A polyanion solid electrolyte and its preparation method and solid-state battery

Abstract

The present invention relates to a polyanion solid electrolyte and a preparation method thereof and a solid-state battery, belonging to the field of energy storage batteries. The polyanion solid electrolyte is A a M (3‑a) / m (SO4) b E 1‑b G c A is one of Li, Na, and K; M is one or more of Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba, Al, Ga, In, La, and Y; E is SO4 2‑ , CO3 2‑ , NO3 ‑ , NO2 ‑ , PO3 3‑ , PO4 3‑ , CrO4 2‑ , MnO4 2‑ , SiO4 4‑ , SiO3 2‑ , BO3 3‑ , TeO4 2‑ One or more of; G is a halogen element; a=0-3, b=0-1, c=0-1, and m is the valence of the M cation. The present invention enhances the ion transport capability of the polyanion solid electrolyte, improves the ionic conductivity, and thus improves the performance of the solid-state battery.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage batteries, and in particular to a polyanion solid electrolyte, a preparation method thereof, and a solid-state battery. Background Art

[0002] In recent years, lithium-ion batteries have played an increasingly important role in the development of portable consumer electronics and new energy vehicles. However, current commercial lithium-ion batteries are based on organic electrolyte systems, which are prone to leakage, combustion, and even explosion when impacted or punctured. These batteries pose significant safety risks, threatening property and personal safety, and hindering the further development of industries such as new energy vehicles. In contrast, all-solid-state batteries, which use solid-state electrolytes (SSEs), offer advantages such as high energy density and enhanced safety. They are attracting widespread attention and are expected to become the next generation of energy storage batteries.

[0003] Solid-state electrolytes are generally classified into three categories: inorganic solid electrolytes (ISEs), polymer solid electrolytes (SPEs), and composite solid electrolytes (CPEs). Each type of SSE has distinct advantages and disadvantages. Although SPEs offer good flexibility and processability, their ionic conductivity is relatively low. While CPEs also offer good flexibility and processability, and their ionic conductivity is superior to that of SPEs, their preparation process is complex, making performance optimization challenging. ISEs offer high thermal stability, mechanical strength, and a wide operating temperature range. Currently, common SSE types include halide SSEs, sulfide SSEs, and oxide SSEs. However, these types of ISEs also have numerous disadvantages, such as the high interfacial impedance and low ionic conductivity of oxide SSEs, the poor interfacial compatibility of halide SSEs, and the poor air stability and reaction with electrode materials of sulfide SSEs, which severely limit their widespread application in high-performance battery systems.

[0004] Therefore, the existing technology still needs to be improved and developed. Summary of the Invention

[0005] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a polyanion solid electrolyte, a preparation method thereof, and a solid-state battery, aiming to solve the problem of low ionic conductivity of existing solid electrolytes.

[0006] The technical solutions of the present invention are as follows:

[0007] The first aspect of the present invention provides a polyanion solid electrolyte, wherein the chemical formula of the polyanion solid electrolyte is A a M (3-a) / m (SO4) b E 1-b G c ;

[0008] Wherein, A is one of Li, Na, and K;

[0009] M is one or more of Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba, Al, Ga, In, La, and Y, and M and A are different elements;

[0010] E is SO4 2- , CO3 2- , NO3 - , NO2 - , PO3 3- , PO4 3- , CrO4 2- , MnO4 2- , SiO4 4- , SiO3 2- , BO3 3- , TeO4 2- One or more of;

[0011] G is one or more of F, Cl, Br, and I;

[0012] a=0~3, b=0~1, c=0~1, and a, b and c are not 0, and m is the valence state of the M cation.

[0013] The second aspect of the present invention provides a method for preparing the polyanion solid electrolyte of the present invention, wherein when A is Li, the chemical formula of the polyanion solid electrolyte is Li a M (3-a) / m (SO4) b E 1-b G c , the Li a M (3-a) / m (SO4) b E 1-b G c The preparation method comprises the following steps:

[0014] LiG, ME and Li2SO4 or LiE, MG and MSO4 are used as raw materials, the raw materials are put into a mortar for grinding, the ground raw materials are put into a ball mill for ball milling, the ball milled materials are placed in a vacuum environment for heating and drying, and finally the dried materials are heated to a predetermined temperature and then cooled to obtain the Li a M (3-a) / m (SO4) b E 1-b G c .

[0015] The third aspect of the present invention provides a method for preparing the polyanion solid electrolyte of the present invention, wherein when A is Na, the chemical formula of the polyanion solid electrolyte is Na a M (3-a) / m (SO4) b E 1-b G c , the Na a M (3-a) / m (SO4) b E 1-b G c The preparation method comprises the following steps:

[0016] NaG, ME and Na2SO4 or NaE, MG and MSO4 are used as raw materials, the raw materials are put into a mortar for grinding, the ground raw materials are put into a ball mill for ball milling, the ball milled materials are placed in a vacuum environment for heating and drying, and finally the dried materials are heated to a predetermined temperature and then cooled to obtain the Na a M (3-a) / m (SO4) b E 1-b G c .

