Oxide solid electrolyte and preparation method thereof, and all-solid-state battery

Abstract

The application relates to an oxide solid electrolyte and a preparation method thereof and a full solid-state battery, and belongs to the technical field of solid electrolytes. a‑b M b X c Ti 2‑c Z d P 3‑d O e , wherein a=1-2, b=0-1, c=0-1, d=0-1.5, and e=(12-d)-12; A comprises any one of Li, Na and K elements; M comprises at least one of Na, K, Rb, Cs, Be, Mg, Ca, Sr and Ba elements; X comprises at least one of Al, Ga, In, La, Y, Sc, Fe and Cr elements; Z comprises at least one of B, S, Si, V, Tc, Re, As, Xe, W, Se, Nb and Mn elements; A is different from M, and b, c and d are not 0 at the same time. The ion conductivity is improved by doping and modifying key lattice sites in the electrolyte.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solid-state electrolyte, and particularly relates to an oxide solid-state electrolyte, a preparation method thereof and a full solid-state battery. BACKGROUND

[0002] Compared with the electrolyte in the traditional liquid lithium battery, the solid-state electrolyte can not only transport lithium ions, but also can act as a diaphragm to avoid short circuit of the battery. After decades of research and development, the solid-state electrolyte (SSE) is divided into three types of inorganic solid-state electrolyte (ISE), solid-state polymer electrolyte (SPE) and composite polymer electrolyte (CPE), and the solid-state inorganic electrolyte includes halide solid-state electrolyte, sulfide solid-state electrolyte and oxide solid-state electrolyte.

[0003] The currently reported oxide SSE includes garnet type, LISICON type, NASICON type and the like. Among them, LATP as the NASICON type SSE has been widely studied in the solid-state lithium battery due to its non-flammability, high electrical conductivity, wide electrochemical window, easy processing and the like. However, in the process of preparing the LATP, there are main challenges such as unsatisfactory phase purity, low sintering activity, high production cost and ion conductivity. SUMMARY

[0004] In view of the deficiencies in the prior art, the purpose of the embodiments of the present application includes providing an oxide solid-state electrolyte, a preparation method thereof and a full solid-state battery, so as to improve the ion conductivity of the oxide solid-state electrolyte.

[0005] The embodiments of the present application are implemented as follows:

[0006] In a first aspect, the embodiments of the present application provide an oxide solid-state electrolyte, and a chemical formula of the oxide solid-state electrolyte is A a-b M b X c Ti 2-c Z d P 3-d O e , wherein a = 1-2, b = 0-1, c = 0-1, d = 0-1.5, e = (12-d)-12; A includes any one of Li, Na and K elements; M includes one or more of Na, K, Rb, Cs, Be, Mg, Ca, Sr and Ba elements; X includes one or more of Al, Ga, In, La, Y, Sc, Fe and Cr elements; Z includes one or more of B, S, Si, V, Tc, Re, As, Xe, W, Se, Nb and Mn elements; wherein A is not the same as M, and b, c and d are not 0 at the same time.

[0007] The present application is through a plurality of functional ionsa-b M b X c Ti 2-c Z d P 3-d O 12 The modification of the key lattice sites includes partial substitution of Li or Na or K ions with large size cations (M ions), partial substitution of Ti ions with low valence cations (X ions), and partial substitution of PO4 with other polyanions (Z and O are combined to form) 3- The ion conductivity can be further improved by the synergistic effect of multi-ion co-doping. The ion with a larger atomic radius (such as Na + , K + , etc.) introduced into the Li site can effectively increase the lattice constant, providing a more spacious diffusion channel for Li + , thereby reducing the migration energy barrier of Li + and promoting the rapid migration of Li in the electrolyte; the low valence cation (such as Al 3+ , Ga 3+ , etc.) substituted for the Ti ion increases the concentration of Li or Na vacancies in the lattice, accelerates the migration rate of lithium ions, and further improves the ion conductivity; the -3 valence, -4 or -5 valence other polyanion (such as BO3 3- , SiO4 4- , SO4 4- , etc.) partially substituted for the traditional -3 valence PO4 3- not only increases the concentration of Li or Na in the lattice, but also enhances the stability of the crystal structure due to the introduction of high valence anions, thereby improving the ion conductivity. Therefore, the oxide solid electrolyte provided in the present application has an ultra-high ion conductivity of more than 1 mS cm -1 at room temperature through the synergistic effect of multi-ion doping.

[0008] In some embodiments of the present application, the chemical formula of the oxide solid electrolyte is Li a-b M b X c Ti 2-c Z d P 3-d O 12 , wherein M includes one or more of Na, K, Rb, Cs, Be, Mg and Ca elements; X includes one or more of Al, Ga, In, La, Y, Sc, Fe and Cr elements; Z includes one or more of S, Si, V, Nb, W, Se and Mn elements; or, the chemical formula of the oxide solid electrolyte is Li a-b M b X c Ti 2-c Zd P 3-d O 12-d , wherein Z comprises B; or, the chemical formula of the oxide solid-state electrolyte is K a-b M b X c Ti 2-c Z d P 3-d O 12 , wherein M comprises one or more of K, Rb, Cs, Be, Mg and Ca elements; X comprises one or more of Al, Ga, In, La, Y, Sc, Fe and Cr elements; Z comprises one or more of B, S, Si, V, Nb, W, Se and Mn elements; or, the chemical formula of the oxide solid-state electrolyte is K a-b M b X c Ti 2-c Z d P 3-d O 12-d , wherein Z comprises B; or, the chemical formula of the oxide solid-state electrolyte is K a-b M b X c Ti 2-c Z d P 3-d O 12 , wherein M comprises one or more of Rb, Cs, Be, Mg and Ca elements; X comprises one or more of Al, Ga, In, La, Y, Sc, Fe and Cr elements; Z comprises one or more of B, S, Si, V, Nb, W, Se and Mn elements; or, the chemical formula of the oxide solid-state electrolyte is K a-b M b X c Ti 2-c Z d P 3- d O 12-d , wherein Z comprises B.

