Solid-state electrolyte material, solid-state electrolyte, positive electrode material, preparation method thereof and sodium ion battery

Abstract

The application relates to the field of sodium ion batteries, and discloses a solid-state electrolyte material, a solid-state electrolyte, a positive electrode material, a preparation method of the positive electrode material, and a sodium ion battery. (020) and a peak area A (421) of a (421) crystal face obtained by XRD satisfy 0.9 <= I (020) / I (421) <1; a ratio of a peak area A (020) of a (020) crystal face obtained by XRD and a peak area A (421) of a (421) crystal face satisfy 0.45 <= A (020) / A (421) <1. The solid-state electrolyte material has good crystallinity, high ionic conductivity, and good structural stability. The positive electrode material prepared from the solid-state electrolyte material has high capacity, excellent rate, cycle, and thermal stability.

Description

Technical Field

[0001] This invention relates to the field of sodium-ion batteries, specifically to solid electrolyte materials, solid electrolytes, cathode materials, their preparation methods, and sodium-ion batteries. Background Technology

[0002] Lithium-ion rechargeable batteries possess advantages such as high specific energy density, wide operating temperature range, long charge-discharge life, low self-discharge, and minimal memory effect. Their gravimetric energy density can reach 270 Wh / kg, making them considered the most promising chemical power source. Since Sony commercialized them in 1990, they have not only dominated the market for small mobile consumer electronics such as laptops, mobile phones, camcorders, digital cameras, and MP3 players, but have also shown remarkable development prospects in the fields of power batteries and energy storage batteries in recent years.

[0003] However, lithium resources on Earth are not abundant, with an abundance of only 0.0065% in the Earth's crust and an uneven distribution. With the advent of electric vehicles and smart grids, the scarcity and high cost of lithium resources will inevitably become significant factors restricting its development. Therefore, developing new energy storage battery systems is essential. Sodium, with an abundance of 2.64% in the Earth's crust, is inexpensive, and sodium ions have a similar intercalation mechanism to lithium ions. Therefore, sodium-ion rechargeable batteries have recently regained attention.

[0004] However, most reported sodium battery research to date is based on liquid electrolytes using organic solvents, such as ethers and carbonates. The flammability and leakage risks of organic solvents pose potential safety concerns for liquid sodium batteries. In contrast, solid-state sodium batteries offer significant improvements in safety performance due to their high stability, lack of leakage risk, and ease of direct stacking and processing.

[0005] In solid-state battery systems, one of the most critical materials is the solid electrolyte. Solid electrolytes include organic polymers, sulfides, halides, perovskites, nASICON, and garnets, among others. NASICON-type solid electrolytes, in particular, possess advantages such as high conductivity, good thermal stability, and a wide electrochemical window, making them one of the most promising solid electrolytes for industrialization.

[0006] NASICON-type solid electrolytes can achieve a theoretical ionic conductivity of up to 10. -3 S / cm is above, but current research reports generally show values ​​below 0.5 × 10⁻⁶. -3The S / cm ratio indicates that there is still significant room for improvement in its ionic conductivity. Furthermore, poor electrode-electrolyte interface compatibility limits its practical application. NASICON-type solid electrolytes, after nano-sizing, suffer from structural instability and easy phase separation, hindering the long-term preservation of nano-slurries. In addition, to effectively improve ionic conductivity, researchers primarily utilize wet chemical reaction methods such as hydrothermal and sol-gel methods, which are not suitable for low-cost, large-scale production. Traditional solid-phase reactions are prone to generating impurities due to uneven mixing of raw materials. On the other hand, the high residual sodium content on the surface of mainstream sodium-ion layered cathode materials affects sodium ion diffusion and transport, damages the material structure, and leads to reduced battery cycle life, energy efficiency, and decreased safety. Summary of the Invention

[0007] The purpose of this invention is to overcome the problems of low ionic conductivity and poor structural stability of existing solid electrolyte materials.

[0008] To achieve the above objectives, a first aspect of the present invention provides a solid electrolyte material, wherein the peak intensity I of the (020) crystal plane obtained by XRD is... (020) Peak intensity I of (421) crystal plane (421) The ratio satisfies 0.9 ≤ I (020) / I (421) <1;

[0009] The peak area A of the (020) crystal plane of the solid electrolyte material obtained by XRD (020) The peak area A of the (421) crystal plane (421) The ratio satisfies 0.45 ≤ A (020) / A (421) <1.

[0010] A second aspect of the present invention provides a method for preparing a solid electrolyte material as described in the first aspect, the method comprising the following steps:

[0011] (1) In the presence of a solvent, Na source, Zr source, Si source and P source are mixed to obtain mixture A; optionally, mixture A also contains M. 1 Source and / or M 2 source;

[0012] (2) The mixture B containing the mixture A, organic monomer, initiator and catalyst is heated to carry out a polymerization reaction to obtain solid electrolyte precursor I;

[0013] (3) The solid electrolyte precursor I is subjected to pre-sintering and crushing treatment in sequence to obtain solid electrolyte precursor II;

[0014] (4) The solid electrolyte precursor II is subjected to sintering and crushing treatment in sequence.

[0015] A third aspect of the present invention provides a solid electrolyte comprising the solid electrolyte material, polymer, and sodium salt described in the first aspect.

[0016] A fourth aspect of the present invention provides a method for preparing a solid electrolyte as described in the third aspect, the method comprising:

[0017] (a) A mixture is obtained by mixing solid electrolyte material, polymer and sodium salt;

[0018] (b) The mixture is subjected to hot pressing.

[0019] The fifth aspect of the present invention provides a positive electrode material, the positive electrode material comprising a positive electrode active material and a solid electrolyte material coated on the surface of the positive electrode active material, wherein the solid electrolyte material is the solid electrolyte material described in the first aspect.

[0020] A sixth aspect of the present invention provides a method for preparing a cathode material as described in the fifth aspect, the method comprising:

[0021] The mixture containing solid electrolyte material and positive electrode active material is heat-treated at 300-750°C; wherein the solid electrolyte material is the solid electrolyte material described in the first aspect.

[0022] The seventh aspect of the present invention provides a sodium-ion battery, the sodium-ion battery comprising a solid electrolyte material as described in the first aspect or a positive electrode material as described in the fifth aspect.

[0023] Through the above technical solution, the present invention has the following advantages:

[0024] (1) The solid electrolyte material provided by the present invention has a peak intensity I of (020) crystal plane obtained by XRD. (020) Peak intensity I of (421) crystal plane (421) The ratio satisfies 0.9 ≤ I (020) / I (421) <1; The peak area A of the (020) crystal plane obtained by XRD (020) The peak area A of the (421) crystal plane (421) The ratio satisfies 0.45 ≤ A (020) / A (421)<1. The peak intensity and peak area ratio of the (020) and (421) crystal planes of the solid electrolyte material are within the above-mentioned specific range, which makes the solid electrolyte material have good crystallinity, thereby ensuring that the microstructure of the prepared solid electrolyte material is highly dense, free of pores and microcracks, and has a monoclinic phase structure, which improves its ionic conductivity; preferably, by doping the solid electrolyte material with elements, the sintering temperature of the material can be reduced, while improving the stability and ionic conductivity of the material.

[0025] (2) The method for preparing solid electrolyte materials provided by this invention introduces dopant elements during the mixing process to achieve atomic-level uniform mixing of the elements and the main phase. Combined with the subsequent polymerization reaction of the mixture A with organic monomers, as well as pre-sintering, sintering, and crushing treatments, and preferably by controlling the values ​​of x, y, and z to regulate the content of Na, Zr, Si, P, and dopant elements, along with the process conditions of the dry preparation process, the lattice constant is comprehensively controlled. The prepared solid electrolyte material has uniform composition, high ionic conductivity, and an average particle size reaching the nanometer scale. Furthermore, the presence of dopant elements within the lattice contributes to its excellent structural stability, allowing the nanoscale slurry to maintain a pure phase state for a long time without phase decomposition. In addition, the prepared nanoscale solid electrolyte slurry and powder have a high specific surface area and strong specific surface energy. Moreover, the method has the advantages of readily available raw materials, low cost, simple preparation method, and ease of large-scale industrial production.

[0026] (3) The positive electrode material provided by the present invention has a solid electrolyte material coated on the surface of the positive electrode active material and is uniformly distributed. In a preferred case, the positive electrode material is subjected to acid-base titration treatment, and a relatively obvious characteristic titration peak appears in the pH range of 5-8. This indicates that the coating of the NASICON type solid electrolyte material can broaden the diffusion channel of sodium ions, so that the positive electrode material has high capacity, excellent rate capability, cycling performance and thermal stability.

[0027] (4) The method for preparing cathode material provided by the present invention consumes residual sodium on the surface of the cathode active material by coating it with NASICON-type solid electrolyte material. At the same time, the NASICON-type solid electrolyte material has a three-dimensional sodium ion diffusion channel, which can be widened after coating to improve the electrochemical performance of sodium ion battery. Secondly, the NASICON-type solid electrolyte material with stable structure has excellent thermal stability, which can improve the safety of cathode material. Attached Figure Description

[0028] Figure 1 These are the XRD spectra of the solid electrolyte materials prepared in the preparation examples and comparative preparation examples;

[0029] Figure 2These are the XRD patterns of the solid electrolyte materials prepared in the preparation examples and the comparative preparation examples after abuse tests. Detailed Implementation

[0030] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0031] In this invention, unless otherwise stated, room temperature and ambient temperature refer to 25±2℃.