[0017] The fourth aspect of the present invention provides a method for preparing the polyanion solid electrolyte of the present invention, wherein when A is K, the chemical formula of the polyanion solid electrolyte is K a M (3-a) / m (SO4) b E 1-b G c , the K a M (3-a) / m (SO4) b E 1-b G c The preparation method comprises the following steps:

[0018] KG, ME and K2SO4 or KE, MG and MSO4 are used as raw materials, the raw materials are put into a mortar for grinding, the evenly ground raw materials are put into a ball mill for ball milling, the ball milled materials are placed in a vacuum environment for heating and drying, and finally the dried materials are heated to a predetermined temperature and then cooled to obtain the K a M (3-a) / m (SO4) b E 1-b G c .

[0019] A fifth aspect of the present invention provides a solid-state battery, which includes the polyanion solid electrolyte described in the present invention.

[0020] Beneficial effect: The present invention provides a polyanion solid electrolyte A a M (3-a) / m (SO4) b E 1-b G c , and its room temperature ionic conductivity can reach 0.1 mS cm -1 The above. The wet high-energy ball milling used in the present invention can effectively mix a variety of polyanion raw materials, which is conducive to the high-temperature sintering reaction to obtain the final product. The polyanion clusters of various sizes in the lattice can bring about the distortion of the lattice, which is conducive to bringing more ion transmission channels. At the same time, the multiple rotational couplings between the polyanion clusters can effectively promote the transmission of ions in the solid electrolyte, which is conducive to improving ionic conductivity and reducing activation energy. In addition, the doping of high-valent cations can not only introduce cation vacancies and provide more hopping sites for ion migration, but also effectively weaken the Coulomb attraction of lithium, sodium and potassium ions by anions, thereby improving the migration ability of lithium, sodium and potassium ions in the lattice. The present invention adopts multiple strategies to synergistically enhance the ion transmission ability of the polyanion solid electrolyte, improve ionic conductivity, and reduce activation energy, so that it can ultimately be applied to the preparation of secondary batteries with high safety and high specific energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 XRD patterns of lithium-based monoanion SSE and lithium-based trimerized anion SSE.

[0022] Figure 2 These are the AC impedance spectra of lithium-based monoanion SSE and lithium-based trimerized anion SSE.

[0023] Figure 3 This is the limiting current density test result of lithium-based mono-polyanion SSE and lithium-based tri-polyanion SSE.

[0024] Figure 4 The graph shows the cycling test results of lithium metal symmetric batteries of lithium-based single-polyanion SSE and lithium-based trimerized anion SSE.

[0025] Figure 5 The graph shows the cycling test results of lithium metal full batteries of lithium-based single-polyanion SSE and lithium-based trimerized anion SSE.

[0026] Figure 6 These are the electrochemical impedance spectroscopy (EIS) spectra of sodium-based double polyanion SSE and cation-doped sodium-based double polyanion SSE. DETAILED DESCRIPTION

[0027] The present invention provides a polyanion solid electrolyte, a preparation method thereof, and a solid-state battery. To make the objectives, technical solutions, and effects of the present invention more clear and explicit, the present invention is further described below in detail. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0028] The embodiment of the present invention provides a polyanion solid electrolyte, wherein the chemical formula of the polyanion solid electrolyte is A a M (3-a) / m (SO4) b E 1-b G c ;

[0029] Wherein, A is one of Li, Na, and K;

[0030] M is one or more of Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba, Al, Ga, In, La, and Y, and M and A are different elements;

[0031] E is SO4 2- , CO3 2- , NO3 - , NO2 - , PO3 3- , PO4 3- , CrO4 2- , MnO4 2- , SiO4 4- , SiO3 2- , BO3 3- , TeO4 2- One or more of;

[0032] G is one or more of F, Cl, Br, and I;

[0033] a=0~3, b=0~1, c=0~1, and a, b and c are not 0, and m is the valence state of the M cation.

[0034] Embodiments of the present invention are applicable to lithium-, sodium-, and potassium-based polyanion solid electrolytes. The transport of lithium, sodium, and potassium ions within solid electrolytes (SSEs) is influenced by factors such as ionic and electronic Coulombic interactions, defects, and lattice space dimensions. The rotational coupling mechanism of polyanion clusters within SSE materials can effectively promote ion transport. By introducing multiple polyanion clusters into the lattice of SSE materials, ion transport within the SSE can be effectively regulated, thereby improving the ionic conductivity of the SSE and reducing the activation energy.