[0009] The oxide solid-state electrolyte provided in the present application comprises a Li source electrolyte, a Na source electrolyte and a K source electrolyte, and the chemical formulae are Li a-b M b X c Ti 2-c Z d P 3-d O 12 , Na a-b M b X c Ti 2-c Z d P 3-d O12 and K a-b M b X c Ti 2-c Z d P 3-d O 12 In the above electrolyte, the use of large size cations (such as Na + , K + , etc.) to partially replace Li or Na or K ions, the use of low valence cations (such as Al 3+ , Ga 3+ , etc.) to partially replace Ti ions, and the use of other polyanions (such as BO3 3- , SiO4 4- , SO4 4- , etc.) to partially replace PO4 3- , and the realization of the synergistic effect of multi-ion co-doping can further improve the ionic conductivity.

[0010] In some embodiments of the present application, the oxide solid electrolyte includes any one of Li a Al c Ti 2-c (PO4) 3-d (ZO4) d , Na a Al c Ti 2-c (PO4) 3-d (ZO4) d and K a Al c Ti 2-c (PO4) 3-d (ZO4) d , wherein a = 1-2, c = 0-1, d = 0-1.5, and Z includes one or more of S, Si, V, and Nb; or, the oxide solid electrolyte includes any one of Li a Al c Ti 2-c (PO4) 3-d (ZO3) d , Na a Al c Ti 2-c (PO4) 3-d (ZO3) d and K a Al c Ti 2-c (PO4) 3-d (ZO3) d , wherein a = 1-2, c = 0.5-1, d = 0.15-1.5, and Z includes B.

[0011] In some embodiments of the present application, the oxide solid electrolyte comprises Li 1.44 Al 0.5 Ti 1.5 (PO4) 2.94 (SO4) 0.06 , Li 1.35 Al 0.5 Ti 1.5 (PO4) 2.85 (SO4) 0.15 , Li 1.51 Al 0.5 Ti 1.5 (PO4) 2.99 (SiO4) 0.01 , Li 1.53 Al 0.5 Ti 1.5 (PO4) 2.97 (SiO4) 0.03 , Li 1.55 Al 0.5 Ti 1.5 (PO4) 2.95 (SiO4) 0.05 , Li 1.5 Al 0.5 Ti 1.5 (PO4)3, Li 1.5 Al 0.5 Ti 1.5 (PO4) 2.85 (BO3) 0.15 , and Li 1.5 Al 0.5 Ti 1.5 (PO4) 2.95 (BO3) 0.05 .

[0012] In a second aspect, the embodiments of the present application provide a preparation method of the oxide solid electrolyte, comprising: mixing and reacting a titanium source compound with a catalyst to obtain a solution containing TiO 2+ , and then adding a complexing agent, A2CO3, a M source compound, an X source compound, NH4H2PO4 and a Z source compound into the solution containing TiO 2+ , stirring to form a sol; drying the sol, and then sequentially performing ball milling, molding treatment and sintering to obtain the oxide solid electrolyte.

[0013] Among them, the M source compound includes MCO3, the X source compound includes XNO3, and the Z source compound includes AZO4 and / or H3BO3. A includes any one of Li, Na, and K; M includes one or more of Na, K, Rb, Cs, Be, Mg, Ca, Sr, and Ba; X includes one or more of Al, Ga, In, La, Y, Sc, Fe, and Cr; and Z includes one or more of S, B, Si, V, Tc, Re, As, Xe, W, Se, Nb, and Mn.

[0014] This application involves mixing a titanium source compound with a catalyst to obtain a product containing TiO2. 2+ The solution was then mixed with a complexing agent, A2CO3, M-source compound, X-source compound, NH4H2PO4, and Z-source compound, and added to a solution containing TiO2. 2+ In a solution, stirring forms a sol, achieving uniform mixing of all components and creating a homogeneous sol. Further steps such as ball milling and sintering are used to adjust the microstructure of the electrolyte material, forming a nanostructure with a high specific surface area, thereby preparing an oxide solid electrolyte material with high ionic conductivity. In other words, this application utilizes the sol-gel method to prepare electrolyte materials, achieving uniform mixing of all components and effectively controlling the microstructure of the material to form a nanostructure with a high specific surface area, thus further improving the ionic conductivity of the electrolyte.

[0015] In some embodiments of this application, the titanium source compound includes C 12 H 28 O4Ti.

[0016] C 12 H 28 O4Ti, as a titanium source compound, exhibits good solubility in organic solvents, enabling it to form homogeneous solutions. Furthermore, it possesses high reactivity, allowing for the rapid generation of high-purity, high-quality titanium oxides under relatively mild conditions, thereby improving the ionic conductivity of solid-state electrolytes.

[0017] In some embodiments of this application, the catalyst includes HNO3.

[0018] HNO3, as a catalyst, can effectively increase the reaction rate, promote the conversion of titanium source compounds, and facilitate the formation of purer and more homogeneous TiO2. 2+ The solution can also enhance the stability and uniformity of the sol, promoting the formation of high-quality sols.

