Silicon negative electrode sheet, sodium-ion solid-state battery and preparation method thereof

Abstract

The application relates to the technical field of batteries, and provides a silicon negative electrode sheet, a sodium-ion solid-state battery and a preparation method thereof.The silicon negative electrode sheet comprises a current collector and an active material layer arranged on the current collector; the active material layer comprises a binder and an active material; the binder comprises a polymer and a carboxylic acid compound which forms a gradient hydrogen bond with a main chain of the polymer; and the polymer contains an electrically-conductive polymer. By introducing a suitable functional group into the binder of the silicon negative electrode sheet to form a coating layer on the surface of silicon particles, the silicon negative electrode sheet can produce a dipole moment interaction with fluorides in an electrolyte when applied in a sodium-ion solid-state battery, so that the reduction of the fluorides is promoted, a lithium fluoride-rich SEI film is generated, the stability of the silicon negative electrode sheet is improved, and the cycle stability of the sodium-ion solid-state battery is finally improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a silicon negative electrode sheet, a sodium-ion solid-state battery and a preparation method thereof. BACKGROUND

[0002] Traditional liquid batteries have poor safety because they use organic solvents as electrolytes. Solid-state batteries are a type of battery that uses solid electrodes and solid electrolytes. In recent years, solid-state batteries have inherited the position of liquid batteries.

[0003] Sodium has a higher reserve than lithium in the earth's crust, and the cost is lower, which makes the manufacturing cost of sodium-ion solid-state batteries relatively low, and thus attracts much attention. Sodium-ion batteries are less likely to overheat or explode during use and charging and discharging, and have high safety. After tests such as short circuit, needle puncture and extrusion, there is no case of fire or explosion, and the battery works normally in a temperature range of-40℃ to 80℃, especially in a low-temperature environment, and has a high capacity retention rate.

[0004] The silicon negative electrode sheet has obvious application advantages in all-solid-state batteries in terms of the negative electrode used in sodium-ion solid-state batteries. The theoretical capacity of the silicon negative electrode sheet is more than ten times that of graphite-based negative electrode materials, which means that the silicon negative electrode sheet can store more electrical energy under the same volume or weight, thereby improving the energy density and endurance of the battery. In addition, the silicon negative electrode sheet charges faster and can significantly shorten the charging time. However, during charging and discharging, silicon will undergo a huge volume change, leading to particle breakage and pulverization, which affects the transmission efficiency of sodium ions. This volume change also leads to poor electrical contact and forms an "island effect", which further affects the performance of the battery and seriously affects the cycle life of the battery. The commonly used methods to improve the silicon negative electrode sheet include optimizing the structure of silicon particles, surface modification, electrolyte and binder modification. Among them, the binder suitable for the silicon negative electrode sheet has high requirements for mechanical properties and recoverability. Most binders mainly improve by constructing a cross-linked conductive network or designing a layered structure, but these methods aim to improve the tolerance of the binder to silicon expansion and reduce internal stress, thereby stabilizing the electrode structure, and the degree of improvement of the cycle stability and rate performance of the battery is limited. SUMMARY

[0005] In order to overcome the above-mentioned deficiencies in the prior art, the present application has carried out a large number of research tests, and it has been found that when the binder and the active material form an active material layer, the components of the binder participate in the electrochemical reduction, which helps the formation of SEI, and the binder usually contains many polar groups, which interact with electrolyte molecules, significantly affecting the distribution and decomposition of the electrolyte on the silicon surface. Therefore, through in-depth research, the structure of the binder is redesigned, and the mechanical properties of the binder and the influence of the binder on the chemical composition of SEI (solid electrolyte interface) are fully considered.

[0006] Specifically, in the first aspect, the application provides a silicon negative electrode sheet, a sodium ion solid-state battery and a preparation method thereof. Specifically, by introducing a suitable functional group into the binder of the silicon negative electrode sheet, a coating layer is formed on the surface of the silicon particles. When applied in a sodium ion solid-state battery, it can interact with the fluoride in the electrolyte to promote the reduction of these fluorides and generate a lithium fluoride-rich SEI film, thereby improving the stability of the silicon negative electrode sheet and ultimately improving the cycle stability of the sodium ion solid-state battery.

[0007] In the first aspect, the application provides a silicon negative electrode sheet, comprising a current collector, and further comprising: an active material layer arranged on the current collector.

[0008] The active material layer comprises a binder and an active material.

[0009] The binder comprises a polymer and a carboxylic acid compound forming a gradient hydrogen bond with the main chain of the polymer; and the polymer contains an electrically conductive polymer.

[0010] The application optimizes the structure of the binder, which comprises a polymer and a carboxylic acid compound forming a gradient hydrogen bond with the main chain of the polymer, and the polymer contains an electrically conductive polymer. On the one hand, the binder forms a "stiff with soft" polymer network main chain combined by gradient hydrogen bonds and covalent bonds. Specifically, the carboxylic acid compound forms a gradient hydrogen bond between the polymers, which gives the binder the ability to dissipate stress. On the other hand, the carboxylic acid compound on the surface of the active material also interacts with the fluoride in the electrolyte to preferentially attract fluoride to the surface of the active material. Moreover, the electrically conductive polymer (such as polypyrrole) in the polymer, which has electronic conductivity, can provide abundant electrons to promote the reduction of these fluorides and generate a lithium fluoride-rich SEI to protect the active material. Ultimately, the silicon negative electrode sheet is stable in macro and mesoscopic scales.

[0011] According to the silicon negative electrode sheet provided by the application, the carboxylic acid compound is selected from one or more than two combinations of citric acid, propane tricarboxylic acid and butane tetracarboxylic acid, and preferably, the carboxylic acid compound can be selected from one or more than two combinations of CAS: 77-92-9, CAS: 125139-13-1 and CAS: 16922-05-7.

[0012] In experiments, it is found that the above-mentioned carboxylic acid compound has good compatibility with the polymer, which is more conducive to forming the above-mentioned gradient hydrogen bond and constructing covalent bonds between the polymers to form a "stiff with soft" polymer network main chain.

[0013] The silicon negative electrode plate provided by the application, wherein the active material comprises a silicon-based material, and the silicon-based material is silicon particles, preferably micron silicon particles;

[0014] Preferably, the active material further comprises a carbon-based material.

[0015] Further preferably, the carbon-based material is selected from one or a combination of more than one of hard carbon, soft carbon and graphite; preferably hard carbon.

