100°C to 150°C for 5h to 12h to obtain a modified conductive agent for all-solid-state batteries.

[0011] Preferably, the conductive agent includes at least one of superconducting carbon black, graphene or carbon nanofiber.

[0012] Preferably, the reducing atmosphere comprises argon and hydrogen, and the volume ratio of the argon to the hydrogen is (8-10):1.

[0013] More preferably, the construction of the reducing atmosphere comprises the following step: continuously introducing the argon gas and the hydrogen gas into a closed heating device.

[0014] More preferably, the ventilation rate of the argon gas is 80-100 mL / min, and the ventilation rate of the hydrogen gas is 8-12 mL / min.

[0015] Preferably, the heating rate is 1°C / min to 3°C / min.

[0016] Preferably, the treated conductive agent is allowed to cool naturally to room temperature in a reducing atmosphere before step S2 is performed; wherein the room temperature is 20°C to 30°C.

[0017] An all-solid-state battery comprises a modified conductive agent prepared by the pretreatment method.

[0018] Preferably, the all-solid-state battery comprises a solid-state positive electrode, a solid-state negative electrode and an electrolyte layer; The solid-state electrode comprises a positive electrode active material and the modified conductive agent; The electrolyte layer includes a sulfide solid electrolyte.

[0019] More preferably, the sulfide solid electrolyte includes Li6PS5Cl, Li 10 GeP2S 12 、Li7P3S 11 、Li3PS4、xLi2S (100-x) At least one of P2S5.

[0020] More preferably, the positive electrode active material includes a layered transition metal oxide.

[0021] An electrical device comprises the all-solid-state battery.

[0022] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention provides a pretreatment method for a conductive agent for an all-solid-state battery. The method performs thermal reduction modification through a specific heat treatment process, thereby removing oxygen-containing functional groups on the surface of the conductive agent at a lower temperature, thereby solving the problem of interfacial side reactions between the sulfide solid electrolyte and the conductive agent in the all-solid-state battery.

[0023] (2) The all-solid-state battery prepared by using the modified conductive agent of the present invention can show weaker interfacial side reactions at high voltage when using sulfide as the solid electrolyte; the sulfide all-solid-state battery positive electrode can achieve the goal of weakening the deterioration process of the battery positive electrode interface caused by the conductive agent while fully utilizing the role of the conductive agent in establishing a conductive network. When different types of conductive agents are combined with specific positive electrode active materials, the battery shows a significant performance improvement at a lower conductive agent content, and the battery capacity retention rate is close to the level of carbon-free batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 Provided are Fourier transform infrared spectra of Super P and the modified Super P of Example 1; Figure 2 Provided are the first effect results of cyclic voltammetry tests for Example 1, Comparative Example 1, and a blank control group; Figure 3 Provided are the first cycle charge and discharge curves of Example 1, Comparative Example 1 and a blank control group at a current density of 0.1C; Figure 4 Provided are the cycling performance test graphs of Example 1, Comparative Example 1 and a blank control group at a current density of 0.1C; Figure 5 Provides a cycling performance test graph of Example 5, Comparative Example 2 and a blank control example at a current density of 0.1C; Figure 6 Provided are the first cycle charge and discharge curves of Example 9, Comparative Example 3 and a blank control at a current density of 0.1C; Figure 7 Provided are cycle performance test graphs of Example 9, Comparative Example 3 and a blank control example at a current density of 0.1C. DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but those skilled in the art will understand that the embodiments described below are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially. In addition, the terms "one", "two", "S1" etc. are only used for descriptive purposes and should not be understood as indicating or implying relative importance.

[0027] The first aspect of the present invention is to provide a method for pretreating a conductive agent for an all-solid-state battery, which mainly comprises the following steps: S1. Place the conductive agent in a reducing atmosphere, raise the temperature at a rate of 0.5°C / min to 5°C / min, and keep it at 750°C to 900°C for 1h to 5h; S2. Under vacuum conditions, keep the temperature at 100°C to 150°C for 5h to 12h to obtain a modified conductive agent for all-solid-state batteries.

[0028] As a preferred embodiment, the conductive agent includes one or more of superconducting carbon black (Super P), graphene, or carbon nanofiber (CNF).