[0035] The polyanion solid electrolyte A provided by the embodiment of the present invention a M (3-a) / m(SO4) b E 1-b G c A is any of the elements Li, Na, and K, and M is one or more of the elements Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba, Al, Ga, In, La, and Y. Doping with heterovalent ions or ions of varying sizes introduces structural disorder (or high entropy). These cations, M, upon introduction into the lattice, occupy the same lattice site as the carrier ions, A. Doping with heterovalent ions introduces additional charge compensation mechanisms. For example, Mg ions have a valence of +2, while A ions have a valence of +1. This Mg ion creates a vacancy for A ions (based on the principle of charge balance). This vacancy enhances lattice flexibility, increases hopping sites for A ions, and facilitates diffusion pathways for A ions. Furthermore, the varying sizes of the doped ions induce local lattice distortion, which disrupts the periodic static potential field, thereby reducing the energy barrier encountered by A ions during diffusion. Furthermore, adjusting the doping ratio of M ions can effectively adjust the concentration of carrier A ions, further regulating ionic conductivity. E is SO4 2- , CO3 2- , NO3 - , NO2 - , PO3 3- , PO4 3- , CrO4 2- , MnO4 2- , SiO4 4- , SiO3 2- , BO3 3- , TeO4 2- One or more of them. Polyanion clusters are the structural skeleton of this type of solid electrolyte. By constructing the structural skeleton of a single or multiple polyanions, the lattice environment and ion diffusion kinetics of this type of solid electrolyte can be optimized. The introduction of multiple polyanions can change the size characteristics of the crystal structure. For example, the larger polyanion CrO4 2- and SO4 2- (2.4~2.6 Å) provides a high-strength local framework to ensure structural stability; while the small polyanion CO3 2-(1.8~2.0 Å) introduces a certain degree of flexibility and lattice distortion. This balance helps to form channels in the lattice that are more suitable for the migration of A ions and reduces the energy barrier of the migration path. The chemical properties of different polyanions (such as electronegativity and bond length) will introduce different local potential environments. This diversity helps to form more migration paths for A ions, allowing A ions to choose the optimal path to diffuse. In addition, the rotational coupling mechanism between different types of polyanions will also promote the transport of carrier ions A. G is one or more of F, Cl, Br, and I. The high electronegativity of halogen elements will bring about a polarization effect in the local lattice. This effect can weaken the electrostatic interaction between A ions and the surrounding environment, making it easier for them to leave their original position and migrate.

[0036] Among them, for Li-based SSE, its chemical composition is Li a M (3-a) / m (SO4) b E 1-b G c ; Among them, a=0~3; b=0~1; c=0~1; M=Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba, Al, Ga, In, La, Y; E= SO4 2- , CO3 2- , NO3 - , NO2 - , PO3 3- , PO4 3- , CrO4 2- , MnO4 2- , SiO4 4- , SiO3 2- , BO3 3- , TeO4 2- ;G=F, Cl, Br, I.

[0037] For Na-based SSE, its chemical composition is Na a M (3-a) / m (SO4) b E 1-b G c ; Among them, a=0~3; b=0~1; c=0~1; M=Li, K, Rb, Cs, Be, Mg, Ca, Sr, Ba, Al, Ga, In, La, Y; E= SO4 2- , CO3 2- , NO3 - , NO2 - , PO3 3- , PO4 3- , CrO4 2- , MnO4 2- , SiO4 4- , SiO32- , BO3 3- , TeO4 2- ;G=F, Cl, Br, I.

[0038] For K-based SSE, its chemical composition is K a M (3-a) / m (SO4) b E 1-b G c ; Among them, a=0~3; b=0~1; c=0~1; M=Li, Na, Rb, Cs, Be, Mg, Ca, Sr, Ba, Al, Ga, In, La, Y; E= SO4 2- , CO3 2- , NO3 - , NO2 - , PO3 3- , PO4 3- , CrO4 2- , MnO4 2- , SiO4 4- , SiO3 2- , BO3 3- , TeO4 2- ;G=F, Cl, Br, I.

[0039] In one embodiment, the polyanion solid electrolyte is in the form of irregular particles, and the particle size distribution is below 10 μm.

[0040] The embodiment of the present invention provides a method for preparing the above-mentioned polyanion solid electrolyte, wherein when A is Li, the chemical formula of the polyanion solid electrolyte is Li a M (3-a) / m (SO4) b E 1-b G c , the Li a M (3-a) / m (SO4) b E 1-b G c The preparation method comprises the following steps:

[0041] LiG, ME and Li2SO4 or LiE, MG and MSO4 are used as raw materials, the raw materials are put into a mortar for grinding, the ground raw materials are put into a ball mill for ball milling, the ball milled materials are placed in a vacuum environment for heating and drying, and finally the dried materials are heated to a predetermined temperature and then cooled to obtain the Li a M (3-a) / m (SO4) b E 1-b G c .

[0042] In one embodiment, the step of placing the evenly ground raw materials into a ball mill for ball milling specifically includes: placing the evenly ground raw materials into the ball mill, adding ball milling beads ten times the mass of the raw materials, adding a wet milling solvent, the solvent is ethanol, isopropanol, n-hexane, acetone, methanol, ethylene glycol, cyclohexane, dichloromethane, n-heptane, and the ball milling parameters are set to a speed of 200-600 rpm and a time of 12-24 hours.

[0043] In one embodiment, the ball-milled material is placed in a vacuum environment at 50-120°C for heating and drying, and finally the dried material is placed in a container, transferred to a high-temperature furnace, and heated to a certain temperature (preferably 500-600°C) at a certain heating rate (preferably a heating rate of 5-10°C / min), and kept at this temperature for 12-18 hours, and then cooled naturally or rapidly to room temperature, and then the prepared solid is crushed and ground to obtain powdered Li a M (3-a) / m (SO4) b E 1-b G c .