[0016] Most preferably, the active material contains silicon particles and hard carbon in a mass ratio of (4-7):(1-4.5).

[0017] The mass ratio of the silicon particles and the hard carbon in the application can be any value or a range of values formed by any value in 4:1, 4.5:1, 5:1, 5.5:1.5, 6:2, 6.5:2.5, 6.5:3.5, 6.5:4 and 7:4.5.

[0018] By using silicon particles and hard carbon as the active material of the silicon negative electrode plate of the application and optimizing the ratio of the two within the above range, the structural performance advantages of the silicon particles and the hard carbon can be fully utilized, so that the energy density, cycle stability and rate capability of the silicon negative electrode plate are better.

[0019] The silicon negative electrode plate provided by the application, wherein the polymer comprises an acrylic agent, an enolic agent and a polypyrrole;

[0020] Preferably, at least part of the polymers of different types form a covalent bond.

[0021] In a second aspect, the application further provides a preparation method of the silicon negative electrode plate as described above, comprising:

[0022] Mixing a polymer raw material, a carboxylic compound and an oxidizing agent to obtain a mixture with a viscosity of 100-20,000 mPa·s; the viscosity is preferably 500-3,500 mPa·s;

[0023] Mixing the mixture with an active material to obtain a slurry;

[0024] Forming an active material layer on a current collector by using the slurry.

[0025] The preparation method of the silicon negative electrode plate provided by the application, comprising:

[0026] Mixing an acrylic agent with a carboxylic compound to obtain a first mixture;

[0027] Mixing the first mixture with an enolic agent to obtain a second mixture;

[0028] Mixing the second mixture with a pyrrole agent and an oxidizing agent to obtain the mixture.

[0029] The acrylic reagent is selected from polyacrylic acid and / or acrylic acid; preferably, the acrylic reagent is selected from one or a combination of two or more of CAS: 9003-01-4, CAS: 79-10-7, CAS: 38071-32-8 and CAS: 9007-20-9;

[0030] The enolic reagent is selected from one or a combination of two or more of polyvinyl alcohol, vinyl alcohol and propylene alcohol; preferably, the enolic reagent is selected from one or a combination of two or more of CAS: 9002-89-5, CAS: 557-75-5, CAS: 107-18-6 and CAS: 98002-49-4;

[0031] The pyrrole reagent is selected from poly-pyrrole and / or pyrrole; preferably, the pyrrole reagent is selected from CAS: 109-97-7 and / or CAS: 30604-81-0;

[0032] The oxidizing agent is selected from peroxodisulfuric acid and / or ammonium persulfate; preferably, the oxidizing agent is selected from one or a combination of two or more of CAS: 7727-54-0, CAS: 52900-28-4 and CAS: 13445-49-3.

[0033] The present application can realize the construction of the gradient hydrogen bond and the polymer network main chain on the basis of the sufficient mixing of the above-mentioned specific materials in combination with the above-mentioned mixing order. The acrylic reagent and the enolic reagent can be either a polymer or a monomer as the raw material. The purpose of the present application is to form the "stiffness-in-flexibility-out" polymer network main chain by the functional groups of the raw materials, and the gradient hydrogen bond and the covalent bond. Different types of raw materials can be adjusted by adjusting the mixing temperature and time after the addition of each material. As long as the viscosity of the material system is within the range controlled by the present application, the gradient hydrogen bond and the "stiffness-in-flexibility-out" polymer network main chain structure can be realized.

[0034] The preparation method of the silicon negative electrode sheet provided by the present application comprises the following steps:

[0035] Mixing the acrylic reagent with the aqueous solution of the carboxylic compound for H1 hours to obtain a first mixture; wherein H1 is 2-8 hours;

[0036] Stirring the first mixture with the aqueous solution of the enolic reagent at 15-35°C for H2 hours to obtain a second mixture; wherein H2 is 3-10 hours;

[0037] The second mixture is placed in H3 for a period of time at 0-4 DEG C, then a pyrrole reagent and an oxidizing agent are added to obtain the mixture; wherein H3 is 10-60 min.

[0038] The ice bath can be used at 0-4 DEG C.

[0039] The mixture is mixed with an active material to obtain a slurry;

[0040] The slurry is coated on a current collector, and is first treated at a first temperature for a period of H4, and then is treated at a second temperature for a period of H5 to form an active material layer; preferably, the first temperature is 50-80 DEG C, the second temperature is 120-150 DEG C, H4 is 8-15 h, and H5 is 30-180 min.

[0041] In one aspect, the mixing degree of each raw material is optimized by adjusting the mixing order of each raw material, and in another aspect, the reaction degree of the mixture at different stages is further optimized by controlling the temperature and time of the above mixing, and especially by combining the oxidizing agent and the heat treatment process after coating, so that a polymer network main chain with a structure of "stiffness with flexibility" formed by gradient hydrogen bonds and covalent bonds can be obtained while ensuring that the slurry is easy to coat.

[0042] H1 in the application can be any value or a range of values formed by any value in 2 h, 3 h, 4 h, 5 h, 6 h, 7 h and 8 h.

[0043] H2 in the application can be any value or a range of values formed by any value in 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h and 10 h.

[0044] H3 in the application can be any value or a range of values formed by any value in 10-60 min.

[0045] The first temperature in the application can be any value or a range of values formed by any value in 50 DEG C, 60 DEG C, 70 DEG C and 80 DEG C.

[0046] The second temperature in the application can be any value or a range of values formed by any value in 120 DEG C, 130 DEG C, 140 DEG C and 150 DEG C.

[0047] H4 in the application can be any value or a range of values formed by any value in 8 h, 9 h, 10 h, 11 h, 12 h, 13 h, 14 h and 15 h.

[0048] The H5 in the application can be any value or a range of values formed by any value in 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min, 130 min, 140 min, 150 min, 160 min, 170 min and 180 min.

[0049] It is found through experiments that introducing the carboxylic compound in the form of an aqueous solution helps to build gradient hydrogen bonds between the carboxylic compound and the polymer, and preferably, the mass concentration of the carboxylic compound aqueous solution is 1-15%; specifically, the mass concentration of the carboxylic compound aqueous solution in the application can be any value or a range of values formed by any value in 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% and 15%.