[0029] It is worth noting that there are many conductive agents that can be used for solid-state batteries in the field, including carbon-based conductive agents such as acetylene black (AB), vapor-grown carbon fiber reinforcement (VGCF), or non-carbon-based metal-based conductive agents such as silver nanowires and copper nanowires, in addition to the types used in the present invention; however, in the process of the present invention, the above three conductive agents and their combinations are preferably used. Through the thermal reduction modification process of the present invention, oxygen-containing functional groups can be effectively removed, and good electrochemical performance levels can be achieved under conditions of lower conductive agent content levels, while other types of conductive agents are difficult to achieve the same level of effect.

[0030] On the one hand, when the conductive agent uses Super P, compared with the existing sulfide all-solid-state battery system that tends to use high-dimensional one-dimensional conductive agents such as VGCF, carbon fiber, carbon nanotubes, etc., the zero-dimensional conductive agent Super P with a particle morphology shows a lower matching degree with the sulfide all-solid-state battery system. However, after the thermal reduction process of the present invention, low-cost Super P can be applied to all-solid-state batteries and exhibit good electrochemical performance, which plays an important role in promoting the commercial development of sulfide all-solid-state batteries. When the solid-state positive electrode contains a low carbon content, an efficient electron transmission network can be established, performance improvement can be achieved, and the production cost of the battery is greatly reduced.

[0031] On the other hand, when the conductive agent is graphene or CNF, these two conductive agents are inherently more suitable for industrially produced sulfide solid-state batteries and can be more easily integrated into current mass production lines. At the same time, the resulting modified conductive agent weakens the interfacial side reactions between the conductive agent and the sulfide solid electrolyte with low energy consumption, inhibiting the battery's capacity decay during charge and discharge, and has very high commercial value. In addition, the modified conductive agent obtained from these two conductive agents can also achieve a significant improvement in battery performance, with the battery capacity retention rate approaching the level of carbon-free batteries, broadening research ideas for the development of conductive agents for sulfide solid-state batteries and possessing very high commercial value.

[0032] As a preferred embodiment, the reducing atmosphere comprises argon and hydrogen, and the volume ratio of the argon to the hydrogen is (80~100):(5~10); in some more preferred embodiments, the volume ratio is 90:10 or 95:5.

[0033] As a more preferred embodiment, since the pretreatment method of the present invention will continuously consume reducing gas, in order to keep the reducing atmosphere continuously in compliance with the above preferred embodiment, the construction of the reducing atmosphere includes: placing the conductive agent in a closed heating device, continuously introducing the argon gas and the hydrogen gas, and satisfying the above volume ratio.

[0034] However, it should be noted that in this embodiment, before heating, it is necessary to ensure that the closed heating equipment is completely filled with a reducing atmosphere without any air. Therefore, before heating, the argon and hydrogen can be continuously introduced for 20 minutes to 70 minutes, and then the temperature can be increased at the rate specified in the present invention.

[0035] As a further preferred embodiment, the ventilation rate of the argon gas is 80~100 (mL / min), including but not limited to any one of 80, 82, 85, 88, 90, 92, 95, 98, 100 (mL / min) or a numerical range consisting of any two thereof; the ventilation rate of the hydrogen gas is 5~10 (mL / min), including but not limited to any one of 5, 5.5, 6, 6.5, 7, 7..5, 8, 8.5, 9, 9.5, 10 (mL / min) or a numerical range consisting of any two thereof.

[0036] As a preferred embodiment, the heating rate is 1°C / min to 3°C / min.

[0037] As an optional embodiment, in step S1, the insulation temperature includes but is not limited to any one of 750, 760, 775, 780, 800, 820, 825, 840, 850, 860, 870, 880, 890, 900 (℃) or a numerical range consisting of any two of them; the insulation duration includes but is not limited to any one of 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 (h) or a numerical range consisting of any two of them.

[0038] As an optional embodiment, in step S2, the insulation temperature includes but is not limited to any one of 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150 (°C) or a numerical range consisting of any two of them; the insulation duration includes but is not limited to any one of 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12 (h) or a numerical range consisting of any two of them.