[0032] In this invention, unless otherwise stated, the term "optionally" means to perform or not perform the operation, or to add or not add the material.

[0033] As previously stated, the first aspect of the present invention provides a solid electrolyte material, wherein the peak intensity I of the (020) crystal plane obtained by XRD is... (020) Peak intensity I of (421) crystal plane (421) The ratio satisfies 0.9 ≤ I (020) / I (421) <1;

[0034] The peak area A of the (020) crystal plane of the solid electrolyte material obtained by XRD (020) The peak area A of the (421) crystal plane (421) The ratio satisfies 0.45 ≤ A (020) / A (421) <1.

[0035] During the research process, the inventors of this invention discovered that the peak intensity and peak area of ​​the (020) crystal plane obtained by XRD of the NASICON-type solid electrolyte material, as well as the peak intensity and peak area of ​​the (421) crystal plane obtained by XRD, meet the above requirements. This allows for the regulation of its crystal structure, and the peak intensity and peak area exhibit suitable crystallinity and good structural stability. By changing the bond length of oxygen atoms, the interaction between Na and O is weakened, the migration potential energy of charge carriers is reduced, the charge carrier concentration is increased, and thus the ionic conductivity is improved.

[0036] According to some embodiments of the present invention, preferably, 0.97 ≤ I (020) / I (421) <1;

[0037] According to some embodiments of the present invention, preferably, 0.46 ≤ A (020) / A(421) <1.

[0038] The above-described preferred embodiments are beneficial for further improving the ionic conductivity of the solid electrolyte material and for achieving better structural stability.

[0039] According to some embodiments of the present invention, preferably, the solid electrolyte material has the structure shown in Formula I:

[0040] Na 3+x [Zr 2-y M 1 y ][Si 2-z M 2 z ]PO 12 Formula I;

[0041] Where, 0 ≤ x < 1.15, 0 ≤ y ≤ 0.5, 0 ≤ z ≤ 1; M 1 It is at least one of Mg, La, Y, Al, and Ca; M 2 It is at least one of Ga, In, Ge and Sc.

[0042] According to some embodiments of the present invention, preferably, the average particle size D of the solid electrolyte material is... 50 The nanometer size is 5-500 nm, preferably 100-200 nm. The nanoscale slurry of the solid electrolyte material can be left to stand for a long time without precipitation or phase decomposition.

[0043] According to some embodiments of the present invention, preferably, the ionic conductivity of the solid electrolyte material is greater than 8 × 10⁻⁶. -5 S / cm, preferably greater than 1×10 -4 S / cm.

[0044] A second aspect of the present invention provides a method for preparing a solid electrolyte material as described in the first aspect, the method comprising the following steps:

[0045] (1) In the presence of a solvent, Na source, Zr source, Si source and P source are mixed to obtain mixture A; optionally, mixture A also contains M. 1 Source and / or M 2 source;

[0046] (2) The mixture B containing the mixture A, organic monomer, initiator and catalyst is heated to carry out a polymerization reaction to obtain solid electrolyte precursor I;

[0047] (3) The solid electrolyte precursor I is subjected to pre-sintering and crushing treatment in sequence to obtain solid electrolyte precursor II;

[0048] (4) The solid electrolyte precursor II is subjected to sintering and crushing treatment in sequence.

[0049] According to some embodiments of the present invention, preferably, in step (1), the solvent is selected from at least one of water, N-methyl-2-pyrrolidone, phthalate, diester, long-chain alcohol and pyrrolidone, preferably water.

[0050] According to some embodiments of the present invention, preferably, in step (1), the Na source is selected from at least one of Na-containing oxides, hydroxides, nitrates, oxalates, organic alkoxides and carbonates, and preferably sodium carbonate.

[0051] According to some embodiments of the present invention, preferably, in step (1), the Zr source is selected from at least one of oxides, hydroxides, nitrates, oxalates, organic alkoxides and carbonates containing Zr, preferably at least one of ZrO2, zirconium silicate and zirconium tetrachloride, more preferably ZrO2.

[0052] According to some embodiments of the present invention, preferably, in step (1), the Si source is selected from at least one of oxides, hydroxides, nitrates, oxalates, organic alkoxides and carbonates containing Si, preferably at least one of SiO2, sodium silicate and silicon carbide, and more preferably SiO2.

[0053] According to some embodiments of the present invention, preferably, in step (1), the P source is at least one of NH4H2PO4, sodium dihydrogen phosphate and phosphoric acid, preferably NH4H2PO4.

[0054] According to some embodiments of the present invention, preferably, in step (1), the M 1 Source and the M 2 Each source is independently selected from those containing M. 1 and / or M 2 At least one of oxides, hydroxides, nitrates, oxalates, organic alkoxides, and carbonates; preferably, the M 1 The source is Y₂O₃ and / or La₂O₃; preferably, the M 2 The source is at least one of Sc2O3, Ga2O3 and GeO2.

[0055] According to some embodiments of the present invention, preferably, in step (1), the molar ratio of Na in the Na source to Si in the Si source, n(Na) / n(Si), is 1.65-1.725; when the mixture A also contains M 2 When the source is Na, the molar amount of Na in the Na source is equal to the molar amount of Si in the Si source and the molar amount of M. 2 Source M 2The ratio of the sum of the molar amounts of n(Na) / [n(Si)+n(M)] 2 The value is 1.65-1.725.

[0056] According to some embodiments of the present invention, preferably, in step (1), the Na source, the Zr source, the Si source, the P source, and the M source are... 1 Source and the M 2 The amount of source used results in a solid electrolyte material with the structure shown in Formula I, the specific structure of which is described above and will not be repeated here. The Zr source, the Si source, the P source, and the M source are used in this process. 1 Source and the M 2 The molar amount of the source satisfies the stoichiometry of the structure shown in Equation I.

[0057] According to some embodiments of the present invention, preferably, in step (1), the solid content of the mixture A at 25°C is 40-60 wt%.

[0058] According to some embodiments of the present invention, preferably, in step (1), the mixing can be carried out in conventional equipment with mixing and / or crushing functions, without any particular limitation, for example, in a planetary ball mill or a high-energy ball mill.

[0059] According to some embodiments of the present invention, preferably, in step (2), the organic monomer is selected from at least one of acrylamide (AM), methylenebisacrylamide (MBAM), styrene, butadiene and methyl methacrylate, and preferably acrylamide.

[0060] According to some embodiments of the present invention, preferably, in step (2), the initiator is selected from at least one of benzoyl peroxide, (NH4)2S2O8 and K2S2O8, preferably (NH4)2S2O8.

[0061] According to some embodiments of the present invention, preferably, in step (2), the catalyst is N,N,N',N'-tetramethylethylenediamine (TEMED).

[0062] According to some embodiments of the present invention, preferably, in step (2), the mass ratio of the mixture A to the organic monomer is 1:0.5-0.6.

[0063] According to some embodiments of the present invention, preferably, in step (2), the mass ratio of the organic monomer, the initiator and the catalyst is 1:0.5-1.5:0.5-1.5.

[0064] According to some embodiments of the present invention, preferably, in step (2), the conditions of the polymerization reaction include: a polymerization temperature of 80-200°C and a polymerization time of 10-15h.

[0065] According to some embodiments of the present invention, preferably, in step (3), the pre-sintering conditions include: a pre-sintering temperature of 300-700°C and a pre-sintering time of 2-6 hours.

[0066] According to some embodiments of the present invention, preferably, in step (3), the average particle size D of the solid electrolyte precursor II is... 50 The value is 1-50 μm, preferably 40-50 μm.

[0067] According to some embodiments of the present invention, preferably, in step (4), the sintering conditions include: a sintering temperature of 1000-1200℃ and a sintering time of 4-10h. The above preferred embodiments are beneficial for synthesizing monoclinic phase solid electrolyte materials.

[0068] According to some embodiments of the present invention, preferably, the method further includes: subjecting the product obtained from the crushing process in step (4) to nano-sizing in the presence of water to obtain a nanoscale solid electrolyte material. Using the above preferred embodiments is beneficial for obtaining an average particle size D. 50 Nanoscale solid electrolyte materials that meet the above requirements.

[0069] Preferably, the nano-sizing process includes: milling the product obtained from the crushing process in step (4) in the presence of water to obtain a nano-sized slurry, wherein the solid content of the nano-sized slurry at 25°C is 40-60 wt%; then drying the nano-sized slurry and grinding the resulting dried product. Preferably, the milling conditions are: a rotation speed of 800-1200 r / min and a time of 1-3 hours; preferably, the drying method is at least one of forced-air drying, vacuum drying, and freeze drying; the drying conditions include: a temperature of 25-60°C and a time of 8-12 hours; the grinding is performed using an air jet mill.