[0044] In one embodiment, the LiG comprises one or more of LiF, LiCl, LiBr, and LiI;

[0045] The ME includes Na2SO4, Na2CO3, NaNO3, NaNO2, Na3PO3, Na3PO4, Na2CrO4, Na2MnO4, Na4SiO4, Na2SiO3, Na3BO3, Na2TeO4, K2SO4, K2CO3, KNO3, KNO2, K3PO3, K3PO4, K2CrO4, K2MnO4, K4SiO4, K2SiO3, K3BO3, K2TeO4, Rb2SO4, Rb2CO3, RbNO3, RbNO2, Rb3PO3, Rb3PO4, Rb2CrO4, Rb2MnO4, Rb4SiO4, Rb2SiO3, Rb3BO3, Rb2TeO4, Cs2SO4, Rb2CO3, CsNO3, CsNO2, Cs3PO3, Cs3PO4, Cs2CrO4, Cs2MnO4, Cs4SiO4, Cs2SiO3, Cs3BO3, Cs2TeO4, BeSO4, BeCO3, Be(NO3)2, Be(NO2)2, Be3(PO3)2, Be3(PO4)2, BeCrO4, BeMnO4, Be2SiO4, BeSiO3, Be3(BO3)2, MgSO4, MgCO3, Mg(NO3)2, Mg(NO2)2, Mg3(PO3)2, Mg3(PO4)2, MgCrO4, MgMnO4, Mg2SiO4, MgSiO3, Mg3(BO3)2, CaSO4, CaCO3, Ca(NO3)2, Ca(NO2)2, Ca3(PO3)2, Ca3(PO4)2, CaCrO4, CaMnO4, Ca2SiO4, CaSiO3, Ca3(BO3)2, SrSO4, SrCO3, Sr(NO3)2, Sr(NO2)2, Sr3(PO3)2, Sr3(PO4)2, SrCrO4, SrMnO4, Sr2SiO4, SrSiO3, Sr3(BO3)2, BaSO4, BaCO3, Ba(NO3)2, Ba(NO2)2, Ba3(PO3)2, Ba3(PO4)2, BaCrO4, BaMnO4, Ba2SiO4, BaSiO3, Ba3(BO3)2, Al2(SO4)3, Al2(CO3)3, Al(NO3)3, Al(NO2)3, AlPO3, AlPO4, Al2(CrO4)3, Al2(MnO4)3, Al4(SiO4)3, Al2(SiO3)3, AlBO3, Al2(TeO4)3, Ga2(SO4)3, Ga2(CO3)3, Ga(NO3)3, Ga(NO2)3, GaPO3, GaPO4, Ga2(CrO4)3, Ga2(MnO4)3, Ga4(SiO4)3, Ga2(SiO3)3, GaBO3,Ga2(TeO4)3, In2(SO4)3, In2(CO3)3, In(NO3)3, In(NO2)3, InPO3, InPO4, In2(CrO4)3, In2(MnO4)3, I n4(SiO4)3, In2(SiO3)3, InBO3, In2(TeO4)3, La2(SO4)3, La2(CO3)3, La(NO3)3, La(NO2)3, LaPO3, LaP One or more of O4, La2(CrO4)3, La2(MnO4)3, La4(SiO4)3, La2(SiO3)3, LaBO3, La2(TeO4)3, Y2(SO4)3, Y2(CO3)3, Y(NO3)3, Y(NO2)3, YPO3, YPO4, Y2(CrO4)3, Y2(MnO4)3, Y4(SiO4)3, Y2(SiO3)3, YBO3, Y2(TeO4)3. ,

[0046] In one embodiment, the LiE includes one or more of Li2SO4, Li2CO3, LiNO3, LiNO2, Li3PO3, Li3PO4, Li2CrO4, Li2MnO4, Li4SiO4, Li2SiO3, Li3BO3, and Li2TeO4;

[0047] The MG includes one or more of NaF, NaCl, NaBr, NaI, KF, KCl, KBr, RbF, RbCl, RbBr, RbI, CsF, CsCl, CsBr, CsI, BeF2, BeCl2, BeBr2, BeI2, MgF2, MgCl2, MgBr2, MgI2, CaF2, CaCl2, CaBr2, CaI2, SrF2, SrCl2, SrBr2, SrI2, BaF2, BaCl2, BaBr2, BaI2, AlF3, AlCl3, AlBr3, AlI3, GaF3, GaCl3, GaBr3, GaI3, InF3, InCl3, InBr3, InI3, LaF3, LaCl3, LaBr3, LaI3, YF3, YCl3, YBr3, and YI3;

[0048] The MSO4 includes one or more of Na2SO4, K2SO4, Rb2SO4, Cs2SO4, BeSO4, MgSO4, CaSO4, SrSO4, BaSO4, Al2(SO4)3, Ga2(SO4)3, In2(SO4)3, La2(SO4)3, and Y2(SO4)3.

[0049] The embodiment of the present invention provides a method for preparing the above-mentioned polyanion solid electrolyte, wherein when A is Na, the chemical formula of the polyanion solid electrolyte is Na a M (3-a) / m (SO4) b E 1-b G c , the Na a M (3-a) / m (SO4) b E 1-b G c The preparation method comprises the following steps:

[0050] NaG, ME and Na2SO4 or NaE, MG and MSO4 are used as raw materials, the raw materials are put into a mortar for grinding, the ground raw materials are put into a ball mill for ball milling, the ball milled materials are placed in a vacuum environment for heating and drying, and finally the dried materials are heated to a predetermined temperature and then cooled to obtain the Na a M (3-a) / m (SO4) b E 1-b G c .

[0051] In one embodiment, the step of placing the evenly ground raw materials into a ball mill for ball milling specifically includes: placing the evenly ground raw materials into the ball mill, adding ball milling beads ten times the mass of the raw materials, adding a wet milling solvent, the solvent is ethanol, isopropanol, n-hexane, acetone, methanol, ethylene glycol, cyclohexane, dichloromethane, n-heptane, and the ball milling parameters are set to a speed of 200-600 rpm and a time of 12-24 hours.