[0039] As a preferred embodiment, after step S1, the treated conductive agent is allowed to cool naturally to room temperature under a reducing atmosphere before proceeding to step S2; wherein the room temperature is 20°C to 30°C. It is understood that after cooling to room temperature, if the material needs to be transferred to the heat treatment equipment, planners in this field should do so in a fume hood or transfer the material as quickly as possible to minimize the material's exposure to air.

[0040] As a preferred embodiment, step S1 is performed in a tube furnace, and step S2 is performed in a vacuum oven.

[0041] As a preferred embodiment, the content of oxygen-containing functional groups in the modified conductive agent is ≤30 wt.%, and in some embodiments is about 27 wt.%, wherein the oxygen-containing functional groups include CO and C=O.

[0042] The second aspect of the present invention is to provide an all-solid-state battery, comprising a modified conductive agent prepared by the pretreatment method as described in the first aspect.

[0043] As a preferred embodiment, the all-solid-state battery includes a solid-state positive electrode, a solid-state negative electrode and an electrolyte layer; the solid-state electrode includes a positive electrode active material and the modified conductive agent; and the electrolyte layer includes a sulfide solid electrolyte.

[0044] As a preferred embodiment, the solid-state electrode also includes sulfide solid-state electrolysis.

[0045] As a preferred embodiment, the sulfide solid electrolyte includes Li6PS5Cl, Li 10 GeP2S 12 、Li7P3S 11 、Li3PS4、xLi2S (100-x) At least one of P2S5; As a preferred embodiment, the positive electrode active material includes layered transition metal oxides, including but not limited to lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium manganese oxide (LiMnO2), lithium nickel cobalt manganese oxide (LiNix Co y Mn 1-x-y O2), lithium nickel cobalt aluminum oxide (LiNi x Co y Al 1-x-y O2) or more.

[0046] As a more preferred embodiment, the positive electrode active material is a high-nickel NCM positive electrode active material, and more preferably NCM90.

[0047] As a preferred embodiment, the solid-state negative electrode includes but is not limited to at least one of indium-lithium alloy, metallic lithium, metallic indium or lithium-aluminum alloy.

[0048] It is understood that the present invention does not impose any restrictions on the preparation method of the all-solid-state battery, and it can be carried out by any conventional or unconventional process, such as conventional dry process, wet process, etc. in the art. In addition to the solid-state positive electrode, the solid-state negative electrode, and the electrolyte layer mentioned above, the all-solid-state battery may also include other necessary or non-essential functional elements or packaging components, etc., which can be arbitrarily selected and assembled by those skilled in the art.

[0049] The third aspect of the present invention is to provide an electrical device comprising the all-solid-state battery described in the third aspect. It is understood that the electrical device may be any device or apparatus that relies on electrical energy to operate or function, including but not limited to new energy vehicles, building electrical equipment, industrial appliances, and household and agricultural appliances. When the all-solid-state battery is included, any electrical device equipped with the all-solid-state battery may be an embodiment of the present invention. Example 1 (1) Place Super P in a corundum boat, place the corundum boat containing Super P in a tube furnace, and close the tube furnace.

[0050] (2) At room temperature, introduce an argon-hydrogen mixture into the tubular furnace at a flow rate of 90 mL / min for argon and 10 mL / min for hydrogen, and maintain this for 50 min.

[0051] (3) Gradually increase the temperature to 800°C at a heating rate of 2°C / min and maintain the thermal reduction temperature of 800°C for 3 h.

[0052] (4) Let it cool down to room temperature and take out the corundum porcelain boat.

[0053] (5) The treated material was transferred into a vacuum oven for drying at 120°C for 10 h.

[0054] (6) Quickly transfer the dried material to the glove box and keep it for later use.

[0055] Example 2: basically the same as Example 1, except that the temperature in step (3) is replaced with 750°C.

[0056] Example 3: basically the same as Example 1, except that the temperature in step (3) is replaced with 850°C.

[0057] Example 4: basically the same as Example 1, except that the temperature in step (3) is replaced with 900°C.

[0058] Example 5: is basically the same as Example 1, except that Super P is replaced by Graphene in step (1).

[0059] Example 6: is basically the same as Example 2, except that Super P is replaced by Graphene in step (1).

[0060] Example 7: is basically the same as Example 3, except that Super P is replaced by Graphene in step (1).