[0070] A third aspect of the present invention provides a solid electrolyte comprising the solid electrolyte material, polymer, and sodium salt described in the first aspect.

[0071] According to some embodiments of the present invention, preferably, the polymer is selected from at least one of polyvinylidene fluoride, polytetrafluoroethylene, vinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, polydimethylsiloxane, polymethyl methacrylate, polypropylene carbonate, polyvinyl carbonate, and polycaprolactone, and is preferably polyethylene oxide (PEO).

[0072] According to some embodiments of the present invention, preferably, the sodium salt is selected from at least one of NaTFSI, sodium hexafluorophosphate, sodium perchlorate and sodium trifluoromethanesulfonate, and preferably NaTFSI.

[0073] According to some embodiments of the present invention, preferably, based on the total mass of the solid electrolyte, the content of the solid electrolyte material is 5-30 wt%, the content of the polymer is 50-75 wt%, and the content of the sodium salt is 15-30 wt%.

[0074] According to some embodiments of the present invention, preferably, the solid electrolyte is a membrane structure, and the thickness of the membrane structure is 5-200 μm, preferably 20-100 μm.

[0075] A fourth aspect of the present invention provides a method for preparing a solid electrolyte as described in the third aspect, the method comprising:

[0076] (a) A mixture is obtained by mixing solid electrolyte material, polymer and sodium salt;

[0077] (b) The mixture is subjected to hot pressing.

[0078] According to some embodiments of the present invention, preferably, the mixing conditions in step (a) include: a mixing temperature of 0.5-1.5T. m , among which, T m The softening temperature of the polymer; the rotation speed is 300-500 rpm; the mixing time is until the mixer torque reaches a steady state.

[0079] According to some embodiments of the present invention, preferably, the conditions for the hot pressing treatment in step (b) include: a hot pressing temperature of 60-80°C, a hot pressing pressure of 1-10 MPa, and a hot pressing time of 5-20 min. The hot pressing pressure can be adjusted according to the desired thickness of the solid electrolyte membrane. There are no particular limitations on the equipment used for the hot pressing treatment; the equipment can be selected from at least one of a flatbed hot press, a roller hot press, and a pulse hot press.

[0080] According to some embodiments of the present invention, preferably, the method further includes: drying the hot-pressed product obtained by the hot-pressing treatment in step (b), wherein the drying conditions include: a drying temperature of 60-120°C and a drying time of 4-24 hours.

[0081] The fifth aspect of the present invention provides a positive electrode material, the positive electrode material comprising a positive electrode active material and a solid electrolyte material coated on the surface of the positive electrode active material, wherein the solid electrolyte material is the solid electrolyte material described in the first aspect.

[0082] According to some embodiments of the present invention, preferably, the mass ratio of the solid electrolyte material to the positive electrode active material is 0.05-1:100, more preferably 0.5-0.8:100.

[0083] According to some embodiments of the present invention, preferably, the positive electrode active material is NaNi. 1 / 3 Fe 1 / 3 Mn 1 / 3 O2, Na 2 / 3 Ni 1 / 3 Mn 1 / 2 O2 and at least one of its derived layered oxide cathode materials. The derived layered oxide cathode material is NaNi... 1 / 3 Fe 1 / 3 Mn 1 / 3 O2 and / or Na 2 / 3 Ni 1 / 3 Mn 1 / 2 Layered oxide cathode materials obtained by doping O2 with elements and / or adjusting the element ratios, such as including but not limited to Na 0.45 Ni 0.22 Co 0.11 Mn 0.66 O2, Na[Ni 0.25 Fe 0.5 Mn 0.25 O2, NaNi 0.25 Fe 0.25 Co 0.25 Mn 0.25 At least one of O2.

[0084] According to some embodiments of the present invention, preferably, the positive electrode material exhibits characteristic titration peaks at pH 5-8 during acid-base titration treatment. This indicates that Na3PO4 is generated at the interface between the solid electrolyte material provided by the present invention and the positive electrode active material during the coating process. Na3PO4 is a fast ion conductor and can act as a buffer layer to balance the potential difference between the NASICON-type solid electrolyte material and the positive electrode active material, alleviate the generation of the space charge layer, and reduce the interfacial impedance. Therefore, it is beneficial for the electrochemical properties of the positive electrode material to be better utilized.

[0085] According to some embodiments of the present invention, preferably, the starting temperature of the main exothermic peak in the differential scanning calorimetry (DSC) spectrum of the positive electrode material is above 290°C. The significant shift in the starting temperature of the main exothermic peak of the positive electrode material indicates that the solid electrolyte material provided by the present invention, after being coated on the surface of the positive electrode active material, can improve the thermal stability of the obtained positive electrode material.

[0086] The cathode material can improve structural stability, alleviate oxygen evolution problems under high sodium desorption conditions, and reduce the degree of side reactions between the cathode material and the electrolyte under high voltage conditions, thereby improving the electrochemical performance and safety of sodium-ion batteries.

[0087] A sixth aspect of the present invention provides a method for preparing a cathode material as described in the fifth aspect, the method comprising:

[0088] The mixture containing solid electrolyte material and positive electrode active material is heat-treated at 300-750°C; wherein the solid electrolyte material is the solid electrolyte material described in the first aspect.

[0089] According to some embodiments of the present invention, preferably, the mixture is obtained by mixing solid electrolyte material and positive electrode active material in a mixing device; the mixing device can be, for example, a ball mill, high-speed mixer, vertical mixer, horizontal mixer, inclined mixer, or other conventional dry mixing equipment, and there are no particular limitations thereto. Preferably, the heating device for the heat treatment can be, for example, a tube furnace, oxygen furnace, muffle furnace, roller kiln, or other conventional sintering and heat treatment equipment, and there are no particular limitations thereto.

[0090] According to some embodiments of the present invention, preferably, the temperature of the heat treatment is 400-750°C; preferably, the time of the heat treatment is 2-12 hours, more preferably 5-12 hours.

[0091] The seventh aspect of the present invention provides a sodium-ion battery, the sodium-ion battery comprising a solid electrolyte material as described in the first aspect or a positive electrode material as described in the fifth aspect.

[0092] The present invention will be described in detail below through embodiments.

[0093] Unless otherwise specified, all raw materials used in the following examples and comparative examples are commercially available products.

[0094] In the following examples and comparative examples:

[0095] Phase and crystal structure analysis of the materials was performed using an automated X-ray diffractometer manufactured by Rigaku Corporation of Japan.

[0096] Particle size distribution was measured using a Malvern Mastersizer 2000 laser particle size analyzer. The experiment only characterized the average particle size D of the material. 50 ;

[0097] The CT-3008 from Xinwei Electronics Co., Ltd. was used to perform charge-discharge and cycle tests on the button cells.

[0098] AC impedance and electrochemical window were measured using a Bio-logic SP-150 electrochemical workstation from France.

[0099] Preparation examples are provided to illustrate the solid electrolyte material provided by the present invention and the method for preparing the solid electrolyte material.

[0100] Preparation Example 1

[0101] (1) In the presence of a solvent, Na source, Zr source, Si source and P source are mixed to obtain mixture A; wherein:

[0102] The solvent is water; the Na source is Na2CO3; the Zr source is ZrO2; the Si source is SiO2; and the P source is NH4H2PO4.

[0103] The ratio of the molar amount of Na in the Na source to the molar amount of Si in the Si source, n(Na) / n(Si), is 1.65.

[0104] The mixing was carried out in a ball mill mixer under the following conditions: 900 rpm for 6 hours.

[0105] The solid content of mixture A at 25°C is 50 wt%.

[0106] (2) Mixture B, containing mixture A, organic monomer, initiator, and catalyst, is heated to undergo a polymerization reaction to obtain solid electrolyte precursor I; wherein:

[0107] The organic monomer is acrylamide; the initiator is (NH4)2S2O8; and the catalyst is N,N,N',N'-tetramethylethylenediamine (TEMED).

[0108] The mass ratio of mixture A to organic monomer is 1:0.55; the mass ratio of organic monomer, initiator and catalyst is 1:1:1.

[0109] Mixture B is obtained by adding organic monomers, initiators and catalysts to mixture A and then stirring and dispersing them.

[0110] The polymerization reaction was carried out in a forced-air drying oven under the following conditions: polymerization temperature of 100℃ and polymerization time of 12 hours.

[0111] (3) Solid electrolyte precursor I is subjected to pre-sintering and crushing treatments in sequence to obtain solid electrolyte precursor II; wherein:

[0112] Pre-sintering was carried out in a muffle furnace, and the pre-sintering conditions were: pre-sintering temperature of 500℃ and pre-sintering time of 2 hours.

[0113] The crushing process is carried out in a high-speed blender; the average particle size D of the solid electrolyte precursor II is...50 It is 48μm;

[0114] (4) Solid electrolyte precursor II was sintered and crushed sequentially to obtain micron-sized solid electrolyte material with an average particle size D. 50 It has a diameter of 13 μm and the chemical formula is Na3Zr2Si2PO4. 12 ;in:

[0115] Sintering was carried out in a muffle furnace under the following conditions: sintering temperature of 1050℃ and sintering time of 8 hours; crushing was carried out in an air jet mill.