[0052] In one embodiment, the ball-milled material is placed in a vacuum environment at 50-120°C and heated to dry. Finally, the dried material is placed in a container and transferred to a high-temperature furnace. It is heated to a certain temperature (preferably 500-600°C) at a certain heating rate (preferably a heating rate of 5-10°C / min) and kept at this temperature for 12-18 hours. The temperature is then naturally cooled or rapidly cooled to room temperature. The prepared solid is then crushed and ground to obtain powdered Na a M (3-a) / m (SO4) b E 1-b G c .

[0053] In one embodiment, the NaG comprises one or more of NaF, NaCl, NaBr, and NaI;

[0054] The ME includes Li2SO4, Li2CO3, LiNO3, LiNO2, Li3PO3, Li3PO4, Li2CrO4, Li2MnO4, Li4SiO4, Li2SiO3, Li3BO3, Li2TeO4, K2SO4, K2CO3, KNO3, KNO2, K3PO3, K3PO4, K2CrO4, K2MnO4, K4SiO4, K2SiO3, K3BO3, K2TeO4, Rb2SO4, Rb2CO3, RbNO3, RbNO2, Rb3PO3, Rb3PO4, Rb2CrO4, Rb2MnO4, Rb4SiO4, Rb2SiO3, Rb3BO3, Rb2TeO4, Cs2SO4, Rb2CO3, CsNO3, CsNO2, Cs3PO3, Cs3PO4, Cs2CrO4, Cs2MnO4, Cs4SiO4, Cs2SiO3, Cs3BO3, Cs2TeO4, BeSO4, BeCO3, Be(NO3)2, Be(NO2)2, Be3(PO3)2, Be3(PO4)2, BeCrO4, BeMnO4, Be2SiO4, BeSiO3, Be3(BO3)2, MgSO4, MgCO3, Mg(NO3)2, Mg(NO2)2, Mg3(PO3)2, Mg3(PO4)2, MgCrO4, MgMnOGa2(TeO4)3, In2(SO4)3, In2(CO3)3, In(NO3)3, In(NO2)3, InPO3, InPO4, In2(CrO4)3, In2(MnO4)3, I n4(SiO4)3, In2(SiO3)3, InBO3, In2(TeO4)3, La2(SO4)3, La2(CO3)3, La(NO3)3, La(NO2)3, LaPO3, LaP One or more of O4, La2(CrO4)3, La2(MnO4)3, La4(SiO4)3, La2(SiO3)3, LaBO3, La2(TeO4)3, Y2(SO4)3, Y2(CO3)3, Y(NO3)3, Y(NO2)3, YPO3, YPO4, Y2(CrO4)3, Y2(MnO4)3, Y4(SiO4)3, Y2(SiO3)3, YBO3, Y2(TeO4)3. ,

[0055] In one embodiment, the NaE includes one or more of Na2SO4, Na2CO3, NaNO3, NaNO2, Na3PO3, Na3PO4, Na2CrO4, Na2MnO4, Na4SiO4, Na2SiO3, Na3BO3, and Na2TeO4;

[0056] The MG includes one or more of LiF, LiCl, LiBr, LiI, KF, KCl, KBr, KI, RbF, RbCl, RbBr, RbI, CsF, CsCl, CsBr, CsI, BeF2, BeCl2, BeBr2, BeI2, MgF2, MgCl2, MgBr2, MgI2, CaF2, CaCl2, CaBr2, CaI2, SrF2, SrCl2, SrBr2, SrI2, BaF2, BaCl2, BaBr2, BaI2, AlF3, AlCl3, AlBr3, AlI3, GaF3, GaCl3, GaBr3, GaI3, InF3, InCl3, InBr3, InI3, LaF3, LaCl3, LaBr3, LaI3, YF3, YCl3, YBr3, and YI3;

[0057] The MSO4 includes one or more of Li2SO4, K2SO4, Rb2SO4, Cs2SO4, BeSO4, MgSO4, CaSO4, SrSO4, BaSO4, Al2(SO4)3, Ga2(SO4)3, In2(SO4)3, La2(SO4)3, and Y2(SO4)3.

[0058] The embodiment of the present invention provides a method for preparing the above-mentioned polyanion solid electrolyte, wherein when A is K, the chemical formula of the polyanion solid electrolyte is K a M (3-a) / m (SO4) b E 1-b G c , the K a M (3-a) / m (SO4) b E 1-b G c The preparation method comprises the following steps:

[0059] KG, ME and K2SO4 or KE, MG and MSO4 are used as raw materials, the raw materials are put into a mortar for grinding, the evenly ground raw materials are put into a ball mill for ball milling, the ball milled materials are placed in a vacuum environment for heating and drying, and finally the dried materials are heated to a predetermined temperature and then cooled to obtain the K a M (3-a) / m (SO4) b E 1-b G c .

[0060] In one embodiment, the step of placing the evenly ground raw materials into a ball mill for ball milling specifically includes: placing the evenly ground raw materials into the ball mill, adding ball milling beads ten times the mass of the raw materials, adding a wet milling solvent, the solvent is ethanol, isopropanol, n-hexane, acetone, methanol, ethylene glycol, cyclohexane, dichloromethane, n-heptane, and the ball milling parameters are set to a speed of 200-600 rpm and a time of 12-24 hours.