[0061] Example 8: is basically the same as Example 4, except that Super P is replaced by Graphene in step (1).

[0062] Example 9: is basically the same as Example 1, except that Super P is replaced by Carbon nanofiber in step (1).

[0063] Example 10: is basically the same as Example 2, except that Super P is replaced by Carbon nanofiber in step (1).

[0064] Example 11: basically the same as Example 3, except that Super P is replaced by Carbon nanofiber in step (1).

[0065] Example 12: is basically the same as Example 4, except that Super P is replaced by Carbon nanofiber in step (1).

[0066] Comparative Example 1: Super P was placed in a vacuum oven and dried at 120°C for 10 hours.

[0067] Comparative Example 2: Graphene was placed in a vacuum oven and dried at 120° C. for 10 h.

[0068] Comparative Example 3: The carbon nanofiber was placed in a vacuum oven and dried at 120° C. for 10 h.

[0069] Test example (1) Super P and the modified Super P obtained in Example 1 were detected by Fourier transform infrared spectroscopy. Figure 1 The test results are shown in Figure 1, where SP corresponds to the original Super P material and R-SP corresponds to the modified Super P obtained in Example 1. Figure 1 It can be clearly seen that the modification method of the present invention can effectively remove the oxygen-containing functional groups on the surface of the conductive agent.

[0070] (2) The conductive material (CA) prepared in each embodiment and comparative example was assembled to obtain a test all-solid-state battery (NCM 90 -CA / Li6PS5Cl / In-Li), the specific steps are as follows: in an argon glove box, ultra-high nickel NCM90 and conductive agent material (the addition amount is 1wt.% of the positive electrode material) are used as the positive electrode, Li-In alloy is used as the negative electrode, and Li6PS5Cl is used as the electrolyte. They are assembled in a pressure mold battery, wherein the test pressure is 2T, and the solid-state batteries for testing corresponding to the embodiments and comparative examples are obtained.

[0071] The batteries were subjected to 0.1C constant current charge-discharge tests and cyclic voltammetry tests using a constant current charge-discharge tester. In the 0.1C charge-discharge test, the charge step was first performed, with the current at the specific value at 0.1C, calculated based on the active material mass and the theoretical specific capacity. After the charge was completed, the discharge step was performed, with the current remaining constant during the charge and discharge process. The cyclic voltammetry test was performed at a sweep rate of 0.01V / s within the voltage range of 1.9V to 3.7V.

[0072] (2.1) If Figure 2 The example 1 (corresponding to Figure 2 LPSCI-R-SP in), Comparative Example 1 (corresponding to Figure 2 The results of the first effect in the cyclic voltammetry test of the LPSCI-SP in the blank control example are shown; Among them, the blank control group refers to the all-solid-state battery without any conductive material (corresponding to Figure 2 LPSCI-N in ).

[0073] Depend on Figure 2It can be seen from the first cycle cyclic voltammetry test of the battery that Super P and Li6PS5Cl exhibit a large oxidation current after experiencing high voltage, while the oxidation current of LPSCI-R-SP is greatly reduced, which indicates that the interfacial side reaction between R-SP and Li6PS5Cl is greatly weakened after Super P undergoes thermal reduction; further, the same performance is found in the subsequent 2 to 5 cycles of cyclic voltammetry tests, indicating that the method of the present invention can effectively weaken the side reaction between Super P and Li6PS5Cl in the high voltage range.

[0074] (2.2) If Figure 3 The example 1 (corresponding to Figure 3 1% R-SP in), Comparative Example 1 (corresponding to Figure 3 1% SP in) and blank control (corresponding to Figure 3 The first cycle charge and discharge curve of CA-free at 0.1C current density; Figure 3 It can be seen that the battery shows a significant increase in first-cycle capacity.

[0075] (2.3) If Figure 4 The example 1 (corresponding to Figure 4 1% R-SP in), Comparative Example 1 (corresponding to Figure 4 1% SP in) and blank control (corresponding to Figure 4 CA-free in the cycle performance test diagram at 0.1C current density; combined with Figure 4 The test showed that the capacity retention rate of the solid-state battery corresponding to Example 1 was 86.1%, which was significantly improved compared with Comparative Example 1.