[0050] The amount control of the acrylic reagent and the carboxylic compound is mainly used to achieve the balance of the gradient hydrogen bonds and the polymer network main chain, and if the content of the carboxylic compound is too high or too low, it is not conducive to obtaining the gradient hydrogen bonds; preferably, the molar ratio of the acrylic reagent to the carboxylic compound is (0.5-2):(0.5-2); specifically, the molar ratio of the acrylic reagent to the carboxylic compound in the application can be any value or a range of values formed by any value in 0.5:1, 0.5:2, 1:1, 1:0.5 and 2:0.5.

[0051] It is found through experiments that introducing the enolic reagent in the form of an aqueous solution is conducive to mixing it with the premixed mixture to build gradient hydrogen bonds and a polymer network main chain with better performance and “stiffness in the middle with softness”; preferably, the mass concentration of the enolic reagent aqueous solution is 1-15%; specifically, the mass concentration of the enolic reagent aqueous solution in the application can be any value or a range of values formed by any value in 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% and 15%.

[0052] Preferably, the mass ratio of the acrylic reagent to the enolic reagent is (5-15):1;

[0053] The amount of the oxidizing agent in the present application is determined based on the required reaction degree, if the amount of the oxidizing agent is too high, it will cause the viscosity of the slurry to be too high to be used for coating, and if the amount of the oxidizing agent is too low, it is not conducive to the formation of the above-mentioned gradient hydrogen bond and effective polymer network, preferably, the mass ratio of the pyrrole reagent and the oxidizing agent is (1-2.5):(0.1-1); specifically, the mass ratio of the pyrrole reagent and the oxidizing agent in the present application can be any value or a range consisting of any values in 1:1, 1:0.5, 1:0.1, 2:0.1 and 2.5:0.1.

[0054] The content of the pyrrole reagent is too low, which is not conducive to the formation of lithium fluoride-rich SEI, and the content is too high, which will lead to the decrease of mechanical properties on the one hand, and will destroy the structure of the polymer network main chain with "rigidity in the middle and softness on the sides", on the other hand, will also lead to the increase of interface impedance, affecting the charge transfer efficiency; preferably, the content of the pyrrole reagent is 0.1-0.5wt% of the total mass of the acrylic reagent; specifically, the content of the pyrrole reagent in the present application can be any value or a range consisting of any values in 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt% and 0.5wt% of the total mass of the acrylic reagent.

[0055] Preferably, the mass ratio of the silicon-based material in the active material to the mixture is (5-7):(0.5-3.5). Specifically, the mass ratio of the silicon-based material in the active material to the mixture in the present application can be any value or a range consisting of any values in 5:3.5, 5:2, 5:1, 5:0.5, 6:3, 6:2, 6:1, 7:3.5, 7:2, 7:1 and 7:0.5.

[0056] Specifically, when the acrylic reagent, the enol reagent and the pyrrole reagent are all selected as polymers, the preparation method of the silicon negative electrode sheet comprises:

[0057] (1) mixing the acrylic reagent with the aqueous carboxylic compound solution for H1 hours to make a uniform first mixture; wherein H1 is 4-6h; the mass concentration of the aqueous carboxylic compound solution is 1-5%; the molar ratio of the acrylic reagent to the carboxylic compound is (1-1.5):(1-1.5);

[0058] (2) stirring the first mixture with the aqueous enol reagent solution at 25-30℃ for H2 hours to make a uniform second mixture; wherein H2 is 6-8h; the mass concentration of the aqueous enol reagent solution is 5-8%; the mass ratio of the enol reagent to the acrylic reagent is (8-10):1;

[0059] (3) the second mixture is placed in an ice bath for H3, then pyrrole reagent and oxidant are added to obtain the mixture with the viscosity; wherein, H3 is 30-45 min; the mass ratio of pyrrole reagent to oxidant is (1.5-2.5):(0.5-1); the content of pyrrole reagent is 0.25-0.5 wt% of the total mass of acrylic reagent.

[0060] (4) the mixture is mixed with active material to obtain slurry; the active material is a mixture of micron silicon and hard carbon with a mass ratio of (4-7):(2-3); the mass ratio of silicon-based material in the active material to the mixture is (5-7):(1.5-2.5).

[0061] (5) the slurry is coated on the current collector, first treated at a first temperature for H4, then treated at a second temperature for H5 to form an active material layer; preferably, the first temperature is 50-80℃, the second temperature is 120-150℃, H4 is 8-11 h, and H5 is 90-110 min.

[0062] When the acrylic reagent, enol reagent and pyrrole reagent are all monomers, the preparation method of the silicon negative electrode sheet comprises:

[0063] (1) acrylic reagent is mixed with carboxylic compound aqueous solution for H1 to obtain a first mixture; wherein, H1 is 6.5-8 h; the mass concentration of carboxylic compound aqueous solution is 12-14%; the molar ratio of acrylic reagent to carboxylic compound is (0.5-1):(1-2).

[0064] (2) the first mixture is stirred with enol reagent aqueous solution at 15-30℃ for H2 to obtain a second mixture; wherein, H2 is 8-10 h; the mass concentration of enol reagent aqueous solution is 11-14%; the mass ratio of enol reagent to acrylic reagent is (5-6):1.

[0065] (3) the second mixture is placed in an ice bath for H3, then pyrrole reagent and oxidant are added to obtain the mixture with the viscosity; wherein, H3 is 45-60 min; the mass ratio of pyrrole reagent to oxidant is (2-2.5):(0.5-1); the content of pyrrole reagent is 0.35-0.5 wt% of the total mass of acrylic reagent.

[0066] (4) the mixture is mixed with active material to obtain slurry; the active material is a mixture of micron silicon and hard carbon with a mass ratio of (5.5-6):(1.5-2); the mass ratio of silicon-based material in the active material to the mixture is (5-7):(0.5-3).

[0067] (5) the slurry is coated on the current collector, and is treated at a first temperature for a time period H4, and then is treated at a second temperature for a time period H5, to form the active material layer; preferably, the first temperature is 50-80 DEG C, the second temperature is 140-150 DEG C, H4 is 13-15 h, and H5 is 165-180 min.

[0068] In a third aspect, the present application further provides a sodium-ion solid-state battery, comprising: a positive electrode sheet, a negative electrode sheet, and an electrolyte;

[0069] The electrolyte element facing the negative electrode sheet contains F;

[0070] The negative electrode sheet is the silicon negative electrode sheet as described above or the silicon negative electrode sheet prepared by the preparation method as described above.

[0071] Preferably, the electrolyte element facing the positive electrode sheet contains Na, P, S, and X; the X is Cl and / or Br.

[0072] According to the sodium-ion solid-state battery provided by the present application, the positive electrode sheet contains a P2-type structure sodium-ion positive electrode material.