[0116] (5) In the presence of water, the micron-sized solid electrolyte material was subjected to nano-sizing treatment to obtain a nano-sized solid electrolyte material with an average particle size D. 50 It is 148nm; where:

[0117] The nano-sizing process involves milling the micron-sized solid electrolyte material with water in a sand mill to obtain a nano-sized slurry with a solid content of 50 wt% at 25°C. The nano-sized slurry is then dried, and the dried product is ground using an air jet mill.

[0118] The conditions for sand milling are: rotation speed of 1000 r / min and time of 2 hours;

[0119] The drying conditions were: temperature 60℃ and time 12h.

[0120] Preparation Example 2

[0121] (1) In the presence of a solvent, Na source and M 1 The source, Zr source, Si source and P source are mixed to obtain mixture A; wherein:

[0122] The solvent is water; the Na source is Na₂CO₃; the Zr source is ZrO₂; the Si source is SiO₂; the P source is NH₄H₂PO₄; M 1 The source is Y2O3;

[0123] The ratio of the molar amount of Na in the Na source to the molar amount of Si in the Si source, n(Na) / n(Si), is 1.65.

[0124] The mixing was carried out in a ball mill mixer under the following conditions: 900 rpm for 6 hours.

[0125] The solid content of mixture A at 25°C is 50 wt%.

[0126] (2) Mixture B, containing mixture A, organic monomer, initiator, and catalyst, is heated to undergo a polymerization reaction to obtain solid electrolyte precursor I; wherein:

[0127] The organic monomer is acrylamide; the initiator is (NH4)2S2O8; and the catalyst is N,N,N',N'-tetramethylethylenediamine (TEMED).

[0128] The mass ratio of mixture A to organic monomer is 1:0.55; the mass ratio of organic monomer, initiator and catalyst is 1:1:1.

[0129] Mixture B is obtained by adding organic monomers, initiators and catalysts to mixture A and then stirring and dispersing them.

[0130] The polymerization reaction was carried out in a forced-air drying oven under the following conditions: polymerization temperature of 100℃ and polymerization time of 12 hours.

[0131] (3) Solid electrolyte precursor I is subjected to pre-sintering and crushing treatments in sequence to obtain solid electrolyte precursor II; wherein:

[0132] Pre-sintering was carried out in a muffle furnace under the following conditions: pre-sintering temperature of 450℃ and pre-sintering time of 2 hours.

[0133] The crushing process is carried out in a high-speed blender; the average particle size D of the solid electrolyte precursor II is... 50 It is 45μm;

[0134] (4) Solid electrolyte precursor II was sintered and crushed sequentially to obtain micron-sized solid electrolyte material with an average particle size D. 50 It has a diameter of 14 μm and the chemical formula is Na. 3.05 Zr 1.95 Y 0.05 Si2PO 12 ;in:

[0135] Sintering was carried out in a muffle furnace under the following conditions: sintering temperature of 1050℃ and sintering time of 6 hours; crushing was carried out in an air jet mill.

[0136] (5) In the presence of water, the micron-sized solid electrolyte material was subjected to nano-sizing treatment to obtain a nano-sized solid electrolyte material with an average particle size D. 50 It is 128nm; where:

[0137] The nano-sizing process involves milling the micron-sized solid electrolyte material with water in a sand mill to obtain a nano-sized slurry with a solid content of 50 wt% at 25°C. The nano-sized slurry is then dried, and the dried product is ground using an air jet mill.

[0138] The conditions for sand milling are: rotation speed of 1000 r / min and time of 2 hours;

[0139] The drying conditions were: temperature 60℃ and time 12h.

[0140] Preparation Example 3

[0141] (1) In the presence of a solvent, Na source and M 2 The source, Zr source, Si source and P source are mixed to obtain mixture A; wherein:

[0142] The solvent is water; the Na source is Na₂CO₃; the Zr source is ZrO₂; the Si source is SiO₂; the P source is NH₄H₂PO₄; M 2 The source is Sc2O3;

[0143] The molar amount of Na in the Na source and the molar amount of Si in the Si source, and M 2 Source M 2 The ratio of the sum of the molar amounts of n(Na) / [n(Si)+n(M)] 2 The value is 1.65.

[0144] The mixing was carried out in a ball mill mixer under the following conditions: 900 rpm for 6 hours.

[0145] The solid content of mixture A at 25°C is 50 wt%.

[0146] (2) Mixture B, containing mixture A, organic monomer, initiator, and catalyst, is heated to undergo a polymerization reaction to obtain solid electrolyte precursor I; wherein:

[0147] The organic monomer is acrylamide; the initiator is (NH4)2S2O8; and the catalyst is N,N,N',N'-tetramethylethylenediamine (TEMED).

[0148] The mass ratio of mixture A to organic monomer is 1:0.55; the mass ratio of organic monomer, initiator and catalyst is 1:1:1.

[0149] Mixture B is obtained by adding organic monomers, initiators and catalysts to mixture A and then stirring and dispersing them.

[0150] The polymerization reaction was carried out in a forced-air drying oven under the following conditions: polymerization temperature of 100℃ and polymerization time of 12 hours.

[0151] (3) Solid electrolyte precursor I is subjected to pre-sintering and crushing treatments in sequence to obtain solid electrolyte precursor II; wherein:

[0152] Pre-sintering was carried out in a muffle furnace under the following conditions: pre-sintering temperature of 400℃ and pre-sintering time of 3 hours.

[0153] The crushing process is carried out in a high-speed blender; the average particle size D of the solid electrolyte precursor II is... 50 It is 46μm;

[0154] (4) Solid electrolyte precursor II was sintered and crushed sequentially to obtain micron-sized solid electrolyte material with an average particle size D. 50 It has a diameter of 14 μm and the chemical formula is Na. 3.05 Zr2Si 1.95 Sc 0.05 PO 12 ;in:

[0155] Sintering was carried out in a muffle furnace under the following conditions: sintering temperature of 1150℃ and sintering time of 7 hours; crushing was carried out in an air jet mill.

[0156] (5) In the presence of water, the micron-sized solid electrolyte material was subjected to nano-sizing treatment to obtain a nano-sized solid electrolyte material with an average particle size D. 50 It is 126nm; where:

[0157] The nano-sizing process involves milling the micron-sized solid electrolyte material with water in a sand mill to obtain a nano-sized slurry with a solid content of 50 wt% at 25°C. The nano-sized slurry is then dried, and the dried product is ground using an air jet mill.

[0158] The conditions for sand milling are: rotation speed of 1000 r / min and time of 2 hours;

[0159] The drying conditions were: temperature 60℃ and time 12h.

[0160] Preparation Example 4

[0161] (1) In the presence of a solvent, Na source and M 1 Source, M 2 The source, Zr source, Si source and P source are mixed to obtain mixture A; wherein:

[0162] The solvent is water; the Na source is Na₂CO₃; the Zr source is ZrO₂; the Si source is SiO₂; the P source is NH₄H₂PO₄; M 1 The source is Y2O3; M 2 The source is Sc2O3;

[0163] The molar amount of Na in the Na source and the molar amount of Si in the Si source, and M 2 Source M 2 The ratio of the sum of the molar amounts of n(Na) / [n(Si)+n(M)] 2 The value is 1.65.

[0164] The mixing was carried out in a ball mill mixer under the following conditions: 900 rpm for 6 hours.

[0165] The solid content of mixture A at 25°C is 50 wt%.

[0166] (2) Mixture B, containing mixture A, organic monomer, initiator, and catalyst, is heated to undergo a polymerization reaction to obtain solid electrolyte precursor I; wherein:

[0167] The organic monomer is acrylamide; the initiator is (NH4)2S2O8; and the catalyst is N,N,N',N'-tetramethylethylenediamine (TEMED).

[0168] The mass ratio of mixture A to organic monomer is 1:0.55; the mass ratio of organic monomer, initiator and catalyst is 1:1:1.

[0169] Mixture B is obtained by adding organic monomers, initiators and catalysts to mixture A and then stirring and dispersing them.

[0170] The polymerization reaction was carried out in a forced-air drying oven under the following conditions: polymerization temperature of 100℃ and polymerization time of 12 hours.

[0171] (3) Solid electrolyte precursor I is subjected to pre-sintering and crushing treatments in sequence to obtain solid electrolyte precursor II; wherein:

[0172] Pre-sintering was carried out in a muffle furnace under the following conditions: pre-sintering temperature of 550℃ and pre-sintering time of 2 hours.

[0173] The crushing process is carried out in a high-speed blender; the average particle size D of the solid electrolyte precursor II is... 50 It is 42μm;

[0174] (4) Solid electrolyte precursor II was sintered and crushed sequentially to obtain micron-sized solid electrolyte material with an average particle size D. 50 It has a diameter of 12 μm and the chemical formula is Na. 3.1 Zr 1.95 Y 0.05 Si 1.95 Sc 0.05 PO 12 ;in:

[0175] Sintering was carried out in a muffle furnace under the following conditions: sintering temperature of 1100℃ and sintering time of 8 hours; crushing was carried out in an air jet mill.