[0076] (2.4) If Figure 5 Example 5 (corresponding to Figure 5 1% R-GPE in), Comparative Example 2 (corresponding to Figure 5 1% GPE in) and blank control (corresponding to Figure 5 CA-free in the cycle performance test diagram at 0.1C current density; combined with Figure 5 The test shows that the capacity retention rate of the solid-state battery corresponding to Example 5 is 84.7%, which is greatly improved compared with Comparative Example 2.

[0077] (2.5) If Figure 6 Example 9 (corresponding to Figure 6 1% R-CNF in), Comparative Example 3 (corresponding to Figure 6 1% CNF in) and blank control (corresponding to Figure 6 The first cycle charge and discharge curve of CA-free at 0.1C current density; Figure 6 It can be seen that the solid-state batteries of the embodiments show a significant improvement in first-cycle capacity; the first-cycle capacities of the batteries of Comparative Example 3 and Example 9 are 134.3 mAh / g and 145.0 mAh / g, respectively, and the first-cycle coulombic efficiencies are 74.1% and 75.2%, respectively.

[0078] (2.6) If Figure 7 Example 9 (corresponding to Figure 7 1% R-CNF in), Comparative Example 3 (corresponding to Figure 7 1% CNF in) and blank control (corresponding to Figure 7 CA-free in the cycle performance test diagram at 0.1C current density; combined with Figure 7 After testing, it was shown that the capacity retention rate of the solid-state battery corresponding to Example 9 was 82.6%, which was significantly improved compared with Comparative Example 3.

[0079] Table 1

[0080] Although the present invention has been illustrated and described using specific embodiments, it should be appreciated that the above embodiments are merely intended to illustrate the technical solutions of the present invention rather than to limit them. Those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced by equivalents, without departing from the spirit and scope of the present invention. However, these modifications or replacements do not deviate from the essence of the corresponding technical solutions within the scope of the technical solutions of the embodiments of the present invention. Therefore, this means that all such replacements and modifications within the scope of the present invention are included in the appended claims.

Claims

1. A method for pretreating a conductive agent for an all-solid-state battery, characterized in that: The steps include: S1. Place the conductive agent in a reducing atmosphere, heat it at a rate of 0.5°C / min to 5°C / min, and keep it at 750°C to 900°C for 1h to 5h; S2. Under vacuum conditions, keep the temperature at 100°C to 150°C for 5h to 12h to obtain a modified conductive agent for all-solid-state batteries.

2. The pretreatment method according to claim 1, wherein The conductive agent includes at least one of superconducting carbon black, graphene or carbon nanofiber.

3. The pretreatment method according to claim 1, characterized in that The reducing atmosphere includes argon and hydrogen, and the volume ratio of the argon to the hydrogen is (80-100): (5-10).

4. The pretreatment method according to claim 3, characterized in that The construction of the reducing atmosphere comprises the following steps: continuously introducing the argon gas and the hydrogen gas into a closed heating device; Preferably, the ventilation rate of the argon gas is 80-100 mL / min, and the ventilation rate of the hydrogen gas is 5-10 mL / min.

5. The pretreatment method according to claim 1, characterized in that The heating rate is 1°C / min to 3°C / min.

6. The pretreatment method according to claim 1, characterized in that After step S1, the treated conductive agent is allowed to cool naturally to room temperature in a reducing atmosphere, and then step S2 is performed; wherein the room temperature is 20°C to 30°C.

7. An all-solid-state battery, characterized in that: The modified conductive agent is prepared by the pretreatment method according to claims 1 to 6.

8. The all-solid-state battery according to claim 7, characterized in that: The all-solid-state battery comprises a solid-state positive electrode, a solid-state negative electrode and an electrolyte layer; The solid-state electrode comprises a positive electrode active material and the modified conductive agent; The electrolyte layer includes a sulfide solid electrolyte.

9. The all-solid-state battery according to claim 8, characterized in that: The sulfide solid electrolyte includes Li6PS5Cl, Li 10 GeP2S 12 、Li7P3S 11 、Li3PS4、xLi2S (100-x) At least one of P2S5; Preferably, the positive electrode active material comprises a layered transition metal oxide.

10. An electrical device, characterized in that: Including the all-solid-state battery as described in any one of claims 7 to 9.

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