[0061] In one embodiment, the ball-milled material is placed in a vacuum environment at 50-120°C and heated to dryness. The dried material is then placed in a container and transferred to a high-temperature furnace. The material is heated to a certain temperature (preferably 500-600°C) at a certain heating rate (preferably 5-10°C / min) and kept at this temperature for 12-18 hours. The material is then cooled naturally or rapidly cooled to room temperature. The prepared solid is then crushed and ground to obtain powdered K a M (3-a) / m (SO4) b E 1-b G c .

[0062] In one embodiment, the KG comprises one or more of KF, KCl, KBr, and KI;

[0063] The ME includes Li2SO4, Li2CO3, LiNO3, LiNO2, Li3PO3, Li3PO4, Li2CrO4, Li2MnO4, Li4SiO4, Li2SiO3, Li3BO3, Li2TeO4, Na2SO4, Na2CO3, NaNO3, NaNO2, Na3PO3, Na3PO4, Na2CrO4, Na2MnO4, Na4SiO4, Na2SiO3, Na3BO3, Na2TeO4, Rb2SO4, Rb2CO3, RbNO3, RbNO2, Rb3PO3, Rb3PO4, Rb2CrO4, Rb2MnO4, Rb4SiO4, Rb2SiO3, Rb3BO3, Rb2TeO4, Cs2SO4, Rb2CO3, CsNO3, CsNO2, Cs3PO3, Cs3PO4, Cs2CrO4, Cs2MnO4, Cs4SiO4, Cs2SiO3, Cs3BO3, Cs2TeO4, BeSO4, BeCO3, Be(NO3)2, Be(NO2)2, Be3(PO3)2, Be3(PO4)2, BeCrO4, BeMnO4, Be2SiO4, BeSiO3, Be3(BO3)2, MgSO4, MgCO3, Mg(NO3)2, Mg(NO2)2, Mg3(PO3)2, Mg3(PO4)2, MgCrO4, MgMnO4, Mg2SiO4, MgSiO3, Mg3(BO3)2, CaSO4, CaCO3, Ca(NO3)2, Ca(NO2)2, Ca3(PO3)2, Ca3(PO4)2, CaCrO4, CaMnO4, Ca2SiO4, CaSiO3, Ca3(BO3)2, SrSO4, SrCO3, Sr(NO3)2, Sr(NO2)2, Sr3(PO3)2, Sr3(PO4)2, SrCrO4, SrMnO4, Sr2SiO4, SrSiO3, Sr3(BO3)2, BaSO4, BaCO3, Ba(NO3)2, Ba(NO2)2, Ba3(PO3)2, Ba3(PO4)2, BaCrO4, BaMnO4, Ba2SiO4, BaSiO3, Ba3(BO3)2, Al2(SO4)3, Al2(CO3)3, Al(NO3)3, Al(NO2)3, AlPO3, AlPO4, Al2(CrO4)3, Al2(MnO4)3, Al4(SiO4)3, Al2(SiO3)3, AlBO3, Al2(TeO4)3, Ga2(SO4)3, Ga2(CO3)3, Ga(NO3)3, Ga(NO2)3, GaPO3, GaPO4, Ga2(CrO4)3, Ga2(MnO4)3, Ga4(SiO4)3,Ga2(SiO3)3, GaBO3, Ga2(TeO4)3, In2(SO4)3, In2(CO3)3, In(NO3)3, In(NO2)3, InPO3, InPO4, In2(CrO4)3, In2(MnO4)3, In4(SiO4)3, In2(SiO3)3, InBO3, In2(TeO4)3, La2(SO4)3, La2(CO3)3, La(NO3)3, La(NO2)3, L One or more of aPO3, LaPO4, La2(CrO4)3, La2(MnO4)3, La4(SiO4)3, La2(SiO3)3, LaBO3, La2(TeO4)3, Y2(SO4)3, Y2(CO3)3, Y(NO3)3, Y(NO2)3, YPO3, YPO4, Y2(CrO4)3, Y2(MnO4)3, Y4(SiO4)3, Y2(SiO3)3, YBO3, Y2(TeO4)3. ,

[0064] In one embodiment, the KE comprises one or more of K2SO4, K2CO3, KNO3, KNO2, K3PO3, K3PO4, K2CrO4, K2MnO4, K4SiO4, K2SiO3, K3BO3, and K2TeO4;

[0065] The MG includes one or more of LiF, LiCl, LiBr, LiI, NaF, NaCl, NaBr, NaI, RbF, RbCl, RbBr, RbI, CsF, CsCl, CsBr, CsI, BeF2, BeCl2, BeBr2, BeI2, MgF2, MgCl2, MgBr2, MgI2, CaF2, CaCl2, CaBr2, CaI2, SrF2, SrCl2, SrBr2, SrI2, BaF2, BaCl2, BaBr2, BaI2, AlF3, AlCl3, AlBr3, AlI3, GaF3, GaCl3, GaBr3, GaI3, InF3, InCl3, InBr3, InI3, LaF3, LaCl3, LaBr3, LaI3, YF3, YCl3, YBr3, and YI3;

[0066] The MSO4 includes one or more of Li2SO4, Na2SO4, Rb2SO4, Cs2SO4, BeSO4, MgSO4, CaSO4, SrSO4, BaSO4, Al2(SO4)3, Ga2(SO4)3, In2(SO4)3, La2(SO4)3, and Y2(SO4)3.