[0176] (5) In the presence of water, the micron-sized solid electrolyte material was subjected to nano-sizing treatment to obtain a nano-sized solid electrolyte material with an average particle size D.50 It is 125nm; where:

[0177] The nano-sizing process involves milling the micron-sized solid electrolyte material with water in a sand mill to obtain a nano-sized slurry with a solid content of 50 wt% at 25°C. The nano-sized slurry is then dried, and the dried product is ground using an air jet mill.

[0178] The conditions for sand milling are: rotation speed of 1000 r / min and time of 2 hours;

[0179] The drying conditions were: temperature 60℃ and time 12h.

[0180] Preparation Example 5

[0181] (1) In the presence of a solvent, Na source and M 1 Source, M 2 The source, Zr source, Si source and P source are mixed to obtain mixture A; wherein:

[0182] The solvent is water; the Na source is Na₂CO₃; the Zr source is ZrO₂; the Si source is SiO₂; the P source is NH₄H₂PO₄; M 1 The source is Y2O3; M 2 The source is Ga2O3;

[0183] The molar amount of Na in the Na source and the molar amount of Si in the Si source, and M 2 Source M 2 The ratio of the sum of the molar amounts of n(Na) / [n(Si)+n(M)] 2 The value is 1.65.

[0184] The mixing was carried out in a ball mill mixer under the following conditions: 900 rpm for 6 hours.

[0185] The solid content of mixture A at 25°C is 50 wt%.

[0186] (2) Mixture B, containing mixture A, organic monomer, initiator, and catalyst, is heated to undergo a polymerization reaction to obtain solid electrolyte precursor I; wherein:

[0187] The organic monomer is acrylamide; the initiator is (NH4)2S2O8; and the catalyst is N,N,N',N'-tetramethylethylenediamine (TEMED).

[0188] The mass ratio of mixture A to organic monomer is 1:0.55; the mass ratio of organic monomer, initiator and catalyst is 1:1:1.

[0189] Mixture B is obtained by adding organic monomers, initiators and catalysts to mixture A and then stirring and dispersing them.

[0190] The polymerization reaction was carried out in a forced-air drying oven under the following conditions: polymerization temperature of 100℃ and polymerization time of 12 hours.

[0191] (3) Solid electrolyte precursor I is subjected to pre-sintering and crushing treatments in sequence to obtain solid electrolyte precursor II; wherein:

[0192] Pre-sintering was carried out in a muffle furnace, and the pre-sintering conditions were: pre-sintering temperature of 500℃ and pre-sintering time of 2 hours.

[0193] The crushing process is carried out in a high-speed blender; the average particle size D of the solid electrolyte precursor II is... 50 It is 44μm;

[0194] (4) Solid electrolyte precursor II was sintered and crushed sequentially to obtain micron-sized solid electrolyte material with an average particle size D. 50 It has a diameter of 12 μm and the chemical formula is Na. 3.1 Zr 1.95 Y 0.05 Si 1.95 Ga 0.05 PO 12 ;in:

[0195] Sintering was carried out in a muffle furnace under the following conditions: sintering temperature of 1100℃ and sintering time of 8 hours; crushing was carried out in an air jet mill.

[0196] (5) In the presence of water, the micron-sized solid electrolyte material was subjected to nano-sizing treatment to obtain a nano-sized solid electrolyte material with an average particle size D. 50 It is 137nm; where:

[0197] The nano-sizing process involves milling the micron-sized solid electrolyte material with water in a sand mill to obtain a nano-sized slurry with a solid content of 50 wt% at 25°C. The nano-sized slurry is then dried, and the dried product is ground using an air jet mill.

[0198] The conditions for sand milling are: rotation speed of 1000 r / min and time of 2 hours;

[0199] The drying conditions were: temperature 60℃ and time 12h.

[0200] Preparation Example 6

[0201] (1) In the presence of a solvent, Na source and M 1 Source, M 2The source, Zr source, Si source and P source are mixed to obtain mixture A; wherein:

[0202] The solvent is water; the Na source is Na₂CO₃; the Zr source is ZrO₂; the Si source is SiO₂; the P source is NH₄H₂PO₄; M 1 The source is Y2O3; M 2 The source is GeO2;

[0203] The molar amount of Na in the Na source and the molar amount of Si in the Si source, and M 2 Source M 2 The ratio of the sum of the molar amounts of n(Na) / [n(Si)+n(M)] 2 The value is 1.65.

[0204] The mixing was carried out in a ball mill mixer under the following conditions: 900 rpm for 6 hours.

[0205] The solid content of mixture A at 25°C is 50 wt%.

[0206] (2) Mixture B, containing mixture A, organic monomer, initiator, and catalyst, is heated to undergo a polymerization reaction to obtain solid electrolyte precursor I; wherein:

[0207] The organic monomer is acrylamide; the initiator is (NH4)2S2O8; and the catalyst is N,N,N',N'-tetramethylethylenediamine (TEMED).

[0208] The mass ratio of mixture A to organic monomer is 1:0.55; the mass ratio of organic monomer, initiator and catalyst is 1:1:1.

[0209] Mixture B is obtained by adding organic monomers, initiators and catalysts to mixture A and then stirring and dispersing them.

[0210] The polymerization reaction was carried out in a forced-air drying oven under the following conditions: polymerization temperature of 100℃ and polymerization time of 12 hours.

[0211] (3) Solid electrolyte precursor I is subjected to pre-sintering and crushing treatments in sequence to obtain solid electrolyte precursor II; wherein:

[0212] Pre-sintering was carried out in a muffle furnace, and the pre-sintering conditions were: pre-sintering temperature of 500℃ and pre-sintering time of 2 hours.

[0213] The crushing process is carried out in a high-speed blender; the average particle size D of the solid electrolyte precursor II is... 50 It is 44μm;

[0214] (4) Solid electrolyte precursor II was sintered and crushed sequentially to obtain micron-sized solid electrolyte material with an average particle size D. 50 It has a diameter of 12 μm and the chemical formula is Na. 3.05 Zr 1.95 Y 0.05 Si 1.95 Ge 0.05 PO 12 ;in:

[0215] Sintering was carried out in a muffle furnace under the following conditions: sintering temperature of 1100℃ and sintering time of 8 hours; crushing was carried out in an air jet mill.

[0216] (5) In the presence of water, the micron-sized solid electrolyte material was subjected to nano-sizing treatment to obtain a nano-sized solid electrolyte material with an average particle size D. 50 It is 132nm; where:

[0217] The nano-sizing process involves milling the micron-sized solid electrolyte material with water in a sand mill to obtain a nano-sized slurry with a solid content of 50 wt% at 25°C. The nano-sized slurry is then dried, and the dried product is ground using an air jet mill.

[0218] The conditions for sand milling are: rotation speed of 1000 r / min and time of 2 hours;

[0219] The drying conditions were: temperature 60℃ and time 12h.

[0220] Preparation Example 7

[0221] Following the method of Preparation Example 1, except that step (5) is excluded, all other steps are the same, and a micron-sized solid electrolyte material is obtained.

[0222] Preparation Example 8

[0223] (1) In the presence of a solvent, Na source and M 1 The source, Zr source, Si source and P source are mixed to obtain mixture A; wherein:

[0224] The solvent is water; the Na source is Na₂CO₃; the Zr source is ZrO₂; the Si source is SiO₂; the P source is NH₄H₂PO₄; M 1 The source is La2O3;

[0225] The ratio of the molar amount of Na in the Na source to the molar amount of Si in the Si source, n(Na) / n(Si), is 1.65.

[0226] The mixing was carried out in a ball mill mixer under the following conditions: 900 rpm for 6 hours.

[0227] The solid content of mixture A at 25°C is 50 wt%.

[0228] (2) Mixture B, containing mixture A, organic monomer, initiator, and catalyst, is heated to undergo a polymerization reaction to obtain solid electrolyte precursor I; wherein:

[0229] The organic monomer is acrylamide; the initiator is (NH4)2S2O8; and the catalyst is N,N,N',N'-tetramethylethylenediamine (TEMED).

[0230] The mass ratio of mixture A to organic monomer is 1:0.55; the mass ratio of organic monomer, initiator and catalyst is 1:1:1.

[0231] Mixture B is obtained by adding organic monomers, initiators and catalysts to mixture A and then stirring and dispersing them.

[0232] The polymerization reaction was carried out in a forced-air drying oven under the following conditions: polymerization temperature of 100℃ and polymerization time of 12 hours.

[0233] (3) Solid electrolyte precursor I is subjected to pre-sintering and crushing treatments in sequence to obtain solid electrolyte precursor II; wherein:

[0234] Pre-sintering was carried out in a muffle furnace under the following conditions: pre-sintering temperature of 450℃ and pre-sintering time of 2 hours.

[0235] The crushing process is carried out in a high-speed blender; the average particle size D of the solid electrolyte precursor II is... 50 It is 43μm;

[0236] (4) Solid electrolyte precursor II was sintered and crushed sequentially to obtain micron-sized solid electrolyte material with an average particle size D. 50 It has a diameter of 10 μm and the chemical formula is Na. 3.05 Zr 1.95 La 0.05 Si2PO 12 ;in:

[0237] Sintering was carried out in a muffle furnace under the following conditions: sintering temperature of 1050℃ and sintering time of 6 hours; crushing was carried out in an air jet mill.