[0073] Preferably, the sodium-ion positive electrode material is a high-entropy positive electrode material formed by mixing more than 7 kinds of elements; the more than 7 kinds of elements include Na, Ni, Cu, O, and other metal elements; the types of the other metal elements are more than 3.

[0074] Research shows that, compared with other types of positive electrode materials, the negative electrode sheet of the present application is combined with the above-mentioned type of positive electrode material, and the cycle stability and rate performance of the obtained solid-state battery are improved more significantly.

[0075] The silicon negative electrode sheet, the sodium-ion solid-state battery and the preparation method thereof provided by the present application optimize the structure of the binder, which includes a polymer and a carboxylic compound forming a gradient hydrogen bond with the main chain of the polymer, and the polymer contains a conductive polymer. On the one hand, the binder constructs a "stiff with soft" polymer network main chain formed by gradient hydrogen bond and covalent bond combination, and on the other hand, the carboxylic compound on the surface of the active material also produces a dipole interaction with the fluoride in the electrolyte, preferentially attracting fluoride to the surface of the active material, and at the same time, the conductive polymer (such as polypyrrole) with electronic conductivity in the polymer can provide abundant electrons to promote the reduction of these fluorides, generate fluorine-rich lithium SEI, and protect the active material. Finally, the silicon negative electrode sheet is stable in macroscopic and mesoscopic scales.

[0076] Further, the above-mentioned silicon negative electrode sheet of the present application is assembled with a high-entropy sodium-ion-like positive electrode material to obtain a full-solid-state battery, wherein the high-entropy sodium-ion-like positive electrode material is doped with at least three metal elements, which can strengthen the metal layer and effectively avoid cracks and the formation of O2 phase during the sodium extraction process, thereby inhibiting the phase transition of the positive electrode material under high pressure and enhancing the structural stability and sodium ion diffusion performance. Thus, the assembled high-entropy sodium-ion-like positive electrode material / silicon-carbon negative electrode full-solid-state battery has good cycle stability and rate performance. DETAILED DESCRIPTION

[0077] To make the objectives, technical solutions, and advantages of the present application clearer, the technical solutions in the present application will be described clearly and completely below. Obviously, the described embodiments are part of, rather than all of, the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0078] If a specific technology or condition is not specified in the embodiments, the technology or condition described in the literature in the art or according to the product manual is used. If the manufacturer of the reagent or instrument is not specified, it is a conventional product that can be purchased through a regular channel.

[0079] The silicon particles in the present application can be selected from factories such as Biti, Tianmu Pioneer, and Songshan.

[0080] The hard carbon in the present application can be selected from factories such as Japan Sumitomo, Biti, and Songshan.

[0081] Embodiment 1

[0082] A silicon negative electrode sheet, comprising a current collector and an active material layer provided on the current collector;

[0083] The active material layer comprises a binder and an active material.

[0084] The binder comprises a polymer containing polypyrrole and a carboxylic acid compound forming a gradient hydrogen bond with the main chain of the polymer.

[0085] The polymer comprises an acrylic polymer, an enol polymer, and a polypyrrole; and different types of polymers are partially combined by covalent bonds.

[0086] The present embodiment also provides a preparation method of the above-mentioned silicon negative electrode sheet, comprising:

[0087] (1) mixing polyacrylic acid (CAS: 9003-01-4) with a citric acid (CAS: 77-92-9) aqueous solution for a time H1 to obtain a first mixture; wherein H1 is 5 h; the mass concentration of the carboxylic acid compound aqueous solution is 1%; the molar ratio of the acrylic reagent to the carboxylic acid compound is 1:1;

[0088] (2) stirring the first mixture with a polyvinyl alcohol (CAS: 9002-89-5) aqueous solution at 25°C for a time H2 to obtain a second mixture; wherein H2 is 6 h; the mass concentration of the enolic reagent aqueous solution is 5.5%; the mass ratio of the acrylic reagent to the enolic reagent is 8:1;

[0089] (3) after the second mixture is placed in an ice bath for a time H3, polyazole and peroxodisulfuric acid are added to obtain a mixture with a viscosity of 1500 mPa·s; wherein H3 is 45 min; the mass ratio of the azole reagent to the oxidizing agent is 2:1; the content of the azole reagent is 0.25 wt% of the total mass of the acrylic reagent.

[0090] (4) mixing the mixture with an active material to obtain a slurry; the active material is a mixture of micron silicon and hard carbon with a mass ratio of 5.5:3; the mass ratio of the silicon-based material in the active material to the mixture is 5.5:1.5.

[0091] (5) the slurry is coated on a current collector, first treated at a first temperature for a time H4, then treated at a second temperature for a time H5, to form an active material layer; preferably, the first temperature is 75°C, the second temperature is 125°C, H4 is 8.5 h, and H5 is 90 min.

[0092] Example 2

[0093] A silicon negative electrode sheet, comprising a current collector, and an active material layer provided on the current collector;

[0094] The active material layer comprises a binder and an active material.

[0095] The binder comprises a polymer containing polyazole and a carboxylic acid compound forming a gradient hydrogen bond with the main chain of the polymer.

[0096] The polymer comprises an acrylic polymer, an enolic polymer, and a polyazole; different kinds of polymers are partially covalently bonded.

[0097] The embodiment also provides a preparation method of the silicon negative electrode sheet as above, comprising:

[0098] (1) mixing the acrylic reagent (CAS: 38071-32-8) with the carboxylic acid aqueous solution for a time H1 to obtain a first mixture; wherein H1 is 4.5 h; the mass concentration of the carboxylic acid aqueous solution is 3%; the molar ratio of the acrylic reagent to the carboxylic acid compound is 1.5:1;

[0099] (2) stirring the first mixture with the polyvinyl alcohol 2099 aqueous solution at 27℃ for a time H2 to obtain a second mixture; wherein H2 is 7 h; the mass concentration of the enolic reagent aqueous solution is 6.5%; the mass ratio of the acrylic reagent to the enolic reagent is 9:1;

[0100] (3) after the second mixture is placed in an ice bath for a time H3, polyazole and ammonium persulfate are added to obtain a mixture with a viscosity of 2500 mPa·s; wherein H3 is 40 min; the mass ratio of the pyrrole reagent to the oxidizing agent is 1.5:0.5; the content of the pyrrole reagent is 0.35wt% of the total mass of the acrylic reagent.