[0067] The embodiment of the present invention provides a novel polyanion solid electrolyte A that is prepared efficiently and simply a M (3-a) / m (SO4) b E 1-b G c This method integrates multiple means of improving the ionic conductivity of solid electrolytes. Through the synergistic effect of each technology, namely the synergistic strategy of polyanion skeleton construction and heterovalent cation M doping, high entropy effect, lattice distortion, increase in current-carrying A ion vacancies and polyanion rotational coupling are brought about, which synergistically promotes the transport of ion A in the lattice and significantly improves the ionic conductivity of the solid electrolyte. The solid electrolyte prepared by this method has a unique polyanion cluster structure. These structures are conducive to regulating the spatial distribution and charge balance of anions, bringing about lattice distortion, and are conducive to the formation of highly disordered metal cation distribution and ion transport channels. The rotational coupling mechanism between multiple polyanion clusters can also effectively promote ion transport and reduce the energy barrier of ion migration. In addition, doping cations with a valence of +2 or +3 can increase the vacancy concentration in the solid electrolyte, further promoting ion transport and reducing the activation energy of ion migration.

[0068] The polyanion solid electrolyte prepared by this method has the advantages of high ionic conductivity, good stability, low cost, high efficiency, and suitability for large-scale production. It is suitable for widespread application in the next generation of solid-state batteries and provides a new technical path for the development of low-cost, high-performance solid-state batteries.

[0069] An embodiment of the present invention provides a solid-state battery, comprising the polyanion solid electrolyte described in the embodiment of the present invention. The solid-state battery has high electrochemical performance.

[0070] The present invention will be further described below through several embodiments.

[0071] Example 1

[0072] A lithium-based trimer anion SSE Li3(SO4) 0.8 (CO3) 0.1 (CrO4) 0.1 Cl and a preparation method thereof, wherein the preparation method comprises the following steps:

[0073] LiCl, Li2CO3, Li2CrO4 and Li2SO4 are used as raw materials, and the raw materials are placed in a mortar for grinding. The evenly ground raw materials are placed in a ball mill, and ball mill beads with a mass ten times that of the raw materials are added. A wet grinding solvent is added, and the solvent is a mixed solution of ethanol and isopropanol (volume ratio 1:1). The ball milling parameters are set to a speed of 200 rpm and a time of 12 hours. The ball-milled material is placed in a vacuum environment at 80°C for heating and drying. Finally, the dried material is placed in a container, transferred to a high-temperature furnace, and heated to 500°C at a heating rate of 5°C / min. It is kept warm for 12 hours and then naturally cooled to room temperature. The prepared solid is then crushed and ground to obtain powdered Li3(SO4). 0.8 (CO3) 0.1 (CrO4) 0.1 Cl.

[0074] A lithium-based single polyanion SSE Li3SO4Cl and a preparation method thereof, the preparation method comprising the following steps:

[0075] With lithium-based trimer anion SSE Li3(SO4) 0.8 (CO3) 0.1 (CrO4) 0.1 The preparation method of Cl is basically the same, the only difference is that Li3SO4Cl uses LiCl and Li2SO4 as raw materials.

[0076] from Figure 1 From the XRD data, we can see that the lithium-based single anion SSE (i.e., Li3SO4Cl) and lithium-based trimer anion SSE (i.e., Li3(SO4) 0.8 (CO3) 0.1 (CrO4) 0.1 The XRD diffraction peaks of lithium-based trimerized anion SSE do not show the peaks of the raw materials, indicating that the reaction is complete. The diffraction peak positions of the two are basically unchanged, indicating that the lattice structures of the two have not changed significantly and correspond to the same space group. The intensity of some diffraction peaks of lithium-based trimerized anion SSE changes relative to lithium-based single-polyanion SSE, while the intensity of some diffraction peaks remains unchanged, indicating that certain specific orientations or crystal planes in the lithium-based trimerized anion SSE crystal may be affected by the polyanion clusters. Polyanion clusters of different sizes occupy the same lattice site. The lattice distortion caused by such local size effects often does not affect the lattice constant (peak position), but may cause changes in the scattering intensity on certain specific orientations of the crystal plane. Such a high entropy structure provides more possible migration channels for lithium ions. The ionic conductivity of the prepared lithium-based trimerized anion SSE can reach up to 10 -4 S cm -1 Order of magnitude, see Figure 2 , and its impedance is one-sixth of that of lithium-based single polyanion SSE.

[0077] Lithium metal symmetric batteries were assembled using lithium-based single-polyanion SSE and lithium-based trimerized anion SSE. The test results showed that the lithium metal symmetric battery assembled with lithium-based trimerized anion SSE has lower polarization voltage, higher limiting current density and stronger lithium cycling stability. Figure 3 and Figure 4 .

[0078] Using lithium iron phosphate as the positive electrode and lithium metal as the negative electrode, lithium metal full batteries equipped with lithium-based single polyanion SSE and lithium-based trimerized anion SSE were tested. Figure 5 As shown, the lithium metal full battery assembled using lithium-based ternary anion SSE has better cycling performance.