[0238] Comparative Preparation Example 1

[0239] (1) The Na source, Zr source, Si source and P source are mixed to obtain a mixture; wherein:

[0240] The Na source is Na₂CO₃; the Zr source is ZrO₂; the Si source is SiO₂; and the P source is NH₄H₂PO₄.

[0241] The ratio of the molar amount of Na in the Na source to the molar amount of Si in the Si source, n(Na) / n(Si), is 1.65.

[0242] The mixing was carried out in a ball mill mixer under the following conditions: 900 rpm for 6 hours.

[0243] (2) The mixture is subjected to pre-sintering and crushing treatment in sequence to obtain a solid electrolyte precursor;

[0244] The pre-sintering was carried out in a muffle furnace, and the pre-sintering conditions were: a pre-sintering temperature of 700℃ and a pre-sintering time of 2 hours.

[0245] The crushing process is carried out in a high-speed blender; the average particle size D of the solid electrolyte precursor is... 50 It is 45μm;

[0246] (3) The solid electrolyte precursor is sintered and crushed sequentially to obtain micron-sized solid electrolyte material with an average particle size D. 50 It has a diameter of 15 μm and the chemical formula is Na3Zr2Si2PO4. 12 ;

[0247] The sintering process was carried out in a muffle furnace under the following conditions: sintering temperature of 1050℃ and sintering time of 8 hours; the crushing process was carried out in an air jet mill.

[0248] Test Example 1

[0249] (a) The solid electrolyte materials obtained in the preparation example and the comparative preparation example were respectively mixed with polymer and sodium salt to obtain a mixture;

[0250] The amount of solid electrolyte material used is 8g; the polymer is polyethylene oxide (PEO), which is 69g; and the sodium salt is NaTFSI, which is 23g.

[0251] The mixing conditions are: mixing temperature of 85℃, speed of 500rpm, and mixing time until the mixer torque reaches a steady state.

[0252] (b) The mixture was placed on the heating table of a flat hot press and hot-pressed to obtain a solid electrolyte membrane with a thickness of 20 μm.

[0253] The hot pressing conditions are as follows: hot pressing temperature is 70℃, hot pressing pressure is 3MPa, and hot pressing time is 20min.

[0254] The solid electrolyte membrane was punched into a disc with a diameter of 22 mm. After vacuum drying at 60 °C for 12 h, it was assembled in a glove box with H2O content <1 ppm and O2 content <1 ppm in the following order: positive electrode shell, stainless steel sheet I (diameter 18 mm, thickness 1 mm), solid electrolyte membrane, stainless steel sheet II (diameter 18 mm, thickness 1 mm), nickel foam, and negative electrode shell. After sealing under 450 MPa pressure, a test assembly was obtained. The test assembly was chemically activated by heating at 65 °C for 12 h, then charged at 1.3 mA for 5 min, left to stand for 3 min, discharged at 1.3 mA for 5 min, and left to stand for 3 min. The above charging and discharging steps were repeated 3 times for electrochemical activation to obtain a sample for ionic conductivity testing.

[0255] The sample obtained for ionic conductivity testing was placed in an electrochemical workstation to test its AC impedance at room temperature. The test conditions were: perturbation voltage 5-10mV, and scanning frequency range 1Hz-1MHz. Based on the obtained impedance data, the impedance was calculated using the formula σ = L / (R·S) (where: σ is the ionic conductivity, in S / cm; L is the thickness of the solid electrolyte membrane after disassembly of the test component, in cm; R is the impedance value, in Ω; and S is the area of ​​the solid electrolyte membrane, in cm²). 2 The ionic conductivity of the sample was calculated, and the results are shown in Table 1.

[0256] Test Example 2

[0257] 10g of each of the solid electrolyte materials obtained in the preparation example and the comparative preparation example were placed in 90g of boiling water at 100℃ and stirred for 2h. The stirred samples were then evaporated, dried, and subjected to XRD testing. The peak intensity I of the (020) crystal plane obtained by XRD was... (020) Peak intensity I of (421) crystal plane (421) The ratio of I (020) / I (421) Peak area A of (020) crystal plane (020) The peak area A of the (421) crystal plane (421) The ratio A (020) / A (421) The structural stability test results are shown in Table 1. The XRD spectra of the solid electrolyte materials obtained from the preparation examples and comparative preparation examples are shown in the table below. Figure 1 As shown; the XRD patterns of the solid electrolyte materials prepared in the preparation examples and the comparative preparation examples after abuse tests are shown in the figures. Figure 2 As shown. Wherein:

[0258] The solid electrolyte material sample obtained in Example 1 was predominantly a pure phase, with a small amount of sodium phosphate impurity phase appearing at diffraction angles of 2θ = 28° and 32°. After treatment with the abuse method, the sample showed no impurity phase, indicating good structural stability.

[0259] The solid electrolyte material obtained in Preparation Example 2 was a pure phase; after treatment by the abuse method, the sample was basically free of impurities, indicating that the sample structure had good stability.

[0260] The solid electrolyte materials obtained in Preparation Examples 3-6 were pure phases; after treatment with the abuse method, the samples showed no impurities, indicating that the samples had excellent structural stability.

[0261] The micron-sized solid electrolyte material sample obtained in Example 7 was predominantly a pure phase, with a small amount of sodium phosphate impurity phase appearing at diffraction angles of 2θ = 26° and 28°. After treatment with the abuse method, the peak intensity of the sodium phosphate impurity phase at diffraction angles of 2θ = 26° and 28° increased, while a large amount of zirconium oxide impurity phase appeared at diffraction angle of 2θ = 32°, indicating that the sample underwent a phase transformation and had poor structural stability.

[0262] Compared with the micron-sized solid electrolyte material sample obtained in Example 1, the main body of the sample is pure phase, with a small amount of sodium phosphate impurity phase appearing at diffraction angles of 2θ = 26° and 28°. After the abusive treatment, the peak intensity of sodium phosphate impurity phase at diffraction angles of 2θ = 26° and 28° becomes stronger, and a large amount of zirconium oxide impurity phase appears at diffraction angle of 2θ = 32°, indicating that the sample has undergone phase transformation and has poor structural stability.

[0263] The sample of the micron-sized solid electrolyte material prepared in Example 8 was predominantly pure phase; after treatment with the abuse method, a large number of zirconia impurity phases appeared at the diffraction angle position of 2θ = 32°, indicating that the sample underwent a phase transformation and had poor structural stability.

[0264] Table 1

[0265] unit / / S / cm / Preparation Example 1 0.963 0.46 <![CDATA[1.3×10 -4 ]]> It has impurities but is stable. Preparation Example 2 0.985 0.47 <![CDATA[5.2×10 -4 ]]> Pure phase and stable Preparation Example 3 0.975 0.47 <![CDATA[7.6×10 -4 ]]> Pure phase and stable Preparation Example 4 0.993 0.52 <![CDATA[9.5×10 -4 ]]> Pure phase and stable Preparation Example 5 0.986 0.49 <![CDATA[8.3×10 -4 ]]> Pure phase and stable Preparation Example 6 0.992 0.49 <![CDATA[5.1×10 -4 ]]> Pure phase and stable Preparation Example 7 0.966 0.46 <![CDATA[8.5×10 -5 ]]> It contains impurities and is unstable. Preparation Example 8 0.967 0.45 <![CDATA[9.3×10 -5 ]]> Pure phase but unstable Comparative Preparation Example 1 0.934 0.44 <![CDATA[3.7×10 -5 ]]> It contains impurities and is unstable.

[0266] The examples illustrate the cathode material provided by the present invention and the method for preparing the cathode material.

[0267] Example 1

[0268] S1: The nanoscale solid electrolyte material obtained in Preparation Example 1 is mixed with the positive electrode active material in a high-speed mixer to obtain a mixture;

[0269] The positive electrode active material is O3-type layered oxide NaNi. 1 / 3 Fe 1 / 3 Mn 1 / 3 O2;

[0270] The mass ratio of nanoscale solid electrolyte material to positive electrode active material is 0.8:100;

[0271] S2: The obtained mixture is heat-treated in an oxygen furnace to obtain a positive electrode material, in which nanoscale solid electrolyte material is coated on the surface of the positive electrode active material.

[0272] The heat treatment conditions were: temperature 500℃, time 6h.

[0273] Example 2

[0274] S1: The nanoscale solid electrolyte material obtained in Preparation Example 2 is mixed with the positive electrode active material in a high-speed mixer to obtain a mixture;

[0275] Among them, the positive electrode active material is P2 type layered oxide Na. 2 / 3 Ni 1 / 3 Mn 1 / 2 O2;

[0276] The mass ratio of nanoscale solid electrolyte material to positive electrode active material is 0.5:100;

[0277] S2: The obtained mixture is heat-treated in an oxygen furnace to obtain a positive electrode material, in which nanoscale solid electrolyte material is coated on the surface of the positive electrode active material.