[0019] In some embodiments of this application, the complexing agent includes citric acid.

[0020] As a polycarboxylic acid, citric acid has good complexing ability and can effectively form stable complexes with metal ions (such as titanium, aluminum, etc.). Through complexation with metal ions, citric acid can affect the crystal structure and phase composition of the material during sintering, thereby improving the ionic conductivity.

[0021] In some embodiments of the present application, the drying comprises: a drying temperature of 100-150℃, and a drying time of 12-24h.

[0022] Within the above temperature and time ranges, water and other volatile solvents in the sol can be effectively removed, and the material can be uniformly dried.

[0023] In some embodiments of the present application, the ball milling comprises: a mass ratio of the ball milling raw material to the ball milling beads of 1:(5-10); and / or, a ball milling rotation speed of 300-400r / min, and a ball milling time of 24-48h.

[0024] In some embodiments of the present application, the sintering comprises: heating at a heating rate of 5-10℃ / min to 550-600℃, holding for 1-3h, then continuing to heat to 950-1050℃, holding for 5-6h, and then naturally cooling.

[0025] By setting the mass ratio of the ball milling raw material to the ball milling beads to 1:(5-10), and the ball milling rotation speed to 300-400r / min and the ball milling time to 24-48h, the fineness and uniformity can be effectively improved, the morphology and size distribution of the particles can be effectively controlled, the interaction between the materials can be promoted, impurities and agglomeration can be reduced, and the physical and chemical properties can be improved.

[0026] In a third aspect, the embodiments of the present application provide a full solid-state battery, comprising the oxide solid-state electrolyte described above. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0028] Figure 1 Li 1.5 Al 0.5 Ti 1.5 (PO4)3-doped SO4 2- XRD patterns before and after;

[0029] Figure 2 Li 1.35Al 0.5 Ti 1.5 (PO4) 2.85 (SO4) 0.15 SEM images and EDS element analysis;

[0030] Figure 3 Li 1.5 Al 0.5 Ti 1.5 (PO4)3doped SiO4 4- XRD patterns before and after;

[0031] Figure 4 LiTi2(PO4)3doped Al 3+ XRD patterns before and after;

[0032] Figure 5 Li 1.5 Al 0.5 Ti 1.5 (PO4)3doped SO4 2- Room temperature electrochemical impedance spectra before and after;

[0033] Figure 6 Li 1.5 Al 0.5 Ti 1.5 (PO4)3doped SiO4 4- Room temperature electrochemical impedance spectra before and after;

[0034] Figure 7 LiTi2(PO4)3doped Al 3+ Room temperature electrochemical impedance spectra before and after. DETAILED DESCRIPTION

[0035] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below. If specific conditions are not indicated in the embodiments, the conventional conditions or the conditions suggested by the manufacturers are adopted. If the manufacturers of the reagents or instruments are not indicated, the conventional products that can be obtained by market purchase are adopted.

[0036] The oxide solid electrolyte, the preparation method thereof and the all-solid-state battery according to the embodiments of the present application will be described in detail below.

[0037] The oxide solid electrolyte according to the embodiments of the present application has a chemical formula of A a-b M b X c Ti 2-c Z d P 3-d O eWhere a = 1 to 2, b = 0 to 1, c = 0 to 1, d = 0 to 1.5, e = (12-d) to 12; A includes any one of Li, Na and K; M includes one or more of Na, K, Rb, Cs, Be, Mg, Ca, Sr and Ba; X includes one or more of Al, Ga, In, La, Y, Sc, Fe and Cr; Z includes one or more of B, S, Si, V, Tc, Re, As, Xe, W, Se, Nb and Mn; where A and M are not the same, and b, c and d are not simultaneously 0.

[0038] This application is approved because: 1. Introducing ions with larger atomic radii (such as Na, K, etc.) into the Li site can effectively increase the lattice constant, thus improving the Li... + It provides a wider diffusion channel, thereby lowering the ion migration barrier and promoting Li + 1. Rapid migration in electrolytes; 2. Partial substitution of Ti ions with low-valent cations (such as Al, Ga, etc.) to increase the concentration of Li or Na vacancies in the crystal lattice, thereby accelerating the lithium ion migration rate and further improving ionic conductivity; 3. Employing other polyanions with -3, -4, or -5 valence (such as BO3) 3- SiO4 4- SO4 4- (etc.) partially replaces the traditional -3 valent PO4 3- This not only increases the concentration of Li or Na in the crystal lattice, but also enhances the stability of the crystal structure and improves the ionic conductivity due to the introduction of high-valence anions; in other words, through the synergistic effect of multi-ion doping, it achieves a conductivity exceeding 1 mS / cm at room temperature. -1 It has ultra-high ionic conductivity.

[0039] When A represents Li, Na, and K respectively, the chemical formula of the oxide solid electrolyte is Li a- b M b X c Ti 2-c Z d P 3-d O 12 Na a-b M b X c Ti 2-c Z d P 3-d O 12 and K a-b M b X c Ti 2-c Z d P 3-d O 12wherein M comprises one or more of K, Rb, Cs, Be, Mg, and Ca; X comprises one or more of Al, Ga, In, La, Y, Sc, Fe, and Cr; Z comprises one or more of S, Si, V, Nb, W, Se, and Mn; or, when A is Li, Na, and K, respectively, the chemical formula of the oxide solid electrolyte is Li a-b M b X c Ti 2-c Z d P 3-d O 12-d , Na a-b M b X c Ti 2-c Z d P 3-d O 12-d and K a-b M b X c Ti 2-c Z d P 3- d O 12-d , Z comprises B.