[0101] (4) mixing the mixture with the active material to obtain a slurry; the active material is a mixture of micron silicon and hard carbon with a mass ratio of 6:2; the mass ratio of the silicon-based material in the active material to the mixture is 6:2.

[0102] (5) coating the slurry on the current collector, first treating at a first temperature for a time H4, then treating at a second temperature for a time H5, to form an active material layer; preferably, the first temperature is 65℃, the second temperature is 130℃, H4 is 10 h, and H5 is 100 min.

[0103] Embodiment 3

[0104] A silicon negative electrode sheet, comprising a current collector, and an active material layer provided on the current collector;

[0105] The active material layer comprises a binder and an active material.

[0106] The binder comprises a polymer containing polyazole and a carboxylic acid compound forming a gradient hydrogen bond with the main chain of the polymer.

[0107] The polymer comprises an acrylic polymer, an enolic polymer, and a polyazole; and different types of polymers are partially covalently bonded.

[0108] The embodiment also provides a preparation method of the silicon negative electrode sheet as above, comprising:

[0109] (1) mixing polyacrylic acid (CAS: 9007-20-9) with a citric acid (CAS: 125139-13-1) aqueous solution for a time H1 to obtain a first mixture; wherein H1 is 5.5 h; the mass concentration of the carboxylic acid compound aqueous solution is 4%; the molar ratio of the acrylic reagent to the carboxylic acid compound is 1:1.5;

[0110] (2) stirring the first mixture with a polyvinyl alcohol (CAS: 98002-49-4) aqueous solution at 30°C for a time H2 to obtain a second mixture; wherein H2 is 8 h; the mass concentration of the enolic reagent aqueous solution is 7.5%; the mass ratio of the acrylic reagent to the enolic reagent is 10:1;

[0111] (3) after the second mixture is placed in an ice bath for a time H3, polyazole and peroxydisulfuric acid are added to obtain a mixture with a viscosity of 2000 mPa·s; wherein H3 is 35 min; the mass ratio of the azole reagent to the oxidizing agent is 2.5:1; the content of the azole reagent is 0.45 wt% of the total mass of the acrylic reagent.

[0112] (4) mixing the mixture with an active material to obtain a slurry; the active material is a mixture of micron silicon and hard carbon with a mass ratio of 6.5:2.5; the mass ratio of the silicon-based material in the active material to the mixture is 6.5:2.5.

[0113] (5) the slurry is coated on a current collector, first treated at a first temperature for a time H4, then treated at a second temperature for a time H5, to form an active material layer; preferably, the first temperature is 70°C, the second temperature is 135°C, H4 is 11 h, and H5 is 110 min.

[0114] Example 4

[0115] A silicon negative electrode sheet, comprising a current collector, and an active material layer provided on the current collector;

[0116] The active material layer comprises a binder and an active material.

[0117] The binder comprises a polymer containing polyazole and a carboxylic acid compound forming a gradient hydrogen bond with the main chain of the polymer.

[0118] The polymer comprises an acrylic polymer, an enolic polymer, and a polyazole; different kinds of polymers are partially covalently bonded.

[0119] The present embodiment also provides a preparation method of the above silicon negative electrode sheet, comprising:

[0120] (1) mixing acrylic acid with a citric acid (CAS: 77-92-9) aqueous solution for a mixing time H1 to make a first mixture uniform; wherein H1 is 8 h; the mass concentration of the carboxylic acid compound aqueous solution is 13%; the molar ratio of the acrylic acid reagent to the carboxylic acid compound is 0.5:1.5;

[0121] (2) stirring the first mixture with a vinyl alcohol aqueous solution at 15°C for a stirring time H2 to make a second mixture uniform; wherein H2 is 8 h; the mass concentration of the enolic reagent aqueous solution is 11%; the mass ratio of the acrylic acid reagent to the enolic reagent is 5:1;

[0122] (3) after the second mixture is placed in an ice bath for a time H3, pyrrole and peroxodisulfuric acid are added to make a mixture with a viscosity of 1000 mPa·s; wherein H3 is 60 min; the mass ratio of the pyrrole reagent to the oxidizing agent is 2.5:1; the content of the pyrrole reagent is 0.35 wt% of the total mass of the acrylic acid reagent.

[0123] (4) mixing the mixture with an active material to make a slurry; the active material is a mixture of micron silicon and hard carbon with a mass ratio of 6:2; the mass ratio of the silicon-based material in the active material to the mixture is 7:1.5.

[0124] (5) the slurry is coated on a current collector, first treated at a first temperature for a time H4, then treated at a second temperature for a time H5, to form an active material layer; preferably, the first temperature is 65°C, the second temperature is 150°C, H4 is 15 h, and H5 is 170 min.

[0125] Example 5

[0126] A silicon negative electrode sheet, comprising a current collector, and an active material layer provided on the current collector;

[0127] The active material layer comprises a binder and an active material.

[0128] The binder comprises a polymeric material containing poly-pyrrole and a carboxylic acid compound forming a gradient hydrogen bond with the main chain of the polymeric material.

[0129] The polymeric material comprises an acrylic polymer, an enolic polymer, and poly-pyrrole; and the different kinds of polymers are partially covalently bonded.

[0130] The present embodiment also provides a method for preparing the silicon negative electrode sheet as above, comprising:

[0131] (1) mixing acrylic acid with a propane tricarboxylic acid aqueous solution for a mixing time H1 to make a first mixture uniform; wherein H1 is 6.5 h; the mass concentration of the carboxylic acid compound aqueous solution is 14%; the molar ratio of the acrylic acid reagent to the carboxylic acid compound is 1:2.

[0132] (2) the first mixture is stirred with an aqueous propylene glycol solution at 20°C for H2 to obtain a second mixture; wherein H2 is 8.5 h; the mass concentration of the aqueous enolic reagent is 12.5%; the mass ratio of the acrylic reagent to the enolic reagent is 6:1;

[0133] (3) the second mixture is placed in an ice bath for H3, then pyrrole and ammonium persulfate are added to obtain a mixture with a viscosity of 1500 mPa·s; wherein H3 is 50 min; the mass ratio of the pyrrole reagent to the oxidizing agent is 2:0.7; the content of the pyrrole reagent is 0.4 wt% of the total mass of the acrylic reagent.

[0134] (4) the mixture is mixed with an active material to obtain a slurry; the active material is a mixture of micron silicon and hard carbon with a mass ratio of 5.5:1.5; the mass ratio of the silicon-based material in the active material to the mixture is 6.5:0.5.