[0278] The heat treatment conditions were: temperature 750℃, time 12h.

[0279] Example 3

[0280] S1: The nanoscale solid electrolyte material obtained in Preparation Example 3 is mixed with the positive electrode active material in a high-speed mixer to obtain a mixture;

[0281] The positive electrode active material is O3-type layered oxide NaNi. 1 / 3 Fe 1 / 3 Mn 1 / 3 O2;

[0282] The mass ratio of nanoscale solid electrolyte material to positive electrode active material is 0.5:100;

[0283] S2: The obtained mixture is heat-treated in an oxygen furnace to obtain a positive electrode material, in which nanoscale solid electrolyte material is coated on the surface of the positive electrode active material.

[0284] The heat treatment conditions were: temperature 550℃, time 6h.

[0285] Example 4

[0286] S1: The nanoscale solid electrolyte material obtained in Preparation Example 4 is mixed with the positive electrode active material in a high-speed mixer to obtain a mixture;

[0287] The positive electrode active material is O3-type layered oxide NaNi. 1 / 3 Fe 1 / 3 Mn 1 / 3 O2;

[0288] The mass ratio of nanoscale solid electrolyte material to positive electrode active material is 0.6:100;

[0289] S2: The obtained mixture is heat-treated in an oxygen furnace to obtain a positive electrode material, in which nanoscale solid electrolyte material is coated on the surface of the positive electrode active material.

[0290] The heat treatment conditions were: temperature 450℃ and time 10h.

[0291] Example 5

[0292] S1: The nanoscale solid electrolyte material obtained in Preparation Example 5 is mixed with the positive electrode active material in a high-speed mixer to obtain a mixture;

[0293] Among them, the positive electrode active material is P2 type layered oxide Na. 2 / 3 Ni 1 / 3 Mn 1 / 2 O2;

[0294] The mass ratio of nanoscale solid electrolyte material to positive electrode active material is 0.6:100;

[0295] S2: The obtained mixture is heat-treated in an oxygen furnace to obtain a positive electrode material, in which nanoscale solid electrolyte material is coated on the surface of the positive electrode active material.

[0296] The heat treatment conditions were: temperature 450℃ and time 10h.

[0297] Example 6

[0298] S1: The nanoscale solid electrolyte material obtained in Preparation Example 6 is mixed with the positive electrode active material in a high-speed mixer to obtain a mixture;

[0299] Among them, the positive electrode active material is P2 type layered oxide Na. 2 / 3 Ni 1 / 3 Mn 1 / 2 O2;

[0300] The mass ratio of nanoscale solid electrolyte material to positive electrode active material is 0.6:100;

[0301] S2: The obtained mixture is heat-treated in an oxygen furnace to obtain a positive electrode material, in which nanoscale solid electrolyte material is coated on the surface of the positive electrode active material.

[0302] The heat treatment conditions were: temperature 450℃ and time 10h.

[0303] Example 7

[0304] S1: The nanoscale solid electrolyte material obtained in Preparation Example 7 is mixed with the positive electrode active material in a high-speed mixer to obtain a mixture;

[0305] The positive electrode active material is O3-type layered oxide NaNi. 1 / 3 Fe 1 / 3 Mn 1 / 3 O2;

[0306] The mass ratio of nanoscale solid electrolyte material to positive electrode active material is 0.8:100;

[0307] S2: The obtained mixture is heat-treated in an oxygen furnace to obtain a positive electrode material, in which nanoscale solid electrolyte material is coated on the surface of the positive electrode active material.

[0308] The heat treatment conditions were: temperature 500℃, time 6h.

[0309] Example 8

[0310] S1: The micron-sized solid electrolyte material obtained in Preparation Example 8 is mixed with the positive electrode active material in a high-speed mixer to obtain a mixture; wherein:

[0311] The positive electrode active material is P2-type layered oxide Na. 2 / 3 Ni 1 / 3 Mn 1 / 2 O2;

[0312] The mass ratio of micron-scale solid electrolyte material to positive electrode active material is 0.5:100;

[0313] S2: The obtained mixture is heat-treated in an oxygen furnace to obtain a positive electrode material, in which a micron-sized solid electrolyte material is coated on the surface of the positive electrode active material; wherein:

[0314] The heat treatment conditions were: temperature 750℃, time 12h.

[0315] Comparative Example 1

[0316] The positive electrode active material (O3-type layered oxide NaNi) 1 / 3 Fe 1 / 3 Mn 1 / 3 O2 is heat-treated in an oxygen furnace to obtain the cathode material;

[0317] The heat treatment conditions were: temperature 850℃ and time 8h.

[0318] Comparative Example 2

[0319] The positive electrode active material (P2 type layered oxide Na) 2 / 3 Ni 1 / 3 Mn 1 / 2 O2 is heat-treated in an oxygen furnace to obtain the cathode material;

[0320] The heat treatment conditions were: temperature 900℃ and time 6h.

[0321] Comparative Example 3

[0322] S1: The micron-sized solid electrolyte material obtained in Comparative Preparation Example 1 was mixed with the positive electrode active material in a high-speed mixer to obtain a mixture; wherein:

[0323] The positive electrode active material is O3-type layered oxide NaNi 1 / 3 Fe 1 / 3 Mn 1 / 3 O2;

[0324] The mass ratio of micron-scale solid electrolyte material to positive electrode active material is 0.8:100;

[0325] S2: The obtained mixture is heat-treated in an oxygen furnace to obtain a positive electrode material, in which a micron-sized solid electrolyte material is coated on the surface of the positive electrode active material; wherein:

[0326] The heat treatment conditions were: temperature 750℃, time 12h.

[0327] Test Example 3

[0328] 5g of the positive electrode material obtained in the examples and comparative examples was weighed and placed in 95g of room temperature deionized water. 水 Stir for 5 minutes. Filter the resulting slurry through a Buchner funnel fitted with filter paper to obtain a slurry with a mass of M. 滤液 The filtrate was titrated in a Metrohm 888 potentiometric titrator at room temperature to obtain a titration curve. The equivalence point value EP in the titration curve was recorded. x =V x (x = 1, 2, 3, ...). The results are shown in Table 2.

[0329] Test Example 4

[0330] The positive electrode materials obtained in the examples and comparative examples were mixed with conductive carbon black, PVDF and NaTFSI in a mass ratio of 90:3:5:2. An appropriate amount of NMP was added, and the mixture was stirred evenly and then coated onto aluminum foil. The mixture was dried in a 120°C forced-air oven for 1 hour and punched into a positive electrode sheet with a diameter of 11 mm.

[0331] 69g of PEO and 23g of NaTFSI were dissolved in acetonitrile and stirred for 12 hours. The resulting slurry was then poured into a polytetrafluoroethylene mold and vacuum dried in an oven at 50°C for 10 hours. The resulting product was then hot-pressed in a press for 5 minutes and then punched into a disc-shaped PEO electrolyte membrane with a diameter of 19mm.

[0332] The negative electrode (lithium metal), the prepared positive electrode sheet, and the PEO electrolyte membrane were assembled into a 2025-type coin cell in an Ar gas glove box with a water content and oxygen content of less than 5 ppm. The battery was tested for charge-discharge capacity at 2.0–4.2V, 0.1C, and 60℃; and its charge-discharge cycle performance was tested by 50 cycles at 2.0–4.2V, 1C, and 60℃. The results are shown in Table 2.

[0333] Test Example 5

[0334] The positive electrode materials obtained in the examples and comparative examples were mixed with acetylene black and polyvinylidene fluoride (PVDF) at a mass ratio of 95:2.5:2.5. An appropriate amount of NMP was added, and after thorough stirring, the mixture was coated onto aluminum foil and dried in a 120°C forced-air oven for 1 hour. The resulting positive electrode was then pressed into a 12mm diameter, 120μm thick positive electrode sheet using a pressure of 100MPa. The positive electrode sheet was then dried in a vacuum drying oven at 120°C for 12 hours. Carbon black was used as the negative electrode; a 25μm thick polyethylene porous membrane was used as the separator; and a 1mol / L mixture of equal parts NaPF6, ethylene carbonate (EC), and propylene carbonate (PC) was used as the electrolyte. The positive electrode sheet, separator, negative electrode sheet, and electrolyte were assembled into a 2025 type coin cell in an Ar gas glove box with a water content and oxygen content of less than 5ppm.

[0335] The above-mentioned button cells were charged and discharged twice at 2.0-4.2V, 0.2C, and 25℃. After being fully charged, the positive electrode was disassembled and tested using a differential thermal-thermogravimetric analyzer to obtain the corresponding DSC curves. The results are shown in Table 2.

[0336] Table 2

[0337]

[0338]

[0339] The above results show that the solid electrolyte material provided by this invention has high ionic conductivity and a stable structure. Specifically:

[0340] Because the micron-sized solid electrolyte material obtained in Comparative Preparation Example 1 contains a zirconium oxide impurity phase, it affects the grain boundary impedance and has poor structural stability. After it is coated on the surface of the positive electrode active material, the presence of the impurity phase will hinder sodium ion transport and affect the electrochemical performance of the obtained positive electrode material.