[0040] For example, the oxide solid electrolyte comprises Li a Al c Ti 2-c (PO4) 3-d (ZO4) d , Na a Al c Ti 2-c (PO4) 3-d (ZO4) d and K a Al c Ti 2-c (PO4) 3-d (ZO4) d wherein a = 1-2, c = 0-1, d = 0-1.5, Z comprises one or more of S, Si, V, and Nb; or, the oxide solid electrolyte comprises Li a Al c Ti 2-c (PO4) 3-d (ZO3) d , Na a Al c Ti 2-c (PO4) 3-d (ZO3) d and K a Al c Ti2-c (PO4) 3-d (ZO3) d Any one of the above, wherein a = 1-2, c = 0-1, d = 0-1.5, and Z comprises B.

[0041] Specifically, as an example, the oxide solid-state electrolyte comprises Li 1.44 Al 0.5 Ti 1.5 (PO4) 2.94 (SO4) 0.06 , Li 1.35 Al 0.5 Ti 1.5 (PO4) 2.85 (SO4) 0.15 , Li 1.51 Al 0.5 Ti 1.5 (PO4) 2.99 (SiO4) 0.01 , Li 1.53 Al 0.5 Ti 1.5 (PO4) 2.97 (SiO4) 0.03 , Li 1.55 Al 0.5 Ti 1.5 (PO4) 2.95 (SiO4) 0.05 , Li 1.5 Al 0.5 Ti 1.5 (PO4)3, Li 1.5 Al 0.5 Ti 1.5 (PO4) 2.85 (BO3) 0.15 , and Li 1.5 Al 0.5 Ti 1.5 (PO4) 2.95 (BO3) 0.05 Any one of the above.

[0042] The preparation method of the oxide solid-state electrolyte is described below.

[0043] A preparation method of an oxide solid-state electrolyte, comprising: mixing and reacting a titanium source compound with a catalyst to obtain a solution containing TiO 2+ , and then adding a complexing agent, A2CO3, a M source compound, an X source compound, NH4H2PO4, and a Z source compound to the solution containing TiO 2+The preparation method of the oxide solid electrolyte material includes the following steps: adding a titanium source compound, a X source compound, and a Z source compound into a solution, and stirring to form a sol; drying the sol, and then sequentially performing ball milling, molding treatment, and sintering to obtain the oxide solid electrolyte; wherein the titanium source compound includes MCO3, the X source compound includes XNO3, and the Z source compound includes AZO4 and / or H3BO3, wherein A includes any one of Li, Na, and K elements; M includes one or more of Na, K, Rb, Cs, Be, Mg, Ca, Sr, and Ba elements; X includes one or more of Al, Ga, In, La, Y, Sc, Fe, and Cr elements; and Z includes one or more of S, Si, V, Tc, Re, As, Xe, W, Se, Nb, and Mn elements.

[0044] In the preparation method, the titanium source compound is reacted with a catalyst to generate a TiO 2+ containing solution, and a complexing agent and other compounds are added, and stirring is performed to form a uniform sol, and then the sol is subjected to ball milling and sintering treatment to obtain an oxide solid electrolyte material with high ionic conductivity.

[0045] The titanium source compound includes but is not limited to C 12 H 28 O4Ti; the catalyst includes but is not limited to HNO3; and the complexing agent includes but is not limited to citric acid.

[0046] For example, the preparation method of Li a-b M b X c Ti 2-c Z d P 3-d O 12 includes the following steps:

[0047] C 12 H 28 O4Ti is added into deionized water, and stirring immediately generates Ti(OH)4precipitate, after water washing and filtration, a small amount of deionized water is added into the Ti(OH)4precipitate, and an appropriate amount of concentrated HNO3 is added to generate TiO 2+After the precipitate is completely dissolved, a citric acid stabilizing solution is immediately added. Then Na2CO3, MCO3, XNO3 are added, after complete dissolution by stirring, NH4H2PO4, NaZO4 are added again, and a sol is formed after stirring for half an hour. Then the dried material is placed in a ball mill tank at a material to bead ratio of 1: (5-10) and an appropriate amount of alcohol is added for wet ball milling, with parameters set to 300-400 r / min and 24-48 h. Then the ball-milled sample is dried, ground, and pressed into a tablet, the pressed tablet is placed in an alumina crucible, and sintering is performed in a muffle furnace, with a temperature increasing rate of 5-10 ℃ / min to 550-600 ℃, holding for 1-3 h, then continuously increasing the temperature to 950-1050 ℃, holding for 5-6 h, and then naturally cooling to obtain the target product.

[0048] As an example, Na a-b M b X c Ti 2-c Z d P 3-d O 12 The preparation method comprises the following steps:

[0049] C 12 H 28 O4Ti is added to deionized water, and Ti (OH) 4 precipitate is immediately formed by stirring. After water washing and filtration, a small amount of deionized water is added to the Ti (OH) 4 precipitate, and an appropriate amount of concentrated HNO3 is added to generate TiO 2+ After the precipitate is completely dissolved, a citric acid stabilizing solution is immediately added. Then Na2CO3, MCO3, XNO3 are added, after complete dissolution by stirring, NH4H2PO4, NaZO4 are added again, and a sol is formed after stirring for half an hour. Then the dried material is placed in a ball mill tank at a material to bead ratio of 1: (5-10) and an appropriate amount of alcohol is added for wet ball milling, with parameters set to 300-400 r / min and 24-48 h. Then the ball-milled sample is dried, ground, and pressed into a tablet, the pressed tablet is placed in an alumina crucible, and sintering is performed in a muffle furnace, with a temperature increasing rate of 5-10 ℃ / min to 550-600 ℃, holding for 1-3 h, then continuously increasing the temperature to 950-1050 ℃, holding for 5-6 h, and then naturally cooling to obtain the target product.