[0135] (5) the slurry is coated on a current collector, and then treated at a first temperature for H4 and at a second temperature for H5 to form an active material layer; preferably, the first temperature is 70°C, the second temperature is 145°C, H4 is 14 h, and H5 is 180 min.

[0136] Embodiment 6

[0137] A silicon negative electrode sheet, comprising a current collector and an active material layer provided on the current collector.

[0138] The active material layer comprises a binder and an active material.

[0139] The binder comprises a polymeric compound containing polypyrrole and a carboxylic compound forming a gradient hydrogen bond with the main chain of the polymeric compound.

[0140] The polymeric compound comprises an acrylic polymer, an enolic polymer, and polypyrrole; and different kinds of polymers are partially covalently bonded.

[0141] The embodiment also provides a preparation method of the silicon negative electrode sheet, comprising:

[0142] (1) mixing acrylic acid and an aqueous citric acid (CAS: 125139-13-1) solution for H1 to obtain a first mixture; wherein H1 is 7.5 h; the mass concentration of the aqueous carboxylic compound is 12%; the molar ratio of the acrylic reagent to the carboxylic compound is 1.5:1;

[0143] (2) the first mixture is stirred with an aqueous vinyl alcohol solution at 35°C for H2 hours to obtain a second mixture; wherein H2 is 9.5 hours; the mass concentration of the aqueous vinyl alcohol reagent is 14%; the mass ratio of the acrylic reagent to the vinyl alcohol reagent is 5.5:1;

[0144] (3) the second mixture is placed in an ice bath for H3 hours, then pyrrole and a peroxodisulfuric acid mixture are added to obtain a mixture with a viscosity of 2000 mPa·s; wherein H3 is 45 minutes; the mass ratio of the pyrrole reagent to the oxidizing agent is 2:1; the content of the pyrrole reagent is 0.5% of the total mass of the acrylic reagent.

[0145] (4) the mixture is mixed with an active material to obtain a slurry; the active material is a mixture of micron silicon and hard carbon with a mass ratio of 6.5:1.75; the mass ratio of the silicon-based material in the active material to the mixture is 5:3.

[0146] (5) the slurry is coated on a current collector, and then treated at a first temperature for H4 hours and at a second temperature for H5 hours to form an active material layer; preferably, the first temperature is 75°C, the second temperature is 140°C, H4 is 13 hours, and H5 is 165 minutes.

[0147] Example 7

[0148] A silicon negative electrode sheet includes a current collector and an active material layer provided on the current collector.

[0149] The active material layer includes a binder and an active material.

[0150] The binder includes a polymeric compound containing polypyrrole and a carboxylic compound forming a gradient hydrogen bond with the main chain of the polymeric compound.

[0151] The polymeric compound includes an acrylic polymer, a vinyl alcohol polymer, and polypyrrole; and different types of polymeric compounds are partially covalently bonded.

[0152] The present embodiment also provides a preparation method of the silicon negative electrode sheet as described above, which includes:

[0153] (1) polyacrylic acid (CAS: 9003-01-4) is mixed with an aqueous citric acid solution for H1 hours to obtain a first mixture; wherein H1 is 8 hours; the mass concentration of the aqueous carboxylic compound is 8%; and the molar ratio of the acrylic reagent to the carboxylic compound is 1.5:1.

[0154] (2) the first mixture is stirred with an aqueous solution of an enolic reagent at 30°C for H2 to obtain a second mixture; wherein H2 is 3.5 h; the mass concentration of the aqueous solution of the enolic reagent is 8.5%; the mass ratio of the acrylic reagent to the enolic reagent is 9.5:1;

[0155] (3) the second mixture is placed in an ice bath for H3, and then polypyrrole and peroxydisulfuric acid are added to obtain a mixture with a viscosity of 500 mPa·s; wherein H3 is 40 min; the mass ratio of the pyrrole reagent to the oxidizing agent is 2.5:0.5; the content of the pyrrole reagent is 0.15 wt% of the total mass of the acrylic reagent.

[0156] (4) the mixture is mixed with an active material to obtain a slurry; the active material is a mixture of micron silicon and hard carbon with a mass ratio of 4.5:1; the mass ratio of the silicon-based material in the active material to the mixture is 6:2.

[0157] (5) the slurry is coated on a current collector, and then treated at a first temperature for H4 and at a second temperature for H5 to form an active material layer; preferably, the first temperature is 50°C, the second temperature is 150°C, H4 is 8.5 h, and H5 is 120 min.

[0158] Embodiment 8

[0159] A silicon negative electrode sheet includes a current collector and an active material layer provided on the current collector.

[0160] The active material layer includes a binder and an active material.

[0161] The binder includes a polymer containing polypyrrole and a carboxylic compound forming a gradient hydrogen bond with the main chain of the polymer.

[0162] The polymer includes an acrylic polymer, an enolic polymer, and polypyrrole; and different types of polymers are partially covalently bonded.

[0163] The embodiment also provides a preparation method of the silicon negative electrode sheet, including:

[0164] (1) polyacrylic acid (CAS: 9003-01-4) is mixed with an aqueous solution of citric acid (CAS: 77-92-9) for H1 to obtain a first mixture; wherein H1 is 5 h; the mass concentration of the aqueous solution of the carboxylic compound is 9%; and the molar ratio of the acrylic reagent to the carboxylic compound is 0.5:2.

[0165] (2) the first mixture is stirred with an aqueous vinyl alcohol solution at 15°C for H2 to make a second mixture; wherein H2 is 5 h; the mass concentration of the aqueous vinyl alcohol reagent is 10%; the mass ratio of the acrylic reagent to the vinyl alcohol reagent is 11:1;

[0166] (3) the second mixture is placed in an ice bath for H3, then pyrrole and ammonium persulfate are added to make a mixture with a viscosity of 750 mPa·s; wherein H3 is 50 min; the mass ratio of the pyrrole reagent to the oxidizing agent is 1.5:0.8; the content of the pyrrole reagent is 0.2 wt% of the total mass of the acrylic reagent.

[0167] (4) the mixture is mixed with an active material to make a slurry; the active material is a mixture of micron silicon and hard carbon with a mass ratio of 4.5:1; the mass ratio of the silicon-based material in the active material to the mixture is 6.5:2.5.

[0168] (5) the slurry is coated on a current collector, which is first treated at a first temperature for H4, then treated at a second temperature for H5 to form an active material layer; preferably, the first temperature is 80°C, the second temperature is 125°C, H4 is 12.5 h, and H5 is 150 min.