[0341] Although the micron-scale solid electrolyte material obtained in Preparation Example 8 has the introduction of La dopant, the atomic-level uniform mixing of the element and the main phase is not achieved. The abusive treatment method results in the appearance of zirconium oxide impurity phase, which affects the grain boundary impedance and has poor structural stability. After it is coated on the surface of the positive electrode active material, the presence of the impurity phase will hinder sodium ion transport and affect the electrochemical performance of the positive electrode material.

[0342] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A solid electrolyte material, characterized in that, The peak intensity I of the (020) crystal plane of the solid electrolyte material obtained by XRD (020) Peak intensity I of (421) crystal plane (421) The ratio satisfies 0.9 ≤ I (020) / I (421) <1; The peak area A of the (020) crystal plane of the solid electrolyte material obtained by XRD (020) The peak area A of the (421) crystal plane (421) The ratio satisfies 0.45 ≤ A (020) / A (421) <1; The solid electrolyte material is a nanoscale solid electrolyte material and has a monoclinic phase structure; The solid electrolyte material has the structure shown in Formula I: Na 3+x [Zr 2-y M 1 y [Si 2-z M 2 z PO 12 Formula I; Where, 0≤ x <1.15, 0≤ y ≤0.5, 0≤ z ≤1; M 1 It is at least one of Mg, La, Y, Al, and Ca; M 2 It is at least one of Ga, In, Ge and Sc.

2. The solid electrolyte material according to claim 1, wherein, 0.97≤I (020) / I (421) <1。 3. The solid electrolyte material according to claim 2, wherein, 0.46≤A (020) / A (421) <1。 4. The solid electrolyte material according to any one of claims 1-3, wherein, The average particle size D of the solid electrolyte material 50 The range is 5-500 nm.

5. The solid electrolyte material according to claim 4, wherein, The average particle size D of the solid electrolyte material 50 It is 100-200 nm.

6. The solid electrolyte material according to any one of claims 1-3, wherein, The ionic conductivity of the solid electrolyte material is greater than 8 × 10⁻⁶. -5 S / cm.

7. The solid electrolyte material according to claim 6, wherein, The ionic conductivity of the solid electrolyte material is greater than 1×10⁻⁶. -4 S / cm.

8. A method for preparing a solid electrolyte material as described in any one of claims 1-7, characterized in that, The method includes the following steps: (1) In the presence of a solvent, Na source, Zr source, Si source and P source are mixed to obtain mixture A; optionally, mixture A also contains M. 1 Source and / or M 2 source; (2) The mixture B containing the mixture A, organic monomer, initiator and catalyst is heated to carry out a polymerization reaction to obtain solid electrolyte precursor I; (3) The solid electrolyte precursor I is subjected to pre-sintering and crushing treatment in sequence to obtain solid electrolyte precursor II; (4) The solid electrolyte precursor II is sintered and crushed in sequence. In the presence of water, the product obtained by the crushing process is nano-sized to obtain nanoscale solid electrolyte material.

9. The method according to claim 8, wherein, In step (1), the solvent is selected from at least one of water, N-methyl-2-pyrrolidone, phthalate, diester, long-chain alcohol and pyrrolidone.

10. The method according to claim 8 or 9, wherein, In step (1), the M 1 Source and the M 2 Each source is independently selected from those containing M. 1 and / or M 2 It contains at least one of the following: oxides, hydroxides, nitrates, oxalates, organic alkoxides, and carbonates.

11. The method according to claim 8 or 9, wherein, In step (1), the molar ratio of Na in the Na source to Si in the Si source, n(Na) / n(Si), is 1.65-1.725; when the mixture A also contains M 2 When the source is Na, the molar amount of Na in the Na source is equal to the molar amount of Si in the Si source and the molar amount of M. 2 Source M 2 The ratio of the sum of the molar amounts of n(Na) / [n(Si)+n(M)] 2 The value is 1.65-1.

725.

12. The method according to claim 8 or 9, wherein, In step (1), the solid content of the mixture A at 25°C is 40-60 wt%.

13. The method according to claim 8 or 9, wherein, In step (2), the organic monomer is selected from at least one of acrylamide, methylenebisacrylamide, styrene, butadiene and methyl methacrylate.

14. The method according to claim 8 or 9, wherein, In step (2), the initiator is selected from at least one of benzoyl peroxide, (NH4)2S2O8 and K2S2O8.

15. The method according to claim 8 or 9, wherein, In step (2), the catalyst is N,N,N',N'-tetramethylethylenediamine.

16. The method according to claim 8 or 9, wherein, In step (2), the mass ratio of the mixture A to the organic monomer is 1:0.5-0.

6.

17. The method according to claim 8 or 9, wherein, In step (2), the mass ratio of the organic monomer, the initiator and the catalyst is 1:0.5-1.5:0.5-1.

5.

18. The method according to claim 8 or 9, wherein, In step (2), the conditions for the polymerization reaction include: a polymerization temperature of 80-200℃ and a polymerization time of 10-15h.

19. The method according to claim 8 or 9, wherein, In step (3), the pre-sintering conditions include: a pre-sintering temperature of 300-700℃ and a pre-sintering time of 2-6h.

20. The method according to claim 8 or 9, wherein, In step (3), the average particle size D of the solid electrolyte precursor II is... 50 The range is 1-50 μm.

21. The method according to claim 20, wherein, In step (3), the average particle size D of the solid electrolyte precursor II is... 50 It is 40-50μm.

22. The method according to claim 8 or 9, wherein, In step (4), the sintering conditions include: a sintering temperature of 1000-1200℃ and a sintering time of 4-10h.

23. A solid electrolyte, characterized in that, The solid electrolyte includes the solid electrolyte material, polymer, and sodium salt as described in any one of claims 1-7.

24. The solid electrolyte according to claim 23, wherein, The polymer is selected from at least one of polyvinylidene fluoride, polytetrafluoroethylene, vinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, polydimethylsiloxane, polymethyl methacrylate, polypropylene carbonate, polyvinyl carbonate, and polycaprolactone.

25. The solid electrolyte according to claim 23, wherein, The sodium salt is selected from at least one of NaTFSI, sodium hexafluorophosphate, sodium perchlorate, and sodium trifluoromethanesulfonate.

26. The solid electrolyte according to claim 23, wherein, Based on the total mass of the solid electrolyte, the content of the solid electrolyte material is 5-30 wt%, the content of the polymer is 50-75 wt%, and the content of the sodium salt is 15-30 wt%.

27. The solid electrolyte according to claim 23, wherein, The solid electrolyte has a membrane structure with a thickness of 5-200 μm.

28. The solid electrolyte according to claim 27, wherein, The thickness of the membrane structure is 20-100 μm.

29. A method for preparing a solid electrolyte as described in any one of claims 23-28, characterized in that, The method includes: (a) The solid electrolyte material, polymer, and sodium salt are mixed to obtain a mixture; (b) The mixture is subjected to hot pressing.

30. The method according to claim 29, wherein, The mixing conditions described in step (a) include: a mixing temperature of 0.5-1.5T. m , among which, T m The softening temperature of the polymer is 300-500 rpm.

31. The method according to claim 29, wherein, The conditions for hot pressing in step (b) include: hot pressing temperature of 60-80℃, hot pressing pressure of 1-10MPa, and hot pressing time of 5-20min.

32. A positive electrode material, characterized in that, The positive electrode material includes a positive electrode active material and a solid electrolyte material coated on the surface of the positive electrode active material, wherein the solid electrolyte material is the solid electrolyte material according to any one of claims 1-7.

33. The cathode material according to claim 32, wherein, The mass ratio of the solid electrolyte material to the positive electrode active material is 0.05-1:

100.

34. The cathode material according to claim 33, wherein, The mass ratio of the solid electrolyte material to the positive electrode active material is 0.5-0.8:

100.

35. The cathode material according to claim 32, wherein, The positive electrode active material is NaNi. 1 / 3 Fe 1 / 3 Mn 1 / 3 O2, Na 2 / 3 Ni 1 / 3 Mn 1 / 2 At least one of O2 and its derived layered oxide cathode materials.

36. The cathode material according to claim 32 or 33, wherein, The positive electrode material exhibits characteristic titration peaks between pH 5 and 8 after acid-base titration treatment.

37. The cathode material according to claim 32 or 33, wherein, In the differential scanning calorimetry spectrum of the cathode material, the starting temperature of the main exothermic peak is above 290℃.

38. A method for preparing the cathode material according to any one of claims 32-37, characterized in that, The method includes: The mixture containing solid electrolyte material and positive electrode active material is heat-treated at 300-750°C; wherein the solid electrolyte material is the solid electrolyte material according to any one of claims 1-7.

39. The method according to claim 38, wherein, The heat treatment temperature is 400-750℃; the heat treatment time is 2-12h.

40. The method of claim 38, wherein, The heat treatment time is 5-12 hours.

41. A sodium-ion battery, characterized in that, The sodium-ion battery includes a solid electrolyte material as described in any one of claims 1-7 or a positive electrode material as described in any one of claims 32-37.

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