[0050] As an example, K a-b M b X c Ti 2-c Z d P 3-d O 12 The preparation method comprises the following steps:

[0051] C 12 H 28 O4Ti is added into deionized water, and Ti(OH)4 precipitate is immediately generated by stirring. After water washing and filtration, a small amount of deionized water is added into the Ti(OH)4 precipitate, and an appropriate amount of concentrated HNO3 is added to generate TiO 2+ After the precipitate is completely dissolved, a citric acid stabilizing solution is immediately added. Then, K2CO3, MCO3, and XNO3 are added, and after stirring and complete dissolution, NH4H2PO4 and KZO4 are added. After stirring for half an hour, a sol is formed. Then, the dried material is placed in a ball mill tank at a material-to-bead ratio of 1:5-10 and an appropriate amount of alcohol is added for wet ball milling. The parameters are set to 300-400 r / min and 24-48 h. After the ball milling is completed, the sample is dried, ground, and pressed into a tablet. The pressed tablet is placed in an alumina crucible and sintered in a muffle furnace at a heating rate of 5-10 ℃ / min to 550-600 ℃, and then held for 1-3 h. Then, the temperature is continuously increased to 950-1050 ℃, and held for 5-6 h before natural cooling to obtain the target product.

[0052] For example, MCO3 includes but is not limited to Na2CO3, K2CO3, Rb2CO3, Cs2CO3, BeCO3, MgCO3, CaCO3, SrCO3, and BaCO3. XNO3 includes but is not limited to Al(NO3)3, Ga(NO3)3, In(NO3)3, La(NO3)3, Y(NO3)3, Sc(NO3)3, and Fe(NO3)3. LiZO4 includes but is not limited to Li2SO4, Li4SiO4, Li3VO4, LiTcO4, Li2ReO4, Li3AsO4, LiXeO4, Li2WO4, Li2SeO4, and LiMn2O4.

[0053] The features and performance of the present application are further described in detail below in conjunction with the examples.

[0054] Example 1

[0055] This example provides an oxide solid-state electrolyte with a chemical formula of Li 1.44 Al 0.5 Ti 1.5 (PO4) 2.94 (SO4) 0.06 The preparation method includes the following steps:

[0056] 2.8 g of C 12 H 28O4Ti was added into 18 mL deionized water, and Ti(OH)4precipitate was immediately formed by stirring. After water washing and filtration, 8 mL deionized water was added into the Ti(OH)4precipitate, and 1.75 mL concentrated HNO3 was added to form TiO 2+ After the precipitate was completely dissolved, 4.3 g of a citric acid stabilizing solution was immediately added. Then, 0.37 g of Li2CO3 and 1.23 g of Al(NO3)3·9H2O were added, and after complete dissolution by stirring, 2.22 g of NH4H2PO4 and 0.043 g of Li2SO4 were added. After stirring for half an hour, a sol was formed. Then, the dried material was placed in a ball mill tank at a material-to-bead ratio of 1:10 and an appropriate amount of alcohol was added for wet ball milling at a rotation speed of 400 r / min for 24 h. After ball milling, the milled sample was dried, ground, and pressed into a tablet. The pressed tablet was placed in an alumina crucible and sintered in a muffle furnace at a temperature increasing rate of 10 ℃ / min to 600 ℃, and then held for 1 h. After that, the temperature was continuously increased to 950 ℃, and then held for 5 h before natural cooling to obtain the target product.

[0057] Example 2

[0058] This example provides an oxide solid-state electrolyte with a chemical formula of Li 1.35 Al 0.5 Ti 1.5 (PO4) 2.85 (SO4) 0.15 , and a preparation method thereof includes the following steps:

[0059] 2.8 g of C 12 H 28 O4Ti was added into 18 mL deionized water, and Ti(OH)4precipitate was immediately formed by stirring. After water washing and filtration, 8 mL deionized water was added into the Ti(OH)4precipitate, and 1.75 mL concentrated HNO3 was added to form TiO 2+ After the precipitate was completely dissolved, 4.3 g of a citric acid stabilizing solution was immediately added. Then, 0.37 g of Li2CO3 and 1.23 g of Al(NO3)3·9H2O were added, and after complete dissolution by stirring, 2.22 g of NH4H2PO4 and 0.043 g of Li2SO4 were added. After stirring for half an hour, a sol was formed. Then, the dried material was placed in a ball mill tank at a material-to-bead ratio of 1:10 and an appropriate amount of alcohol was added for wet ball milling at a rotation speed of 400 r / min for 24 h. After ball milling, the milled sample was dried, ground, and pressed into a tablet. The pressed tablet was placed in an alumina crucible and sintered in a muffle furnace at a temperature increasing rate of 10 ℃ / min to 600 ℃, and then held for 1 h. After that, the temperature was continuously increased to 950 ℃, and then held for 5 h before natural cooling to obtain the target product.