[0169] Example 9

[0170] A silicon negative electrode sheet includes a current collector and an active material layer disposed on the current collector.

[0171] The active material layer includes a binder and an active material.

[0172] The binder includes a polymer containing polypyrrole and a carboxylic compound forming a gradient hydrogen bond with the main chain of the polymer.

[0173] The polymer includes an acrylic polymer, a vinyl alcohol polymer, and polypyrrole; and different kinds of polymers are partially combined by covalent bonds.

[0174] The present embodiment also provides a preparation method of the above silicon negative electrode sheet, which includes:

[0175] (1) acrylic acid is mixed with an aqueous butane tetracarboxylic acid solution for H1 to make a first mixture; wherein H1 is 6.5 h; the mass concentration of the aqueous carboxylic compound is 10%; the molar ratio of the acrylic reagent to the carboxylic compound is 2:1.5;

[0176] (2) the first mixture is stirred with an aqueous vinyl alcohol solution at 20°C for H2 to make a second mixture; wherein H2 is 7 h; the mass concentration of the aqueous vinyl alcohol reagent is 9%; the mass ratio of the acrylic reagent to the vinyl alcohol reagent is 5:1.

[0177] (3) the second mixture is placed in an ice bath for a period of H3, then polypyrrole and peroxydisulfuric acid are added to obtain a mixture with a viscosity of 1250 mPa·s; wherein H3 is 55 min; the mass ratio of the pyrrole reagent to the oxidizing agent is 2.5:0.25; the content of the pyrrole reagent is 0.35 wt% of the total mass of the acrylic reagent.

[0178] (4) the mixture is mixed with an active material to obtain a slurry; the active material is a mixture of micron silicon and hard carbon with a mass ratio of 7:2.5; the mass ratio of the silicon-based material in the active material to the mixture is 7:1.5.

[0179] (5) the slurry is coated on a current collector, first treated at a first temperature for a period of H4, then treated at a second temperature for a period of H5, to form an active material layer; preferably, the first temperature is 65°C, the second temperature is 130°C, H4 is 10 h, and H5 is 130 min.

[0180] Embodiment 10

[0181] A silicon negative electrode sheet, comprising a current collector, and an active material layer provided on the current collector;

[0182] The active material layer comprises a binder and an active material.

[0183] The binder comprises a polymer containing polypyrrole and a carboxylic compound forming a gradient hydrogen bond with the main chain of the polymer.

[0184] The polymer comprises an acrylic polymer, an enol polymer, and polypyrrole; different kinds of polymers are partially combined by covalent bonds.

[0185] The embodiment also provides a preparation method of the silicon negative electrode sheet as above, comprising:

[0186] (1) mixing acrylic acid with a propanetricarboxylic acid aqueous solution for a period of H1 to make it uniform to obtain a first mixture; wherein H1 is 7.5 h; the mass concentration of the carboxylic compound aqueous solution is 7%; the molar ratio of the acrylic reagent to the carboxylic compound is 1.5:1;

[0187] (2) stirring the first mixture with a polyvinyl alcohol 2099 aqueous solution at 25°C for a period of H2 to make it uniform to obtain a second mixture; wherein H2 is 7.5 h; the mass concentration of the enol reagent aqueous solution is 6.5%; the mass ratio of the acrylic reagent to the enol reagent is 6.5:1;

[0188] (3) the second mixture is placed in an ice bath for a period of H3, then pyrrole and an oxidizing agent (CAS: 52900-28-4) are added to obtain a mixture with a viscosity of 1000 mPa·s; wherein H3 is 60 min; the mass ratio of the pyrrole reagent to the oxidizing agent is 1.75:0.45; the content of the pyrrole reagent is 0.25 wt% of the total mass of the acrylic reagent.

[0189] (4) the mixture is mixed with an active material to obtain a slurry; the active material is a mixture of micron silicon and hard carbon with a mass ratio of 6:3.5; the mass ratio of the silicon-based material in the active material to the mixture is 5.5:1.75.

[0190] (5) the slurry is coated on a current collector, and then treated at a first temperature for a period of H4 and treated at a second temperature for a period of H5 to form an active material layer; preferably, the first temperature is 75°C, the second temperature is 135°C, H4 is 11.5 h, and H5 is 155 min.

[0191] Embodiment 11

[0192] A silicon negative electrode sheet, comprising a current collector, and an active material layer provided on the current collector;

[0193] The active material layer comprises a binder and an active material.

[0194] The binder comprises a polymeric compound containing poly-pyrrole and a carboxylic compound forming a gradient hydrogen bond with the main chain of the polymeric compound.

[0195] The polymeric compound comprises an acrylic polymer, an enolic polymer, and poly-pyrrole; and different types of polymeric compounds are partially covalently bonded.

[0196] The embodiment also provides a preparation method of the silicon negative electrode sheet, comprising:

[0197] (1) acrylic acid is mixed with an aqueous solution of citric acid (CAS: 125139-13-1) for a period of H1 to obtain a first mixture; wherein H1 is 7 h; the mass concentration of the aqueous solution of the carboxylic compound is 6%; and the molar ratio of the acrylic reagent to the carboxylic compound is 2:0.5;

[0198] (2) the first mixture is stirred with an aqueous solution of polyvinyl alcohol 2099 at 25°C for a period of H2 to obtain a second mixture; wherein H2 is 8 h; the mass concentration of the aqueous solution of the enolic reagent is 5.5%; and the mass ratio of the acrylic reagent to the enolic reagent is 7.5:1;

[0199] (3) the second mixture is placed in an ice bath for a period of H3, then polypyrrole and ammonium persulfate are added to obtain a mixture with a viscosity of 3500 mPa·s; wherein H3 is 35 min; the mass ratio of the pyrrole reagent to the oxidizing agent is 2:0.35; the content of the pyrrole reagent is 0.5 wt% of the total mass of the acrylic reagent.

[0200] (4) the mixture is mixed with an active material to obtain a slurry; the active material is a mixture of micron silicon and hard carbon with a mass ratio of 5:1; the mass ratio of the silicon-based material in the active material to the mixture is 6.75:2.25.

[0201] (5) the slurry is coated on a current collector, and then treated at a first temperature for a period of H4 and treated at a second temperature for a period of H5 to form an active material layer; preferably, the first temperature is 80℃, the second temperature is 145℃, H4 is 12.5h, and H5 is 165min.