[0079] Example 2

[0080] A cation-doped sodium-based double polyanion SSE (Na 2.8 Mg 0.1 (SO4) 0.9 (CO3) 0.1 Cl) and a preparation method thereof, the preparation method comprising the following steps:

[0081] NaCl, MgCO3 and Na2SO4 were used as raw materials, and the raw materials were placed in a mortar for grinding. The evenly ground raw materials were placed in a ball mill, and ball mill beads with a mass ten times that of the raw materials were added. A wet grinding solvent was added, and the solvent was a mixed solution of ethanol and isopropanol (volume ratio 1:1). The ball milling parameters were set to a speed of 200 rpm and a time of 12 hours. The ball-milled material was placed in a vacuum environment at 80°C for heating and drying. Finally, the dried material was placed in a container, transferred to a high-temperature furnace, heated to 600°C at a heating rate of 8°C / min, and kept warm for 15 hours, and then naturally cooled to room temperature. The prepared solid was then crushed and ground to obtain powdered Na 2.8 Mg 0.1 (SO4) 0.9 (CO3) 0.1 Cl.

[0082] A sodium-based double polyanion SSE (Na3(SO4) 0.9 (CO3) 0.1 Cl) and a preparation method thereof, the preparation method comprising the following steps:

[0083] With cation-doped sodium-based double polyanion SSE (Na 2.8 Mg 0.1 (SO4) 0.9 (CO3) 0.1 The preparation method of Na3(SO4) is basically the same, the only difference is that 0.9 (CO3)0.1 Cl uses NaCl, Na2CO3 and Na2SO4 as raw materials, and no Mg ions are introduced.

[0084] The results of AC impedance spectroscopy are as follows Figure 6 As shown, cation-doped sodium-based double polyanion SSE (Na 2.8 Mg 0.1 (SO4) 0.9 (CO3) 0.1 Cl)compared with sodium-based double polyanion SSE(Na3(SO4) 0.9 (CO3) 0.1 Cl) has a lower impedance, indicating that the incorporation of cationic Mg effectively improves the Na ion conductivity.

[0085] The above results indicate that the synergistic strategy of polyanion skeleton construction and heterovalent cation M doping effectively promotes the transport of A ions and improves the ionic conductivity of this type of solid electrolyte.

[0086] In summary, the present invention provides a polyanion solid electrolyte and its preparation method and solid-state battery. The present invention adopts a variety of polyanion clusters to construct the anion skeleton of the solid electrolyte. The lattice distortion brought by the polyanion clusters of different sizes can bring more ion transmission channels. At the same time, the rotational coupling mechanism between the polyanion clusters can also effectively promote the transmission of ions, which is conducive to improving ionic conductivity and reducing activation energy. The doped cations with a valence of +2 or +3 can not only introduce cation vacancies and provide more hopping sites for ion migration, but also effectively weaken the Coulomb attraction of lithium, sodium and potassium ions by anions, thereby improving the migration ability of lithium, sodium and potassium ions in the lattice. The present invention adopts a variety of strategies to synergistically enhance the ion transmission ability of the polyanion solid electrolyte, improve ionic conductivity, reduce activation energy, and thus can ultimately be applied to the preparation of solid-state batteries with high safety and high specific energy.

[0087] It should be understood that the application of the present invention is not limited to the above examples. For those skilled in the art, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A polyanion solid electrolyte, characterized in that: The chemical formula of the polyanion solid electrolyte is Na 2.8 Mg 0.1 (SO4) 0.9 (CO3) 0.1 Cl or Li3(SO4) 0.8 (CO3) 0.1 (CrO4) 0.1 Cl; The room temperature ionic conductivity of the polyanion solid electrolyte reaches 0.1 mS cm -1 above; The polyanion solid electrolyte is in a granular form, and the particle size distribution is below 10 μm.

2. A method for preparing the polyanion solid electrolyte according to claim 1, characterized in that: When the chemical formula of the polyanion solid electrolyte is Li3(SO4) 0.8 (CO3) 0.1 (CrO4) 0.1 Cl, the Li3(SO4) 0.8 (CO3) 0.1 (CrO4) 0.1 The preparation method of Cl comprises the following steps: LiCl, Li2CO3, Li2CrO4 and Li2SO4 are used as raw materials, the raw materials are put into a mortar for grinding, the ground raw materials are put into a ball mill for ball milling, the ball milled materials are placed in a vacuum environment for heating and drying, and finally the dried materials are heated to a predetermined temperature and then cooled to obtain the Li3(SO4) 0.8 (CO3) 0.1 (CrO4) 0.1 Cl.

3. A method for preparing the polyanion solid electrolyte according to claim 1, characterized in that: When the chemical formula of the polyanion solid electrolyte is Na 2.8 Mg 0.1 (SO4) 0.9 (CO3) 0.1 When Cl, the Na 2.8 Mg 0.1 (SO4) 0.9 (CO3) 0.1 The preparation method of Cl comprises the following steps: NaCl, MgCO3 and Na2SO4 are used as raw materials, the raw materials are put into a mortar for grinding, the ground raw materials are put into a ball mill for ball milling, the ball milled materials are placed in a vacuum environment for heating and drying, and finally the dried materials are heated to a predetermined temperature and then cooled to obtain the Na 2.8 Mg 0.1 (SO4) 0.9 (CO3) 0.1 Cl.

4. A solid-state battery, characterized in that: The invention comprises the polyanion solid electrolyte according to claim 1.

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