[0060] Example 3

[0061] This example provides a kind of oxide solid electrolyte, chemical formula is Li 1.51 Al 0.5 Ti 1.5 (PO4) 2.99 (SiO4) 0.01 Its preparation method includes the following steps:

[0062] 2.8g C 12 H 28 O4Ti is added to 18mL deionized water, and Ti (OH) 4 Precipitate is immediately generated by stirring, after water washing and filtration, 8mL deionized water is added to Ti (OH) 4 Precipitate, and 1.75mL concentrated HNO3 is added to generate TiO 2+ After the precipitate is completely dissolved, 4.3g citric acid stabilizing solution is immediately added. Then 0.392g Li2CO3 and 1.23g Al (NO3) 3 ·9H2O are added, and after stirring and completely dissolving, 2.258g NH4H2PO4 and 0.0079g Li4SiO4 are added, and after stirring for half an hour, sol is formed. Then dry at 150 DEG C for 12h, put the dried material into a ball mill tank with a material bead ratio of 1:10 and add appropriate amount of alcohol for wet ball milling, and the parameter is set to 400rpm and 24h. After ball milling, the sample is dried, ground and pressed into a tablet, the pressed tablet is placed in an alumina crucible, and sintering is carried out in a muffle furnace, with a temperature rising rate of 10 DEG C / min to 600 DEG C, and holding for 1h, then continue to rise to 950 DEG C, and hold for 5h, then naturally cool to obtain the target product.

[0063] Example 4

[0064] This example provides a kind of oxide solid electrolyte, chemical formula is Li 1.53 Al 0.5 Ti 1.5 (PO4) 2.97 (SiO4) 0.03 Its preparation method includes the following steps:

[0065] 2.8g C 12 H 28 O4Ti is added to 18mL deionized water, and Ti (OH) 4 Precipitate is immediately generated by stirring, after water washing and filtration, 8mL deionized water is added to Ti (OH) 4 Precipitate, and 1.75mL concentrated HNO3 is added to generate TiO 2+After the precipitate is completely dissolved, 4.3 g of a citric acid stabilizing solution is immediately added. Then, 0.376 g of Li2CO3 and 1.23 g of Al(NO3)3·9H2O are added, and after complete dissolution by stirring, 2.243 g of NH4H2PO4 and 0.0236 g of Li4SiO4 are added, and a sol is formed after stirring for half an hour. Then, drying is performed at 150°C for 12 h, and the dried material is placed in a ball mill tank at a material-to-bead ratio of 1:10 and an appropriate amount of alcohol is added for wet ball milling, with parameters set to 400 rpm and 24 h. Then, the ball-milled sample is dried, ground, and pressed into a tablet, the pressed tablet is placed in an alumina crucible, and sintering is performed in a muffle furnace, with a temperature increasing rate of 10°C / min to 600°C, holding for 1 h, then continuously increasing the temperature to 950°C, holding for 5 h, and then naturally cooling to obtain the target product.

[0066] Example 5

[0067] This example provides an oxide solid-state electrolyte with a chemical formula of Li 1.55 Al 0.5 Ti 1.5 (PO4) 2.95 (SiO4) 0.05 , and a preparation method thereof includes the following steps:

[0068] 2.8 g of C 12 H 28 O4Ti is added to 18 mL of deionized water, and Ti(OH)4precipitate is immediately formed by stirring. After water washing and filtration, 8 mL of deionized water is added to the Ti(OH)4precipitate, and 1.75 mL of concentrated HNO3 is added to form TiO 2+ After the precipitate is completely dissolved, 4.3 g of a citric acid stabilizing solution is immediately added. Then, 0.376 g of Li2CO3 and 1.23 g of Al(NO3)3·9H2O are added, and after complete dissolution by stirring, 2.243 g of NH4H2PO4 and 0.0236 g of Li4SiO4 are added, and a sol is formed after stirring for half an hour. Then, drying is performed at 150°C for 12 h, and the dried material is placed in a ball mill tank at a material-to-bead ratio of 1:10 and an appropriate amount of alcohol is added for wet ball milling, with parameters set to 400 rpm and 24 h. Then, the ball-milled sample is dried, ground, and pressed into a tablet, the pressed tablet is placed in an alumina crucible, and sintering is performed in a muffle furnace, with a temperature increasing rate of 10°C / min to 600°C, holding for 1 h, then continuously increasing the temperature to 950°C, holding for 5 h, and then naturally cooling to obtain the target product.

[0069] Example 6

[0070] This example provides an oxide solid-state electrolyte with a chemical formula of Li 1.5 Al 0.5 Ti 1.5LiTi2(PO4)3, the preparation method comprising the following steps:

[0071] 2.8 g of C 12 H 28 Ti(OH)4precipitate was immediately formed by stirring. After water washing and filtration, 8 mL of deionized water was added to the Ti(OH)4precipitate, and 1.75 mL of concentrated HNO3was added to generate TiO 2+ After the precipitate was completely dissolved, 4.3 g of a citric acid stabilizing solution was immediately added. Then, 0.4 g of Li2CO3and 1.23 g of Al(NO3)3·9H2O were added, and after complete dissolution by stirring, 2.267 g of NH4H2PO4was added. After stirring for half an hour, a sol was formed. Then, the dried material was placed in a ball mill tank at a material-to-bead ratio of 1:10 and an appropriate amount of alcohol was added for wet ball milling. The ball milling speed was 400 r / min, and the ball milling time was 24 h. Then, the ball-milled sample was dried, ground, and pressed into a tablet. The pressed tablet was placed in an alumina crucible and sintered in a muffle furnace. The temperature was raised to 600°C at a rate of 10°C / min, and the temperature was maintained for 1 h. Then, the temperature was continuously raised to 950°C, and the temperature was maintained for 5 h before natural cooling to obtain the target product.