[0202] Application Example 1

[0203] The application example provides a sodium ion solid-state battery, which comprises a positive electrode sheet, a negative electrode sheet and an electrolyte.

[0204] The electrolyte I facing the positive electrode sheet is Na6PS5Cl 0.5 Br 0.5 ;

[0205] The electrolyte II facing the negative electrode sheet is Na6PS5Cl 0.5 Br 0.5 F 0.5 ;

[0206] The mass ratio of the electrolyte I to the electrolyte II is 1:1.

[0207] The negative electrode sheet is the silicon negative electrode sheet in the above embodiment 1, and the specific corresponding relationship is shown in Table 1.

[0208] The positive electrode material on the positive electrode sheet is Na 0.75 Ni 0.24 Cu 0.07 Zn 0.03 Mn 0.62 Mg 0.05 O2, NaNbOCl4 and conductive carbon black SP with a mass ratio of 60:30:10 are mixed and stirred uniformly to obtain.

[0209] The embodiment also provides an assembling process of the sodium ion solid-state battery, which is specifically as follows.

[0210] (1) 60mg of Na6PS5Cl 0.5 Br 0.5Put into the inner liner of alumina ceramic mold (diameter 10 mm), rotate the stainless steel electrode pressure head to the bottom of the mold, rotate the pressure head to flatten the powder, and then add 60 mg Na6PS5Cl 0.5 Br 0.5 F 0.5 , and press the electrolyte sheet into the pressure machine (parameters: 100 MPa, 30 s), and remove the excess electrolyte powder with an ear cleaning ball.

[0211] (2) Place the positive electrode sheet on the side facing Na6PS5Cl 0.5 Br 0.5 electrolyte, and place the negative electrode on the other side of the electrolyte sheet.

[0212] (3) Tighten the mold and the pressure head, and tighten the nut to obtain a solid-state mold battery; use blue electricity testing, and when the cycle test capacity retention rate of the battery is lower than 80% and the coulomb efficiency is lower than 98% during the test process, stop the test.

[0213] Application Examples 2-11

[0214] The same as Application Example 1, except that the silicon negative electrode sheet of Example 1 is replaced by the silicon negative electrode sheet of Examples 2-11, and the specific corresponding relationship is shown in Table 1 below.

[0215] Comparative Example 1

[0216] The same as Application Example 1, except that the binder used in the process of preparing the negative electrode sheet is PAA.

[0217] Comparative Example 2

[0218] The same as Application Example 1, except that the electrolyte is Na6PS5Cl 0.5 Br.

[0219] Table 1

[0220]

[0221] From the above test results, it can be seen that by optimizing the binder mixed with the active material on the silicon negative electrode sheet, the cycle stability and rate performance of the silicon negative electrode sheet in the above-mentioned specific solid-state battery can be significantly improved.

[0222] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions described in the foregoing examples can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A sodium-ion solid-state battery, characterized in that, It includes a positive electrode, a negative electrode, and an electrolyte; the positive electrode contains a sodium-ion positive electrode material with a P2-type structure; the sodium-ion positive electrode material is a high-entropy positive electrode material formed by mixing more than 7 elements; the more than 7 elements include Na, Ni, Cu, O, and other metallic elements; the other metallic elements are of 3 or more types; The electrolyte element facing the negative electrode is Na6PS5Cl. 0.5 Br 0.5 F 0.5 ; The negative electrode is a silicon negative electrode. The silicon anode electrode includes a current collector and an active material layer disposed on the current collector; The active material layer includes an adhesive and an active material; The binder comprises a polymer and a carboxylic acid compound that forms gradient hydrogen bonds with the main chain of the polymer; the polymer contains a conductive polymer; The active material comprises silicon-based material and carbon-based material in a mass ratio of (4~7):(1~4.5), wherein the silicon-based material is silicon particles; The method for preparing the silicon negative electrode sheet includes: The polymer raw materials, carboxylic acid compounds and oxidants are mixed to obtain a mixture with a viscosity of 100~3500 mPa·s; The mixture is then combined with the active material to obtain a slurry; The slurry forms an active material layer on the current collector; The carboxylic acid compound is selected from one or more of citric acid, propane tricarboxylic acid and butane tetracarboxylic acid; The polymers include acrylic polymers, enol polymers, and polypyrrole.

2. The sodium-ion solid-state battery according to claim 1, characterized in that, The method for preparing the silicon negative electrode sheet includes: An acrylic reagent is mixed with a carboxylic acid compound to obtain a first mixture; The first mixture is mixed with an enol reagent to obtain a second mixture; The second mixture is mixed with a pyrrole reagent and an oxidizing agent to obtain the mixture; The acrylic reagent is selected from polyacrylic acid and / or acrylic acid; The enol reagent is selected from one or more of polyvinyl alcohol, vinyl alcohol, and allyl alcohol; The pyrrole reagent is selected from polypyrrole and / or pyrrole; The oxidant is selected from persulfate and / or ammonium persulfate.

3. The sodium-ion solid-state battery according to claim 2, characterized in that, The method for preparing the silicon negative electrode sheet includes: An acrylic reagent and an aqueous solution of a carboxylic acid compound are mixed for a time H1 until they become homogeneous to obtain a first mixture; wherein, H1 is 2~8h. The first mixture is stirred with an aqueous solution of an enol reagent at 15-35°C for 3-10 hours to obtain a homogeneous second mixture. The second mixture is placed at 0-4°C for H3 time, and then pyrrole reagent and oxidant are added and mixed to obtain the mixture; wherein, H3 time is 10-60 min. The mixture is then combined with an active material to obtain a slurry; The slurry is coated onto the current collector, and then treated at a first temperature for H4 time, followed by a second temperature for H5 time to form an active material layer; the first temperature is 50~80℃, the second temperature is 120~150℃, H4 time is 8~15h, and H5 time is 30~180min.

4. The sodium-ion solid-state battery according to claim 3, characterized in that, The mass concentration of the aqueous solution of the carboxylic acid compound is 1-15%; the molar ratio of the acrylic acid reagent to the carboxylic acid compound is (0.5-2):(0.5-2). The mass concentration of the enol reagent aqueous solution is 1-15%; the mass ratio of the acrylic reagent to the enol reagent is (5-15):1; The mass ratio of pyrrole reagent to oxidant is (1~2.5):(0.1~1); the content of the pyrrole reagent is 0.1~0.5 wt% of the total mass of the acrylic reagent. The mass ratio of silicon-based material in the active material to the mixture is (5~7):(0.5~3.5).

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