[0072] Comparative Example 2

[0073] The present comparative example provides an oxide solid-state electrolyte with a chemical formula of LiTi2(PO4)3, the preparation method comprising the following steps:

[0074] 3.73 g of C 12 H 28 Ti(OH)4precipitate was immediately formed by stirring. After water washing and filtration, 11 mL of deionized water was added to the Ti(OH)4precipitate, and 2.33 mL of concentrated HNO3was added to generate TiO 2+ After the precipitate was completely dissolved, 5.7 g of a citric acid stabilizing solution was immediately added. Then, 0.27 g of Li2CO3was added, and after complete dissolution by stirring, 2.267 g of NH4H2PO4was added. After stirring for half an hour, a sol was formed. Then, the dried material was placed in a ball mill tank at a material-to-bead ratio of 1:10 and an appropriate amount of alcohol was added for wet ball milling. The ball milling speed was 400 r / min, and the ball milling time was 24 h. Then, the ball-milled sample was dried, ground, and pressed into a tablet. The pressed tablet was placed in an alumina crucible and sintered in a muffle furnace. The temperature was raised to 600°C at a rate of 10°C / min, and the temperature was maintained for 1 h. Then, the temperature was continuously raised to 950°C, and the temperature was maintained for 5 h before natural cooling to obtain the target product.

[0075] The preparation methods of the above embodiments and comparative examples are basically the same, the difference being that the prepared oxide solid electrolytes are different. For some parameters, please refer to Table 1.

[0076] Table 1

[0077] Group Oxide solid state electrolyte Example 1 Li 1.44 Al 0.5 Ti 1.5 (PO4) 2.94 (SO4) 0.06 ]]> Example 2 Li 1.35 Al 0.5 Ti 1.5 (PO4) 2.85 (SO4) 0.15 ]]> Example 3 Li 1.51 Al 0.5 Ti 1.5 (PO4) 2.99 (SiO4) 0.01 ]]> Example 4 Li 1.53 Al 0.5 Ti 1.5 (PO4) 2.97 (SiO4) 0.03 ]]> Example 5 Li 1.55 Al 0.5 Ti 1.5 (PO4) 2.95 (SiO4) 0.05 ]]> Example 6 Li 1.5 Al 0.5 Ti 1.5 (PO4)3]]> Comparative Example LiTi2(PO4)3

[0078] Experimental Example 1

[0079] I. In this experimental example, the molecular structures of the oxide solid electrolytes prepared in Examples 1-2 and 6 were determined. Figure 1 For Li 1.5 Al 0.5 Ti 1.5 (PO4)3 doped SO4 2- XRD patterns before and after. Figure 2 For Li 1.5 Al 0.5 Ti 1.5 (PO4)3-doped SiO4 4- Please refer to the XRD patterns before and after. Figure 1 and Figure 2 .

[0080] from Figure 1 As can be seen, by comparing the XRD diffraction peak positions of the doped sample and the original sample, we can see that the doped SO4... 2- This causes the diffraction peaks to shift towards a direction with a larger 2θ, and the shift increases with the doping ratio. This is because SO4 2- The ionic radius is smaller than that of PO4. 3- The ionic radius of SO4 2- Replace PO4 3- When the position is changed, the cell parameter will decrease, which will increase 2θ, and the corresponding diffraction peak will shift towards the direction where 2θ is larger.

[0081] from Figure 2 EDS elemental analysis showed that sulfur (S) was uniformly distributed within the sample, proving that SO42-... 2- Successfully doped with Li 1.5 Al 0.5 Ti 1.5 (PO4)3.

[0082] Figure 3 For Li 1.5 Al 0.5 Ti 1.5 (PO4)3-doped SiO4 4- Please refer to the XRD patterns before and after. Figure 3 By comparing the XRD diffraction peak positions of the doped sample and the original sample, it can be seen that the doped SiO4 4-The diffraction peaks are all shifted to the direction of smaller 2θ, and the shift is more with the increase of doping ratio. This is because the ionic radius of SiO4 4- is larger than that of PO4 3- . When SiO4 4- replaces PO4 3- , the lattice parameter becomes larger, and thus 2θ becomes smaller, and the corresponding diffraction peak is shifted to the direction of smaller 2θ.

[0083] Figure 4 The XRD patterns of LiTi2(PO4)3 doped with Al 3+ before and after are shown in Figure 4 . By comparing the XRD diffraction peak positions of the doped sample and the original sample, it can be seen that doping Al 3+ causes the diffraction peaks to be shifted to the direction of larger 2θ, and the shift is more with the increase of doping ratio. This is because the ionic radius of Al 3+ is smaller than that of Ti 4+ . When Al 3+ replaces Ti 4+ , the lattice parameter becomes smaller, and thus 2θ becomes larger, and the corresponding diffraction peak is shifted to the direction of larger 2θ.

[0084] Test Example 2

[0085] In this test example, the oxide solid electrolytes prepared in Examples 1-6 and Comparative Examples were subjected to ion conductivity and electrochemical impedance tests,

[0086] Among them, the ion conductivity was determined: in the temperature range of 25-120℃, every 20℃ was taken as a data collection point, and the solid electrolyte was tested by electrochemical impedance spectroscopy (EIS). After temperature change, the test mold needs to be heat treated for 1h to ensure that the electrolyte temperature is stable. After measuring the impedance of the solid electrolyte, its ion conductivity at different temperatures was calculated according to formula 1-1:

[0087]

[0088] Where σ is the ion conductivity (S cm -1 ), d and S are the thickness (cm) and area (cm 2 ) of the solid electrolyte sheet, respectively, and Z is the total impedance of the electrolyte measured (Ω). After obtaining the lithium ion conductivity of the solid electrolyte at different temperatures, the activation energy of lithium ion conduction can be calculated by Arrhenius formula 1-2:

[0089]

[0090] Where E awhere A0 is the activation energy for lithium ion conduction, A0 is a constant, k is the Boltzmann constant, and T is the temperature in Kelvin.

[0091] Electrochemical impedance measurement: Electrochemical impedance spectroscopy is a common technique for measuring the impedance of solid state electrolytes. It mainly measures the phase angle of impedance as a function of the frequency of a small amplitude AC potential wave applied to both sides of the solid state electrolyte, thereby obtaining the impedance spectrum at different frequencies. The results of impedance measurement are shown by Nyquist plot, where the x-axis represents the real part of impedance, and the y-axis represents the absolute value of the imaginary part of impedance. Impedance Z(w) is shown by equation 1-3:

[0092] Z(w) = Z Re -jZ Im (1-3)

[0093] where Z Re is the real part of impedance, Z Im is the imaginary part of impedance, and j represents the phase factor. In this experiment, the EC-lab electrochemical workstation produced by France Bio-logic was used to test the impedance spectrum of the solid state electrolyte, the frequency was set to 7Mhz-1hz, and the voltage amplitude was 10mV.

[0094] The results of the above items are shown in Table 2.

[0095] Table 2

[0096]

[0097] As can be seen from Table 2, the present application can significantly improve the ion conductivity and reduce the impedance by doping the key lattice sites of A a-b M b X c Ti 2-c Z d P 3-d O 12

[0098] Figure 5 Li 1.5 Al 0.5 Ti 1.5 (PO4)3-doped SO4 2- The room temperature electrochemical impedance spectra before and after, please refer to Figure 5 By comparing the electrochemical impedance of the doped sample and the original sample, it can be seen that the electrochemical impedance decreases continuously with the increase of the doping ratio of SO4 2- doping, indicating that SO4 2- doping can improve the ion conductivity.

[0099] Figure 6 Li 1.5 Al​0.5 Ti 1.5 (PO4)3doped SiO4 4- The room temperature electrochemical impedance spectra before and after doping, please refer to Figure 6 By comparing the electrochemical impedance of the doped sample with the original sample, it can be seen that the electrochemical impedance is continuously reduced with the increase of the doping ratio of SiO4 4- , indicating that SiO4 4- doping can improve the ionic conductivity.

[0100] Figure 7 LiTi2(PO4)3doped with Al 3+ The room temperature electrochemical impedance spectra before and after doping, please refer to Figure 7 By comparing the electrochemical impedance of the doped sample with the original sample, it can be seen that the electrochemical impedance is continuously reduced with the increase of the doping ratio of Al 3+ , indicating that Al 3+ doping can improve the ionic conductivity.

[0101] The above-described embodiments are part of the embodiments of the present application, rather than all the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.

Claims

1. An oxide solid state electrolyte, characterized by, The oxide solid electrolyte is Li a Al c Ti 2-c (PO4) 3-d (ZO4) d , Na a Al c Ti 2-c (PO4) 3-d (ZO4) d , and K a Al c Ti 2-c (PO4) 3-d (ZO4) d ; wherein a = 1-2, 0 < c ≤ 1, 0 < d ≤ 1.5, and Z is S.

2. The oxide solid state electrolyte of claim 1, wherein, The oxide solid state electrolyte is Li 1.44 Al 0.5 Ti 1.5 (PO4) 2.94 (SO4) 0.06 and Li 1.35 Al 0.5 Ti 1.5 (PO4) 2.85 (SO4) 0.15 any one of 3. A method for producing the oxide solid electrolyte as claimed in claim 1 or 2, characterized by, The sol is dried, and then sequentially subjected to ball milling, molding treatment and sintering to obtain the oxide solid electrolyte. The titanium source compound is mixed with the catalyst to obtain a solution containing TiO 2+ , and then the complexing agent, A2CO3, the aluminum source compound, NH4H2PO4, and the Z source compound are added to the solution containing TiO 2+ , and stirred to form a sol. The sintering comprises: heat preservation treatment at 550-600 DEG C, and then heat preservation treatment at 950-1050 DEG C. The Al source compound comprises Al (NO3) 3, and the Z source compound comprises A2ZO4, wherein A comprises any one of Li, Na and K elements, and Z is S. The catalyst comprises HNO3.

4. The production method according to claim 3, characterized by, The titanium source compound includes C 12 H 28 O4Ti.

5. The preparation method according to claim 4, characterized in that, The complexing agent comprises citric acid.

6. The preparation method according to claim 3, characterized in that, The drying comprises: a drying temperature of 100-150 DEG C, and a drying time of 12-24h.

7. The production method according to any one of claims 3 to 6, characterized by, The ball milling comprises: a mass ratio of the ball-milled raw material to the ball-milling beads of 1: (5-10), and / or a ball-milling rotation speed of 300-400 r / min, and a ball-milling time of 24-48h.

8. The production method according to any one of claims 3 to 6, characterized by, The sintering comprises: heating at a heating rate of 5-10 DEG C / min to 550-600 DEG C, heat preservation for 1-3h, then continue to heat to 950-1050 DEG C, heat preservation for 5-6h, and then natural cooling.

9. The production method according to any one of claims 3 to 6, characterized by, The oxide solid electrolyte according to claim 1 or 2.

10. An all-solid battery, characterized by, ​

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